JP7104082B2 - Test equipment and test method - Google Patents

Description

The present invention relates to a test device and a test method for measuring transmission characteristics or reception characteristics of an object to be tested using an anechoic box in an OTA (Over The Air) environment.

In recent years, with the development of multimedia, wireless terminals (smartphones, etc.) equipped with antennas for wireless communication such as cellular and wireless LAN have been actively produced. In the future, in particular, wireless terminals that transmit and receive wireless signals compatible with IEEE802.11ad and 5G cellular, which use wideband signals in the millimeter wave band, are required.

At a wireless terminal design / development company or its manufacturing plant, the output level and reception sensitivity of transmitted radio waves specified for each communication standard are measured for the wireless communication antenna provided in the wireless terminal, and these RFs (Radio) are used. Frequency) A performance test is performed to determine whether the characteristics meet a predetermined standard. In the performance test, RRM (Radio Resource Management) characteristics are also measured. The measurement of the RRM characteristic is performed in order to confirm whether or not the radio resource control between the base station and the wireless terminal, for example, the handover between the adjacent base stations, etc. operates correctly.

With the transition of generations from 4G or 4G advance to 5G, the test method of the above-mentioned performance test is also changing. For example, in a performance test in which a wireless terminal for a 5G NR system (New Radio System) (hereinafter referred to as a 5G wireless terminal) is a subject to be tested (Device Under Test: DUT), tests such as 4G and 4G advance are the mainstream. As for the method of connecting the antenna terminal of the DUT and the test device by wire, it is necessary to attach the antenna terminal to the high frequency circuit to deteriorate the characteristics, or to attach the antenna terminal to all the elements due to the large number of array antenna elements. It cannot be used because it is not realistic in consideration of the aspect. Therefore, the DUT is housed together with the test antenna in an anechoic box that is not affected by the surrounding radio wave environment, and the test signal is transmitted from the test antenna to the DUT and the test signal from the DUT that receives the test signal is tested. A so-called OTA test is performed in which reception by an antenna is performed by wireless communication (see, for example, Patent Document 1 and Patent Document 2).

In the OTA test, a quiet zone is formed by the test antenna, and the DUT is arranged in the quiet zone. Here, the quiet zone is a concept representing the range of the spatial region in which the DUT is irradiated with radio waves having substantially uniform amplitude and phase from the test antenna in the radio wave anechoic box constituting the OTA test environment (the quiet zone). For example, see Non-Patent Document 1). The shape of the quiet zone is usually spherical. By arranging the DUT in such a quiet zone, it becomes possible to perform the OTA test in a state where the influence of scattered waves from the surroundings is suppressed.

Japanese Patent Application No. 2018-223942 US2019 / 0302184

3GPP TR 38.810 V16.2.0 (2019-03)

In the test apparatus described in Patent Document 2, a plurality of test antennas capable of transmitting and receiving to and from the DUT's test antenna are provided in the anechoic box, and the RF characteristics and RRM characteristics of the DUT are measured. In the measurement of RF characteristics and RRM characteristics, far field measurement (FFM (Far Field Measurement)) is generally used. Each of the test antennas of Patent Document 2 is provided with a reflector so that the radio wave radiated from the test antenna is reflected toward the DUT or the radio wave radiated from the DUT is reflected toward the test antenna. However, in the test apparatus described in Patent Document 2, since each test antenna is provided with a reflector, the structure is complicated, and a large installation area for installing an anechoic box is required. rice field. In addition, a mechanism for moving the test antenna is required, and the configuration of the signal processing unit connected to the plurality of test antennas is complicated, resulting in high cost.

The present invention has been made to solve such a conventional problem, and is a test capable of performing far-field measurement of transmission / reception characteristics such as RF characteristics and RRM characteristics of an object to be tested at low cost. It is an object of the present invention to provide an apparatus and a test method.

In order to solve the above problems, the test apparatus according to the present invention is a test apparatus (1) that measures the transmission characteristic or the reception characteristic of the subject (100) to be tested having the antenna (110) to be tested, and is a peripheral test apparatus (1). An anechoic box (50) having an internal space (51) that is not affected by the radio wave environment, and a radio signal accommodated in the internal space for measuring transmission characteristics or reception characteristics of the test object are subjected to the test antenna. A plurality of test antennas (6) transmitted or received between them, a posture variable mechanism (56) arranged in a quiet zone (QZ) in the internal space, and a posture variable mechanism (56) arranged in the quiet zone (QZ) in the internal space, and the posture variable. A plurality of measuring devices (2) for measuring transmission characteristics or reception characteristics of the test object by using the test antenna for the test object whose posture is changed by a mechanism. The test antenna is a reflection type test antenna (6a) that transmits or receives a radio signal to and from the test antenna via a reflector (7), and a radio signal directly between the test antenna. The measuring device includes a plurality of direct type test antennas (6b, 6c, 6d, 6e, 6f) that transmit or receive, and the measuring device is a frequency of a signal transmitted as a radio signal by the plurality of test antennas. The signal processing unit (40) that converts the frequency of the radio signal received by the plurality of test antennas, and the plurality of signal paths between the signal processing unit and the plurality of direct type test antennas. The configuration includes a test antenna of one of the direct type test antennas and a switching unit (141) for switching to a signal path to which the signal processing unit is connected.

As described above, the measuring device sets the signal path between the signal processing unit and the plurality of direct type test antennas with one test antenna used among the plurality of direct type test antennas and signal processing. It is equipped with a switching unit that switches to a signal path to which the unit is connected. With this configuration, the number of signal processing units is significantly reduced as compared with the conventional one in which signal processing units are provided for each of the plurality of test antennas, so that cost reduction and space saving can be realized.

Moreover, the plurality of test antennas have a hybrid configuration including a reflection type test antenna that indirectly transmits and receives radio signals using a reflector and a plurality of direct type test antennas that directly transmit and receive radio signals. It has become. This minimizes the number of reflective test antennas with complex structures, while using a single reflective test antenna that can form a relatively wider quiet zone than direct test antennas. In some cases, a large quiet zone is available. In addition, the direct test antenna does not use a reflector, which saves installation space. Therefore, the test apparatus according to the present invention can perform far-field measurement of transmission / reception characteristics such as RF characteristics and RRM characteristics of the test object at low cost.

Further, in the test apparatus according to the present invention, the signal processing unit uses the frequency of the signal transmitted as a radio signal by the reflection type test antenna or the frequency of the radio signal received by the reflection type test antenna. The frequency of the signal transmitted as a radio signal by the first frequency conversion unit (144) for converting the above and the direct type one test antenna switched by the switching unit, or the direct type for the one test. The configuration may include a second frequency conversion unit (145) that converts the frequency of the radio signal received by the antenna.

With this configuration, the test apparatus according to the present invention is provided with a first frequency conversion unit for the reflection type test antenna and a second frequency conversion unit for the direct type one test antenna. Therefore, it is possible to measure the RRM characteristics and the like by using the reflection type test antenna and the direct type one test antenna.

Further, in the test apparatus according to the present invention, the first frequency conversion unit includes a first transmission converter (146) that up-converts a signal transmitted as a radio signal from the reflection type test antenna, and the reflection. A first receiving converter (147) that down-converts a radio signal received by a type test antenna is provided, and the second frequency converter is used as a radio signal from the plurality of direct type test antennas. A second transmission converter (148) for up-converting the transmitted signal and a second reception converter (149) for down-converting the radio signal received by the plurality of direct type test antennas are provided. The first transmission converter includes a first upconverter (150) that up-converts a signal transmitted as a horizontally polarized radio signal from the reflection type test antenna, and a vertical bias from the reflection type test antenna. The first receiving converter includes a second upconverter (151) that up-converts a signal transmitted as a wave radio signal, and the first receiving converter transmits a horizontally polarized radio signal received from the reflection type test antenna. The second transmission converter includes a first down converter (154) for down-converting and a second down converter (155) for down-converting a vertically polarized radio signal received from the reflection type test antenna. Is a third upconverter (152) that up-converts a signal transmitted as a horizontally polarized radio signal from the plurality of direct type test antennas, and vertically polarized from the plurality of direct type test antennas. The second receiving converter includes a fourth upconverter (153) that up-converts a signal transmitted as a radio signal, and the second receiving converter transmits a horizontally polarized radio signal received from the plurality of direct type test antennas. Even in a configuration including a third down converter (156) for down-converting and a fourth down converter (157) for down-converting a vertically polarized radio signal received from the plurality of direct type test antennas. good.

With this configuration, the test apparatus according to the present invention can use the test antenna for both transmission and reception, so that the transmission characteristics and reception characteristics of the test object can be measured. Further, the transmission / reception characteristics such as the RRM characteristics of the test object can be measured by using the horizontally polarized signals and the vertically polarized signals.

Further, in the test apparatus according to the present invention, the plurality of direct type test antennas are different from each other at the arrangement position ( _PDUT ) of the test object with respect to the radio wave arrival direction from the reflection type test antenna. It may be configured to form an arrival angle.

With this configuration, the test apparatus according to the present invention has a different arrival angle depending on the combination of the reflection type test antenna and the direct type test antenna. Therefore, the arrival angle is changed by switching the direct type test antenna. It is possible to efficiently measure the transmission / reception characteristics such as the RRM characteristics of the test device in the far field.

Further, in the test apparatus according to the present invention, the plurality of direct type test antennas may be arranged at least 2D ² / λ away from the test antenna, where D is the subject. The antenna size of the test antenna, λ, is the wavelength of the radio wave transmitted from the plurality of direct type test antennas.

With this configuration, in the test apparatus according to the present invention, since the direct type test antenna is arranged at least 2D ² / λ away from the antenna to be tested, it is located far away from the object to be tested in an anechoic box having a small internal space. Field measurement can be performed.

Further, in the test apparatus according to the present invention, the plurality of direct type test antennas are arranged outside the path of the radio wave beam passing through the quiet zone by reflecting the reflector of the reflection type test antenna. It may be.

With this configuration, the test apparatus according to the present invention can form a good quiet zone.

Further, the test method according to the present invention is a test method using the test apparatus according to any one of the above, and the test antenna and the signal of one of the plurality of direct type test antennas are provided by the switching unit. A step of switching to a signal path to which the processing unit is connected, a step of changing the posture of the object to be tested arranged in the quiet zone by the posture variable mechanism, and a step of changing the posture by the posture variable mechanism. A step of measuring the transmission characteristic or the reception characteristic of the subject to be tested by using the measuring device with the reflection type test antenna and the switched direct type test antenna. And, it is a configuration including.

As described above, the test apparatus used in the test method according to the present invention has a signal path in which one test antenna used among a plurality of direct type test antennas and a signal processing unit are connected by a switching unit. Since the switching is performed, the test can be performed at a lower cost than when a conventional test device in which a signal processing unit is provided for each of the plurality of test antennas is used. Further, in the test apparatus used in this test method, the plurality of test antennas have a hybrid configuration including a reflection type test antenna using a reflector and a plurality of direct type test antennas. This minimizes the number of reflective test antennas with complex structures, while using a single reflective test antenna that can form a relatively wider quiet zone than direct test antennas. In some cases, a large quiet zone is available. Moreover, since the direct type test antenna does not use a reflector, installation space can be saved. Therefore, the test method according to the present invention can carry out far-field measurement of transmission / reception characteristics such as RF characteristics and RRM characteristics of the test object at low cost.

According to the present invention, it is possible to provide a test apparatus capable of performing far-field measurement of transmission / reception characteristics such as RF characteristics and RRM characteristics of an object to be tested at low cost, and a test method using the same.

It is a figure which shows the schematic structure of the whole test apparatus which concerns on embodiment of this invention. It is a block diagram which shows the functional structure of the test apparatus which concerns on embodiment of this invention. It is a block diagram which shows the functional structure of the integrated control apparatus of the test apparatus which concerns on embodiment of this invention. It is a block diagram which shows the functional structure of the NR system simulator in the test apparatus which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the near field and the distant field in the radio wave propagation between an antenna AT and a wireless terminal. It is a schematic diagram which shows the structure of the reflection type test antenna used in the test apparatus which concerns on embodiment of this invention. It is a block diagram which shows the functional structure of the signal processing part and the signal switching part which concerns on embodiment of this invention. It is a top view which removed the top plate of the OTA chamber of the test apparatus which concerns on embodiment of this invention, and was seen from above. It is a front view seen from the front side by removing the side plate on the front side of the OTA chamber of FIG. It is a flowchart which shows the outline of the test method performed using the test apparatus which concerns on embodiment of this invention.

Hereinafter, the test apparatus and the test method according to the embodiment of the present invention will be described with reference to the drawings. The dimensional ratio of each component on each drawing does not always match the actual dimensional ratio.

The test device 1 according to the present embodiment measures the transmission characteristic or the reception characteristic of the DUT 100 having the antenna 110, and for example, measures the RF characteristic and the RRM characteristic of the DUT 100. For this purpose, the test apparatus 1 includes an OTA chamber 50, a plurality of test antennas 6a, 6b, 6c, 6d, 6e, 6f (hereinafter, may be referred to as a test antenna 6), and a posture variable mechanism 56. The integrated control device 10, the NR system simulator 20, the signal processing unit 40, and the signal switching unit 140 are provided. The OTA chamber 50 of the present embodiment corresponds to the anechoic box of the present invention, and the integrated control device 10, the NR system simulator 20, the signal processing unit 40, and the signal switching unit 140 of the present invention are the measuring devices of the present invention. Corresponds to 2.

FIG. 1 shows the external structure of the test device 1, and FIG. 2 shows the functional block of the test device 1. However, FIG. 1 shows an arrangement mode of each component of the OTA chamber 50 in a state of being seen through from the front.

As shown in FIGS. 1 and 2, the OTA chamber 50 has an internal space 51 that is not affected by the surrounding radio wave environment. The test antenna 6 is housed in the internal space 51 of the OTA chamber 50, and transmits or receives a radio signal for measuring the transmission characteristic or the reception characteristic of the DUT 100 with or from the antenna 110. The posture variable mechanism 56 changes the posture of the DUT 100 arranged in the quiet zone QZ in the internal space 51 of the OTA chamber 50. The integrated control device 10, the NR system simulator 20, the signal processing unit 40, and the signal switching unit 140 use the test antenna 6 of 1 or 2 for the DUT 100 whose attitude is changed by the attitude variable mechanism 56, and use the test antenna 6 of the DUT 100. It is designed to measure transmission characteristics or reception characteristics.

The test apparatus 1 is used, for example, together with a rack structure 90 having a plurality of racks 90a as shown in FIG. 1, and is operated in a manner in which each component is placed on each rack 90a. FIG. 1 shows an example in which an integrated control device 10, an NR system simulator 20, and an OTA chamber 50 are mounted on each rack 90a of the rack structure 90, respectively. Hereinafter, each component will be described.

(OTA chamber)
The OTA chamber 50 realizes an OTA test environment for a performance test of a wireless terminal for 5G, and as shown in FIGS. 1 and 2, for example, a metal housing having a rectangular cuboid-shaped internal space 51. It is composed of a body body portion 52. The OTA chamber 50 accommodates the DUT 100 and a plurality of test antennas 6 facing the antenna 110 of the DUT 100 in the internal space 51 in a state of preventing the intrusion of radio waves from the outside and the radiation of radio waves to the outside. As will be described later, as the test antenna 6, for example, a reflection type antenna using a reflector or a directional millimeter wave antenna such as a horn antenna can be used.

Further, the radio wave absorber 55 is attached to the entire inner surface of the OTA chamber 50, that is, the entire surface of the bottom surface 52a, the side surface 52b, and the top surface 52c of the housing body 52, and the function of restricting the radiation of radio waves to the outside is strengthened. There is. In this way, the OTA chamber 50 realizes an anechoic box having an internal space 51 that is not affected by the surrounding radio wave environment. The anechoic chamber used in this embodiment is, for example, an anechoic type.

(DUT)
The DUT 100 to be tested is a wireless terminal such as a smartphone. Communication standards for DUT100 include cellular (LTE, LTE-A, W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, 1xEV-DO, TD-SCDMA, etc.), wireless LAN (IEEE802.11b / g / g / a / n / ac / ad, etc.), Bluetooth®, GNSS (GPS, Galileo, CDMA, BeiDou, etc.), FM, and digital broadcasting (DVB-H, ISDB-T, etc.). Further, the DUT 100 may be a wireless terminal that transmits / receives a radio signal in a millimeter wave band corresponding to 5G cellular or the like.

In this embodiment, the DUT 100 is a 5G NR wireless terminal. For 5G NR wireless terminals, the 5G NR standard stipulates that the communicable frequency range is a predetermined frequency band that includes not only the millimeter wave band but also other frequency bands used in LTE and the like. Therefore, the antenna 110 of the DUT 100 transmits or receives a radio signal of a predetermined frequency band (5G NR band) for measuring the transmission characteristic or the reception characteristic of the DUT 100. The antenna 110 is, for example, an array antenna such as a Massive-MIMO antenna, and corresponds to the antenna under test in the present invention.

In the present embodiment, the DUT 100 can transmit and receive a test signal and a measured signal via one or two test antennas selected from a plurality of test antennas 6 during measurement related to transmission and reception in the OTA chamber 50. It has become.

(Posture variable mechanism)
Next, the posture variable mechanism 56 provided in the internal space 51 of the OTA chamber 50 will be described. As shown in FIG. 1, a posture variable mechanism 56 for changing the posture of the DUT 100 arranged in the quiet zone QZ is provided on the bottom surface 52a of the housing body 52 of the OTA chamber 50 on the internal space 51 side. .. The posture variable mechanism 56 is, for example, a two-axis positioner including a rotation mechanism that rotates around each of the two axes. The attitude variable mechanism 56 constitutes an OTA test system (Combined-axes system) that rotates the DUT 100 with a degree of freedom of rotation around two axes while the test antenna 6 is fixed. Specifically, the posture variable mechanism 56 includes a drive unit 56a, a turntable 56b, a support column 56c, and a DUT mounting unit 56d as a mounting unit to be tested.

The drive unit 56a is composed of a drive motor such as a stepping motor that generates a rotational driving force, and is installed on, for example, a bottom surface 52a. The turntable 56b is adapted to rotate by a predetermined angle around one of the two axes orthogonal to each other by the rotational driving force of the driving unit 56a. The support column 56c is connected to the turntable 56b, extends from the turntable 56b in the direction of one axis, and rotates together with the turntable 56b by the rotational driving force of the drive unit 56a. The DUT mounting portion 56d extends from the side surface of the support column 56c in the direction of the other axis of the two axes, and is rotated by a predetermined angle around the other axis by the rotational driving force of the driving unit 56a. The DUT 100 is mounted on the DUT mounting unit 56d.

The above-mentioned one axis is, for example, an axis extending in the vertical direction with respect to the bottom surface 52a (x-axis in the figure). The other shaft is, for example, a shaft extending in the horizontal direction from the side surface of the support column 56c. The posture variable mechanism 56 configured in this way uses the DUT 100 held in the DUT mounting portion 56d as the center of rotation (also referred to as “arrangement position”) of the DUT 100 as an antenna in all three-dimensional directions. It is possible to rotate the posture so that the posture can be sequentially changed so that the 110 faces. That is, the test apparatus 1 of the present embodiment can be tested by the "Black-box approach" by the posture variable mechanism 56 as described above. Alternatively, the posture variable mechanism 56 may sequentially change the posture of the DUT 100 so that the antenna 110 faces in all three-dimensional directions with the center of the antenna 110 as the center of rotation.

In the OTA test system, the center of the DUT 100 or the center of the antenna 110 is arranged at the center of rotation (also referred to as the origin), which is the intersection of the two rotation axes of the attitude variable mechanism 56. The “arrangement position P _DUT ” of the DUT 100 is the origin of the OTA test system, and is the center of the DUT 100 or the center of the antenna 110 arranged in the OTA chamber 50. That is, the arrangement position P _DUT of the DUT 100 corresponds to the immovable center of rotation when the DUT 100 is rotated about two axes by the posture variable mechanism 56. If the position and antenna size of the antenna 110 in the DUT 100 are known, and the placement position P _DUT of the DUT 100 is set to the center position of the antenna 110, the test antenna 6 required to form a distant field is used. The distance to the antenna 110 can be significantly shortened.

(Link antenna)
In the OTA chamber 50, two types of link antennas 5 and 8 for establishing or maintaining a link (call) with the DUT 100 are used at required positions of the housing body 52 by using holders 57 and 59, respectively. It is attached. The link antenna 5 is a link antenna for LTE and is used in a non-standalone mode. On the other hand, the link antenna 8 is a link antenna for 5G and is used in a stand-alone mode. The link antennas 5 and 8 are held by the holders 57 and 59, respectively, so as to have directivity with respect to the DUT 100 held by the posture variable mechanism 56. Since it is possible to use the test antenna 6 as a link antenna instead of using the above link antennas 5 and 8, the test antenna 6 will be described below assuming that the test antenna 6 also functions as a link antenna. do.

(Near and far fields)
Next, the near field and the far field will be described. FIG. 5 is a schematic diagram showing how radio waves radiated from the antenna AT toward the wireless terminal 100A are transmitted. The antenna AT is equivalent to the primary radiator 6a1 of the test antenna 6a and the direct type test antennas 6b, 6c, 6d, 6e, and 6f, which will be described later. The wireless terminal 100A is equivalent to the DUT 100. In FIG. 5, (a) shows a DFF (Direct Far Field) method in which radio waves are directly transmitted from the antenna AT to the wireless terminal 100A, and (b) is a reflector 7A having a rotating paraboloid from the antenna AT. The IFF (Indirect Far Field) method transmitted to the wireless terminal 100A via the radio wave terminal 100A is shown.

As shown in FIG. 5A, a radio wave having an antenna AT as a radiation source has a property that a surface (wavefront) connecting points having the same phase spreads spherically around the radiation source and propagates. At this time, interference waves generated by disturbances such as scattering, refraction, and reflection as shown by the broken line are also generated. In addition, the wavefront is a curved spherical surface (spherical wave) at a distance close to the radiation source, but the wavefront becomes close to a plane (plane wave) at a distance from the radiation source. Generally, the region where the wavefront needs to be considered as a spherical surface is called the near field (NEAR FIELD), and the region where the wavefront can be regarded as a plane is called the far field (FAR FIELD). In the propagation of the radio wave shown in FIG. 5A, it is preferable that the wireless terminal 100A receives a plane wave rather than a spherical wave in order to perform accurate measurement.

In order to receive a plane wave, the wireless terminal 100A needs to be installed in a distant field. When the position and antenna size of the antenna 110 within the DUT 100 are unknown, the far field is the region beyond ^2D ₀₂ / λ from the antenna AT. Here, D ₀ is the maximum linear size of the wireless terminal 100A, and λ is the wavelength of the radio wave.

Specifically, for example, when the maximum linear size D ₀ = 0.2 m of the wireless terminal 100A and the radio wave frequency is 43.5 GHz, the position 11.6 m from the antenna AT becomes the boundary between the near field and the far field. It becomes necessary to place the wireless terminal 100A at a position farther than that.

On the other hand, when the position and antenna size of the antenna 110 in the DUT 100 are known, the far field is a region beyond 2D ² / λ from the antenna AT. Here, D is the antenna size, and λ is the wavelength of the radio wave.

Specifically, for example, when the antenna size D of the wireless terminal 100A is 0.03 m and the radio wave frequency is 43.5 GHz, the position 26.2 cm from the antenna AT becomes the boundary between the near field and the far field. It becomes necessary to place the wireless terminal 100A at a distant position. Further, for example, when the antenna size D of the wireless terminal 100A is 0.04 m and the radio wave frequency is 43.5 GHz, the position 46.5 cm from the antenna AT is the boundary between the near field and the far field.

In the present embodiment, the maximum linear size D of the target DUT100 is, for example, about 20 cm, and the frequency range to be handled is assumed to be 24.25 GHz to 43.5 GHz.

FIG. 5B shows a method of arranging the reflecting mirror 7A having a rotating paraboloid so as to reflect the radio wave of the antenna AT and bring the reflected wave to the position of the wireless terminal 100A (CATR (Compact)). Antenna Test Range) method). According to this method, the distance between the antenna AT and the wireless terminal 100A can be shortened, and the plane wave region expands from the distance immediately after the reflection on the mirror surface of the reflector 7A, so that the effect of reducing the propagation loss can be expected. The degree of a plane wave can be expressed by the phase difference of waves of the same phase. The acceptable phase difference as the degree of plane wave is, for example, λ / 16. The phase difference can be evaluated, for example, with a vector network analyzer (VNA).

(Test antenna)
Next, the test antenna 6 will be described.
FIG. 8 is a plan view of the OTA chamber 50 of the test apparatus 1 according to the present embodiment with the top plate removed and viewed from above. FIG. 9 is a side plate on the front side of the OTA chamber 50 (lower side in FIG. 8). It is a front view seen from the front side with the side plate) removed.

As shown in FIGS. 8 and 9, the test antenna 6 includes a reflective test antenna 6a and five direct test antennas 6b, 6c, 6d, 6e, 6f. The reflection type test antenna 6a transmits or receives a radio signal for measuring the transmission characteristic or the reception characteristic of the DUT 100 with the antenna 110 via the reflector 7. The direct type test antennas 6b, 6c, 6d, 6e, 6f directly transmit or receive a radio signal for measuring the transmission characteristic or reception characteristic of the DUT 100 with the antenna 110 included in the DUT 100. It has become. Each test antenna 6 includes a horizontally polarized antenna and a vertically polarized antenna (see FIG. 2).

(Reflective test antenna)
First, the reflection type test antenna 6a will be described.
The reflective test antenna 6a includes a primary radiator 6a1 and a reflector 7. The primary radiator 6a1 includes a horizontally polarized antenna 6aH and a vertically polarized antenna 6aV (see FIG. 2). The reflector 7 has an offset parabola (see FIG. 6) type structure described later. As shown in FIG. 1, the reflector 7 is attached to a required position on the side surface 52b of the OTA chamber 50 by using the reflector holder 58. The reflector 7 receives the radio wave of the test signal radiated from the primary radiator 6a1 arranged at the focal position F determined from the rotating paraboloid on the rotating paraboloid, and receives the radio wave of the test signal on the rotating paraboloid to the DUT 100 held by the attitude variable mechanism 56. Reflect toward (when transmitting). At the same time, the reflector 7 receives the radio wave of the measured signal radiated from the antenna 110 by the DUT 100 that has received the test signal on the rotating paraboloid, and reflects the test signal toward the radiated primary radiator 6a1 (at the time of reception). ). The reflector 7 is arranged at a position and a posture in which transmission and reception can be performed at the same time. That is, the reflector 7 reflects the radio wave of the radio signal transmitted and received between the primary radiator 6a1 and the antenna 110 via the rotating paraboloid.

FIG. 6 is a schematic view showing the structure of the reflection type test antenna 6a used in the test apparatus 1 according to the present embodiment. The reflector 7 of the reflection type test antenna 6a is an offset parabolic type, and has a mirror surface (a shape obtained by cutting out a part of the rotating parabolic surface of a perfect circular parabola) that is asymmetric with respect to the axis of the rotating parabolic surface. Have. The primary radiator 6a1 is arranged at the focal position F of the offset parabola in an offset state in which the beam axis BS1 is tilted with respect to the axis RS1 of the rotating parabolic surface, for example, by an angle α (for example, 30 °). As a result, radio waves radiated from the primary radiator 6a1 (for example, a test signal for the DUT 100) are reflected by the rotating parabolic surface in a direction parallel to the axial direction of the rotating parabolic surface, and the axial direction of the rotating parabolic surface. A radio wave (for example, a signal to be measured transmitted from the DUT 100) incident on the rotating parabolic surface in a direction parallel to the rotating parabolic surface can be reflected by the rotating parabolic surface and guided to the primary radiator 6a1. Compared to the parabola type, the offset parabola requires the reflector 7 itself to be smaller and can be arranged so that the mirror surface approaches the vertical, so that the structure of the OTA chamber 50 can be miniaturized.

In the OTA chamber 50 according to the present embodiment, as shown in FIG. 1, a reflector 7 using an offset parabola (see FIG. 6) is arranged in a radio wave propagation path between the DUT 100 and the test antenna 6. The reflector 7 is attached to the side surface 52b of the housing body 52 so that the position indicated by the reference numeral F in the drawing is the focal position. The primary radiator 6a1 is held at an angle such that it faces the reflector 7 at an elevation angle of 30 degrees, that is, faces the reflector 7, and the receiving surface of the primary radiator 6a1 is perpendicular to the beam axis BS1 of the radio signal. Will be done.

As described above, the reflective test antenna 6a includes a primary radiator 6a1 and a reflector 7, so that the primary radiator 6a1 transmits or receives a radio signal to and from the antenna 110 via the reflector 7. It has become. As can be seen from FIG. 9, the primary radiator 6a1 of the reflection type test antenna 6a is arranged below the horizontal plane HP passing through the arrangement position P _DUT of the DUT 100. The radio wave beam radiated from the primary radiator 6a1 and reflected by the reflector 7 is propagated in the Z-axis direction to form a quiet zone QZ having a radius r2. The center of the radio wave beam reflecting the position P0 of the opening center of the reflector 7 is propagated in the Z-axis direction to reach the arrangement position P _DUT of the DUT 100.

(Direct type test antenna)
Next, the direct type test antennas 6b, 6c, 6d, 6e, and 6f will be described.
The direct type test antennas 6b, 6c, 6d, 6e, and 6f each transmit and receive radio signals directly to and from the antenna 110 without using a reflector. The direct test antennas 6b, 6c, 6d, 6e and 6f have horizontally polarized antennas 6bH, 6cH, 6dH, 6eH and 6fH, respectively, and vertically polarized antennas 6bV, 6cV, 6dV, 6eV and 6fV, respectively. (See Fig. 2). These direct type test antennas 6b, 6c, 6d, 6e, and 6f are arranged on the virtual spherical surface S having a radius r1 and on the horizontal surface HP with the arrangement position P _DUT of the DUT 100 as the center. "The test antenna is arranged on the virtual sphere S and on the horizontal surface HP" means that the centers P1, P2, P3, P4, P5 of the radiation openings of the test antennas 6b, 6c, 6d, 6e, 6f. Is located on the virtual sphere S and on the horizontal surface HP. As shown in FIG. 1, the direct type test antennas 6b, 6c, 6d, 6e, and 6f are arranged on a virtual spherical surface S having a radius r1 and on a vertical plane centering on the arrangement position P _DUT of the DUT 100. You may do so. The test antennas 6b, 6c, 6d, 6e, and 6f do not have to be arranged at the same distance from the DUT 100, and the test antennas 6b, 6c, 6d, 6e, and 6f and the DUT 100 may have different distances. good.

In the present embodiment, the direct type test antennas 6b, 6c, 6d, 6e, and 6f form different arrival angles with respect to the radio wave arrival direction from the reflection type test antenna 6a at the arrangement position P _DUT of the DUT 100. is doing. As a result, the arrival angle differs depending on the combination of the reflection type test antenna 6a and one of the direct type test antennas 6b, 6c, 6d, 6e, 6f. Therefore, the direct type test antennas 6b, 6c, 6d, By switching between 6e and 6f, the arrival angle can be changed to efficiently perform far-field measurement of transmission / reception characteristics such as RRM characteristics of the DUT100.

Specifically, the direct type test antenna 6b forms an arrival angle of a predetermined angle θ with reference to the radio wave arrival direction (Z axis) from the reflection type test antenna 6a at the arrangement position P _DUT of the DUT 100. Similarly, the direct test antennas 6c, 6d, 6e, and 6f form arrival angles of 2θ, 3θ, 4θ, and 5θ, respectively. That is, the direct type first to fifth test antennas 6b, 6c, 6d, 6e, and 6f realize relative arrival angles θ, 2θ, 3θ, 4θ, and 5θ together with the reflection type test antennas 6a. be able to. In this way, since it is possible to measure within a predetermined angle range evenly and without leakage, it is possible to accurately measure the transmission / reception characteristics such as the RRM characteristics of the DUT 100 in the far field.

Here, the "angle of attack (AoA)" is a radio wave beam or a radio wave beam arriving at the placement position P _DUT from the test antenna with respect to a specific straight line (for example, the Z axis) passing through the placement position P _DUT of the DUT 100. The angle formed by the center. The arrival angle can also be defined by two test antennas. In this case, the center of the radio wave beam or radio wave beam arriving at the placement position P _DUT from the other test antenna is based on the direction of the radio wave arrival that is the direction of the radio wave beam arriving at the placement position P _DUT from one test antenna. The angle formed by is called "arrival angle" or "relative arrival angle".

In the present embodiment, the predetermined angle θ is 30 °. That is, the direct type test antenna 6b forms an arrival angle of 30 ° with reference to the radio wave arrival direction (Z axis) from the reflection type test antenna 6a at the arrangement position P _DUT of the DUT 100, and similarly, directly. The type test antennas 6c, 6d, 6e, and 6f form arrival angles of 60 °, 90 °, 120 °, and 150 °, respectively. This makes it possible to measure the RRM characteristics specified in Standard 3GPP TR 38.810 V16.2.0 (2019-03).

If the antenna size D of the antenna 110 is known, the direct test antennas 6b, 6c, 6d, 6e, 6f may be located at least 2D ² / λ away from the antenna 110 of the DUT 100. Here, D is the antenna size of the antenna 110, and λ is the wavelength of the radio wave transmitted from the direct type test antennas 6b, 6c, and 6d. This makes it possible to measure the far field of the DUT 100.

Further, the reflection type test antenna 6a forms an indirect far field (IFF), and the direct type test antennas 6b, 6c, 6d, 6e, 6f form a direct far field (DFF). ing. The indirect far field means a far field formed by a reflection type antenna using a reflector, and the direct far field means a far field formed by a direct type antenna using a reflector.

The direct type test antennas 6b, 6c, 6d, 6e, and 6f are arranged outside the path of the radio wave beam passing through the quiet zone QZ by reflecting the reflector 7 of the reflective test antenna 6a. With this configuration, the test apparatus 1 according to the present embodiment can form a good quiet zone QZ.

In this embodiment, six test antennas are provided, but the number is not limited to this, and the number of reflection type test antennas is set to 1 and the number of direct type test antennas is set depending on the test content. It may be any number of 2 or more.

Further, in the present embodiment, the quiet zone formed by the direct type test antennas 6b, 6c, 6d, 6e, and 6f is the same as the quiet zone QZ formed by the reflective test antenna 6a. , Not limited to this. The quiet zone formed by the direct type test antennas 6b, 6c, 6d, 6e, and 6f may be different from the quiet zone QZ formed by the reflective test antenna 6a. For example, if the quiet zone QZ formed by the reflective test antenna 6a is made wider, a wide quiet zone can be obtained when the reflective test antenna 6a is used alone to measure RF characteristics and the like. It can be used.

Next, the integrated control device 10 and the NR system simulator 20 of the test device 1 according to the present embodiment will be described with reference to FIGS. 2 to 4.

(Integrated control device)
As described below, the integrated control device 10 comprehensively controls the NR system simulator 20 and the posture variable mechanism 56. For this purpose, the integrated control device 10 is communicably connected to the NR system simulator 20 and the attitude variable mechanism 56 via a network 19 such as Ethernet (registered trademark).

FIG. 3 is a block diagram showing a functional configuration of the integrated control device 10. As shown in FIG. 3, the integrated control device 10 includes a control unit 11, an operation unit 12, and a display unit 13. The control unit 11 is composed of, for example, a computer device. In this computer device, for example, as shown in FIG. 3, a CPU (Central Processing Unit) 11a, a ROM (Read Only Memory) 11b, a RAM (Random Access Memory) 11c, and an external interface (I / F) unit 11d It has a non-volatile storage medium such as a hard disk device (not shown) and various input / output ports.

The CPU 11a is designed to perform comprehensive control for the NR system simulator 20. The ROM 11b stores an OS (Operating System) for starting up the CPU 11a, other programs, control parameters, and the like. The RAM 11c stores execution codes, data, and the like of the OS and applications used by the CPU 11a for operation. The external interface (I / F) unit 11d has an input interface function for inputting a predetermined signal and an output interface function for outputting a predetermined signal.

The external I / F unit 11d is communicably connected to the NR system simulator 20 via the network 19. Further, the external I / F unit 11d is also connected to the posture variable mechanism 56 in the OTA chamber 50 via the network 19. An operation unit 12 and a display unit 13 are connected to the input / output port. The operation unit 12 is a functional unit for inputting various information such as commands, and the display unit 13 is a functional unit for displaying various information such as an input screen for the various information and measurement results.

The computer device described above functions as a control unit 11 when the CPU 11a executes a program stored in the ROM 11b with the RAM 11c as a work area. As shown in FIG. 3, the control unit 11 includes a call connection control unit 14, a signal transmission / reception control unit 15, and a DUT attitude control unit 17. The call connection control unit 14, the signal transmission / reception control unit 15, and the DUT attitude control unit 17 are also realized by the CPU 11a executing a predetermined program stored in the ROM 11b in the work area of the RAM 11c.

The call connection control unit 14 drives the test antenna 6 to transmit and receive a control signal (wireless signal) to and from the DUT 100, so that the call (radio signal can be transmitted and received) between the NR system simulator 20 and the DUT 100. Control to establish the state).

The signal transmission / reception control unit 15 monitors the user operation in the operation unit 12, and the call connection control unit 14 takes the opportunity of the user performing a predetermined measurement start operation related to the measurement of the transmission characteristic and the reception characteristic of the DUT 100. A signal transmission command is transmitted to the NR system simulator 20 via the call connection control of. Further, the signal transmission / reception control unit 15 controls the NR system simulator 20 to transmit a test signal via the test antenna 6, and also transmits a signal reception command to the NR system simulator 20 to transmit the test antenna 6. Control is performed so that the signal to be measured is received via.

Further, in the test of transmission / reception characteristics such as RRM characteristics performed by using the two test antennas, the signal transmission / reception control unit 15 sets the arrival angle and selects the test antenna to be used. Specifically, one of a plurality of predetermined arrival angles (for example, 30 °, 60 °, 90 °, 120 °, 150 °) is selected and set as a measurement condition (stored in RAM 11c or the like). .. The arrival angle may be selected by the user, or may be automatically selected by the control unit 11 or the like. The signal transmission / reception control unit 15 selects the test antenna to be used from the plurality of test antennas 6 based on the set arrival angle. For example, when the set arrival angle is 30 °, the signal transmission / reception control unit 15 selects the reflection type test antenna 6a and the direct type first test antenna 6b as the test antenna to be used. Therefore, for example, the ROM 11b stores in advance an arrival angle-test antenna correspondence table 17b showing the correspondence relationship between the arrival angle and the test antenna. The arrival angle may be set and the test antenna to be used may be selected by the control unit 11 or the control unit 22 of the NR system simulator 20.

The DUT attitude control unit 17 controls the attitude of the DUT 100 held by the attitude variable mechanism 56 at the time of measurement. In order to realize this control, for example, the DUT attitude control table 17a is stored in advance in the ROM 11b. The DUT attitude control table 17a stores, for example, the number of drive pulses (number of operation pulses) that determine the rotational drive of the stepping motor as control data when the stepping motor is adopted as the drive unit 56a.

The DUT attitude control unit 17 expands the DUT attitude control table 17a into the work area of the RAM 11c, and based on the DUT attitude control table 17a, the DUT 100 makes the antenna 110 sequentially face in all three-dimensional directions as described above. The attitude variable mechanism 56 is driven and controlled so as to change the attitude.

(NR system simulator)
As shown in FIG. 4, the NR system simulator 20 of the test apparatus 1 according to the present embodiment includes a signal measurement unit 21, a control unit 22, an operation unit 23, and a display unit 24. The signal measurement unit 21 includes a signal generation function unit composed of a signal generation unit 21a, a digital / analog converter (DAC) 21b, a modulation unit 21c, a transmission unit 21e of the RF unit 21d, and a reception unit 21f of the RF unit 21d. It has an analog / digital converter (ADC) 21g and a signal analysis function unit composed of an analysis processing unit 21h. The signal measurement unit 21 may be provided with two sets so as to correspond to the two test antennas to be used.

In the signal generation function unit of the signal measurement unit 21, the signal generation unit 21a transmits waveform data having a reference waveform, specifically, for example, an I component baseband signal and a Q component baseband signal which is an orthogonal component signal thereof. Generate. The DAC 21b converts waveform data (I component baseband signal and Q component baseband signal) having a reference waveform output from the signal generation unit 21a from a digital signal to an analog signal and outputs the waveform data to the modulation unit 21c. The modulation unit 21c mixes a local signal with each of the I component baseband signal and the Q component baseband signal, further synthesizes the two, and outputs a digitally modulated signal. The RF unit 21d generates a test signal corresponding to the frequency of each communication standard from the digital modulation signal output from the modulation unit 21c, and the generated test signal is transmitted by the transmission unit 21e via the signal processing unit 40 and the test antenna. And output to DUT100.

Further, in the signal analysis function unit of the signal measurement unit 21, the RF unit 21d receives the signal to be measured transmitted from the DUT 100 that has received the test signal by the antenna 110 at the reception unit 21f via the signal processing unit 40. Then, the signal to be measured is mixed with the local signal to be converted into an intermediate frequency band signal (IF signal). The ADC 21g converts the signal to be measured converted into an IF signal by the receiving unit 21f of the RF unit 21d into a digital signal and outputs it to the analysis processing unit 21h.

The analysis processing unit 21h generates waveform data corresponding to the I component baseband signal and the Q component baseband signal by digital processing of the signal to be measured, which is a digital signal output by the ADC 21g, and then the waveform data. The process of analyzing the I component baseband signal and the Q component baseband signal is performed based on the above. In the measurement of the transmission characteristic (RF characteristic) with respect to the DUT 100, the analysis processing unit 21h determines, for example, Equivalent Isotropically Radiated Power (EIRP), Total Radiated Power (TRP), Spurious Radiated Power, and Modulation Accuracy. (EVM), transmission power, constellation, spectrum, etc. can be measured. Further, the analysis processing unit 21h can measure, for example, the reception sensitivity, the bit error rate (BER), the packet error rate (PER), and the like in the measurement of the reception characteristic (RF characteristic) with respect to the DUT 100. Here, EIRP is the radio signal intensity in the main beam direction of the antenna under test. Further, TRP is the total value of the electric power radiated into the space from the antenna under test.

The analysis processing unit 21h can also analyze the RRM characteristics of the DUT 100, for example, whether or not the handover operation from one selected test antenna to another selected test antenna is normally performed. It has become like.

The control unit 22 is composed of, for example, a computer device including a CPU, RAM, ROM, and various input / output interfaces, like the control unit 11 of the integrated control device 10 described above. The CPU performs predetermined information processing and control for realizing each function of the signal generation function unit, the signal analysis function unit, the operation unit 23, and the display unit 24.

The operation unit 23 and the display unit 24 are connected to the input / output interface of the computer device. The operation unit 23 is a functional unit for inputting various information such as commands, and the display unit 24 is a functional unit for displaying various information such as the input screen of the various information and the measurement result.

In the present embodiment, the integrated control device 10 and the NR system simulator 20 are separate devices, but they may be configured as one device. In this case, the control unit 11 of the integrated control device 10 and the control unit 22 of the NR system simulator 20 may be integrated and realized by one computer device.

Next, the signal processing unit 40 and the signal switching unit 140 will be described.

FIG. 7 is a block diagram showing a functional configuration of the signal processing unit 40 and the signal switching unit 140 according to the embodiment of the present invention. The signal processing unit 40 and the signal switching unit 140 are arranged inside the OTA chamber 50.

(Signal processing unit)
As shown in FIG. 7, the signal processing unit 40 performs processing such as converting the frequency of the signal transmitted as a radio signal by the test antenna 6 or the frequency of the radio signal received by the test antenna 6. , A first frequency conversion unit 144 and a second frequency conversion unit 145 are provided.

The first frequency conversion unit 144 converts the frequency of the radio signal transmitted and received between the reflection type test antenna 6a and the antenna 110. Specifically, the first frequency conversion unit 144 receives by the first transmission converter 146 that up-converts the signal transmitted as a radio signal from the reflection type test antenna 6a and the reflection type test antenna 6a. It includes a first reception converter 147 that down-converts the radio signal.

More specifically, the first transmission converter 146 of the first frequency conversion unit 144 up-converts the signal transmitted as a horizontally polarized radio signal from the reflection type test antenna 6a. And a second upconverter 151 that up-converts a signal transmitted as a vertically polarized radio signal from the reflection type test antenna 6a.

Further, the first reception converter 147 of the first frequency conversion unit 144 is the first down converter 154 that down-converts the horizontally polarized radio signal received from the reflection type test antenna 6a, and the reflection type test. It includes a second down converter 155 that down-converts a vertically polarized radio signal received from the antenna 6a.

With the above configuration, the test apparatus 1 according to the present embodiment can measure transmission / reception characteristics such as RRM characteristics of the DUT 100 using a horizontally polarized signal and a vertically polarized signal.

The second frequency conversion unit 145 converts the frequency of the radio signal transmitted / received between the direct type test antennas 6b, 6c, 6d, 6e, 6f and the antenna 110. Specifically, the second frequency conversion unit 145 directly includes a second transmission converter 148 that up-converts a signal transmitted as a radio signal from the direct type test antennas 6b, 6c, 6d, 6e, and 6f. It includes a second reception converter 149 that down-converts the radio signal received by the type test antennas 6b, 6c, 6d, 6e, 6f.

More specifically, the second transmission converter 148 of the second frequency conversion unit 145 transmits a signal transmitted as a horizontally polarized radio signal from the direct test antennas 6b, 6c, 6d, 6e, 6f. A third upconverter 152 for up-converting and a fourth upconverter 153 for up-converting a signal transmitted as a vertically polarized radio signal from the direct test antennas 6b, 6c, 6d, 6e, 6f are provided. There is.

Further, the second reception converter 149 of the second frequency conversion unit 145 down-converts the horizontally polarized radio signals received from the direct test antennas 6b, 6c, 6d, 6e, and 6f. It includes a converter 156 and a fourth down converter 157 that down-converts vertically polarized radio signals received from direct test antennas 6b, 6c, 6d, 6e, 6f.

As described above, in the test apparatus 1 according to the present embodiment, the first frequency conversion unit 144 is provided for the reflection type test antenna 6a, and the direct type test antennas 6b, 6c, 6d, 6e, Since the second frequency conversion unit 145 is provided for 6f, it is possible to measure the RRM characteristics and the like by using the reflection type test antenna 6a and the direct type one test antenna.

(Signal switching unit)
The signal switching unit 140 includes a switch unit 141, a first switching unit 142, and a second switching unit 143.

The switch unit 141 sets the signal path between the second frequency conversion unit 145 and the direct type test antennas 6b, 6c, 6d, 6e, 6f to one of the direct type test antennas selected. The signal path is switched so that the antenna and the second frequency conversion unit 145 are connected. The signal path can be switched automatically under the control of the control unit 22, but it may be manually switched. The switch unit 141 of the present embodiment corresponds to the switching unit of the present invention.

The first switching unit 142 is provided between the reflection type test antenna 6a and the first frequency conversion unit 144, and the reflection type test antenna 6a is shared for transmission and reception. The second switching unit 143 is provided between the switch unit 141 and the second frequency conversion unit 145 so that one of the direct test antennas selected from the test antennas is shared by transmission and reception. It has become.

Specifically, the first switching unit 142 is, for example, a wideband directional coupler that passes the frequency of the test signal output from the first transmission converter 146, and is composed of, for example, a Wilkinson type distributor. .. The first switching unit 142 is connected to the reflection type test antenna 6a by a coaxial cable, inputs the test signal output from the first transmission converter 146 to the reflection type test antenna 6a, and is a reflection type. It is possible to input the signal to be measured from the DUT 100 received by the test antenna 6a of the above to the first reception converter 147. The first switching unit 142 may be configured by, for example, a circulator.

Similarly, the second switching unit 143 is, for example, a wideband directional coupler that passes the frequency of the test signal output from the second transmission converter 148, and is composed of, for example, a Wilkinson type distributor. The second switching unit 143 is connected to the switch unit 141 with a coaxial cable, and the test signal output from the second transmission converter 148 is directly input to the test antenna 6 of the type via the switch unit 141. At the same time, the signal to be measured from the DUT 100 received by the direct type one test antenna 6 can be input to the second reception converter 149. The second switching unit 143 may be configured by, for example, a circulator. Further, for the purpose of compensating for a large loss caused by a long wiring from the first frequency conversion unit 144 and the second frequency conversion unit 145 to the test antenna 6, and further preventing pressure on the dynamic range. Between the reflective test antenna 6a and the direct test antennas 6b, 6c, 6d, 6e, 6f and the signal switching section 140, with an amplifier and uplink and downlink near each of the test antenna 6 A switch for switching between the two may be provided.

In the test device 1 according to the present embodiment, the signal switching unit 140 of the measuring device 2 sets a signal path between the signal processing unit 40 and the plurality of direct type test antennas 6b, 6c, 6d, 6e, 6f. It is provided with a switch unit 141 that switches to a signal path to which one of the test antennas used among the plurality of direct type test antennas and the signal processing unit 40 are connected. With this configuration, the number of signal processing units is reduced as compared with the conventional one in which the signal processing units are provided for each of the plurality of test antennas 6, so that cost reduction and space saving can be realized.

Further, since the test device 1 according to the present embodiment can share the test antenna 6 for transmission and reception by using the first switching unit 142 and the second switching unit 143, the transmission characteristics and reception characteristics of the DUT 100 can be efficiently used. Can be measured.

Next, the operations of the signal processing unit 40 and the signal switching unit 140 according to the present embodiment will be described. Here, a case where the transmission / reception characteristics of the DUT 100 are measured by using the reflection type test antenna 6a and the direct type test antenna 6c will be described as an example.

First, the first switching unit 142 has a function of enabling the reflection type test antenna 6a to be shared by transmission and reception. Specifically, the first switching unit 142 has a signal path from the first transmission converter 146 to the reflection type test antenna 6a and a signal path from the reflection type test antenna 6a to the first reception converter 147. And at the same time.

More specifically, the first switching unit 142 includes a signal path from the first upconverter 150 to the horizontally polarized antenna 6aH of the reflection type test antenna 6a and a reflection type test antenna from the second upconverter 151. It forms a signal path to the vertically polarized antenna 6aV of 6a. At the same time, the first switching unit 142 receives the signal path from the horizontally polarized antenna 6aH of the reflective test antenna 6a to the first down converter 154 and the vertically polarized antenna 6aV of the reflective test antenna 6a. It forms a signal path to the second down converter 155.

The switch unit 141 switches the signal path so that the selected direct type test antenna 6c and the second switching unit 143 are connected.

The second switching unit 143 has a function of enabling the selected direct type test antenna 6c to be shared by transmission and reception. Specifically, the second switching unit 143 has a signal path from the second transmission converter 148 to the selected direct test antenna 6c and a second reception from the selected direct test antenna 6c. Simultaneously form a signal path to converter 149.

More specifically, the second switching unit 143 includes a signal path from the third upconverter 152 to the horizontally polarized antenna 6cH of the direct type test antenna 6c, and a direct type test antenna from the fourth upconverter 153. It forms a signal path to the vertically polarized antenna 6cV of 6c. At the same time, the second switching unit 143 uses the signal path from the horizontally polarized antenna 6cH of the direct type test antenna 6c to the third down converter 156 and the vertically polarized antenna 6cV of the direct type test antenna 6c. It forms a signal path to the fourth down converter 157.

Then, the horizontally polarized wave modulation signal sent from the signal measuring unit 21 to the first upconverter 150 is up-converted by the first upconverter 150 and sent to the horizontally polarized wave antenna 6aH of the reflection type test antenna 6a. It is radiated from the horizontally polarized antenna 6aH. Similarly, the vertically polarized wave modulation signal sent from the signal measuring unit 21 to the second upconverter 151 is up-converted by the second upconverter 151 and becomes the vertically polarized wave antenna 6aV of the reflection type test antenna 6a. It is sent and radiated from the vertically polarized antenna 6aV.

The radio wave radiated from the reflection type test antenna 6a is reflected by the reflector 7 and sent to the DUT 100, and is received by the antenna 110. The DUT 100 transmits a response signal in response to the received signal.

For the response signal transmitted from the DUT 100, for example, the direct type test antenna 6c receives the response signal. Then, the horizontally polarized signal received by the horizontally polarized antenna 6cH of the direct type test antenna 6c is down-converted by the third down converter 156, sent to the signal measuring unit 21, demodulated, and subjected to analysis processing. Similarly, the vertically polarized signal received by the vertically polarized antenna 6cV of the direct type test antenna 6c is down-converted by the fourth down converter 157, sent to the signal measuring unit 21, demodulated, and subjected to analysis processing. ..

In the above example, a test signal is transmitted from the reflection type test antenna 6a to the DUT 100, and the measured signal transmitted from the DUT 100 is received by the direct type test antenna 6c for analysis. Not limited to this. The test signal transmitted from the DUT 100 may be received by one of the test antennas 6 and analyzed, or the test signal transmitted from any of the test antennas 6 may be received and analyzed by the DUT 100. .. The test antenna 6 used may be one or two.

As described above, the signal processing unit 40 includes a first frequency conversion unit 144 and a second frequency conversion unit 145, but also includes an amplifier, a frequency filter, and the like, and frequency conversion, amplification, and frequency selection. Etc. are to be executed.

(Test method)
Next, a test method performed using the test apparatus 1 according to the present embodiment will be described with reference to the flowchart of FIG. In the following, a test performed using two test antennas (for example, measurement of transmission / reception characteristics such as RRM characteristics) will be described, but this is an example of a test method, and the specific test method differs depending on the type of test. Of course.

First, the user uses the operation unit 12 of the integrated control device 10 to perform a measurement start operation instructing the control unit 11 to start measurement of the transmission characteristic and the reception characteristic of the DUT 100. This measurement start operation may be performed by the operation unit 23 of the NR system simulator 20.

Next, the user sets the DUT 100 to be tested on the DUT mounting portion 56d of the posture variable mechanism 56 provided in the internal space 51 of the OTA chamber 50 (step S1).

The control unit 11 sets one of the predetermined arrival angles (step S2). For example, when the predetermined arrival angles are 30 °, 60 °, 90 °, 120 °, and 150 °, the control unit 11 selects one of the arrival angles (for example, 30 °) and should measure the arrival. It is set as an angle (for example, stored in RAM 11c). The arrival angle may be set by the user.

Next, the control unit 11 selects two test antennas 6 that realize the arrival angle from the arrival angle set in step S2 (step S3). For example, when the set arrival angle is 30 °, the test antenna 6a and the test antenna 6b are selected, and when the set arrival angle is 60 °, the test antenna 6a and the test antenna 6c are selected. When the set arrival angle is 90 °, the test antenna 6a and the test antenna 6d are selected, and when the set arrival angle is 120 °, the test antenna 6a and the test antenna 6e are selected and set. When the arrival angle is 150 °, the test antenna 6a and the test antenna 6f are selected.

Next, the control unit 22 of the NR system simulator 20 switches the signal path to the selected test antenna 6 (step S4). Specifically, the control unit 22 of the NR system simulator acquires the information of the two selected test antennas from the control unit 11 and sends the switching signal to the signal switching unit 140 of the signal processing unit 40. The switch unit 141 switches to a signal path to which the selected direct type test antenna and the second frequency conversion unit 145 are connected according to the switching signal. FIG. 7 shows, as an example, a state in which the second test antenna 6c and the second frequency conversion unit 145 are switched to a signal path to which they are connected. The switch unit 141 can switch to any one of the direct type first to fifth test antennas 6b, 6c, 6d, 6e, and 6f.

The call connection control unit 14 of the control unit 11 uses the selected test antenna 6 to perform call connection control by transmitting and receiving a control signal (radio signal) to and from the DUT 100 (step S5). Specifically, the NR system simulator 20 wirelessly transmits a control signal (call connection request signal) having a predetermined frequency to the DUT 100 via the test antenna 6. On the other hand, the DUT 100 that has received the call connection request signal returns a control signal (call connection response signal) after setting the frequency for which the connection is requested. The NR system simulator 20 receives this call connection response signal and confirms that the response has been performed normally. These series of processes are call connection control. This call connection control establishes a state in which a radio signal of a predetermined frequency can be transmitted and received between the NR system simulator 20 and the DUT 100 via the selected test antenna 6.

The process of receiving the radio signal transmitted from the NR system simulator 20 via the test antenna 6 by the DUT 100 is called the downlink (DL) process. On the contrary, the process of transmitting the radio signal to the NR system simulator 20 by the DUT 100 via the test antenna 6 is called the uplink (UL) process. The test antenna 6 is used to execute the process of establishing the link (call) and the process of downlink (DL) and uplink (UL) after the link is established, and also functions as a link antenna. ing.

After establishing the call connection in step S5, the DUT attitude control unit 17 of the integrated control device 10 controls the attitude of the DUT 100 arranged in the quiet zone QZ to a predetermined attitude by the attitude variable mechanism 56 (step S6).

After the attitude variable mechanism 56 controls the DUT 100 to a predetermined attitude, the signal transmission / reception control unit 15 of the integrated control device 10 transmits a signal transmission command to the NR system simulator 20. The NR system simulator 20 transmits a test signal to the DUT 100 via the selected test antenna 6 based on the signal transmission command (step S7).

The test signal transmission control by the NR system simulator 20 is carried out as follows. In the NR system simulator 20 (see FIG. 4), the signal generation unit 21a generates a signal for generating a test signal under the control of the control unit 22 that has received the signal transmission command. Next, the DAC 21b performs digital / analog conversion processing on the signal generated by the signal generation unit. Next, the modulation unit 21c performs modulation processing on the analog signal obtained by the digital / analog conversion. Next, the RF unit 21d generates a test signal corresponding to the frequency of each communication standard from the modulated signal, and the transmission unit 21e sends this test signal (DL data) to the signal processing unit 40.

The signal processing unit 40 is provided in the OTA chamber 50, performs signal processing such as frequency conversion (up-conversion), amplification, and frequency selection, and outputs the signal to the switching unit 140. The switching unit 140 sends the signal processed by the signal processing unit 40 to the selected test antenna 6, and the test antenna 6 outputs the signal toward the DUT 100.

The signal transmission / reception control unit 15 controls to transmit the test signal at an appropriate timing after starting the control of the test signal transmission in step S6 until the measurement of the transmission characteristic and the reception characteristic of the DUT 100 is completed. ..

On the other hand, the DUT 100 receives the test signal (DL data) transmitted through the test antenna 6 by the antenna 110 in a state of different postures that are sequentially changed based on the posture control in step S6, and the test is performed. A signal to be measured, which is a response signal to the signal, is transmitted.

After starting the transmission of the test signal in step S7, the reception process is subsequently performed under the control of the signal transmission / reception control unit 15 (step S8). In this reception process, the test antenna 6 receives the signal to be measured transmitted from the DUT 100 that has received the test signal, and outputs the signal to be measured to the signal switching unit 140. The signal switching unit 140 switches the signal path and outputs the signal to be measured to the signal processing unit 40. The signal processing unit 40 performs signal processing such as frequency conversion (down-conversion), amplification, and frequency selection, and outputs the signal to the NR system simulator 20.

The NR system simulator 20 executes a measurement process for measuring the frequency-converted signal to be measured by the signal processing unit 40 (step S9).

Specifically, the receiving unit 21f of the RF unit 21d of the NR system simulator 20 inputs the signal to be measured that has been signal-processed by the signal processing unit 40. Under the control of the control unit 22, the RF unit 21d converts the signal to be measured input to the reception unit 21f into an IF signal having a lower frequency. Next, the ADC 21g converts the IF signal from an analog signal to a digital signal and outputs it to the analysis processing unit 21h under the control of the control unit 22. The analysis processing unit 21h generates waveform data corresponding to the I component baseband signal and the Q component baseband signal, respectively. Further, the analysis processing unit 21h analyzes the signal to be measured based on the above-mentioned generated waveform data under the control of the control unit 22.

More specifically, in the NR system simulator 20, the analysis processing unit 21h measures the transmission characteristic and the reception characteristic of the DUT 100 based on the analysis result of the signal to be measured under the control of the control unit 22.

For example, the transmission characteristics (RF characteristics) of the DUT 100 are performed as follows. First, the NR system simulator 20 transmits a request frame for transmitting an uplink signal as a test signal under the control of the control unit 22. The DUT 100 transmits the uplink signal frame as a signal to be measured to the NR system simulator 20 in response to the request frame for transmitting the uplink signal. The analysis processing unit 21h performs a process of evaluating the transmission characteristics of the DUT 100 based on the uplink signal frame.

Further, the reception characteristic (RF characteristic) of the DUT 100 is performed as follows, for example. Under the control of the control unit 22, the analysis processing unit 21h determines the number of transmissions of the measurement frame transmitted from the NR system simulator 20 as a test signal, and the ACK and NACK transmitted from the DUT 100 as the measurement signal to the measurement frame. The ratio of the number of times of receiving is calculated as the error rate (BER).

Regarding the RRM characteristics of the DUT 100, for example, the analysis processing unit 21h normally performs a handover operation from one selected test antenna to another selected test antenna under the control of the control unit 22. Whether or not it may be tested by changing the posture of the DUT 100.

In step S9, the analysis processing unit 21h stores the measurement results of the transmission characteristics and the reception characteristics of the DUT 100 in a storage area such as a RAM (not shown) under the control of the control unit 22.

Next, the control unit 11 of the integrated control device 10 determines whether or not the measurement of the transmission characteristic and the reception characteristic of the DUT 100 has been completed for all the desired postures (step S10). Here, if it is determined that the measurement has not been completed (NO in step S10), the process returns to step S6 to continue the process.

When it is determined that the measurement has been completed for all postures (YES in step S10), the control unit 11 determines whether or not the measurement has been completed for all the arrival angles (step S11).

When it is determined that the measurement has not been completed for all the arrival angles (NO in step S11), the control unit 11 returns to step S2 and continues the process. When it is determined that the measurement has been completed for all the arrival angles (YES in step S11), the control unit 11 ends the test.

Next, the action and effect of this embodiment will be described.

In the test apparatus 1 according to the present embodiment, the signal switching unit 140 sets a signal path between the second frequency conversion unit 145 and the plurality of direct type test antennas 6b, 6c, 6d, 6e, 6f. It includes a switch unit 141 that switches to a signal path to which one of the test antennas of the plurality of direct type test antennas and the second frequency conversion unit 145 are connected. With this configuration, the number of frequency conversion units is significantly reduced as compared with the conventional one in which the frequency conversion units are provided for each of the plurality of test antennas 6, so that cost reduction and space saving can be realized.

Moreover, the test antenna 6 includes a reflection type test antenna 6a that indirectly transmits and receives radio signals using the reflector 7, and a plurality of direct type test antennas 6b, 6c, and 6d that directly transmit and receive radio signals. It has a hybrid configuration including 6e and 6f. As a result, the number of reflective test antennas having a complicated structure can be minimized, while the reflective test antenna 6a, which can form a relatively wide quiet zone as compared with the direct test antenna, can be used alone. When used, a wide quiet zone can be used. In addition, since the direct type test antennas 6b, 6c, 6d, 6e, and 6f do not use a reflector, the installation space can be saved. Therefore, the test apparatus 1 according to the present embodiment can perform far-field measurement of transmission / reception characteristics such as RF characteristics and RRM characteristics of the DUT 100 at low cost.

The present invention can be applied not only to an anechoic box but also to an anechoic chamber.

As described above, the present invention has the effect of being able to carry out far-field measurement of transmission / reception characteristics such as RF characteristics and RRM characteristics of the test object at low cost, and is a test device and test for wireless terminals. Useful for all methods.

1 Test equipment 2 Measuring equipment 5, 8 Link antenna 6 Test antenna 6a Reflective test antenna 6a1 Primary radiator 6b Direct type first test antenna 6c Direct type second test antenna 6d Direct type 3rd test antenna 6e Direct type 4th test antenna 6f Direct type 5th test antenna 7 Reflector 7A Reflector 10 Integrated controller 11 Control unit 11a CPU
11b ROM
11c RAM
11d External interface unit 12 Operation unit 13 Display unit 14 Call connection control unit 15 Signal transmission / reception control unit 17 DUT attitude control unit 17a DUT attitude control table 17b Arrival angle-Test antenna compatible table 19 Network 20 NR system simulator 21 Signal measurement unit 21a Signal generator 21b DAC
21c Modulation section 21d RF section 21e Transmitter section 21f Receiver section 21g ADC
21h Analysis processing unit 22 Control unit 23 Operation unit 24 Display unit 40 Signal processing unit 50 OTA chamber (anechoic chamber)
51 Internal space 52 Housing body 52a Bottom 52b Side 52c Top 55 Radio wave absorber 56 Posture variable mechanism 56a Drive 56b Turntable 56c Strut 56d DUT mounting 57, 59 Holder 58 Reflector holder 90 Rack structure 90a Rack 100 DUT (subject to test)
100A wireless terminal 110 antenna (antenna to be tested)
140 Signal switching unit 141 Switch unit (switching unit)
142 1st switching unit 143 2nd switching unit 144 1st frequency conversion unit 145 2nd frequency conversion unit 146 1st transmission converter 147 1st reception converter 148 2nd transmission converter 149 2nd reception converter 150 1 Upconverter 151 2nd Upconverter 152 3rd Upconverter 153 4th Upconverter 154 1st Downconverter 155 2nd Downconverter 156 3rd Downconverter 157 4th Downconverter F Reflector Focus Position QZ Quiet Zone S Virtual Spherical HP Horizontal plane

Claims (7)

A test device (1) for measuring transmission characteristics or reception characteristics of an object to be tested (100) having an antenna to be tested (110).
An anechoic box (50) having an internal space (51) that is not affected by the surrounding radio wave environment,
A plurality of test antennas (6) housed in the internal space and transmitting or receiving radio signals for measuring transmission characteristics or reception characteristics of the test object with the test antenna.
A posture variable mechanism (56) arranged in a quiet zone (QZ) in the internal space to change the posture of the subject to be tested, and a posture variable mechanism (56).
A measuring device (2) for measuring the transmission characteristic or the reception characteristic of the test object by using the test antenna for the test object whose posture is changed by the posture variable mechanism is provided.
The plurality of test antennas are directly between the reflection type test antenna (6a) that transmits or receives a radio signal to and from the test antenna via the reflector (7) and the test antenna. Includes multiple direct test antennas (6b, 6c, 6d, 6e, 6f) that transmit or receive radio signals.
The measuring device includes a signal processing unit (40) that converts the frequency of a signal transmitted as a radio signal by the plurality of test antennas or the frequency of a radio signal received by the plurality of test antennas, and the signal processing unit. Switching the signal path between the unit and the plurality of direct type test antennas to a signal path in which one of the plurality of direct type test antennas and the signal processing unit are connected. A test device including a part (141). The signal processing unit
A first frequency conversion unit (144) that converts the frequency of a signal transmitted as a radio signal by the reflection type test antenna or the frequency of a radio signal received by the reflection type test antenna.
A second that converts the frequency of the signal transmitted as a radio signal by the direct type one test antenna switched by the switching unit or the frequency of the radio signal received by the direct type one test antenna. Frequency converter (145) and
The test apparatus according to claim 1. The first frequency conversion unit includes a first transmission converter (146) that up-converts a signal transmitted as a radio signal from the reflection type test antenna, and a radio received by the reflection type test antenna. It is equipped with a first reception converter (147) that down-converts the signal.
The second frequency conversion unit includes a second transmission converter (148) that up-converts a signal transmitted as a radio signal from the plurality of direct type test antennas, and the plurality of direct type test antennas. It is equipped with a second reception converter (149) that down-converts the received radio signal.
The first transmission converter includes a first upconverter (150) that up-converts a signal transmitted as a horizontally polarized radio signal from the reflection type test antenna, and a vertical bias from the reflection type test antenna. It is equipped with a second upconverter (151) that upconverts the signal transmitted as a wave radio signal.
The first receiving converter includes a first down converter (154) that down-converts a horizontally polarized radio signal received from the reflection type test antenna and a vertical one received from the reflection type test antenna. It is equipped with a second down converter (155) that down-converts the polarized radio signal.
The second transmission converter includes a third upconverter (152) that up-converts a signal transmitted as a horizontally polarized radio signal from the plurality of direct type test antennas, and the plurality of direct type test antennas. It is equipped with a fourth upconverter (153) that upconverts the signal transmitted from the antenna as a vertically polarized radio signal.
The second receiving converter includes a third down converter (156) that down-converts a horizontally polarized radio signal received from the plurality of direct type test antennas, and the plurality of direct type test antennas. The test apparatus according to claim 2, further comprising a fourth down converter (157) that down-converts the received vertically polarized radio signal. The plurality of direct type test antennas form different arrival angles with respect to the arrival direction of radio waves from the reflection type test antenna at the arrangement position ( _PDUT ) of the test object. The test apparatus according to any one of 3. The plurality of direct type test antennas are arranged at least 2D ² / λ away from the test antenna, where D is the antenna size of the test antenna and λ is the plurality of direct type test antennas. The test apparatus according to any one of claims 1 to 4, which is the wavelength of the radio wave transmitted from. Any one of claims 1 to 5, wherein the plurality of direct type test antennas are arranged outside the path of a radio wave beam passing through the quiet zone by reflecting the reflector of the reflective test antenna. The test equipment described in. A test method using the test apparatus according to any one of claims 1 to 6.
A step of switching to a signal path in which the test antenna of one of the plurality of direct type test antennas and the signal processing unit are connected by the switching unit.
A step of changing the posture of the object to be tested arranged in the quiet zone by the posture variable mechanism, and
With respect to the subject to be tested whose posture has been changed by the posture variable mechanism, the object to be tested uses the reflection type test antenna and the switched direct type test antenna by the measuring device. A test method comprising measuring transmission characteristics or reception characteristics.

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