JP2020010125A - Matching circuit board and radar device - Google Patents

Abstract

To provide a technique capable of achieving narrowing of a packaging region and a suitable impedance matching by reducing restrictions in a region available as a matching circuit.SOLUTION: The matching circuit board, executing impedance matching between an antenna part and a power supply section for supplying electric power to the antenna part, includes: a matching circuit section which is disposed on an inner layer relative to two surfaces of a substrate and executing impedance matching; a connection part for electrically connecting the matching circuit section with the antenna part and the power supply section.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a matching circuit board and a radar device.

  In a radar device, impedance matching is performed between an antenna unit and a power supply unit that supplies power for transmitting and receiving radar waves to the antenna unit. Thus, power can be efficiently supplied from the power supply unit to the antenna unit. For example, the high-frequency substrate disclosed in Patent Document 1 includes an antenna element, an RF chip that transmits and receives millimeter waves, and a matching circuit. The matching circuit is arranged between the antenna element and the RF chip. The matching circuit can adjust the deviation of the impedance generated between the antenna element and the RF chip to a desired value.

JP 2017-215197 A

  However, the conventional technique described in Patent Document 1 has a problem that the matching circuit is arranged on the same surface of the high-frequency substrate as the RF chip, and the mounting area becomes large. Since the area that can be used as the matching circuit is limited, it has been feared that suitable impedance matching cannot be realized and power loss occurs.

  The present invention has been made in view of the above problems, and in a matching circuit board that performs impedance matching between an antenna unit and a power supply unit that supplies power to the antenna unit, a mounting area is reduced and matching is achieved. It is an object of the present invention to provide a technique capable of realizing suitable impedance matching by reducing a restriction on a region that can be used as a circuit.

  The present invention relates to a matching circuit board that performs impedance matching between an antenna unit and a power supply unit that supplies power to the antenna unit, wherein the matching circuit unit is disposed in an inner layer with respect to two surfaces of the board and performs impedance matching. And a connection unit that electrically connects the matching circuit unit with the antenna unit and the power supply unit (first configuration).

  Further, in the matching circuit board of the first configuration, a dielectric constant variable portion arranged adjacent to the matching circuit portion and having a variable dielectric constant, and a dielectric constant for variably controlling the dielectric constant of the dielectric constant variable portion. And a control unit (second configuration).

  In the matching circuit board having the second configuration, the application electrode of the dielectric constant control unit may be configured to be disposed on the surface of the substrate (third configuration).

  Further, a radar device according to the present invention includes a matching circuit board having any one of the first to third configurations, an antenna unit, and a power supply unit that supplies power to the antenna unit (fourth configuration). Configuration).

  Further, a radar device according to the present invention includes a matching circuit board having the second or third configuration, an antenna unit, and a power supply unit that includes the dielectric constant control unit and supplies power to the antenna unit. This is the configuration (fifth configuration) provided.

  According to the configuration of the present invention, the matching circuit unit that performs impedance matching is disposed in the inner layer of the substrate. As a result, the mounting area can be reduced, and the restriction on the area that can be used as a matching circuit can be reduced. Therefore, suitable impedance matching can be realized.

1 is a perspective view illustrating an example of a radar device including a matching circuit board according to a first embodiment. Partial vertical cross section of matching circuit board Partial horizontal cross section of matching circuit board Partial horizontal cross-sectional view of the matching circuit board of the first modification. Partial horizontal cross-sectional view of a matching circuit board of Modification Example 2. Partial vertical sectional view of a matching circuit board according to a second embodiment. Partial vertical cross-sectional view of a matching circuit board of Modification Example 3. Partial vertical sectional view of a matching circuit board according to a third embodiment. Partial vertical sectional view of a matching circuit board according to a fourth embodiment.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following contents.

<1. First Embodiment>
<1-1. Overall configuration of radar device>
FIG. 1 is a perspective view illustrating an example of a radar device 100 including the matching circuit board 1 according to the first embodiment. The radar device 100 according to the present embodiment is, for example, a radar device mounted on a vehicle, and scans around the vehicle itself. The radar device 100 is provided on, for example, a front, side, or back exterior of a vehicle, and transmits a transmission wave in a millimeter wave band toward the periphery of the vehicle. Further, the radar device 100 may be configured to receive a reflected wave reflected by a target such as a preceding vehicle, an oncoming vehicle, or a roadside object.

  The radar device 100 includes a matching circuit board 1, a ground unit 2, a power supply unit 3, a transmission line 4, and an antenna unit 5.

  The matching circuit board 1 is a high-frequency board, and includes a dielectric base material layer of a synthetic resin material such as a fluororesin or an epoxy resin, and is formed in a plate shape. Components (not shown) including the power supply unit 3 and the antenna unit 5 are mounted on the first surface 1a which is one of the two surfaces of the matching circuit board 1. Components may be mounted on the second surface 1b, which is the other surface that is the back surface with respect to the first surface 1a.

  The ground portion 2 is arranged on the second surface 1b of the matching circuit board 1. The ground portion 2 may be a metal foil such as a copper foil bonded to the matching circuit board 1, for example. The ground section 2 may be formed as a conductive metal thin film pattern, for example.

  The power supply unit 3 is an electronic component including a high-frequency integrated circuit that performs signal processing such as oscillation, amplification, modulation, and frequency conversion of a high-frequency signal, and is, for example, an MMIC (Monolithic Microwave Integrated Circuit). The power supply unit 3 is, for example, a transmission MMIC, and is, for example, a reception MMIC.

  The power supply unit 3 is disposed on the same first surface 1a of the matching circuit board 1 as the surface on which the antenna unit 5 is disposed. Note that the power supply unit 3 may be disposed on the second surface 1b. The power supply unit 3 is electrically connected to the antenna unit 5 via the transmission line 4.

  The transmission line 4 is disposed on the first surface 1a of the matching circuit board 1. The transmission line 4 extends linearly, for example, and is disposed between the power supply unit 3 and the antenna unit 5. One end of the transmission line 4 is electrically connected to the power supply unit 3, and the other end is electrically connected to the antenna unit 5.

  The antenna unit 5 is disposed on the first surface 1a of the matching circuit board 1. The antenna section 5 includes a linear section 5a and an antenna element 5b. One end of the linear portion 5 a is electrically connected to the transmission line 4, and extends linearly following the transmission line 4, for example. A plurality of antenna elements 5b are provided at predetermined intervals along the linear portion 5a on both sides in a direction intersecting the extending direction of the linear portion 5a. The antenna unit 5 transmits a transmission wave in a predetermined direction. Alternatively, the antenna unit 5 receives a reflected wave obtained by reflecting a transmission wave on a target.

<1-2. Detailed configuration of matching circuit board>
FIG. 2 is a partial vertical sectional view of the matching circuit board 1. FIG. 3 is a partial horizontal sectional view of the matching circuit board 1. FIG. 2 is a vertical cross section parallel to the transmission line 4 extending in a straight line around the area where the transmission line 4 is arranged in FIG. Alternatively, FIG. 3 is a horizontal section taken along line III-III in FIG.

  The matching circuit board 1 includes a first base material layer 11, a second base material layer 12, a matching circuit part 13, and a connection part 14.

  The matching circuit board 1 is, for example, a multilayer board in which a first base layer 11 and a second base layer 12 are laminated. The first base material layer 11 is arranged on the second surface 1 b side of the matching circuit board 1. The ground part 2 is provided on the lower surface of the first base material layer 11 in FIG. The second base material layer 12 is disposed on the first surface 1 a side of the matching circuit board 1. The power supply unit 3, the transmission line 4, and the antenna unit 5 are provided on the upper surface of the second base material layer 12 in FIG.

  The first base material layer 11 and the second base material layer 12 are bonded via an adhesive layer 15. The adhesive layer 15 is formed of a sheet-shaped prepreg when, for example, the first base layer 11 and the second base layer 12 are bonded. The adhesive layer 15 is heated and pressurized by a press process, so that the first base material layer 11 and the second base material layer 12 are integrated.

  The matching circuit section 13 is disposed between the first base material layer 11 and the second base material layer 12. The matching circuit portion 13 is formed before the first base material layer 11 and the second base material layer 12 are bonded via the adhesive layer 15. That is, matching circuit section 13 is disposed in an inner layer for the two surfaces of matching circuit board 1. The matching circuit unit 13 performs impedance matching between the antenna unit 5 and the power supply unit 3 that supplies power to the antenna unit 5.

  As shown in FIG. 3, the matching circuit unit 13 is electrically connected to the connection unit 14. The matching circuit section 13 is formed of, for example, a rectangular in a plan view extending linearly in a direction away from the connection section 14 in one direction. The shape pattern of the matching circuit section 13 is not limited to the configuration shown in FIG. 3 and FIGS. 4 and 5 described later, and may have another configuration. For example, the shape pattern of the matching circuit section 13 may be separated from the connection section 14.

  The connection portion 14 extends from the transmission line 4 to the ground portion 2 in the stacking direction of the matching circuit board 1 (vertical direction in FIG. 2). The connection portion 14 is formed of, for example, a through hole (via) penetrating the matching circuit board 1 in the stacking direction. Note that the connection section 14 may have another configuration that does not penetrate the matching circuit board 1. The connection section 14 electrically connects the transmission line 4 and the ground section 2. Further, the connection section 14 is electrically connected to the matching circuit section 13 in the inner layer of the matching circuit board 1. That is, the connection unit 14 electrically connects the matching circuit unit 13 with the antenna unit 5 and the power supply unit 3.

  According to the configuration of the first embodiment, since the matching circuit unit 13 that performs impedance matching is disposed in the inner layer of the matching circuit board 1, the mounting area can be reduced. Then, it is possible to reduce restrictions on a region that can be used as a matching circuit. Therefore, suitable impedance matching can be realized.

<1-3. Modification of Matching Circuit Board>
FIG. 4 is a partial horizontal cross-sectional view of the matching circuit board 1 of the first modification. The matching circuit board 1 of the first modification includes a matching circuit unit 13A. The matching circuit portion 13A is disposed between the first base material layer 11 and the second base material layer 12 and in the inner layer of the matching circuit board 1, as in the first embodiment. The matching circuit portion 13A is formed of two rectangular portions in a plan view extending linearly away from the connection portion 14 in directions opposite to each other.

  FIG. 5 is a partial horizontal cross-sectional view of the matching circuit board 1 of the first modification. The matching circuit board 1 of the second modification includes a matching circuit unit 13B. The matching circuit portion 13B is disposed between the first base material layer 11 and the second base material layer 12 and in the inner layer of the matching circuit board 1, as in the first embodiment. The matching circuit portion 13B is formed in a fan shape in a plan view extending in a direction away from the connection portion 14 in one direction.

  According to the configuration of the above-described embodiment, the restriction on the area that can be used as a matching circuit can be reduced. Therefore, the matching circuit unit 13A of the first modification and the matching circuit unit 13B of the second modification have an arbitrary shape. It is possible to form a matching circuit. Therefore, suitable impedance matching can be realized.

<2. Second Embodiment>
<2-1. Detailed configuration of matching circuit board>
FIG. 6 is a partial vertical sectional view of the matching circuit board 1 of the second embodiment. FIG. 6 is a vertical cross section parallel to the transmission line 4 extending in a straight line, around the arrangement area of the transmission line 4 in FIG. Further, in FIG. 6, for convenience of explanation, a permittivity control unit 172 described later is described as being separated from the matching circuit board 1, but the permittivity control unit 172 is provided on the matching circuit board 1.

  The matching circuit board 1 according to the second embodiment includes a first base layer 112, a second base layer 122, a matching circuit section 132, a connection section 142, a dielectric constant variable section 162, and a dielectric constant control section 172.

  The matching circuit board 1 is, for example, a multilayer board in which the second base layer 122, the first base layer 112, and the dielectric constant varying section 162 are stacked. The second base material layer 122 is disposed on the first surface 1a side of the matching circuit board 1. Under the second base layer 122 in FIG. 6, the first base layer 112 and the dielectric constant varying section 162 are sequentially arranged.

  The second base layer 122 and the first base layer 112 are bonded together via an adhesive layer (not shown). The ground 2 is interposed between the second base layer 122 and the first base layer 112. The first base material layer 112 and the variable dielectric constant portion 162 are bonded via an adhesive layer 152.

  The matching circuit section 132 is arranged on the second surface 1b side of the matching circuit board 1 with the second base layer 122, the ground section 2, and the first base layer 112 interposed therebetween. That is, the matching circuit section 132 is arranged on the lower surface side of the first base material layer 112 in FIG. The matching circuit unit 132 is electrically connected to the connection unit 142.

  The connection part 142 extends from the transmission line 4 to the matching circuit part 132 in the stacking direction of the matching circuit board 1 (vertical direction in FIG. 6). The connection section 142 electrically connects the transmission line 4 and the matching circuit section 132.

  The permittivity variable section 162 is disposed closer to the second surface 1b of the matching circuit board 1 than the matching circuit section 132 is. The permittivity variable section 162 is arranged adjacent to the matching circuit section 132. The dielectric constant varying section 162 is provided over the entire surface of the matching circuit board 1, for example, like the first base layer 112 and the second base layer 122.

  The permittivity variable section 162 is made of, for example, a liquid crystal material, and has a variable permittivity. Note that the dielectric constant varying section 162 is not limited to a liquid crystal material, but may be another material as long as the dielectric constant is variable.

  The matching circuit section 132 is disposed between the first base material layer 112 and the dielectric constant varying section 162. The matching circuit section 132 is formed before the first base material layer 112 and the dielectric constant varying section 162 are bonded via the adhesive layer 152. That is, matching circuit section 132 is arranged in an inner layer for the two surfaces of matching circuit board 1.

  The dielectric constant control unit 172 includes, for example, a power supply unit and a control circuit, and its positive electrode is electrically connected to the dielectric constant variable unit 162 via the application electrode 172p, and applies a voltage to the dielectric constant variable unit 162. Accordingly, the permittivity control unit 172 performs variable control of the permittivity of the permittivity variable unit 162.

  According to the configuration of the second embodiment, since the permittivity of the permittivity variable unit 162 can be controlled, it is possible to adjust the matching condition of the impedance matching. Therefore, it is possible to realize more suitable impedance matching.

  The application electrode of the permittivity controller 172 is arranged on the surface of the lower matching circuit board 1 in FIG. That is, a voltage is applied to the dielectric constant varying unit 162 from the outermost layer of the matching circuit board 1. According to this configuration, it is easy to apply a voltage to the dielectric constant varying unit 162. Note that the permittivity variable section 162 may be arranged in an inner layer with respect to the two surfaces of the matching circuit board 1.

<2-2. Modification of Matching Circuit Board>
FIG. 7 is a partial vertical sectional view of the matching circuit board 1 of the third modification. Note that FIG. 7 is a vertical cross section parallel to the transmission line 4 extending in a straight line, around the area where the transmission line 4 is arranged in FIG. Further, in FIG. 7, for convenience of explanation, the permittivity control unit 172 is illustrated as being separated from the matching circuit board 1, but the permittivity control unit 172 is provided on the matching circuit board 1.

  The matching circuit board 1 of the third modification includes a dielectric constant varying unit 162C. The dielectric constant varying unit 162C is provided not on the entire surface of the matching circuit board 1 but only around the matching circuit unit 132.

  The matching circuit section 132 is disposed between the first base material layer 112 and the dielectric constant varying section 162C. The matching circuit section 132 is formed before the first base material layer 112 and the dielectric constant varying section 162C are bonded to each other via the adhesive layer 152C. That is, matching circuit section 132 is arranged in an inner layer for the two surfaces of matching circuit board 1.

  According to the configuration of the above-described embodiment, the dielectric constant varying section 162C can be provided only in the minimum necessary area. Therefore, it is possible to realize a suitable impedance matching by a configuration in which cost is reduced.

<3. Third embodiment>
FIG. 8 is a partial vertical sectional view of the matching circuit board 1 of the third embodiment. FIG. 8 is a vertical cross section parallel to the transmission line 4 extending in a straight line around the area where the transmission line 4 is arranged in FIG. Further, in FIG. 8, for convenience of explanation, the permittivity control unit 173 is illustrated as being separated from the matching circuit board 1, but the permittivity control unit 173 is provided on the matching circuit board 1.

  The matching circuit board 1 according to the third embodiment includes a first base material layer 113, a matching circuit unit 133, a connection unit 143, a dielectric constant variable unit 163, and a dielectric constant control unit 173.

  The matching circuit board 1 is, for example, a multilayer board in which the first base material layer 113 and the dielectric constant varying unit 163 are stacked. The first base material layer 113 is arranged on the first surface 1 a side of the matching circuit board 1. The permittivity variable section 163 is arranged on the second surface 1b side of the matching circuit board 1. The dielectric constant variable section 163 is provided over the entire surface of the matching circuit board 1, for example, like the first base material layer 113. The first base material layer 113 and the variable dielectric constant portion 163 are bonded via an adhesive layer 153.

  The matching circuit unit 133 is disposed between the first base material layer 113 and the dielectric constant varying unit 163. The matching circuit section 133 is formed before the first base material layer 113 and the dielectric constant varying section 163 are bonded via the adhesive layer 153. That is, matching circuit section 133 is arranged in an inner layer with respect to the two surfaces of matching circuit board 1. Note that the permittivity variable section 163 is arranged adjacent to the matching circuit section 133.

  The dielectric constant control unit 173 includes, for example, a power supply unit and a control circuit. Regarding the permittivity control unit 173, the positive terminal 173p and the negative terminal 173n are arranged on the surface of the permittivity variable unit 163. The dielectric constant control section 173 has a positive electrode electrically connected to the dielectric constant variable section 163 via a positive electrode terminal 173p, and a negative electrode electrically connected to the dielectric constant variable section 163 via a negative electrode terminal 173n. The dielectric constant control unit 173 applies a voltage to the dielectric constant variable unit 163, and performs variable control of the dielectric constant of the dielectric constant variable unit 163.

  According to the configuration of the third embodiment, since the permittivity of the permittivity variable unit 163 can be controlled, it is possible to adjust the matching condition of the impedance matching. Therefore, more suitable impedance matching can be realized.

<4. Fourth embodiment>
FIG. 9 is a partial vertical sectional view of the matching circuit board 1 of the fourth embodiment. FIG. 9 is a vertical cross section parallel to the transmission line 4 extending in a straight line around the transmission line 4 arrangement region in FIG.

  The matching circuit board 1 of the fourth embodiment includes a first base material layer 114, a matching circuit section 134, a connection section 144, a permittivity variable section 164, and a permittivity control section 174.

  The matching circuit board 1 is, for example, a multilayer board in which a first base material layer 114 and a dielectric constant variable section 164 are stacked. The first base material layer 114 is disposed on the first surface 1a side of the matching circuit board 1. The permittivity variable section 164 is arranged on the second surface 1b side of the matching circuit board 1. The dielectric constant varying section 164 is provided over the entire surface of the matching circuit board 1, for example, like the first base material layer 114. The first base material layer 114 and the variable dielectric constant portion 164 are bonded via an adhesive layer 154.

  The matching circuit unit 134 is disposed between the first base material layer 114 and the dielectric constant varying unit 164. The matching circuit portion 134 is formed before the first base material layer 114 and the dielectric constant variable portion 164 are bonded via the adhesive layer 154. That is, matching circuit section 134 is arranged in an inner layer for the two surfaces of matching circuit board 1. Note that the permittivity variable section 164 is arranged adjacent to the matching circuit section 134.

  The dielectric constant control unit 174 includes, for example, a power supply unit and a control circuit. Then, the permittivity control unit 174 is included in the power supply unit 3. That is, the power supply unit 3 includes the dielectric constant control unit 174 and supplies power to the antenna unit 5.

  Regarding the permittivity control unit 174, a positive terminal 174p and a negative terminal 174n are arranged on the surface of the permittivity variable unit 164. The dielectric constant control unit 174 has a positive electrode electrically connected to the dielectric constant variable unit 164 via a positive electrode terminal 174p, and a negative electrode electrically connected to the dielectric constant variable unit 164 via a negative electrode terminal 174n. The permittivity control unit 174 applies a voltage to the permittivity variable unit 164 and performs variable control of the permittivity of the permittivity variable unit 164.

  According to the configuration of the fourth embodiment, since the permittivity of the permittivity variable unit 164 can be controlled, it is possible to adjust the matching condition of the impedance matching. Further, since the power supply unit 3 includes the dielectric constant control unit 174, it is not necessary to provide the dielectric constant control unit 174 on the matching circuit board 1, and the mounting area can be made smaller.

<5. Others>
Various technical features disclosed in the present specification can be variously modified without departing from the spirit of the technical creation in addition to the above-described embodiment. That is, the above embodiment is an example in all respects, and should not be considered as limiting. The technical scope of the present invention is described not by the description of the above-described embodiment but by the claims, and it should be understood that the meaning equivalent to the claims and all the modifications belonging to the scope are included. It is. Further, the above-described plurality of embodiments and modifications may be implemented in combination within a possible range.

  For example, the radio waves (transmitted waves and reflected waves) used in the radar device 100 are merely examples, and may be “light waves” or “ultrasonic waves”.

  Further, in the second, third and fourth embodiments, a circuit for automatically adjusting the impedance deviation may be provided. In this case, a detector for the reflected wave, a feedback circuit, and the like are provided, and a voltage related to the reflected wave is detected and fed back to the permittivity control unit to perform variable control of the permittivity of the permittivity variable unit. As a result, even if impedance mismatch occurs due to external environmental factors, it is possible to perform control to correct the mismatch. Therefore, the detection performance of the radar device can be suitably maintained.

DESCRIPTION OF SYMBOLS 1 Matching circuit board 1a 1st surface 1b 2nd surface 2 Ground part 3 Power supply part 4 Transmission line 5 Antenna part 11,112,113,114 1st base material layer 12,122 2nd base material layer 13,13A, 13B , 132, 133, 134 Matching circuit unit 14, 142, 143, 144 Connection unit 15, 152, 153, 154 Adhesive layer 100 Radar device 162, 162C, 163, 164 Dielectric constant variable unit 172, 173, 174 Dielectric constant control unit 172p applied electrode

Claims (5)

An antenna unit, a matching circuit board that performs impedance matching between a power supply unit that supplies power to the antenna unit,
A matching circuit unit disposed on an inner layer for two surfaces of the substrate and performing impedance matching;
A connection unit that electrically connects the matching circuit unit, the antenna unit, and the power supply unit;
A matching circuit board comprising: A dielectric constant variable unit disposed adjacent to the matching circuit unit and having a variable dielectric constant;
A dielectric constant control unit that performs variable control of the dielectric constant of the dielectric constant variable unit,
The matching circuit board according to claim 1, further comprising:   The matching circuit board according to claim 2, wherein the application electrode of the permittivity controller is arranged on the surface of the board. The matching circuit board according to any one of claims 1 to 3,
An antenna section,
A power supply unit for supplying power to the antenna unit,
A radar device comprising: The matching circuit board according to claim 2 or 3,
An antenna section,
Including the dielectric constant control unit, a power supply unit that supplies power to the antenna unit,
A radar device comprising:

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