JP6973091B2 - Antenna device and wireless communication device - Google Patents

Description

The present invention relates to an antenna device and a wireless communication device that perform wireless communication.

Watch-type wearable devices are being used more and more, for example, to detect information on the state of the human body, for example, a pulse as a measure to prevent heat stroke. Since this wearable device has a low battery capacity, it is used in a usage mode in which information such as the detected pulse is transmitted to a wireless communication device (for example, an ad hoc terminal) possessed by the worker, and the information is transmitted from the ad hoc terminal to the data center. Be done.

As a conventional technique for an antenna device, there is a technique in which a radiating element is folded back along a circumference of a main plate so that it can be used in a plurality of frequency bands (see, for example, Patent Document 1 below). In addition, there is a technology in which the first element extending parallel to the GND surface from the feeding point and the second element bent in a U shape are arranged in parallel, and the frequency band of the multiple band can be adjusted independently (the frequency band of the multiple band can be adjusted independently). For example, see Patent Document 2 below.). Further, there is a technique in which a U-shaped element end is connected to a ground pattern as a feeding point and a grounding point to improve antenna characteristics such as a change in input impedance (see, for example, Patent Document 3 below). Further, there is a technique of bending an antenna extending from a feeding point into a U shape to improve the radiation efficiency of the antenna (see, for example, Patent Document 4 below).

Japanese Unexamined Patent Publication No. 2006-197138 Special Table 2010-526471 Gazette Japanese Unexamined Patent Publication No. 2013-026930 Japanese Unexamined Patent Publication No. 2008-252201

In the wearable device described above, the wearing position with respect to the user is fixed by the arm, whereas in the ad hoc terminal, unlike the wearable device, the holding state is free and the user holds the wearable device at an arbitrary position. For example, an ad hoc terminal is held by the user by hand, is not fixed in position with respect to the human body, and is held in a chest or buttock pocket.

In such an ad hoc terminal, the position with respect to the human body, which can be regarded as a conductor, changes without being fixed, so that the radiated electric field differs depending on the position, and the communication characteristics change (deteriorate). Conventional technology has not been able to prevent fluctuations (deterioration) in communication characteristics due to changes in the position of the ad hoc terminal relative to the human body.

In one aspect, it is an object of the present invention to be able to suppress gain fluctuations with a simple structure.

In one proposal, the antenna device is an antenna device having a GND surface and a radiation unit, wherein the radiation unit is provided along one side of the GND surface, and one end thereof is connected to a feeding point. It is provided along the first radiating portion having a length from the feeding point of 1 / 4λ of the communication wavelength λ and the other side portion of the GND surface, is provided parallel to the first radiating portion, and one end is a free end. The second radiation portion having a length from the free end of 1 / 4λ of the communication wavelength λ is conductively connected to the other end portion of the first radiation portion and the other end portion of the second radiation portion. It is required to have three radiating portions and that the currents flowing through the first radiating portion and the second radiating portion are in the same direction.

According to one embodiment, there is an effect that the gain fluctuation can be suppressed with a simple structure.

FIG. 1 is a diagram showing an antenna device according to an embodiment. FIG. 2 is a diagram showing an existing general antenna device. FIG. 3 is a diagram illustrating a gain fluctuation state for each usage position by the existing antenna device. FIG. 4 is a chart showing the directivity of each used position by the existing antenna device. FIG. 5 is a diagram showing a current distribution of an existing antenna device. FIG. 6 is a diagram showing a current distribution of the antenna device according to the embodiment. FIG. 7 is a diagram showing the gain for each used position by the antenna device according to the embodiment. FIG. 8 is a diagram showing a field emission state of the antenna device according to the embodiment. FIG. 9 is a diagram illustrating element spacing of the antenna device according to the embodiment. FIG. 10 is a diagram showing another configuration example of the antenna device of the embodiment. FIG. 11 is a diagram showing the current distribution of the antenna device shown in FIG. FIG. 12 is a diagram showing a hardware configuration example of a wireless communication device provided with the antenna device of the embodiment. FIG. 13 is a diagram showing an example of mounting the antenna device of the embodiment on a wireless communication device.

(Embodiment)
FIG. 1 is a diagram showing an antenna device according to an embodiment. 1 (a) is a perspective view, and FIG. 1 (b) is a side view. The antenna device 100 is provided in a wireless communication device that can be held and carried by a user such as the above-mentioned ad hoc terminal at a free position.

The antenna device 100 shown in FIG. 1 includes a ground (GND) surface 101 made of a conductor having a predetermined area, and a radiating portion 102 made of a rod-shaped conductor. In the radiation portion 102, one base end portion 102a is connected to the feeding point P, and a predetermined length (3/4 λ, λ: wavelength of the fundamental wave of communication) extends around the GND surface 101 to the tip portion 102b which is a free end. ) Is provided. With respect to the length of the radiating portion 102, when the harmonic n is included, the total length is (4n + 3) λ / 4 (however, an integer of n ≧ 0).

For the radiation unit 102, for example, a metal plate or rod can be used. In the example of FIG. 1, the tip portion 102b of the radiation portion 102 is provided so as to project (5 mm) from the GND surface 101 with respect to the length direction Y. Although not shown, a matching circuit for impedance matching is provided at the feeding point P.

The base end portion 102a of the radiation portion 102 is provided at the feeding point P portion, and is electrically connected to a conductive holding block 103 having a predetermined height in the direction Z with respect to the GND surface 101. The radiating portion 102 was along the first radiating portion 111 along one side portion 101a of the GND surface 101, the second radiating portion 112 along the other side portion 101c of the GND surface 101, and the bottom portion 101b of the GND surface 101. The third radiation unit 113 and the like are included.

The radiation unit 102 arranges the first radiation unit 111 and the second radiation unit 112 in parallel at predetermined intervals. Then, by conducting a conductive connection between the end portion 102c of the first radiating portion 111 and the end portion 102d of the second radiating portion 112 by the third radiating portion 113, the radiating portion 102 has a substantially flat surface due to one conductor. It is formed in a U shape. The end portion 102c is located at the other end of the base end portion 102a of the first radiating portion 111, and the end portion 102d is located at the other end of the tip portion 102b of the second radiating portion 112.

The first radiation unit 111, the second radiation unit 112, and the third radiation unit 113 each have a length of approximately 1 / 4λ. In the example of FIG. 1, the GND surface 101 has a rectangular parallelepiped shape in which the length direction Y is formed longer than the width direction X. Not limited to this, a square shape may be formed in which the width direction X and the length direction Y have the same length.

In the example of FIG. 1, the feeding point P is arranged at a predetermined length in the length direction Y from the apex (corner portion of the GND surface 101) of the one side portion 101a, but the feeding point P is arranged on one side. It may be arranged at the apex of the portion 101a (the corner portion of the GND surface 101).

As shown in FIG. 1 (b), the antenna device 100 is entirely covered with a cover 120 formed by filling a resin material such as PET or the like. For example, the antenna device 100 can be manufactured as one component by molding the GND surface 101 and the radiating portion 102 with a resin material. Further, the cover 120 makes it possible to hold the position of the radiating portion 102 with respect to the GND surface 101 at a fixed position.

As a result, a predetermined antenna characteristic can be obtained, and the work of incorporating the antenna device 100 into the wireless communication device can be easily performed. It should be noted that various parts of the wireless communication device, for example, a battery and a display unit can be arranged on the GND surface 101 portion surrounded by the radiation portion 102.

Next, the antenna device 100 having the above configuration will be described including the problems of the existing antenna device.

FIG. 2 is a diagram showing an existing general antenna device. FIG. 2 shows a 1 / 4λ inverted L-shaped antenna device 200, which is provided with a GND surface 201 and a radiation unit provided along one side portion 201a of the GND surface 201 with a length of 1/4λ from the feeding point P. It has 202. 201a is one side of the GND surface 201, 201b is the bottom of the GND surface 201, and 201c is the other side of the GND surface 201.

Here, it is assumed that the existing antenna device 200 shown in FIG. 2 and the antenna device 100 of the embodiment shown in FIG. 1 have the same size, for example, the GND surfaces 101 and 201.

FIG. 3 is a diagram illustrating a fluctuation state of the gain for each used position by the existing antenna device. FIG. 3A is a diagram showing the positional relationship between the human body model as a user and the wireless communication device (antenna device 200). The human body model 300 is a model of a human torso in a rectangular shape, and the human body constant has a relative permittivity of 41.5 and a conductivity of 0.97 S / m. Then, it is assumed that the antenna device 200 is moved along the width direction X with respect to the human body model 300 at the fixed position. The moving distance is 400 mm.

FIG. 3B is a chart showing simulation results of operating gain in the front direction (Z direction) of the human body when the antenna device 200 is moved in the width direction X under each condition shown in FIG. 3A. .. The horizontal axis is the position [mm] of the antenna device 200 with respect to the human body model 300, and the vertical axis is the operating gain [dBi]. The fundamental wave (λ) is 920 MHz, and the matching circuit is a 1/4 inverted L-shaped radiator 202-series inductor (0.8 [nH]) -parallel inductor (1.85 [nH]) -feed point. It is a circuit configuration of P.

As shown in FIG. 3B, as the antenna device 200 is moved from the left end (0 mm) of the human body model 300 in the width direction X, the operating gain greatly fluctuates in the region (300 mm to 400 mm) approaching the right end (400 mm). You can see that it is doing. The operating gain is most reduced near the right end (360 mm). Such a fluctuation in gain depending on the position where the antenna device 200 (wireless communication device) is used with respect to the user's human body leads to deterioration of communication quality. Therefore, it is necessary to suppress the fluctuation of the gain even if the position where the antenna device 200 (wireless communication device) is used with respect to the human body changes. The characteristic of FIG. 3B shows the operating gain with respect to the fundamental wave, but the same characteristic is obtained for the harmonic n (n = 1, 2, ...).

FIG. 4 is a chart showing the directivity of each used position by the existing antenna device. FIG. 4A is a simulation result showing the directivity D when the antenna device 200 (wireless communication device) is arranged at the center (200 mm) of the human body model 300. When the antenna device 200 (wireless communication device) is located at the center (200 mm) of the human body model 300, the radiation pattern of the antenna device 200 has a directivity D facing the front direction (180 °) opposite to the human body model 300.

FIG. 4B is a simulation result showing the directivity D when the antenna device 200 (wireless communication device) is arranged near the right end (360 mm) of the human body model 300. When the antenna device 200 (wireless communication device) is located near the right end (360 mm) of the human body model 300, the radiation pattern of the antenna device 200 has a (0 °) partial directivity d1 in the back direction of the human body model 300. There is. In addition, the frontal (180 °) partial directivity d2 of the human body model 300 has a weaker portion than in FIG. 4 (a).

FIG. 5 is a diagram showing a current distribution of an existing antenna device. The result of simulating the current distribution on the GND surface 201 of the antenna device 200 is shown. As shown in FIG. 5, in the antenna device 200, the current on the one side portion 201a on which the element (radiating portion) 202 is arranged is strong. From this, the inventors presumed that the electric field generated by this current wraps around the side surface (right side) of the human body model 300, and a state in which radio waves are not radiated in the front direction (FIG. 4 (b)) has occurred.

As a countermeasure against the problem of the existing antenna device 200, the inventors are strong not only in the one side portion (right side) 201a provided with the feeding point P of the antenna device 200 but also in the other side portion 201c on the left side. We thought that it would be effective to form an electric current and contribute to radiation. As a result, even if the radio wave wraps around behind the human body on one side (right side) 201a, it is estimated that the radio wave on the other side (left side) 201c can radiate the radio wave in the front direction of the human body.

Then, in addition to the configuration in which one element (radiating portion) 202 is arranged on one side portion (right side) 201a as in the existing antenna device 200, one element (radiating portion) is also arranged on the other side portion (left side) 201c. Part) Considering the additional placement of 202. However, in this configuration, the number of elements (radiating portions) 202 is two, the number of antennas is increased, the antenna circuit is complicated, and the mounting cannot be easily performed.

Therefore, the antenna device 100 of the embodiment solves the problem of the existing antenna device 200 with only one element (radiating unit) 102. The radiation unit 102 of the embodiment shown in FIG. 1 has both sides of the GND surface 101 in the width direction X in which the wireless communication device (antenna device 100) mainly moves when the user (person) holds the wireless communication device in his / her hand. A region with a strong current is formed in the portion (one side portion 101a and the other side portion 101c).

Therefore, as the radiating portion 102, the first radiating portion 111 is provided on one side portion 101a of the GND surface 101, and the second radiating portion 112 is provided on the other side portion 101c. Then, the radiation unit 102 connects the first radiation unit 111 and the second radiation unit 112 by the third radiation unit 113. As will be described later, the first radiation unit 111 and the second radiation unit 112 are set at appropriate intervals with respect to the width direction X so that a predetermined gain can be obtained. Further, the directions of the currents flowing through the first radiating section 111 and the second radiating section 112 are the same. With the antenna device 100 of such an embodiment, even if the position of the antenna device 100 with respect to the human body changes, radio waves can be radiated in the front direction of the human body so that a stable gain can be obtained.

In the example shown in FIG. 1, the radiation unit 102 shows a substantially U-shaped example in which the first radiation unit 111 and the second radiation unit 112 are connected by a linear third radiation unit 113, but the present invention is limited to this. No. The radiation unit 102 of the embodiment may be provided with the third radiation unit 113 so that the current directions flowing through the first radiation unit 111 and the second radiation unit 112 are the same, and the third radiation unit 113 has various shapes. Can be shaped. For example, the third radiating portion 113 that conductively connects the end portion 102c of the first radiating portion 111 and the end portion 102d of the second radiating portion 112 has a curved shape rather than a linear shape, and the entire radiating portion 102 is substantially M. It may be in the shape of a. Further, the third radiating portion 113 may have a jagged shape having more bent points or a meander shape.

FIG. 6 is a diagram showing a current distribution of the antenna device according to the embodiment. FIG. 6A shows the result of simulating the current distribution on the GND surface 101 of the antenna device 100 (see FIG. 1) of the embodiment. FIG. 6A shows the current distribution on the GND surface 101 when the element (radiating unit) 102 is provided as the antenna device 100, although the element (radiating unit) 102 is not shown. FIG. 6B shows the result of simulating the magnitude and direction of the current of the element (radiating portion) 102 of the antenna device 100 of the embodiment.

As shown in FIG. 6A, on the GND surface 101 of the antenna device 100, a region having a strong current is formed not only on the one side portion 101a provided with the feeding point P but also on the other side portion 101c on the opposite side. Has been done.

Further, as shown in FIG. 6B, regarding the radiating portion 102 of the antenna device 100, the first radiating portion 111 has the largest current at the proximal end portion 102a connected to the feeding point P, and has the largest current in the length direction Y ( The current i gradually decreases toward the third radiation unit 113) and reaches 0. Further, in the second radiating portion 112, the current i of the tip portion 102b is 0, and the current i gradually increases toward the length direction Y (third radiating portion 113). Here, the directions of the currents i of the first radiating portion 111 and the second radiating portion 112 are both in the same direction along the length direction Y.

FIG. 7 is a diagram showing the gain for each used position by the antenna device according to the embodiment. FIG. 7A is a diagram showing the positional relationship between the human body model as a user and the wireless communication device (antenna device 100). The human body constant of the human body model 300 is the same as that of the existing antenna device 200 (see FIG. 3) described above. Then, it is assumed that the antenna device 200 is moved along the width direction X with respect to the human body model 300 at the fixed position. The moving distance is 400 mm.

FIG. 7B is a chart showing the simulation results of the operating gain in the front direction (Z direction) of the human body when the antenna device 100 is moved in the width direction X under each condition shown in FIG. 7 (a). .. The horizontal axis is the position [mm] of the antenna device 100 with respect to the human body model 300, and the vertical axis is the operating gain [dBi]. The fundamental wave (λ) is 920 MHz. The matching circuit has a circuit configuration of a 3/4 λ U-shaped radiation unit 102-parallel inductor (5.0 [nH]) -feeding point P. The characteristics of the existing antenna device 200 are also described for comparison.

As shown in FIG. 7B, when the antenna device 100 of the embodiment is moved from the left end (0 mm) of the human body model 300 in the width direction X, the fluctuation of the operating gain is small up to the right end (400 mm). The result was.

In particular, in the existing antenna device 200, the operating gain is greatly reduced (fluctuation of about 2.5 dB) in the region (300 mm to 400 mm) close to the right end (400 mm), whereas it operates in the region near the right end. It was possible to suppress the fluctuation of the gain to a small extent (within 1 dB). Further, the antenna device 100 of the embodiment can improve the overall operating gain as compared with the existing antenna device 200. Although the characteristic of FIG. 7B shows the operating gain with respect to the fundamental wave, the same characteristic can be obtained for the harmonic n (n = 1, 2, ...).

FIG. 8 is a diagram showing a field emission state of the antenna device according to the embodiment. FIG. 8A is a simulation result of field emission when the antenna device 100 (wireless communication device) of the embodiment is arranged near the right end (360 mm) of the human body model 300.

As shown in this figure, according to the antenna device 100 of the embodiment, a strong electric field is generated at both ends of the antenna device 100 (wireless communication device), and the electric fields at both ends are combined to be in the front direction (Z direction) of the human body. You can see that it is being radiated.

According to the embodiment, it can be seen that strong electric fields are radiated from both side portions (one side portion 101a and the other side portion 101c) of the antenna device 100. As described above, on both sides of the antenna device 100 of the embodiment, the first radiating portion 111 is provided on one side portion 101a of the GND surface 101, and the second radiating portion 112 is provided on the other side portion 101c of the GND surface 101. Is provided.

The antenna device 100 of the embodiment also has a component in which the electric field wraps around behind the human body model 300, but the strong electric field corresponding to the first radiating portion 111 and the second radiating portion 112 is two in the width direction X. I have it at the place. As a result, it is presumed that the electric field on the side of the second radiation unit 112 contributes to the radiation in the front direction (Z direction) of the human body model 300.

FIG. 8B is a simulation result of the electrolytic radiation of the existing antenna device 200 for comparison. In the existing antenna device 200, it can be seen that a strong electric field is radiated from one side (right side) of the antenna device 200. As described above, the radiation portion 202 is provided only on one side portion 201a of the GND surface 201 on one side portion (right side) of the existing antenna device 200. In the existing antenna device 200, the radiation from one side portion 201a (right side) of the human body model 300 to the back of the human body model 300 is reduced by that amount in the front direction (Z direction) of the human body model 300. ..

As described above, according to the antenna device 100 of the embodiment, even when the antenna device 100 is located in the vicinity of one side portion 101a of the human body model 300, radiation in the front direction (Z direction) of the human body model 300 is provided. I was able to strengthen. This is because the first radiating portion 111 is provided on one side portion 101a of the GND surface 101 and the second radiating portion 112 is provided on the other side portion 101c of the GND surface 101 as the radiating portion 102 of the antenna device 100. It corresponds.

In the existing antenna device 200, the electric field strength of the radiated radio wave is biased to one side (right side) from the center position of the antenna device 200. As a result, when the existing antenna device 200 is located on the right side of the human body model 300, the electric field radiated from the radiating unit 202 provided only on the one side portion 201a (right side) wraps around from the right side of the human body model 300 to the back. Then, it is presumed that the radiation in the front direction (Z direction) of the human body model 300 is low.

On the other hand, in the antenna device 100 of the embodiment, the electric field strength of the radiated radio wave is radiated evenly from the center position of the antenna device 100 toward the front direction (Z direction) of the human body model 300. As a result, even when the antenna device 100 of the embodiment is located on the right side of the human body model 300, the electric field radiated from the radiating portions 102 provided on both side portions (right side and left side) causes the front direction (Z) of the human body model 300. It is presumed that the radiation in the direction) could be strengthened.

FIG. 9 is a diagram illustrating element spacing of the antenna device according to the embodiment. As shown in FIG. 9A, the first radiation unit 111 and the second radiation unit 112 of the radiation unit 102 of the antenna device 100 have an element spacing λx. The characteristics of the variable element spacing λx are shown in FIG. 9 (b). The horizontal axis of FIG. 9B is the element spacing [λx], and the vertical axis is the operating gain [dBi].

When the element spacing is narrowed, the first radiating portion 111 and the second radiating portion 112 are close to each other, so that the radiating portion 102 has a substantially hairpin shape. On the other hand, when the element spacing is widened, the first radiating portion 111 and the second radiating portion 112 are separated from each other, so that the radiating portion 102 becomes substantially linear.

As shown in FIG. 9B, the gain decreases as the element spacing is narrowed and the element spacing is widened. This is because the narrower the element spacing and the wider the element spacing, the greater the influence from the human body.

Here, the entire element, that is, the total length from the base end portion 102a to the tip end portion 102b of the radiation portion 102 (first radiation portion 111 to third radiation portion 113 to second radiation portion 112) is 3/4 λ, λ = 920 MHz. Suppose there is. In this case, as shown in FIG. 9B, the element spacing λx is preferably in the range of 0.125 to 0.33 [λx], and is based on -6 dB, which has the smallest operating gain. The optimum element spacing is 0.25 [λx] λ where the gain is located at the apex. That is, in order to reduce the influence of the antenna device 100 on the human body, the element spacing may be 0.125 [λx] or more and 0.33 [λx] or less.

FIG. 10 is a diagram showing another configuration example of the antenna device of the embodiment. In the antenna device 100 of FIG. 10, the same components as those of FIG. 1 are designated by the same reference numerals. In the antenna device 100 of FIG. 10, the tip end portion 102b of the radiation portion 102 is bent in the width direction X along the upper portion 101d of the GND surface 101 as compared with FIG.

As long as the radiating portion 102 has a total length of 3/4 λ as described above, the tip portion 102b may be further bent as shown in FIG. In the example of FIG. 10, the width x1 of the bent portion of the tip portion 102b is 5 mm. Here, as shown in FIG. 10, the tip portion 102b is partially accommodated according to the accommodation state of the antenna device 100 with respect to the wireless communication device, for example, the arrangement, shape, and size of various electronic components accommodated inside the wireless communication device. It may be bent as a target.

For example, in the structure of the antenna device 100 shown in FIG. 1, the proximal end portion 102a of the radiating portion 102 (first radiating portion 111) connected to the feeding point P is located at an intermediate position of the GND surface 101 in the length direction Y. doing. In this case, in order to make the total length of the radiating portion 102 3/4 λ, as shown in FIG. 1, the tip portion 102b of the radiating portion 102 (second radiating portion 112) protrudes above the GND surface 101. In such a case, as shown in FIG. 10, the tip portion 102b of the radiation portion 102 is bent. As a result, the tip portion 102b of the radiating portion 102 is prevented from protruding, the antenna device 100 can be easily handled, and the antenna device 100 can be easily incorporated into the wireless communication device.

FIG. 11 is a diagram showing the current distribution of the antenna device shown in FIG. FIG. 11A shows the result of simulating the current distribution on the GND surface 101 of the antenna device 100 of FIG. FIG. 11A shows a current distribution on the GND surface 101 when the element (radiating unit) 102 is provided as the antenna device 100, although the element (radiating unit) 102 is not shown. FIG. 11B shows the result of simulating the magnitude and direction of the current of the element (radiating portion) 102 of the antenna device 100 of FIG.

Then, as shown in FIG. 11A, the GND surface 101 of the antenna device 100 has a region in which the current is strong not only in the one side portion 101a provided with the feeding point P but also in the other side portion 101c on the opposite side. Is formed. FIG. 11A has almost the same current distribution as FIG. 6A.

Further, as shown in FIG. 11B, regarding the radiating portion 102 of the antenna device 100, in the first radiating portion 111, the current of the proximal end portion 102a connected to the feeding point P is the largest, and the current in the length direction Y ( The current i gradually decreases toward the third radiation unit 113) and reaches 0. Further, in the second radiating portion 112, the current i of the bent tip portion 102b is 0, and the current i gradually increases in the length direction Y (third radiating portion 113). Here, the directions of the currents i of the first radiating portion 111 and the second radiating portion 112 are both in the same direction along the length direction Y.

Here, since the current of the tip portion 102b of the radiation portion 102 is small, there is no effect on the reduction of the characteristic variation due to the above-mentioned human body arrangement. That is, both when the tip portion 102b of the radiation portion 102 is bent as shown in FIG. 10 and when the tip portion 102b of the radiation portion 102 is projected from the GND surface 101 as shown in FIG. 1, radiation is emitted. The current of the tip portion 102b of the portion 102 is a small current of about 0. As a result, when the tip portion 102b of a small current is bent as shown in FIG. 10, even if the position of the antenna device 100 with respect to the human body changes, the gain fluctuation can be suppressed as in the configuration example of FIG. Can be done.

FIG. 12 is a diagram showing a hardware configuration example of a wireless communication device provided with the antenna device of the embodiment. The wireless communication device 1200 includes a processor 1201 such as a CPU that functions as a control unit, a memory 1202 such as a ROM and a RAM, a storage unit 1203 such as an HDD, an SSD, and a flash memory, an input / output interface (IF) 1204, and a wireless communication unit 1205. including. Reference numeral 1206 is a bus for transferring data between the CPU 1201 and peripheral devices (memory 1202, storage unit 1203, input / output IF 1204), and wireless communication unit 1205.

The above CPU is an abbreviation for Central Processing Unit, ROM is an abbreviation for Read Only Memory, and RAM is an abbreviation for Random Access Memory. HDD is an abbreviation for Hard Disk Drive, and SSD is an abbreviation for Solid State Drive.

The CPU 1201 executes a control program stored in a memory 1202 such as a ROM, and at this time, by using a part of the memory 1202 such as a RAM for a work area, each function of the wireless communication device, for example, transmission / reception by wireless communication is performed. Perform data processing. For example, as described above, the CPU 1201 receives information on the state of the user (human body) transmitted from the wearable terminal, performs predetermined data processing, and transmits the processed data to the data center. At this time, the CPU 1201 may use the storage unit 1203 as an expansion area or a backup area of the memory 1202.

The input / output interface (IF) 1204 inputs / outputs data to / from the wireless communication device 1200. For example, a touch panel, a keyboard, a microphone, or the like is connected to the input / output IF 1204, and data can be input by user operation. Further, a display unit such as an LCD is connected to the input / output IF 1204, and display data can be output to the screen. LCD is an abbreviation for Liquid Crystal Display.

The wireless communication unit 1205 transmits / receives data to / from the wireless communication device 1200 between other wireless communication devices, for example, a wearable terminal worn by the user and the wireless communication unit of the data center, respectively, as described above. It is a communication unit. The frequency used is, for example, a 920 MHz band and a 2.4 GHz band. The above-mentioned antenna device 100 is connected to the wireless communication unit 1205, and data is transmitted / received by wireless radio waves to and from another wireless communication device via the antenna device 100.

FIG. 13 is a diagram showing an example of mounting the antenna device of the embodiment on a wireless communication device. As described above, the antenna device 100 is mounted inside the wireless communication device 1200 together with various electronic components.

FIG. 13A shows an example of mounting the antenna device 100 on the smartphone 1200a as the wireless communication device 1200. The radiating unit 102 (first radiating unit 111, second radiating unit 112, third radiating unit 113) of the antenna device 100 can be arranged along the side side of the LCD 1301 arranged inside the smartphone 1200a. Further, the GND surface 101 of the antenna device 100 can be GND-connected to the LCD 1301 by a flexible cable or the like.

FIG. 13B shows an example of mounting the antenna device 100 on the tablet 1200b as the wireless communication device 1200. The radiation unit 102 (first radiation unit 111, second radiation unit 112, third radiation unit 113) of the antenna device 100 shall be arranged along the side of an electronic component, for example, SSD 1302, which is arranged inside the tablet 1200b. Can be done. Further, the GND surface 101 of the antenna device 100 can be GND-connected to the SSD 1302 by a flexible cable or the like. Reference numeral 1303 is an LCD.

In the example of FIG. 13A, the radiation unit 102 of the antenna device 100 is arranged along the outer circumference of the smartphone 1200a (wireless communication device 1200). In the example of FIG. 13 (b), the radiation unit 102 of the antenna device 100 is arranged along the outer circumference of the electronic component (SSD 1302) inside the tablet 1200b (wireless communication device 1200).

In any of the examples of FIGS. 13A and 13B, the antenna device 100 is overlapped with an electronic component corresponding to the outer diameter, that is, the GND surface 101, or the width, length, and thickness of the radiation unit 102. Can be placed.

At this time, as shown in FIG. 1, the above LCD1201 is formed in a region on the surface of the GND surface 101 surrounded by the first radiation unit 111, the second radiation unit 112, and the third radiation unit 113 as the radiation unit 102. And SSD1301 are placed. Further, the outer diameter of the electronic component to be accommodated may be determined according to the outer diameter of the antenna device 100. As a result, the antenna device 100 can be efficiently arranged in the wireless communication device 1200, and the installation space can be reduced.

Hereinafter, the comparison between the embodiment and the invention described in the above-mentioned Patent Documents 1 to 4 will be described. In any of the inventions described in Patent Documents 1 to 4, it is not possible to prevent fluctuation (deterioration) of the communication characteristics of the antenna device due to a change in the relative position between the wireless communication device and the human body.

According to the embodiment, the radiation unit 102 is provided with a first radiation unit 111 and a second radiation unit 112 having a length of 1 / 4λ on both sides of the GND surface 101, respectively, and the first radiation unit 102 is provided. The current directions of the radiation unit 111 and the second radiation unit 112 are the same. The first radiation unit 111 and the second radiation unit 112 have an appropriate element spacing λx along the length direction Y orthogonal to the width direction X in which the wireless communication device (antenna device 100) moves. Is provided.

As a result, according to the embodiment, even when the wireless communication device (antenna device 100) moves in the width direction X and is located on the side of the human body (human body model 300), the electric field wraps around the back surface of the human body. It can be suppressed. Then, the component of the electric field in the front direction can be strengthened, and the deterioration of the antenna characteristics due to the decrease in gain can be suppressed.

On the other hand, in the invention described in Patent Document 1, the length of the radiating element is set to (2n + 1) / 4 (n is an integer of n> 1) in order to use a plurality of communication frequency bands. Yes, it does not include the length of 3/4 λ used in the embodiments. If the radiating element of Patent Document 1 has a length of 3/4 λ, the antenna characteristics deteriorate. Further, the radiating element is provided over almost the entire circumference, and is different from the radiating section 102 described in the embodiment, and has the first radiating section 111 and the second radiating section 112 having the same current direction. No. As a result, when the wireless communication device (antenna device 100) moves, the gain changes due to the change in the position relative to the human body, and the antenna characteristics deteriorate.

Further, the invention described in Patent Document 2 has a hairpin structure in which parallel first elements and second elements are arranged close to each other, and does not have the optimum element spacing λx as in the embodiment. Further, the element arrangement does not correspond to the change in the position relative to the human body when the wireless communication device (antenna device 100) moves. As a result, a sufficient gain cannot be obtained, and when the wireless communication device (antenna device 100) moves, the gain changes due to a change in the position relative to the human body, and the antenna characteristics deteriorate.

Further, the invention described in Patent Document 3 is an inverted L-shaped element structure, a hairpin structure in which the first element and the second element are arranged close to each other, and a structure in which detour elements are also arranged close to each other. It does not have the optimum element spacing λx as in the embodiment. Further, the structure is such that the detour element is arranged away from the GND surface, which is different from the configuration in which the radiation unit 102 is arranged along the outer periphery of the GND surface 101 as in the embodiment. As a result, in Patent Document 3, a strong current distribution cannot be obtained on both sides of the GND surface. Further, the element arrangement does not correspond to the change in the position relative to the human body when the wireless communication device (antenna device 100) moves. As a result, when the wireless communication device (antenna device 100) moves, the gain changes due to the change in the position relative to the human body, and the antenna characteristics deteriorate.

Further, although the invention described in Patent Document 4 has a U-shaped element structure, the first conductor portion and the second conductor portion are arranged close to each other, and the optimum element spacing as in the embodiment is obtained. Does not have λx. Further, the structure is such that the first conductor portion and the second conductor portion are arranged apart from the GND surface, which is different from the configuration in which the radiation portion 102 is arranged along the outer periphery of the GND surface 101 as in the embodiment. .. As a result, in Patent Document 3, a strong current distribution cannot be obtained on both sides of the GND surface. Further, the element arrangement does not correspond to the change in the position relative to the human body when the wireless communication device (antenna device 100) moves. As a result, when the wireless communication device (antenna device 100) moves, the gain changes due to the change in the position relative to the human body, and the antenna characteristics deteriorate.

According to the antenna device of the embodiment described above, the gain fluctuation can be suppressed with a simple structure. The antenna device of the embodiment forms a region where a strong current is strong on both sides of the GND surface in the width direction X in which the wireless communication device mainly moves when the user carries the wireless communication device provided with the antenna device. Therefore, as a radiation unit that is an element of the antenna device, a first radiation unit is provided on one side of the GND surface, and a second radiation unit is provided on the other side. Then, the first radiating section and the second radiating section were connected by the third radiating section, and the directions of the currents flowing through the first radiating section and the second radiating section were the same. As a result, according to the embodiment, even if the position of the antenna device is changed to be located on the right side or the left side of the human body and at each position in the middle, radio waves can be radiated in the front direction of the human body and moved. A stable gain can be obtained regardless of the position. This makes it possible to improve the antenna characteristics of the antenna device.

The first radiation unit and the second radiation unit have a predetermined interval with respect to one direction (width direction X) in which the movement of the antenna device changes, and the direction orthogonal to the one direction (length direction Y). Provided along the line. As a result, even when an electric field wraps around the back of the human body from the right side or the left side due to the movement of the wireless communication device as described above, the component on the front side of the radiated electric field can be strengthened and the gain can be improved. Become. Further, the radiating portion is composed of one element by conducting a conductive connection in which the first radiating portion and the second radiating portion are connected by the third radiating portion. As a result, the number of elements can be minimized to reduce the number of parts, the matching circuit can be easily manufactured, and the mounting on a wireless communication device can be facilitated.

Further, by setting the total length of the radiation unit to (4n + 3) λ / 4 (however, an integer of harmonic n ≧ 0), an antenna device having an optimum gain for the communication wavelength including harmonics can be obtained. become. Further, by setting the distance between the first radiation part and the second radiation part of the radiation part to be an appropriate distance with respect to the communication wavelength λ, for example, in the range of 0.125λ or more and 0.33λ or less, a high gain can be obtained. It can be obtained, and the highest gain can be obtained at 0.25λ.

Further, when the tip of the radiation portion protrudes from the GND surface, the free end may be bent along the GND surface by a predetermined length. Even in this case, since the current flowing through the free end of the radiating portion is 0, it is possible to facilitate assembly and handling while preventing a decrease in gain.

Further, the antenna device can be efficiently mounted on the wireless communication device. The GND surface of the antenna device is flat, and various parts of the wireless communication device can be stacked and arranged. At this time, in addition to arranging the radiating portion along the outer circumference of the wireless communication device, the mounting space can be efficiently used by arranging the radiating portion along the outer circumference of various parts of the wireless communication device.

The following additional notes are further disclosed with respect to the above-described embodiment.

(Appendix 1) In an antenna device having a GND surface and a radiation unit,
The radiating part is
A first radiation section provided along one side of the GND surface, one end of which is connected to a feeding point, and a length from the feeding point of 1/4 λ of the communication wavelength λ.
A second portion provided along the other side of the GND surface, parallel to the first radiation portion, one end thereof is a free end, and the length from the free end is 1/4 λ of the communication wavelength λ. Radiant part and
It has a third radiating portion that conductively connects the other end of the first radiating portion and the other end of the second radiating portion.
An antenna device characterized in that the currents flowing through the first radiating portion and the second radiating portion are in the same direction.

(Supplementary note 2) The antenna device according to Supplementary note 1, wherein the total length of the radiation portion is (4n + 3) λ / 4 (provided that the harmonic wave is an integer of n ≧ 0).

(Appendix 3) The first radiation unit and the second radiation unit have a predetermined distance from one direction in which the movement of the antenna device changes, and are provided along the direction orthogonal to the one direction. The antenna device according to Appendix 1 or 2, wherein the antenna device is characterized by the above-mentioned.

(Appendix 4) The description in any one of the appendices 1 to 3, wherein the distance between the first radiating portion and the second radiating portion is in the range of 0.125λ or more and 0.33λ or less. Antenna device.

(Supplementary Note 5) The antenna device according to Supplementary Note 4, wherein the distance between the first radiating portion and the second radiating portion is 0.25λ.

(Supplementary Note 6) The antenna device according to any one of Supplementary note 1 to 5, wherein a portion having a predetermined length from the free end of the second radiating portion is further bent along the GND surface.

(Supplementary Note 7) The antenna device according to Supplementary Note 6, wherein the length of the bent portion of the second radiating portion is a portion having a length in which the flowing current is about 0.

(Appendix 8) In a wireless communication device having an antenna device and performing wireless communication with another wireless communication device.
A control unit that processes data sent and received to and from other wireless communication devices,
It has a wireless communication unit that transmits and receives the data by wireless communication with another wireless communication device via the antenna device.
The antenna device is
It has a GND surface and a radiation part,
The radiating part is
A first radiation section provided along one side of the GND surface, one end of which is connected to a feeding point, and a length from the feeding point of 1/4 λ of the communication wavelength λ.
A second portion provided along the other side of the GND surface, parallel to the first radiation portion, one end thereof is a free end, and the length from the free end is 1/4 λ of the communication wavelength λ. Radiant part and
It has a third radiating portion that conductively connects the other end of the first radiating portion and the other end of the second radiating portion.
A wireless communication device characterized in that the currents flowing through the first radiating section and the second radiating section are in the same direction.

(Supplementary Note 9) The wireless communication device according to Supplementary Note 8, wherein the radiating portion is provided along the outer periphery of the apparatus or along the outer periphery of an electronic component provided in the apparatus.

100 Antenna device 101 GND surface 102 Radiation part 102a Base end 102b Tip part 103 Holding block 111 1st radiation part 112 2nd radiation part 113 3rd radiation part 120 Cover 300 Human body model 1200 Wireless communication device 1200a Smartphone 1200b Tablet 1201 Processor 1202 Memory 1203 Storage unit 1204 Input / output interface 1205 Wireless communication unit 1301, 1303 LCD
1302 SSD
P feeding point λx element spacing

Claims (8)

In an antenna device having a GND surface and a radiation unit,
The radiating part is
A first radiation section provided along one side of the GND surface, one end of which is connected to a feeding point, and a length from the feeding point of 1/4 λ of the communication wavelength λ.
A second portion provided along the other side of the GND surface, parallel to the first radiation portion, one end thereof is a free end, and the length from the free end is 1/4 λ of the communication wavelength λ. Radiant part and
It has a third radiating portion that conductively connects the other end of the first radiating portion and the other end of the second radiating portion.
An antenna device characterized in that the currents flowing through the first radiating portion and the second radiating portion are in the same direction. The antenna device according to claim 1, wherein the total length of the radiation unit is (4n + 3) λ / 4 (provided, an integer of harmonic n ≧ 0). The first radiation unit and the second radiation unit have a predetermined distance from one direction in which the movement of the antenna device changes, and are provided along the direction orthogonal to the one direction. The antenna device according to claim 1 or 2. The antenna device according to any one of claims 1 to 3, wherein the distance between the first radiation unit and the second radiation unit is in the range of 0.125λ or more and 0.33λ or less. The antenna device according to claim 4, wherein the distance between the first radiation unit and the second radiation unit is 0.25λ. The antenna device according to any one of claims 1 to 5, wherein a portion having a predetermined length from the free end of the second radiating portion is further bent along the GND surface. In a wireless communication device that has an antenna device and performs wireless communication with other wireless communication devices,
A control unit that processes data sent and received to and from other wireless communication devices,
It has a wireless communication unit that transmits and receives the data by wireless communication with another wireless communication device via the antenna device.
The antenna device is
It has a GND surface and a radiation part,
The radiating part is
A first radiation section provided along one side of the GND surface, one end of which is connected to a feeding point, and a length from the feeding point of 1/4 λ of the communication wavelength λ.
A second portion provided along the other side of the GND surface, parallel to the first radiation portion, one end thereof is a free end, and the length from the free end is 1/4 λ of the communication wavelength λ. Radiant part and
It has a third radiating portion that conductively connects the other end of the first radiating portion and the other end of the second radiating portion.
A wireless communication device characterized in that the currents flowing through the first radiating section and the second radiating section are in the same direction. The wireless communication device according to claim 7, wherein the radiation unit is provided along the outer circumference of the device or along the outer circumference of an electronic component provided in the device.

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