JP2018046440A - Antenna board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna substrate capable of transmitting and receiving electromagnetic waves in a specific direction. SOLUTION: A strip conductor 3 extending on a first dielectric layer 1a and having a terminal portion 3a, a second dielectric layer 1b laminated on the first dielectric layer 1a, and a second. A first patch conductor 4a arranged on the dielectric layer 1b, a third dielectric layer 1c laminated on the second dielectric layer 1b, and a third dielectric layer 1c. In the antenna substrate provided with the second patch conductor 4b, the upper surface side and the lower surface side ground conductors 9a, 2 and both are placed in the region on the extension direction side of the strip conductor 3 with respect to the first and second patch conductors 4a and 4b. A dielectric tube 6 including a plurality of ground-through conductors 10 arranged so as to be connected is formed, and a first portion is formed in a region sandwiched between the upper surface side and lower surface side ground conductors 9a and 2 and the arrangement of the ground-through conductors 10. A fourth dielectric layer 11 having a specific dielectric constant smaller than the relative dielectric constants of the first to third dielectric layers 1a to 1c is formed. [Selection diagram] Fig. 1

Description

  The present invention relates to an antenna substrate formed by laminating a dielectric layer and a conductor layer in multiple layers.

A conventional antenna substrate is shown in FIG. FIG. 5A is a top view of the antenna substrate, and FIG. 5B is a cross-sectional view of the antenna substrate between ZZ.
The conventional antenna substrate includes a dielectric substrate 21, a ground conductor layer 22, a strip conductor 23, a patch conductor 24, and an auxiliary patch conductor 25.

  The dielectric substrate 21 is configured by laminating five dielectric layers 21a to 21e.

  The ground conductor layer 22 is deposited on the entire lower surface of the lowermost dielectric layer 21a.

  The strip conductor 23 faces the ground conductor layer 22 with the dielectric layer 21a interposed therebetween, and is disposed between the dielectric layers 21a and 21b. The strip conductor 23 is a thin strip-shaped conductor that extends in one direction from the outer peripheral edge to the center of the inside of the dielectric substrate 21, and has a terminal portion 23 a at the center of the dielectric substrate 21.

  The patch conductor 24 includes a first patch conductor 24a, a second patch conductor 24b, and a third patch conductor 24c.

  The first patch conductor 24a is disposed between the dielectric layers 21c and 21d so as to cover the position of the end portion 23a of the strip conductor 23. The first patch conductor 24a is connected to the end portion 23a of the strip conductor 23 through a through conductor 26 that penetrates the dielectric layer 21c and a through conductor 27 that penetrates the dielectric layer 21b.

  The second patch conductor 24b is disposed between the dielectric layers 21d and 21e so that at least a portion thereof covers the position of the first patch conductor 24a.

  The third patch conductor 24c is arranged on the upper surface of the dielectric layer 21e so that at least a part thereof covers the position of the second patch conductor 24b.

  The auxiliary patch conductor 25 is formed on the upper surface of the dielectric layer 21e on both sides in the direction perpendicular to the extending direction of the strip conductor 23 in the third patch conductor 24c.

By the way, in recent years, there is an electronic device that detects a person or an object by intensively transmitting and receiving electromagnetic waves in a specific direction, such as a vehicle-mounted detector. An antenna substrate mounted on such an electronic device is required to be able to transmit and receive electromagnetic waves intensively in a specific direction.
However, the conventional antenna substrate has a problem that electromagnetic waves are distributed and transmitted in a wide range above the patch conductor and cannot be transmitted and received intensively in a specific direction.

JP-A-5-145327

  An object of the present invention is to provide an antenna substrate capable of intensively transmitting and receiving electromagnetic waves corresponding to high frequency signals in a specific direction.

  The antenna substrate of the present invention is disposed on the first dielectric layer and the upper surface of the first dielectric layer, and extends in one direction from the outer periphery to the center of the first dielectric layer. A strip conductor having an end portion, a grounding conductor layer for shielding disposed on the lower surface side of the first dielectric layer, and a second dielectric layer laminated on the upper surface side of the first dielectric layer and the strip conductor A layer, a first patch conductor disposed on the top surface of the second dielectric layer so as to cover the position of the terminal portion, and a third layer laminated on the second dielectric layer and the first patch conductor. And at least a part of the top surface of the dielectric layer and the third dielectric layer at a position where the first patch conductor is formed, and the center of the strip conductor extends from the center of the first patch conductor. Second patch that is offset in the direction and is electrically independent In an antenna substrate comprising a body and a penetrating conductor that penetrates the second dielectric layer and connects the terminal portion and the first patch conductor, the extending direction of the strip conductor rather than the first and second patch conductors A plurality of ground penetrations arranged so as to connect the upper surface ground conductor and the lower surface ground conductor facing each other, and the upper surface ground conductor and the lower surface ground conductor on both sides in the direction orthogonal to the extending direction. A waveguide including a conductor is formed, and at least in a region sandwiched between the arrangement of the upper surface side and lower surface side ground conductors and the ground through conductors, the relative dielectric constant of the first to third dielectric layers is smaller. A fourth dielectric layer having a relative dielectric constant is formed.

According to the antenna substrate of the present invention, the upper surface side ground conductor and the lower surface side ground conductor that are opposed to each other are connected to the extension direction side of the strip conductor with respect to the first and second patch conductors, and both are arranged A waveguide including a plurality of grounded through conductors is formed.
Further, a fourth dielectric having a relative dielectric constant smaller than that of the first to third dielectric layers in a region sandwiched between at least the upper surface side and lower surface side ground conductors and the ground through conductors. A layer is formed.
For this reason, the electromagnetic waves are radiated or incident in a concentrated manner via the fourth dielectric layer in the waveguide that easily propagates.
Thereby, it is possible to provide an antenna substrate capable of intensively transmitting and receiving electromagnetic waves corresponding to high frequency signals in a specific direction.

FIG. 1A to FIG. 1C are a top view and a cross-sectional view showing a first embodiment of an antenna substrate according to the present invention. FIGS. 2A to 2C are a top view and a cross-sectional view showing a second embodiment of the antenna substrate according to the present invention. FIGS. 3A to 3C are a top view and a cross-sectional view showing a third embodiment of the antenna substrate according to the present invention. 4 (a) and 4 (b) are a top view and a cross-sectional view showing a fourth embodiment of the antenna substrate according to the present invention. 5A and 5B are a top view and a cross-sectional view showing a conventional antenna substrate.

Next, an embodiment of an antenna substrate according to the present invention will be described with reference to the accompanying drawings. 1A is a top view of the antenna substrate, and FIGS. 1B and 1C are cross-sectional views taken along the lines XX and YY in FIG. 1A.
The antenna substrate of this example includes a dielectric substrate 1, a ground conductor layer 2, a strip conductor 3, a patch conductor 4, an auxiliary patch conductor 5, and a waveguide 6.

  The dielectric substrate 1 is formed by laminating dielectric layers 1a to 1e. The dielectric layers 1a to 1e are made of a dielectric material such as an epoxy resin, a bismaleimide triazine resin, or an acrylic-modified polyphenylene ether resin. In order to give rigidity to the dielectric substrate 1, for example, a dielectric layer obtained by impregnating the above-mentioned dielectric material into a glass cloth may be provided. Each of the dielectric layers 1a to 1e has a thickness of about 30 to 100 μm. The relative permittivity of the dielectric layers 1a to 1e is about 3 to 5.

  The ground conductor 2 is deposited on the entire lower surface of the lowermost dielectric layer 1a. The ground conductor 2 functions as a shield. The thickness of the ground conductor 2 is about 5 to 20 μm. The ground conductor 2 is made of a highly conductive metal such as copper by a known plating method, for example.

  The strip conductor 3 is disposed between the dielectric layers 1a and 1b in a state of facing the ground conductor 2 with the dielectric layer 1a interposed therebetween. The strip conductor 3 is a thin strip-shaped conductor having a terminal end 3a at the center of the dielectric substrate 1, and extends in one direction from the inside of the dielectric substrate 1 toward the terminal end 3a. The strip conductor 3 functions as a transmission path for inputting and outputting a high-frequency signal in the antenna substrate of this example, and the high-frequency signal is transmitted to the strip conductor 3. The width of the strip conductor 3 is about 50 to 350 μm. The thickness of the strip conductor 3 is about 5 to 20 μm. The strip conductor 3 is made of a highly conductive metal such as copper by a known plating method, for example.

  The patch conductor 4 includes a first patch conductor 4a, a second patch conductor 4b, and a third patch conductor 4c. These patch conductors 4a to 4c are electrically independent from each other. The patch conductors 4a to 4c have a quadrilateral shape having sides parallel to the extending direction in which the strip conductor 3 extends and sides parallel to a direction perpendicular to the extending direction. The length of each side of the patch conductors 4a to 4c is about 0.5 to 5 mm. Each of the patch conductors 4a to 4c has a thickness of about 5 to 20 μm. The patch conductors 4a to 4c are made of a highly conductive metal such as copper by a known plating method, for example.

  The first patch conductor 4a is disposed between the dielectric layers 1c and 1d so as to cover the position of the end portion 3a of the strip conductor 3. Therefore, two dielectric layers 1b and 1c are interposed between the first patch conductor 4a and the strip conductor 3. The first patch conductor 4a is connected to the end portion 3a of the strip conductor 3 via a through conductor 7 that penetrates the dielectric layer 1c and a through conductor 8 that penetrates the dielectric layer 1b. The through conductor 7 has a cylindrical shape with a diameter of about 50 to 200 μm and a thickness of about 5 to 20 μm. The through conductor 8 has a columnar shape or a truncated cone shape with a diameter of about 30 to 100 μm. The first patch conductor 4a receives the high frequency signal from the strip conductor 3 and radiates electromagnetic waves to the outside. Alternatively, a high frequency signal is generated in the strip conductor 3 by receiving an electromagnetic wave from the outside. The through conductors 7 and 8 are formed by depositing a highly conductive metal such as copper in a through hole formed in each of the dielectric layers 1b and 1c by, for example, a known plating method.

The second patch conductor 4b is disposed between the dielectric layers 1d and 1e so that at least a part thereof covers a position corresponding to the first patch conductor 4a. As a result, the second patch conductor 4b is capacitively coupled to the first patch conductor 4a with the dielectric layer 1d interposed therebetween.
Further, the second patch conductor 4b is arranged eccentrically in the extending direction with respect to the first patch conductor 4a. The eccentricity of the second patch conductor 4b is such that it covers an area of 80% or more of the position corresponding to the first patch conductor 4a.
The second patch conductor 4b receives the electromagnetic wave from the first patch conductor 4a and radiates the corresponding electromagnetic wave to the outside. Or the electromagnetic wave from the outside is received and the electromagnetic wave corresponding to it is supplied to the 1st patch conductor 4a. In addition, it is preferable that each side of the second patch conductor 4b is larger by about 0.05 to 0.5 mm than each side of the first patch conductor 4a.

The third patch conductor 4c is disposed on the upper surface of the uppermost dielectric layer 1e so that at least a part thereof covers a position corresponding to the second patch conductor 4b. As a result, the third patch conductor 4c is capacitively coupled to the second patch conductor 4b with the dielectric layer 1e interposed therebetween.
Furthermore, the third patch conductor 4c is arranged eccentrically in the extending direction with respect to the second patch conductor 4b. The eccentricity of the third patch conductor 4c is set so as to cover an area of 80% or more of the position corresponding to the second patch conductor 4b.
The third patch conductor 4c receives the electromagnetic wave from the second patch conductor 4b and radiates the corresponding electromagnetic wave to the outside. Alternatively, it receives an electromagnetic wave from the outside and supplies the corresponding electromagnetic wave to the second patch conductor 4b. In addition, it is preferable that each side of the third patch conductor 4c is larger by about 0.05 to 0.5 mm than each side of the second patch conductor 4b.

  Note that the second patch conductor 4b is eccentric so as to cover an area of less than 80% of the position corresponding to the first patch conductor 4a, or the third patch conductor 4c is the second patch conductor 4b. If it is decentered so as to cover an area of less than 80% of the position corresponding to, the frequency band that can be handled by the antenna substrate becomes narrow. Therefore, the second patch conductor 4b is preferably eccentric so as to cover an area of 80% or more of the position corresponding to the first patch conductor 4a, and the third patch conductor 4c is the second patch conductor. It is preferable to be eccentric so as to cover an area of 80% or more of the position corresponding to 4b.

The auxiliary patch conductor 5 is covered on the upper surface of the dielectric layer 1e at positions corresponding to the first patch conductor 4a and the second patch conductor 4b on both sides in the direction orthogonal to the extending direction of the third patch conductor 4c. It is formed so that there is no.
The auxiliary patch conductors 5 are electrically independent from each other. The auxiliary patch conductor 5 has a quadrangular shape having a side parallel to the extending direction in which the strip conductor 3 extends and a side parallel to a direction perpendicular to the extending direction. The length of each side of the auxiliary patch conductor 5 is about 0.5 to 5 mm. Each of the auxiliary patch conductors 5 has a thickness of about 5 to 20 μm. The auxiliary patch conductors 5 are arranged at positions separated from the third patch conductors 4c by about 0.1 to 1 mm, respectively. The auxiliary patch conductor 5 is formed from a highly conductive metal such as copper by a known plating method, for example.

As described above, the second patch conductor 4b is arranged eccentrically in the extending direction with respect to the first patch conductor 4a, and the third patch conductor 4c extends with respect to the second patch conductor 4b. Since the electromagnetic waves corresponding to the high-frequency signal are radiated through the patch conductors 4a to 4c, for example, from the lower patch conductor 4a to the outer peripheral edge of the upper patch conductors 4b and 4c. Electromagnetic waves are radiated so as to spread sequentially along, and complex resonance occurs and radiates due to eccentricity.
Furthermore, a further complex resonance occurs between the third patch conductor 4c and the auxiliary patch conductor 5 and radiates.
Thereby, the frequency band of the high frequency signal radiated | emitted via the 1st-3rd patch conductors 4a-4c and the auxiliary patch conductor 5 can be made wide.

  The waveguide 6 includes an upper and lower ground conductor layer 9 and a ground through conductor 10 formed in a region on the extension direction side of the patch conductor 4.

  The upper and lower ground conductor layers 9 include, for example, a lower surface side ground conductor 2 formed on the lower surface of the lowermost dielectric layer 1a and an upper surface side ground conductor 9a formed on the upper surface of the dielectric layer 1d. The thickness of the upper and lower ground conductor layers 9 is about 5 to 20 μm. The upper and lower ground conductor layers 9 are made of a highly conductive metal such as copper by a known plating method, for example.

The grounding through conductor 10 is composed of a plurality of through conductors 10a to 10d that coaxially penetrate the dielectric layers 1a to 1d interposed between the upper and lower grounding conductor layers 9, respectively. The through conductor 10a is connected to the ground conductor 2, and the through conductor 10d is connected to the upper surface side ground conductor 9a.
The grounding through conductors 10 are arranged in two rows so as to sandwich the dielectric layers 1a to 1d from the left and right along the extending direction.
The through conductors 10a, 10b, and 10d have a columnar shape or a truncated cone shape with a diameter of about 30 to 100 μm. The through conductor 10c has a cylindrical shape with a diameter of about 50 to 200 μm. The grounding through conductor 10 is formed of a highly conductive metal such as copper so as to fill the through holes provided in the dielectric layers 10a to 10d by, for example, a known plating method.
The two rows of the ground through conductors 10 are preferably formed on the outer peripheral side of the left and right auxiliary patch conductors 5 at least on the patch conductor 4 side. If two rows of the ground through conductors 10 are formed inside the left and right auxiliary patch conductors 5 on the patch conductor 4 side, the electromagnetic waves propagated from the patch conductor 4 and the auxiliary patch conductor 5 to the waveguide 6 are weak. turn into.

It should be noted that the region between the upper and lower ground conductor layers 9 and the ground penetrating conductor 10 in the region on the extending direction side of the strip conductor 3 with respect to the patch conductor 4 has a relative dielectric constant higher than that of the dielectric layers 1a to 1e. A low dielectric layer 11 having a small relative dielectric constant is formed.
As a result, the electromagnetic wave corresponding to the high-frequency signal radiated or incident through the first to third patch conductors 4 a to 4 c and the auxiliary patch conductor 5 is easily propagated in the low dielectric layer 11 in the waveguide 6. Is radiated in a concentrated manner through the low dielectric layer 11 when receiving an electromagnetic wave from the outside.
The relative dielectric constant of the low dielectric layer 11 is preferably 2 or more smaller than that of the dielectric layers 1a to 1e. If the difference in relative dielectric constant is less than 2, the difference in electromagnetic wave propagation between the low dielectric layer 11 and the dielectric layers 1a to 1e is reduced, and the electromagnetic wave transmission / reception function in a specific direction is impaired.
Such a low dielectric layer 11 is formed as follows, for example.
First, a substrate in the middle of manufacturing is prepared in a state where the dielectric layers 1b and 1d are respectively laminated on the upper and lower surfaces of the dielectric layer 1c on which the first patch conductor 4a and the through conductors 7 and 10c are formed. Next, the dielectric layers 1b to 1d in the region sandwiched between the arrays of through conductors 10c are cut and removed. Next, the low dielectric layer 11 is formed by filling or fitting a paste-like or sheet-like insulating resin for the low dielectric layer 11 in a region that has been vacated by cutting, and curing it.

As described above, according to the antenna substrate of the present invention, the upper surface side ground conductor 9 a and the lower surface side ground conductor 2 that face each other and the both are connected to the region in the extending direction of the strip conductor 3 with respect to the patch conductor 4. A waveguide 6 including a plurality of ground through conductors 10 arranged in this manner is formed. For this reason, a part of the electromagnetic wave corresponding to the high frequency signal radiated or incident via the third patch conductor 4 c and the auxiliary patch conductor 5 is preferentially radiated or incident via the waveguide 6.
Further, a low dielectric having a relative dielectric constant smaller than that of the dielectric layers 1a to 1e in a region sandwiched between at least the upper surface side ground conductor 9a, the lower surface side ground conductor 2, and the ground through conductor 10 is arranged. Layer 11 is formed.
For this reason, the electromagnetic waves are radiated or incident more intensively through the low dielectric layer 11 that easily propagates in the waveguide 6.
Thereby, it is possible to provide an antenna substrate capable of intensively transmitting and receiving electromagnetic waves corresponding to high frequency signals in a specific direction.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.
For example, in the example of the above-described embodiment, two rows of the ground through conductors 10 are arranged in series along the extending direction from the patch conductor 4 side to the outer peripheral side. For example, FIG. As shown in (c), the interval between the columns on the outer peripheral side may be smaller than the interval between the columns on the patch conductor 4 side.
Further, as shown in FIGS. 3A to 3C, the interval between the columns on the outer peripheral side may be larger than the interval between the columns on the patch conductor 4 side.
Thus, by arranging the upper and lower ground conductor layers 9 and the ground through conductors 10, an antenna substrate capable of efficiently transmitting and receiving signals according to the frequency of the high frequency signal can be provided.

Further, for example, in the example of the embodiment described above, the first patch conductor 4a and the terminal end portion 3a of the strip conductor 3 are connected by a pair of through conductors 7 and 8, but as shown in FIG. You may connect by two sets of penetration conductors 7, 8 and 17, 18 arrange | positioned adjacent to each other along the extending | stretching direction. As described above, by arranging the two sets of through conductors 7, 8 and 17, 18 so as to be adjacent to each other and providing a capacity between them, a complex resonance can be generated. As a result, the frequency band of the high-frequency signal can be further expanded.
In addition, it is preferable that an adjacent space | interval is 1/2 or less of the wavelength of the high frequency signal transmitted to the strip conductor 3. FIG. When the adjacent interval exceeds ½, sufficient capacity cannot be provided, so that complex resonance cannot be generated, and the effect of expanding the frequency band of the high-frequency signal is reduced.

1a to 1e Dielectric layer 2 Ground conductor layer (lower surface side ground conductor)
DESCRIPTION OF SYMBOLS 3 Strip conductor 3a End part of strip conductor 4 Patch conductor 4a 1st patch conductor 4b 2nd patch conductor 4c 3rd patch conductor 6 Waveguide 7 Through conductor 9a Upper surface side ground conductor 10 Ground through conductor 11 Low dielectric layer

Claims (7)

A first dielectric layer;
A strip conductor disposed on the upper surface of the first dielectric layer, extending in one direction from the outer periphery to the center of the first dielectric layer, and having a termination at the center;
A grounding conductor layer for shielding disposed on the lower surface side of the first dielectric layer;
A second dielectric layer laminated on the upper surface side of the first dielectric layer and the strip conductor;
A first patch conductor disposed on an upper surface of the second dielectric layer so as to cover the terminal portion;
A third dielectric layer laminated on the second dielectric layer and the first patch conductor;
The upper surface of the third dielectric layer is at least partially covered with the position where the first patch conductor is formed, and the center thereof extends in the extending direction of the strip conductor with respect to the center of the first patch conductor. A second patch conductor that is offset and electrically independent;
In the antenna substrate comprising a through conductor that penetrates through the second dielectric layer and connects the terminal portion and the first patch conductor,
The upper surface side ground conductor and the lower surface side ground conductor facing each other in the extending direction side region of the strip conductor with respect to the first and second patch conductors, and the upper surface side grounding on both sides in the direction orthogonal to the extending direction A waveguide including a plurality of ground through conductors arranged so as to connect the conductor and the lower surface side ground conductor is formed, and is sandwiched between at least the upper surface side and lower surface side ground conductors and the ground through conductors. An antenna substrate, wherein a fourth dielectric layer having a relative dielectric constant smaller than that of the first to third dielectric layers is formed in the region.   The antenna substrate according to claim 1, wherein the array of ground through conductors is provided in series along the extending direction of the strip conductor.   The antenna substrate according to claim 1, wherein the grounding through conductor includes one provided in series along the extending direction and one provided at a position out of the series.   The antenna according to any one of claims 1 to 3, wherein the second patch conductor is disposed so as to cover an area of 80% or more of a position where the first patch conductor is formed. substrate.   Assisting the upper surface of the third dielectric layer not to cover the positions where the first and second patch conductors are formed on both sides of the second patch conductor in the direction perpendicular to the extending direction. The antenna substrate according to any one of claims 1 to 4, further comprising a patch conductor, wherein the auxiliary patch conductor is electrically independent from the first and second patch conductors.   The antenna substrate according to any one of claims 1 to 5, wherein the terminal portion and the first patch conductor are connected by a plurality of the through conductors disposed adjacent to each other along the extending direction.   The antenna substrate according to claim 6, wherein an interval between the through conductors is ½ or less of a high frequency signal wavelength transmitted to the strip conductor.

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