JP2019016929A - Multilayer Substrate Array Antenna - Google Patents

Abstract

To make the thickness from a radiating element to a ground conductor different from the thickness from a balun to the ground conductor even when the radiating element and the balun are incorporated in the same board.SOLUTION: An array antenna 2 includes a dielectric laminated plate 14, a plurality of radiating elements 21 formed on the main surface 14b of the dielectric laminated plate 14, a balun 30 formed on the main surface 14b of the dielectric laminated plate 14, an unbalanced feed line 24 formed on the main surface 14b of the dielectric laminated plate 14 and routed from the balun 30 to the radiating element 21, balanced feed lines 41 and 42 formed on the main surface 14b of the dielectric laminated plate 14 and routed from feeding points 41a and 42a to the balun 30, a first ground conductor layer 50 formed in a region 57 between the layers of the dielectric laminated plate 14, and a second ground conductor layer 60 formed in a region 68 of the main surface 14a of the dielectric laminated plate 14.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a multilayer substrate type array antenna.

  In recent years, with the increase in speed and capacity of wireless communication, the use frequency of transmission signals has been rapidly widened and increased in frequency. A microstrip antenna is known as an antenna that operates in a high frequency band. The microstrip antenna is an unbalanced feed type antenna, and an unbalanced signal is fed to the radiating element of the microstrip antenna by a feed line. On the other hand, an IC chip for high-frequency wireless communication is often in a balanced connection due to various restrictions (see, for example, Patent Document 1), and a balanced signal (differential signal) is output from the IC chip for high-frequency wireless communication.

JP-A-2015-198350

Therefore, a balun (balanced-unbalanced converter) for converting a balanced signal into an unbalanced signal is required in the middle of the feed line from the IC chip for high-frequency wireless communication to the microstrip antenna.
By the way, the performance of the microstrip antenna improves as the thickness of the dielectric from the radiation element of the microstrip antenna to the ground conductor increases. On the other hand, in order for a microstrip line structure balun to operate satisfactorily, it is necessary to appropriately set the thickness of the dielectric from the ground conductor to the line in accordance with the frequency used. Therefore, the thickness of the dielectric that operates well differs between the microstrip antenna and the balun. Therefore, the radiating element and the balun of the microstrip antenna cannot be incorporated in the same dielectric substrate.

  Therefore, the present invention has been made in view of the above circumstances. An object of the present invention is to make the thickness from the radiating element to the ground conductor different from the thickness from the balun to the ground conductor even if the radiating element and the balun are incorporated in the same substrate.

  A main invention for achieving the above object is that a dielectric laminated plate in which dielectrics are laminated, a plurality of radiating elements formed on one main surface of the dielectric laminated plate, and the dielectric laminated plate A balun formed on one main surface, an unbalanced feed line formed on one main surface of the dielectric laminate and routed from the balun to the plurality of radiating elements, and the dielectric laminate A pair of balanced feed lines formed on one main surface and routed from a pair of feed points to the balun, and formed in a region facing the balanced feed line and the balun, between the layers of the dielectric laminate. A first ground conductor layer formed on the other main surface of the dielectric laminate, and a second ground conductor layer formed in a region facing the plurality of radiating elements and the unbalanced feed line. It is an array antenna.

  Other characteristics of the present invention will be made clear by the description and drawings described later.

  According to the present invention, the thickness from the balun and the balanced feed line to the first ground conductor layer can be made different from the thickness from the radiating element and the unbalanced feed line to the second ground conductor layer.

FIG. 1 is a side view of a wireless module according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the array antenna. FIG. 3 is a plan view of the conductor pattern layer. FIG. 4 is an enlarged plan view showing a part of the conductor pattern layer. FIG. 5 is a plan view of the first ground conductor layer. FIG. 6 is a plan view of a first ground conductor layer according to a modification. FIG. 7 is a plan view of the second ground conductor layer. FIG. 8 is a plan view of a modified second ground conductor layer. FIG. 9 is a graph showing a simulation result of the reflection characteristics of the array antenna according to the embodiment of the present invention. FIG. 10 is a graph showing a simulation result of the gain of the antenna according to the embodiment of the present invention. FIG. 11 is a graph showing a simulation result of the reflection characteristics of the array antenna according to the embodiment of the present invention. FIG. 12 is a graph showing a simulation result of the reflection characteristics of the array antenna according to the embodiment of the present invention. FIG. 13 is a graph showing a simulation result of the reflection characteristics of the array antenna according to the embodiment of the present invention.

  At least the following matters will be apparent from the description and drawings described below.

A dielectric laminate formed by laminating a dielectric, a plurality of radiating elements formed on one principal surface of the dielectric laminate, and a balun formed on one principal surface of the dielectric laminate;
An unbalanced feed line formed on one main surface of the dielectric laminate and routed from the balun to the plurality of radiating elements, and a pair of feeds formed on one main surface of the dielectric laminate. A pair of balanced feed lines routed from a point to the balun; a first ground conductor layer formed in a region facing the balanced feed line and the balun among layers of the dielectric laminate; and the dielectric An array antenna including the second ground conductor layer formed in a region facing the plurality of radiating elements and the unbalanced feed line in the other main surface of the body laminate is apparent.

  In such an array antenna, the first ground conductor layer is formed between the layers of the dielectric laminate, and the second ground conductor layer is formed on the main surface of the dielectric laminate. The thickness to the first ground conductor layer is different from the thickness from the radiation element and the unbalanced feed line to the second ground conductor layer. Therefore, even if the thickness of the dielectric that operates well differs between the radiating element and the balun, both the radiating element and the balun can be operated well.

The first ground conductor layer protrudes from a region facing the balanced feed line and the balun in a region facing the plurality of radiating elements and the unbalanced feed line among the layers of the dielectric laminate. Thereby, the resonance frequency of the array antenna can be set according to the length of the first ground conductor layer protruding.

The length of the first ground conductor layer protruding from the region facing the balanced feed line and the balun to the region facing the plurality of radiating elements and the unbalanced feed line is divided by the wavelength used by the array antenna. The value obtained by this is 0.07.
As a result, the array antenna resonates at the operating frequency.

The second ground conductor layer extends to a region facing the balanced feed line and the balun on the other main surface of the dielectric laminate.
As a result, impedance matching can be achieved and both the balun and the antenna can be operated satisfactorily.

=== Embodiment ===
Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below are given various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

1. Configuration of Wireless Module FIG. 1 is a side view of the wireless module 1. 1 to 8 illustrate the X axis, the Y axis, and the Z axis as arrows or symbols representing directions. The X axis, the Y axis, and the Z axis are orthogonal to each other.

  As shown in FIG. 1, the wireless module 1 includes a multilayer substrate type array antenna 2 and a wireless chip 3 that is surface-mounted on one main surface of the array antenna 2. Here, the main surface means a pair of surfaces having the largest area among the surfaces (hymen) of the plate-like material. In FIG. 1, the pair of principal surfaces of the rectangular plate-shaped array antenna 2 are orthogonal to the Z axis and parallel to the XY plane.

  The surface mounting method of the wireless chip 3 is, for example, a BGA (Ball Grid Array) method, an LGA (Land Grid Array) method, or a WB (Wire Bonding) method. The wireless chip 3 is a so-called RFIC (Radio Frequency Integrated Circuit), and is an IC chip in which a receiving circuit or a transmitting circuit or both of them are incorporated.

FIG. 2 is a cross-sectional view of the array antenna 2.
As shown in FIG. 2, the array antenna 2 is formed between the dielectric laminate 14, the conductive pattern layer 20 formed on the main surface 14 b on the front side of the dielectric laminate 14, and the dielectric laminate 14. A first ground conductor layer 50 and a second ground conductor layer 60 formed on the main surface 14a on the back side of the dielectric laminate 14.

  The dielectric laminate 14 is a laminate of the dielectric substrate 11, the dielectric adhesive layer 13, and the dielectric substrate 12. That is, the dielectric base material 11 and the dielectric base material 12 are dielectrically bonded in a state where the thin plate-like dielectric base material 11 and the thin plate-shaped dielectric base material 12 sandwich the dielectric adhesive layer 13 therebetween. Joined by layer 13. The dielectric substrates 11 and 12 are made of, for example, a resin (for example, a liquid crystal polymer or polyimide), a fiber reinforced resin (for example, a glass cloth epoxy resin), a fluororesin, or a ceramic. The dielectric adhesive layer 13 is made of, for example, an epoxy resin.

  The dielectric laminate 14 is a rectangular plate, the long side of the dielectric laminate 14 is parallel to the Y axis, and the short side of the dielectric laminate 14 is parallel to the X axis. A conductive pattern layer 20 is formed on the main surface 14 b on the front side of the dielectric laminate 14, that is, on the surface of the dielectric substrate 12. A second ground conductor layer 60 is formed on the main surface 14 a on the back side of the dielectric laminate 14, that is, on the surface of the dielectric substrate 11. More specifically, a first ground conductor layer 50 is formed between the dielectric laminates 14 and between the dielectric substrate 12 and the dielectric adhesive layer 13. Hereinafter, the conductor pattern layer 20, the first ground conductor layer 50, and the second ground conductor layer 60 will be described in detail with reference to the plan view shown in the direction of arrow A shown in FIG.

2. Conductor Pattern Layer FIG. 3 is a plan view of the conductor pattern layer 20. FIG. 4 is an enlarged view of a part of the conductor pattern layer 20.

  The conductor pattern layer 20 is processed (patterned) by a subtractive method or an additive method, for example. As a result, a plurality of radiating elements 21, unbalanced feed lines 24, baluns (balance-unbalance converter) 30, balanced feed lines 41, 42, and ground portions 43, 44, 45 are formed in the conductor pattern layer 20. ing.

  When the main surface 14b on the front side of the dielectric laminate 14 is divided into two rectangular regions 17 and 18 arranged in the Y-axis direction (long side direction of the dielectric laminate 14), a plurality of radiation elements 21 and The unbalanced feed line 24 is disposed in the region 18, and the balun 30, the balanced feed lines 41 and 42, and the ground portions 44, 45, and 46 are disposed in the region 17.

The unbalanced feed line 24 is formed in a straight line so as to extend in the Y-axis direction.
The plurality of radiating elements 21 are arranged in two rows along the unbalanced feed line 24, and the unbalanced feed line 24 is arranged between one row 22 and the other row 23. Hereinafter, one row 22 is referred to as a radiating element row 22 and the other row 23 is referred to as a radiating element row 23. The radiating element 21 of the radiating element row 22 and the radiating element 21 of the radiating element row 23 are arranged so as to be shifted in the Y-axis direction by the half pitch of the radiating element rows 22 and 23.

The radiating element 21 farthest from the balun 30 is composed of a feeding element 21a and parasitic elements 21b and 21c. The other radiating element 21 includes a feeding element 21a and parasitic elements 21b, 21c, and 21d. The feed element 21a of the radiation element 21 of the radiation element row 22 is connected to the unbalanced feed line 24, and these feed elements 21a extend from the unbalanced feed line 24 in the negative X-axis direction. The feed elements 21a of the radiating elements 21 of the radiating element array 23 are connected to the unbalanced feed line 24, and these feed elements 21a extend from the unbalanced feed line 24 in the X-axis positive direction.
In any of the radiating elements 21, the parasitic element 21b is formed in a rectangular shape along the edge at a position slightly away from the edge on the Y axis positive direction side of the feeding element 21a. It is formed in a rectangular shape along the edge at a position slightly away from the edge on the Y axis negative direction side of 21a. In the radiating elements 21 other than the radiating element 21 farthest from the balun 30, the parasitic element 21 d is rectangular so as to extend in the direction orthogonal to the edge at a position slightly away from the edge on the side where the feeding element 21 a extends. It is formed in a shape.

  The balun 30 is a rat race circuit. That is, the balun 30 is a square ring line, and three ports P1 to P3 are provided on the line. If the wavelength of the transmission signal wave (high frequency) in the microwave or millimeter wave frequency band is λ, the electrical length of the line 31 between the ports P1 and P2 is λ / 2, and the electrical length of the line 32 between the ports P1 and P3. The length is 3λ / 4, and the electrical length of the line 33 between the ports P2 and P3 is λ / 4. The balanced signals (differential signals) at the ports P1 and P2 are converted into unbalanced signals at the port P3 by the balun 30, and the unbalanced signals at the port P3 are converted into balanced signals at the ports P1 and P2. Port P1 and port P2 are isolated from each other.

The balun 30 is disposed near the region 18 in the region 17.
The port P3 of the balun 30 is connected to one end of the unbalanced feed line 24, and the unbalanced feed line 24 extends from the port P3 in the Y-axis direction. Here, the boundary 19 between the region 17 and the region 18 is set by the balun 30 (wrinkle). More specifically, the boundary 19 between the region 17 and the region 18 is a straight line that circumscribes the balun 30 at the port P3.

  The ground portions 43, 44, and 45 are arranged in the X-axis direction (the short side direction of the dielectric laminate 14) with an interval therebetween. A balun 30 is disposed between the ground portion 43 and the unbalanced feed line 24.

  The ground portion 43 is electrically connected to the first ground conductor layer 50 by a plurality of via holes 43 a penetrating the dielectric base material 12. The ground portion 44 is electrically connected to the first ground conductor layer 50 through a via hole 44 a penetrating the dielectric base material 12. The ground portion 45 is electrically connected to the first ground conductor layer 50 by a plurality of via holes 45 a penetrating the dielectric base material 12.

  A portion 41 a on one end side of the balanced feed line 41 is disposed between the ground portion 43 and the ground portion 44. The part 41a is connected to the terminal of the wireless chip 3, and the part 41a serves as a power feeding unit. The balanced feed line 41 is routed from between the ground part 43 and the ground part 44 to the port P1 of the balun 30 and the other end of the balanced feed line 41 is connected to the port P1 of the balun 30.

A portion 42 a on one end side of the balanced feed line 42 is disposed between the ground portion 44 and the ground portion 45. The part 42a is connected to the terminal of the wireless chip 3, and the part 42a serves as a power feeding unit. The balanced feed line 42 is routed from between the ground part 43 and the ground part 44 to the port P2 of the balun 30 and the other end of the balanced feed line 42 is connected to the port P2 of the balun 30.
The electrical length of the balanced feed line 41 and the electrical length of the balanced feed line 42 are equal to each other.

3. First Ground Conductor Layer FIG. 5 is a plan view of the first ground conductor layer 50. In FIG. 5, the conductor pattern layer 20 is indicated by a two-dot chain line in order to specify the relationship between the position of the first ground conductor layer 50 and the position of the conductor pattern layer 20.
As shown in FIG. 5, the first ground conductor layer 50 extends over the entire region 57 facing the region 17 among the layers of the dielectric base material 12 and the dielectric adhesive layer 13. Accordingly, the balun 30, the balanced feed lines 41, 42 and the ground portions 44, 45, 46 overlap the first ground conductor layer 50 with the dielectric base material 12 sandwiched between them and the first ground conductor layer 50. .

  The first ground conductor layer 50 does not protrude from the region 58 facing the region 18 among the layers between the dielectric substrate 12 and the dielectric adhesive layer 13. Therefore, the unbalanced feed line 24 and the plurality of radiating elements 21 do not overlap the first ground conductor layer 50.

  As shown in the plan view of FIG. 6, the first ground conductor layer 50 may protrude from the region 57 to the region 58 by a length L. In this case, a part of the unbalanced feed line 24 overlaps the first ground conductor layer 50 with the dielectric base material 12 interposed therebetween. In FIG. 6, the conductor pattern layer 20 is indicated by a two-dot chain line in order to specify the relationship between the position of the first ground conductor layer 50 and the position of the conductor pattern layer 20.

4. Second Ground Conductor Layer FIG. 7 is a plan view of the second ground conductor layer 60. In FIG. 7, the conductor pattern layer 20 is indicated by a two-dot chain line in order to specify the relationship between the position of the second ground conductor layer 60 and the position of the conductor pattern layer 20.
As shown in FIG. 7, the second ground conductor layer 60 extends over the entire main surface 14 a on the back side of the dielectric laminate 14, that is, the entire surface of the dielectric substrate 11. Therefore, the second ground conductor layer 60 and the first ground conductor layer 50 face each other with the dielectric base material 11 and the dielectric adhesive layer 13 interposed therebetween. Further, the balun 30, the balanced feed lines 41 and 42, and the ground portions 44, 45, and 46 are between the dielectric base 12, the first ground conductor layer 50, and the dielectric adhesive layer between them and the second ground conductor layer 60. 13 and the dielectric base material 11 are sandwiched between the second ground conductor layers 60. In addition, the unbalanced feed line 24 and the plurality of radiating elements 21 are sandwiched between the dielectric base material 12, the dielectric adhesive layer 13, and the dielectric base material 11 between them and the second ground conductor layer 60. It overlaps with the ground conductor layer 60. Thereby, impedance matching is achieved between the balanced feed lines 41 and 42 and the balun 30 and the unbalanced feed line 24 and the radiating element rows 22 and 23, and both the balun 30 and the radiating element rows 22 and 23 can be operated well. it can.

  The second ground conductor layer 60 is electrically connected to the first ground conductor layer 50 through a plurality of via holes 60a (see FIG. 5 or FIG. 6) penetrating the dielectric substrate 12 and the dielectric adhesive layer 13. However, the second ground conductor layer 60 and the first ground conductor layer 50 may be insulated and the first ground conductor layer 50 and the second ground conductor layer 60 may be electrostatically coupled.

  In the example shown in FIG. 7, the second ground conductor layer 60 extends to the region 68 on the main surface 14 a on the back side of the dielectric laminate 14 and further extends to the region 67. On the other hand, as shown in the plan view of FIG. 8, the second ground conductor layer 60 may extend not only to the region 67 but only to the region 68. In the example shown in FIG. 8, the balun 30, the balanced feed lines 41 and 42, and the ground portions 44, 45, and 46 do not overlap the second ground conductor layer 60, but the unbalanced feed line 24 and the plurality of radiating elements 21 are The dielectric base material 12, the dielectric adhesive layer 13, and the dielectric base material 11 are sandwiched between these and the second ground conductor layer 60 so as to overlap the second ground conductor layer 60. In FIG. 8, the conductor pattern layer 20 is indicated by a two-dot chain line in order to specify the relationship between the position of the second ground conductor layer 60 and the position of the conductor pattern layer 20.

  When the second ground conductor layer 60 does not reach the region 67 as shown in FIG. 8 and the first ground conductor layer 50 does not protrude into the region 58 as shown in FIG. The conductor layer 60 does not overlap with the dielectric adhesive layer 13 and the dielectric base material 11 in between. On the other hand, when the second ground conductor layer 60 does not reach the region 67 as shown in FIG. 8 and the first ground conductor layer 50 protrudes into the region 58 as shown in FIG. A portion of the conductor layer 50 that protrudes from the region 58 overlaps the second ground conductor layer 60 with the dielectric adhesive layer 13 and the dielectric base material 11 interposed therebetween.

5. Effect As described above, in order to make the balun 30 and the balanced feed lines 41 and 42 operate favorably and reduce the transmission loss, and further to set the resonance frequency to a target value, the balun 30 and the balanced feed line The thickness of the dielectric substrate 12 from 41, 42 to the first ground conductor layer 50 is optimized. On the other hand, in order for the plurality of radiating elements 21 and the unbalanced feed line 24 to operate satisfactorily and not to reduce the gain, from the radiating element 21 and the unbalanced feed line 24 to the second ground conductor layer 60. The thickness of the dielectric laminate 14 is preferably as thick as possible. Thus, by using the dielectric laminate 14, the thickness from the conductor pattern layer 20 to the first ground conductor layer 50 is made different from the thickness from the conductor pattern layer 20 to the second ground conductor layer 60. . Therefore, the balun 30, the balanced feed lines 41 and 42, the unbalanced feed line 24, and the radiation element 21 can be optimally operated.

  Further, when the first ground conductor layer 50 protrudes from the region 57 to the region 58, the resonance frequency can be adjusted to a value corresponding to the protrusion length L. That is, the protruding length L can be designed to set the resonance frequency to a target value.

  A portion 41 a on one end side of the balanced feed line 41 is disposed between the ground portion 43 and the ground portion 44, and a portion 42 a on one end side of the balanced feed line 42 is disposed between the ground portion 44 and the ground portion 45. Therefore, these parts 41a and 42a are not electrostatically coupled to each other or to other conductors.

6). Simulation results A simulation was performed to examine the characteristics of the array antenna 2. In any simulation, the thickness of the dielectric substrate 11 is 50 μm, the thickness of the dielectric substrate 12 is 50 μm, and the thickness of the dielectric adhesive layer 13 is 35 μm.

(1) FIG. 9 is a graph showing a simulation result of the reflection characteristics of the array antenna 2. FIG. 10 is a graph showing a simulation result of the directivity of 60 GHz radio waves radiated by the array antenna 2. In obtaining the simulation results of FIGS. 9 and 10, it is assumed that the protruding length L of the first ground conductor layer 50 is 350 μm, as shown in FIG. Further, as shown in FIG. 7, the second ground conductor layer 60 extends over the entire main surface 14a on the back side of the dielectric laminate 14, and the second ground conductor layer 60 and the first ground conductor layer 50 are static. It shall be electrocoupled.

  In the graph of FIG. 9, the horizontal axis indicates the frequency, and the vertical axis indicates the S-parameter reflection characteristic | S11 |. As is apparent from the graph of FIG. 9, it can be seen that the resonance frequency of the array antenna 2 is 60 GHz.

  The horizontal axis in the graph of FIG. 10 indicates an angle with respect to the Z axis on the ZX plane or the YZ plane, and the vertical axis indicates the gain. As shown in FIG. 10, it can be seen that the direction of the maximum gain is the normal direction of the dielectric laminate 14, that is, the Z-axis direction. It can also be seen that the maximum gain is close to 10 dBi and the array antenna 2 has a high gain.

(2) With reference to the graph of FIG. 11, the simulation result (broken line in the graph) in the case where the second ground conductor layer 60 and the first ground conductor layer 50 are electrically connected by the via hole 60a (see FIG. 6), The simulation results (solid line in the graph) when the second ground conductor layer 60 and the first ground conductor layer 50 are electrostatically coupled are compared. In obtaining the simulation result of FIG. 11, it is assumed that the protruding length L of the first ground conductor layer 50 is 350 μm as shown in FIG. 6, and further, as shown in FIG. It is assumed that it extends over the entire main surface 14a on the back side of the dielectric laminate 14.

  In the graph of FIG. 11, the horizontal axis indicates the frequency, and the vertical axis indicates the S-parameter reflection characteristic | S11 |. As shown in FIG. 11, even when the second ground conductor layer 60 and the first ground conductor layer 50 are electrostatically coupled, the second ground conductor layer 60 and the first ground conductor layer 50 are electrically connected by the via hole 60a. Even in this case, it can be seen that the resonance frequency of the array antenna 2 is 60 GHz and the characteristics are almost the same.

(3) Referring to the graph of FIG. 12, the simulation result (graph) when the second ground conductor layer 60 extends over the entire main surface 14a on the back side of the dielectric laminate 14 as shown in FIG. 8 and the simulation result (dotted line in the graph) when the second ground conductor layer 60 does not reach the region 67 in the main surface 14a on the back side of the dielectric laminate 14 as shown in FIG. To do. In obtaining the simulation result of FIG. 12, it is assumed that the protruding length L of the first ground conductor layer 50 is 350 μm as shown in FIG. 6, and the second ground conductor layer 60 and the first ground conductor layer 50 are insulated. It is assumed that

  In the graph of FIG. 12, the horizontal axis represents frequency, and the vertical axis represents S-parameter reflection characteristics | S11 |. As shown in FIG. 12, even when the second ground conductor layer 60 extends over the entire principal surface 14 a on the back side of the dielectric laminate 14, the second ground conductor layer 60 does not reach the region 67. However, it can be seen that the resonance frequency of the array antenna 2 is 60 GHz and the characteristics are almost the same.

(4) When the first ground conductor layer 50 protrudes into the region 58, the influence of the protrusion length L on the resonance frequency was verified with reference to the graph of FIG. Specifically, when the protrusion length L is 150 μm, 250 μm, 350 μm, 450 μm, and 550 μm, the reflection characteristic | S11 | of the S parameter was obtained by simulation. In obtaining the simulation result of FIG. 13, it is assumed that the second ground conductor layer 60 extends over the entire main surface 14a on the back side of the dielectric laminate 14 as shown in FIG. And the first ground conductor layer 50 are insulated.

  As can be seen from FIG. 13, the resonance frequency increases as the protrusion length L decreases. Further, when the dimension is made non-dimensional by dividing the protrusion length L by the use wavelength λ (λ = 5000 μm) corresponding to the use frequency f (f = 60 GHz) of the array antenna 2, λ / L is 0.07. It can be seen that the array antenna 2 in this case resonates at the use frequency f.

DESCRIPTION OF SYMBOLS 2 ... Array antenna 14 ... Dielectric laminated plate 21 ... Radiation element 24 ... Unbalanced feed line 30 ... Balun 41 ... Balanced feed line 42 ... Balanced feed line 50 ... First ground conductor layer 60 ... Second ground conductor layer

Claims (4)

A dielectric laminate formed by laminating dielectrics;
A plurality of radiating elements formed on one main surface of the dielectric laminate;
A balun formed on one main surface of the dielectric laminate;
An unbalanced feed line formed on one main surface of the dielectric laminate and routed from the balun to the plurality of radiating elements;
A pair of balanced feed lines formed on one main surface of the dielectric laminate and routed from a pair of feed points to the balun;
Among the layers of the dielectric laminate, a first ground conductor layer formed in a region facing the balanced feed line and the balun,
Of the other main surface of the dielectric laminate, a second ground conductor layer formed in a region facing the plurality of radiating elements and the unbalanced feed line,
An array antenna comprising: The first ground conductor layer protrudes from a region facing the balanced feed line and the balun in a region facing the plurality of radiating elements and the unbalanced feed line among the layers of the dielectric laminate. The array antenna according to claim 1. 3. The array antenna according to claim 2, wherein a length of the first ground conductor layer protruding from a region facing the balanced feed line and the balun to a region facing the plurality of radiating elements and the unbalanced feed line is defined. The array antenna according to claim 2, wherein a value obtained by dividing by the wavelength used is 0.07. The array according to any one of claims 1 to 3, wherein the second ground conductor layer extends to a region facing the balanced feed line and the balun on the other main surface of the dielectric laminate. antenna.

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