JP7370916B2 - array antenna - Google Patents

Description

The present invention relates to an array antenna.

Conventionally, an array antenna has been proposed that includes a plurality of feeding elements lined up in a first direction and parasitic elements arranged to sandwich the feeding element in the first direction (for example, see Patent Document 1). ). In the array antenna described in Patent Document 1, a parasitic element is provided to cause multiple resonance and to achieve a wide band.

JP2019-186966A

However, in an array antenna including fed elements and parasitic elements as described in Patent Document 1, as the number of fed elements and parasitic elements increases, the frequency dependence of the antenna gain increases (that is, the frequency dependence of the antenna gain increases). When graphed with the horizontal axis as the horizontal axis and the antenna gain as the vertical axis, there were cases in which the flatness of the antenna gain decreased. Therefore, it has been desired to further improve the flatness of the antenna gain.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide an array antenna that can improve the flatness of antenna gain.

In order to achieve the above object, an array antenna according to the present invention includes an insulating part, an antenna part provided on one surface side with respect to the insulating part, and a spaced apart part from the antenna part in the insulating part. a conductor section provided in the antenna section, and the antenna section includes a plurality of element rows in which a plurality of first elements connected to the signal generation section from a predetermined direction are arranged in a cross direction intersecting the predetermined direction; and a second element arranged to sandwich the first element from the intersecting direction, and at least one of the plurality of second elements is electrically connected to the conductor part. shall be.

In the array antenna according to one aspect of the present invention, the second elements located second from one end and the other end in the cross direction among the plurality of second elements are electrically connected to the conductor part. ing.

In the array antenna according to one aspect of the present invention, the second elements located third from one end and the other end in the cross direction among the plurality of second elements are electrically connected to the conductor part. ing.

In the array antenna according to one aspect of the present invention, the insulating section includes a substrate main body, a through hole formed in the substrate main body, and a conductive via provided on an inner peripheral surface of the through hole. , the second element is electrically connected to the conductor portion via the conductive via.

In the array antenna according to one aspect of the present invention, a position where the second element and the conductive via contact each other is arranged on a line connecting excitation centers of the plurality of first elements.

According to the array antenna according to the present invention, the flatness of antenna gain can be improved.

FIG. 1 is a front view of an array antenna according to an embodiment of the present invention. FIG. 1 is a plan view of an array antenna according to an embodiment of the present invention. 2 is a graph of electric field distribution of an array antenna according to an embodiment of the present invention and Comparative Example 1. FIG. 2 is a plan view and a front view for explaining simulation conditions of an example of the present invention. 3 is a graph of antenna gain frequency characteristics of array antennas of Example 1 and Comparative Example 2 of the present invention. 3 is a graph of antenna gain frequency characteristics of array antennas according to Examples 1 and 2 of the present invention. 3 is a graph of antenna patterns of array antennas of Example 2 of the present invention and Comparative Example 2. It is a graph of the antenna gain frequency characteristic of the array antenna of Examples 1, 3, 4, and 5 of this invention. 3 is a graph of antenna gain frequency characteristics of array antennas of Examples 6 to 10 of the present invention and Comparative Example 3. 3 is a graph of antenna gain frequency characteristics of array antennas of Examples 1 to 15 of the present invention. It is a graph of the gain ratio when changing the through-hole position in the array antenna of the example of the present invention. 3 is a graph of antenna gain frequency characteristics of array antennas of Examples 16A to 16C of the present invention. 7 is a graph of antenna gain frequency characteristics of array antennas of Examples 17A to 17C of the present invention. 7 is a graph of the gain ratio when the position of the second element is changed in the array antennas of Example 18 of the present invention and Comparative Example 3.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of an array antenna 1 according to an embodiment of the present invention, FIG. 2 is a plan view of an array antenna 1 according to an embodiment of the present invention, and FIG. 3 is a front view of an array antenna 1 according to an embodiment of the present invention. 3 is a graph of the electric field distribution of the array antenna 1 according to the configuration and Comparative Example 1. FIG.

As shown in FIGS. 1 and 2, the array antenna 1 according to the embodiment of the present invention has an insulating section 2 and one surface (hereinafter sometimes referred to as "one surface") with respect to the insulating section 2. ) An antenna section 4 provided on the 2B side, and a conductor section 3 provided at a distance from the antenna section 4 in the insulating section 2. The antenna section 4 includes an element array 41 in which a plurality of first elements 5 connected to the signal generation section from a predetermined direction (Y direction) are lined up in a cross direction (X direction) intersecting the predetermined direction, and each and a second element 6 arranged to sandwich the first element 5 from the intersecting direction. At least one of the plurality of second elements 6 is electrically connected to the conductor section 3. The array antenna 1 will be specifically explained below.

The array antenna 1 is, for example, a planar antenna constructed of a multilayer dielectric substrate. Hereinafter, the plane on which the array antenna 1, which is formed as a flat plate as a whole, extends will be referred to as the XY plane, and the direction perpendicular to the XY plane (thickness direction) will be referred to as the Z direction. In the Z direction, the conductor part 3, the insulating part 2, and the antenna part 4 are stacked in this order, and the conductor part 3 side is sometimes called the lower side, and the antenna part 4 side is sometimes called the upper side.

The insulating section 2 includes a substrate body 21 that is an insulating substrate (dielectric substrate) along the XY plane, a through hole 22 formed in the substrate body 21, and a conductor provided on the inner peripheral surface of the through hole 22. A conductive via 23 is formed. The lower surface in the Z direction of the substrate body 21 of the insulating section 2 is the other surface 2A, and the upper surface in the Z direction is the one surface 2B. A component provided on the other surface 2A and a component provided on one surface 2B with the conductive via 23 sandwiched therebetween are electrically connected.

The conductor portion 3 is a metal layer laminated on the other surface 2A of the insulating portion 2. The potential of the conductor portion 3 can be the reference potential of the array antenna. The conductor portion 3 only needs to have a volume sufficient to function as a metal layer serving as a reference potential, and may be formed so as to cover the entire surface 2A, or may be formed so as to cover only a part of the surface 2A. may be provided. In addition, the insulating part 2 is separated from the array antenna 1 by a structure in which the insulating part 2 includes the conductor part 3, a structure in which the insulating part 2 has the conductor part 3 and one or more other metal layers, etc. The conductor portion 3 can be provided so as to. Note that the conductor portion 3 may be grounded.

The antenna section 4 includes one element row 41 and a plurality of second elements 6. An element row 41 is formed by lining up the plurality of first elements 5 along the X direction in the XY plane. The first element 5 is a power feeding element connected to the signal generating section via a power feeding line 7 extending along the Y direction (direction orthogonal to the X direction in the XY plane). That is, a transmission signal is generated by a signal generation section having an oscillator, a modulator, etc., and this transmission signal is supplied as an electric signal to the first element 5, so that the first element 5 emits electromagnetic waves. There is. The element array 41 configured in this manner can radiate radio waves whose main polarization direction is the Y direction.

The first element 5 is composed of, for example, a metal thin film, and the metal thin film has a pair of sides 511 and 512 along the Y direction, and an end of the pair of sides 511 and 512 on one side in the Y direction (the upper side in FIG. 2). It has a side 513 that connects the two sides and extends along the X direction, and a connecting part 514 that is located between the pair of sides 511 and 512 on the other side of the side 513 in the Y direction (lower side in FIG. 2). A thin-film power supply line 7 is connected to the central portion of the connecting portion 514 in the X direction, and convex portions 52 and 53 protruding toward one side in the Y direction are formed at both ends of the connecting portion 514 in the X direction. ing. That is, recesses 54 and 55 are formed between the projections 52 and 53 and the power supply line 7, respectively. The first element 5 and the feeder line 7 are integrally formed. The first element 5 has the Y direction as the main polarization direction, and the resonance frequency is determined by the Y direction dimension of the first element 5 including the convex portions 52 and 53.

The second element 6 is a parasitic element (so-called parasitic element) and is not connected to the signal generating section. The second elements 6 are arranged to sandwich each first element 5 from the X direction. That is, one first element 5 and one second element 6 are arranged alternately in the X direction, and there are only one more second element 6 than first element 5. The Y-direction dimension of the second element 6 is slightly larger or slightly smaller than the Y-direction dimension of the first element 5 including the convex portions 52 and 53. In this way, the resonant frequency of the second element 6 is slightly different from the resonant frequency of the first element 5. The distance between the centers of the adjacent first element 5 and second element 6 is set to half the wavelength corresponding to the resonant frequency.

In the example shown in FIGS. 1 and 2, four first elements 5A to 5D and five second elements 6A to 6E are provided. In the following, when pointing to each of the first elements 5A to 5D or second elements 6A to 6E, the order is counted from the left side in FIGS. 1 and 2. For example, the first element 5A located on the leftmost side is The first element 5D located on the rightmost side is taken as the fourth first element, the second element 6A located on the leftmost side is taken as the first second element, and the second element 6E located on the rightmost side is taken as the first second element. This is the fifth second element.

The second second element 6B and the fourth second element 6D are electrically connected to the conductor portion 3 by conductive vias 23. In other words, through holes 22 are formed in the substrate body 21 of the insulating section 2 at the positions where the second second element 6B and the fourth second element 6D are provided. The other second elements 6A, 6C, and 6E are not connected to the conductor portion 3. The second second element 6B and the fourth second element 6D are both second elements located second from the end in the X direction. Note that "the second element is electrically connected to the conductor section" means that the second element is short-circuited without using a resistor or the like, unless otherwise specified.

Further, the positions of the through holes 22 and the conductive vias 23 in the Y direction correspond to the central portion of the first element 5 in the Y direction including the convex portions 52 and 53. The center portion of the first element 5 in the Y direction including the convex portions 52 and 53 becomes the excitation center of the first element 5. That is, if a straight line connecting the excitation centers of the plurality of first elements 5 is defined as X0 (indicated by a dashed line in FIG. 2), the through hole 22 and the conductive via 23 are arranged on the line X0. The second element 6 is electrically connected to the conductor section 3 via a conductive via 23 as a connection section. The circumferential surface of the through hole 22 in which the conductive via 23 is formed is arranged to intersect the line X0 connecting the excitation centers of the plurality of first elements 5. That is, the position where the second element 6 and the conductive via 23 come into contact is arranged on the line X0 that connects the excitation centers of the plurality of first elements 5. At this time, the center of the through hole 22 may be placed on the line X0.

Furthermore, a conductive via 23 is provided at the center of the second element 6 in the Y direction. Therefore, the center portion of the first element 5 in the Y direction including the convex portions 52 and 53 corresponds to the center portion of the second element 6 in the Y direction (they are aligned in the X direction).

Here, changes in the electric field distribution of the array antenna 1 caused by electrically connecting the second element 6 to the conductor portion 3 will be explained with reference to the simulation results of FIG. 3. This simulation was performed under the condition that six first elements 5 and seven second elements 6 were provided, and all the second elements 6 were electrically connected to the conductor portion 3. Other simulation conditions, such as the dimensions of each part, are the same as in the examples described later. Furthermore, as Comparative Example 1, simulation results under conditions in which all the second elements 6 are not electrically connected to the conductor portion 3 are also shown. The only difference in the conditions between the embodiment and Comparative Example 1 is whether or not the second element 6 is connected to the conductor portion 3.

The horizontal axis in FIG. 3 is the displacement on the above line X0, which is the central part of the array antenna consisting of six first elements 5 (the position of the central second element 6 among the seven second elements 6). is set as the origin (0 mm). The vertical axis in FIG. 3 corresponds to the electric field strength at each displacement on the line X0. Note that in this simulation, the oscillation frequency is 80 GHz. In both simulation results, the electric field strength reaches a minimum value at the center of each first element 5 in the X direction and at the center of the second element 6 in the X direction, and at both ends of each first element 5 in the X direction. The electric field strength reaches its maximum value at . Below, we will compare the strengths of local maximum values of the electric field. In the electric field distribution of Comparative Example 1 shown by the broken line, the electric field is strong at both ends and the center in the X direction of the entire antenna section, and is weak between the ends and the center. In contrast, in the electric field distribution of the embodiment, the electric field at both ends of the entire antenna section becomes stronger, and the electric field between the ends and the center also becomes stronger. Therefore, in the embodiment, the change in the maximum value of the electric field in the X direction becomes smaller, and the bias of the electric field distribution becomes smaller.

According to the array antenna 1 according to the embodiment of the present invention as described above, the second element 6 that sandwiches the first element from the X direction (the direction intersecting the Y direction, which is the excitation direction) is electrically connected to the conductor part 3. By being connected to the antenna, it is possible to suppress the bias in the electric field distribution and improve the flatness of the antenna gain.

Furthermore, the second elements 6B and 6D located second from the end in the X direction among the plurality of second elements 6 are electrically connected to the conductor section 3, thereby further improving the flatness of the antenna gain. can be done.

Furthermore, since the second element 6 is electrically connected to the conductor portion 3 via the conductive via 23, the connection structure complication can be suppressed.

Note that the present invention is not limited to the above-described embodiments, but includes other configurations that can achieve the object of the present invention, and the present invention also includes the following modifications. For example, in the embodiment of the present invention described above, of the five second elements 6, the second second element 6B and the fourth second element 6D are electrically connected to the conductor portion 3. However, it is sufficient that at least one second element is electrically connected to the conductor part, and the position of the second element to be electrically connected to the conductor part may be determined as appropriate depending on the number of second elements, etc. It only needs to be set.

When seven or more second elements are provided (six or more first elements are provided), a total of four second elements located second and third from both ends in the X direction are connected to the conductor section. may be electrically connected to. That is, the second element not connected to the conductor part may be sandwiched from the X direction by the second element connected to the conductor part. Further, the second element located first from both ends in the X direction or the second element located at the center of the entire antenna section may be electrically connected to the conductor section.

Furthermore, in the embodiment of the present invention described above, the second element 6 is electrically connected to the conductor section 3 via the conductive via 23, but it is assumed that the second element 6 is electrically connected to the conductor section 3 via another connection section. may be connected to. For example, the connecting portion may be a bar-shaped metal that is inserted through the through hole, or an electric wire that is not inserted through the through hole but passes outside the insulating portion.

Further, in the embodiment of the present invention described above, it is assumed that the position where the second element 6 and the conductive via 23 contact each other is arranged on the line X0 connecting the excitation centers of the plurality of first elements 5. However, if, for example, other components are provided in the insulating section and space is limited, the contact position between the second element 6 and the conductive via 23 may be shifted with respect to the line X0 connecting the excitation centers. Good too. In such a case, the second element 6 may be electrically connected to the conductor portion 3 via a resistor having a resistance value depending on the amount of deviation from the line X0.

Further, in the above embodiment of the present invention, the antenna section 4 has only one element row 41 in which the plurality of first elements 5 are lined up, but the antenna section has a plurality of element rows. You can leave it there. For example, a plurality of element rows may be arranged in the Y direction.

In addition, in the embodiment of the present invention described above, the plurality of first elements 5 are arranged in a straight line in a direction perpendicular to the excitation direction to form an element row, but the direction in which the plurality of element rows are arranged is may have an inclination with respect to the direction orthogonal to the excitation direction, or may have a curved shape.

Further, in the embodiment of the present invention described above, the second element 6 is directly electrically connected to the conductor part 3 by the conductive via 23, but the second element 6 and the conductor part 3 are directly connected to each other. They may not be directly connected, and a resistor (having a DC resistance component) or the like may be provided between them.

Although the embodiments of the present invention have been described above, the present invention is not limited to the array antenna according to the embodiments of the present invention described above, but includes all aspects included in the concept of the present invention and the scope of the claims. Moreover, each structure may be selectively combined as appropriate so as to achieve at least some of the problems and effects described above. For example, the shape, material, arrangement, size, etc. of each component in the above embodiments may be changed as appropriate depending on the specific usage of the present invention.

Examples of the present invention will be described below.

[Simulation conditions]
The antenna gains of each example will be explained, but all the antenna gains were calculated by simulation, and first, the conditions of the simulation will be explained with reference to FIG. 4. Ansys HFSS was used for the simulation (electromagnetic field calculation). The X-direction dimension L1 of the first element 5 is 1.03 mm, the Y-direction dimension L2 of the first element 5 is 1.03 mm, the X-direction dimension L3 of the second element 6 is 0.22 mm, and the The dimension L4 in the Y direction is 0.94 mm, the distance L5 between the first element 5 and the second element 6 in the X direction is 0.31 mm, the depth L6 of the recesses 54 and 55 is 0.35 mm, and the The X-direction dimension L7 is 0.3 mm, the X-direction dimensions L8A and L8B of the recesses 54 and 55 are each 0.1 mm, and the Z-direction dimension of the antenna section 4 (first element 5, second element 6, feeder line 7) Each thickness) L9 was set to 0.018 mm, the Z-direction dimension L10 of the insulating part 2 was set to 0.3 mm, and the diameter L11 of the through hole 22 was set to 0.2 mm. As a result, the distance between the central portions of the first elements 5 in the X direction (array distance) is 1.87 mm. The material of the insulating part 2 is Megtron 6, and the dielectric constant ε of this material is 3.6 at 12 GHz, and the dielectric loss tangent tan δ is 0.004 at 12 GHz. Further, when evaluating the flatness of the antenna gain in the following, the ratio between the maximum value and the minimum value of the antenna gain in the range of 77 to 81 GHz (hereinafter referred to as "gain ratio") will be used.

[Comparison with and without connection of second element]
The array antenna of Example 1 includes four first elements 5 and five second elements 6, and the second and fourth (i.e., second from the end) second elements 6 are It is electrically connected to the conductor section 3. The array antenna of Comparative Example 2 includes four first elements 5 and five second elements 6, and none of the second elements 6 are connected to the conductor portion 3. FIG. 5 shows the relationship between these antenna gains and frequencies. In Example 1, the gain ratio was approximately 0 dB, and in Comparative Example 2, the gain ratio was approximately 3 dB, indicating that the flatness of the antenna gain was improved in Example 1 compared to Comparative Example 2.

The array antenna of the second embodiment includes four first elements 5 and five second elements 6, and the second, third, and fourth second elements 6 are electrically connected to the conductor portion 3. connected. As shown in FIG. 6, in Example 2, the gain ratio was approximately 1.5 dB, and an improvement in the flatness of the antenna gain was observed compared to Comparative Example 2. In addition, in the antenna pattern of the H plane shown in FIG. 7, in Comparative Example 2, the antenna gain rapidly decreases to a minimum value around ±30°, whereas in Example 2, the antenna gain suddenly decreases to a minimum value around ±30°. Such a local minimum value is not observed, and the value is reduced to a low null value. Such an effect is suitable, for example, when the present array antenna is applied to a vehicle-mounted radar that detects the presence of a target at such an angle. In FIG. 7, the 0° direction coincides with the Z direction, and the ±90° direction coincides with the Y direction.

[Comparison by through-hole position in Y direction]
The array antennas of Examples 1 and 3 to 5 each include four first elements 5 and five second elements 6, with the second and fourth elements (i.e., the second from the end) A second element 6 is electrically connected to the conductor portion 3. Examples 1, 3 to 5 differ in the position of the through hole 22 (the position of the conductive via 23). Let LY be the amount of deviation of the through hole 22 in the Y direction with respect to the center portion (line X0) in the Y direction of the first element 5 including the convex portions 52 and 53. It is assumed that the deviation amount LY takes a positive value when the through hole 22 is located on the opposite side of the feeder line 7 with respect to the line X0.

In Example 1, the amount of deviation LY between the two through holes 22 is 0 mm. In Example 3, the amount of deviation LY between the two through holes 22 is 0.1 mm. In the fourth embodiment, the deviation amount LY of the through hole 22 corresponding to the second second element 6 is 0 mm, and the deviation amount LY of the through hole 22 corresponding to the fourth second element 6 is -0.2 mm. It has become. In Example 5, the deviation amount LY of the through hole 22 corresponding to the second second element 6 is 0.2 mm, and the deviation amount LY of the through hole 22 corresponding to the fourth second element 6 is 0 mm. ing. As shown in FIG. 8, in all of Examples 3 to 5, the gain ratio was within 1 dB, and an improvement in the flatness of the antenna gain was observed compared to Comparative Example 2.

[Comparison using the second element connected to the conductive part]
The array antennas of Examples 6 to 15 and Comparative Example 3 each include six first elements 5 and seven second elements 6. In Example 6, the second, fourth, and sixth second elements 6 are electrically connected to the conductive part 3. In Example 7, the second and sixth second elements 6 are electrically connected to the conductive part 3. In Example 8, the third and fifth second elements 6 are electrically connected to the conductive part 3. In Example 9, the third, fourth, and fifth second elements 6 are electrically connected to the conductive part 3. In Example 10, the first and seventh second elements 6 are electrically connected to the conductive part 3. That is, in Examples 6 to 10, the second elements 6 at symmetrical positions are electrically connected to the conductive portion 3 with respect to the fourth second element 6 located at the center in the X direction.

In Example 11, the second, third, and fourth second elements 6 are electrically connected to the conductive part 3. In Example 12, the third and fourth second elements 6 are electrically connected to the conductive part 3. In Example 13, the second and third second elements 6 are electrically connected to the conductive part 3. In Example 14, the first, second, and third second elements 6 are electrically connected to the conductive part 3. In Example 15, the first and second second elements 6 are electrically connected to the conductive part 3. That is, in Examples 11 to 15, the second elements 6 at asymmetric positions are electrically connected to the conductive portion 3 with respect to the fourth second element 6 located at the center in the X direction. In Comparative Example 3, all the second elements 6 are not connected to the conductor portion 3.

As shown in FIGS. 9 and 10, in Comparative Example 3, the gain ratio was 9 dB or more, whereas in Examples 6 to 15, the gain ratios were all within 7 dB, indicating an improvement in the flatness of the antenna gain. In particular, in Examples 6 to 10 in which the second elements 6 at symmetrical positions were connected to the conductive portion 3, the gain ratio was 3 dB or less, and the flatness of the antenna gain was significantly improved.

FIG. 11 shows the gain ratio when the second elements 6 at symmetrical positions are connected to the conductive part 3. The horizontal axis indicates each example, and the number following "TH" indicates which second element 6 is connected to the conductive portion 3. For example, "TH2356" indicates that the second elements 6 arranged at the second, third, fifth, and sixth positions are connected to the conductive part 3. Further, the array antenna of the embodiment shown in FIG. 11 includes six first elements 5 and seven second elements 6, as in Examples 6 to 10.

The second and sixth second elements 6 are located second from the end in the X direction, and the third and fifth second elements 6 are located third from the end in the X direction. In the examples in which at least the second and sixth second elements 6 are connected to the conductive portion 3, the gain ratios were all 1 dB or less, and the flatness of the antenna gain was significantly improved. Further, in the examples in which the third and fifth second elements 6 are connected to the conductive portion 3, the gain ratios were all 0.5 dB or less, and the flatness of the antenna gain was significantly improved.

[Comparison by Y direction position of through hole when adding resistance component]
The array antennas of Examples 16A to 16C and 17A to 17C each include six first elements 5 and seven second elements 6, and the second, fourth, and sixth second elements Element 6 is electrically connected to conductive part 3. In Examples 16A to 16C, the amount of deviation LY of the through holes 22 is 0.2 mm, and in Examples 17A to 17C, the amount of deviation LY of the through holes 22 is 0.4 mm. In Examples 16A and 17A, the second element 6 is connected to the conductive part 3 without a resistor, and in Examples 16B and 17B, the second element 6 is connected to the conductive part 3 through a 50Ω resistor. In Examples 16C and 17C, the second element 6 is connected to the conductive part 3 via a 300Ω resistor.

As shown in FIG. 12, in Examples 16A to 16C, the gain ratio was 8 dB or less, and an improvement in the flatness of the antenna gain was observed compared to Comparative Example 3. Further, by providing the resistor, the shape of the curve of the frequency characteristic of the antenna gain changed, and in particular, the frequency at which the antenna gain reached a minimum value was shifted to the high frequency side. Furthermore, in Example 16B in which a 50Ω resistor was provided, the flatness of the antenna gain was improved compared to Example 16A in which no resistor was provided.

As shown in FIG. 13, in Examples 17A to 17C, the gain ratio was 6 dB or less, and an improvement in antenna gain was observed compared to Comparative Example 3. Further, by providing the resistor, the shape of the curve of the frequency characteristic of the antenna gain changed, and in particular, the frequency at which the antenna gain reached a minimum value was shifted to the high frequency side. Further, in Examples 17B and 17C in which a resistor was provided, an improvement in the flatness of the antenna gain was observed compared to Example 17A in which a resistor was not provided.

[Comparison based on the Y-direction position of the second element]
The array antenna of Example 18 includes six first elements 5 and seven second elements 6, and the second, fourth, and sixth second elements 6 are electrically connected to the conductive part 3. connected. Here, the amount of deviation in the Y direction of the center portion of the second element 6 in the Y direction with respect to the line X0 connecting the excitation centers of the plurality of first elements 5 is defined as LY2. Note that the shift amount LY2 assumes a positive value when the center portion of the second element 6 in the Y direction is located on the opposite side of the power supply line 7 with respect to the line X0. In the array antenna of Example 18, the amount of deviation LY2 was varied between -1 and 1 mm. Similarly, in the array antenna of Comparative Example 3, the deviation amount LY2 was varied between -1 and 1 mm. At this time, the through hole 22 was positioned at the center of the second element 6 in the Y direction.

As shown in FIG. 14, in Example 18, the gain ratio was 3 dB or less for all deviation amounts LY2. On the other hand, in Comparative Example 3, the gain ratio was greater than 3 dB in the range of the deviation amount LY2 from -0.3 to 0.3 mm. At a frequency of 80 GHz, 1/8 of the corresponding wavelength is 0.47 mm, and in Example 18, improvement in the flatness of the antenna gain was observed in the range where the shift amount LY2 was 1/8 wavelength.

DESCRIPTION OF SYMBOLS 1... Array antenna, 2... Insulating part, 22... Through hole, 23... Conductive via, 3... Conductor part, 4... Antenna part, 41... Element row, 5... First element, 6... Second element

Claims (5)

an insulating section;
an antenna section provided on one surface side with respect to the insulating section;
In the insulating part, a conductor part provided spaced apart from the antenna part,
In the antenna section, a first element connected to a signal generating section from a predetermined direction is sandwiched between a plurality of element rows arranged in a cross direction intersecting the predetermined direction, and each of the first elements from the cross direction. a second element arranged as shown in FIG.
An array antenna characterized in that at least one of the plurality of second elements is electrically connected to the conductor section. 2. The second element located second from one end and the other end in the cross direction among the plurality of second elements is electrically connected to the conductor part. Array antenna as described. 3. The second element located third from one end and the other end in the cross direction among the plurality of second elements is electrically connected to the conductor part. Array antenna as described. The insulating section includes a substrate main body, a through hole formed in the substrate main body, and a conductive via provided on an inner peripheral surface of the through hole,
The array antenna according to claim 1, wherein the second element is electrically connected to the conductor portion via the conductive via. 5. The array antenna according to claim 4, wherein a position where the second element and the conductive via come into contact is located on a line connecting excitation centers of the plurality of first elements.

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