JP2007013531A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce unnecessary radiation of an antenna device without increasing the number of components or upsizing an entire device. <P>SOLUTION: The antenna device is provided with: a dielectric substrate 100 on one side of which a high frequency circuit is mounted and on the other side of which patch array antennas 110 and 120, feedlines 131 and 132 distribution connected to the patch array antennas, and high frequency connection lines 141 to 145 connected to the high frequency circuit are formed; and a shield member 200 which is provided on the latter side of the dielectric substrate 100 and covers at least a part of the feedlines 131 and 132 and the high frequency connection lines 141 to 145. Thus, since it is not necessary to provide the shield member on both sides of the dielectric substrate, influences by noise due to the unnecessary radiation is reduced, while suppressing the increase in the number of component items and upsizing of the entire device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antenna device, and more particularly to a type of antenna device in which a high frequency circuit is mounted on one surface of a dielectric substrate and a patch array antenna is formed on the other surface.

  In recent years, many radar devices using microwaves and millimeter waves have been proposed. The range of application of such a radar device is various. For example, if it is mounted on an automobile, it is possible not only to accurately detect the distance from the preceding vehicle and the following vehicle, but also to be a driver's blind spot. Pre-crash such as detecting obstacles in the position, for example, diagonally behind or near the bumper to alert the driver, or even detecting the inevitable collision approaching and tightening the seat belt Control can be performed.

  As an antenna used in such a radar apparatus, an array antenna apparatus may be used (see Patent Document 1). The array antenna device has a structure in which a plurality of patch antenna elements are arranged in an array. In order to achieve cost reduction in such an antenna device, it is preferable to mount a high frequency circuit on one surface of the dielectric substrate and to form a plurality of patch antenna elements (patch array antennas) on the other surface. .

  A patch array antenna is distributed and connected to a high-frequency circuit by a feed line. When the patch array antenna and the feed line are arranged on the same plane, in addition to radiation from the patch array antenna, a bent portion or a branch of the feed line is used. Since unnecessary radiation is also emitted from discontinuous parts such as parts, there is a problem that directivity is reduced. Such a problem can be solved by covering the upper part of the feed line with a shield member as described in Patent Document 1.

In addition, the technique described in Patent Document 2 is known as a technique for preventing unnecessary radiation by covering the periphery of the feeder line with a shield member.
JP-A-8-167812 JP-A-9-135118

  However, the generation source of unnecessary radiation is not only a bent portion or a branch portion of the feed line, but a connection line between the patch array antenna and the high frequency circuit, or a connection line connecting the high frequency circuits is also a generation source of unnecessary radiation. In order to suppress such unwanted radiation, a shield member that covers these connection lines may be provided, but in a type of antenna device in which a high-frequency circuit and a patch array antenna are formed on different surfaces of a dielectric substrate Therefore, it is necessary to provide shield members on both surfaces of the dielectric substrate, which causes an increase in the number of components and an increase in the thickness of the antenna device.

  On the other hand, if the high-frequency circuit and the patch array antenna are formed on the same surface of the dielectric substrate, only one shield member is sufficient. However, if such an arrangement is used, there is a risk that noise will increase significantly. In addition, since the area required for the dielectric substrate is increased, there is a problem that the mounting area of the antenna device is increased.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to reduce unnecessary radiation of an antenna device without increasing the number of components and increasing the size of the entire device.

  In the antenna device according to the present invention, a high-frequency circuit is mounted on one surface, and a dielectric on which a patch antenna, a feed line connected to the patch antenna, and a high-frequency connection line connected to the high-frequency circuit are formed on the other surface. It is provided with the board | substrate and the shielding member which is provided in the said other surface side of the said dielectric substrate, and covers at least one part of the said electric power feeding line and the said high frequency connection line.

  According to the present invention, the shield member is provided on both surfaces of the dielectric substrate because the shield member provided on the other surface side of the dielectric substrate covers at least a part of the feed line and the high-frequency connection line. There is no need. Thereby, it becomes possible to reduce the influence of noise due to unnecessary radiation while suppressing an increase in the number of parts and an increase in the size of the entire apparatus. The high-frequency connection line may be led out from the one surface side of the dielectric substrate to the other surface side through a through-hole electrode.

  In the present invention, the patch antenna includes a transmission-side patch antenna and a reception-side patch antenna, and the shield member has an opening that exposes the transmission-side patch antenna and an opening that exposes the reception-side patch antenna. It is preferable that they are provided separately. According to this, since the transmission-side patch antenna and the reception-side patch antenna are separated by a part of the shield member, it is possible to greatly reduce the radio wave input directly from the transmission-side patch antenna to the reception-side patch antenna. It becomes.

  In the present invention, it is possible to provide a ground pattern surrounding the high-frequency circuit on the one surface of the dielectric substrate. This is because the high-frequency connection line is provided on the other surface side of the dielectric substrate, whereby the routing of the high-frequency connection line is not performed planarly on one surface of the dielectric substrate, Once drawn to the other surface side, it can be routed on the other surface side. As a result, by providing a shield case in contact with the ground pattern, the shield case can cover the high-frequency circuit without any gaps, and can effectively shield unwanted radiation generated from the high-frequency circuit. .

  In the present invention, the shield member is preferably formed with a groove in a portion covering the feed line and the high-frequency connection line. According to this, it becomes possible to prevent a shield member, a feed line, and a high frequency connection line from contacting.

  In the present invention, in the other surface of the dielectric substrate, the region covered with the shield member is provided with a ground pattern in contact with the shield member over almost the entire surface except the periphery of the feed line and the high-frequency connection line. Is preferred. According to this, it becomes possible to give a ground potential to the shield member.

  In the present invention, a baseband circuit that handles baseband signals is provided on the one surface of the dielectric substrate, and a connection between the baseband circuit and the high-frequency circuit is provided on the other surface of the dielectric substrate. A baseband signal line to be performed is further provided, and the shield member preferably further covers at least a part of the baseband signal line. According to this, since the baseband signal line is also covered with the shield member, it is possible not only to further reduce the influence of unnecessary radiation, but also to eliminate the need to form almost any wiring on the one surface of the dielectric substrate. Therefore, the structure of the one surface of the dielectric substrate can be greatly simplified.

  As described above, according to the present invention, the shield member provided on the other surface side of the dielectric substrate covers at least part of the feed line and the high-frequency connection line. There is no need to provide both sides of the body substrate. As a result, it is possible to reduce the influence of noise by covering a portion that causes unnecessary radiation while suppressing an increase in the number of parts and an increase in the size of the entire apparatus.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1A and 1B are schematic perspective views showing an antenna device according to a preferred embodiment of the present invention, in which FIG. 1A is a view seen from an oblique direction on the radiation surface side, and FIG. FIG. 2 is an exploded perspective view of an antenna device according to a preferred embodiment of the present invention.

  As shown in FIGS. 1A, 1B, and 2, the antenna device according to the present embodiment includes a dielectric substrate 100 and a shield member 200 provided on the surface (radiation surface) 100a of the dielectric substrate 100. Both members are mechanically fixed by fixing screws 300 arranged at least near the corners of the dielectric substrate 100 and the shield member 200.

  The dielectric substrate 100 is a single-layer substrate having a radiation surface 100a and a component mounting surface 100b which is the back surface thereof. As shown in FIGS. 1A and 2, on the radiation surface 100 a of the dielectric substrate 100, a transmission-side patch array antenna 110 and a reception-side patch array antenna 120 made up of a plurality of patch antenna elements, and a transmission-side patch array are provided. A feed line 131 distributed and connected to the antenna 110, a feed line 132 distributed and connected to the receiving-side patch array antenna 120, and high-frequency connection lines 141 to 145 are formed. In addition, a ground pattern 150 is formed on almost the entire blank area where the patch array antennas 110 and 120, the feed lines 131 and 132, and the high-frequency connection lines 141 to 145 are not formed.

  On the other hand, as shown in FIG. 1B, the component mounting surface 100b of the dielectric substrate 100 is mounted with a plurality of high-frequency circuits (161 to 164) that handle high-frequency signals, and is lower than these high-frequency circuits. A sub-board 180 on which a baseband circuit for handling a frequency signal is formed is mounted. In the present embodiment, there are four high-frequency circuits mounted on the component mounting surface 100 b of the dielectric substrate 100, that is, an oscillation circuit 161, an output circuit 162, a low noise amplifier (LNA) 163, and a mixer circuit 164. The frequency of the high-frequency signal is set to, for example, about 24 GHz when used as an in-vehicle short range radar device.

  As will be described later, among these high-frequency circuits, the output circuit 162 includes a modulation circuit and a power amplifier, and the mixer circuit 164 includes a 90-degree phase shifter and first and second mixers. The oscillation circuit 161, the output circuit 162, the LNA 163, and the mixer circuit 164 are all circuit components integrated on a single chip, and are arranged in regions surrounded by annular ground patterns 171 to 174, respectively. These ground patterns 171 to 174 completely surround the corresponding chips (161 to 164), and are not provided with cuts or the like for allowing the wiring to pass on the component mounting surface 100b.

  The shield member 200 is a member for blocking unnecessary radiation made of a conductive material such as aluminum (Al), and corresponds to the transmission-side patch array antenna 110 as shown in FIGS. Transmission side opening 210 and reception side opening 220 provided corresponding to reception side patch array antenna 120, and these openings 210 and 220 are provided separately from each other. Yes. When the shield member 200 is attached to the dielectric substrate 100, as shown in FIG. 1A, the transmission side patch array antenna 110 is exposed through the transmission side opening 210, and the reception side patch array antenna 120 is exposed to the reception side opening. It will be in the state exposed through the part 220. FIG.

  On the other hand, most of the other conductors formed on the radiation surface 100a of the dielectric substrate 100, that is, the feed lines 131 and 132, the high frequency connection lines 141 to 145, and the ground pattern 150 are covered with the shield member 200. Become. In the present embodiment, a part of the feed lines 131 and 132 and all of the high-frequency connection lines 141 to 145 are covered with the shield member 200, so that the bent portions and branch portions of the feed lines 131 and 132 are not covered. The shield member 200 blocks unnecessary radiation generated from the continuous portion and unnecessary radiation generated from the high-frequency connection lines 141 to 145.

  FIG. 3 is a schematic plan view of the shield member 200 viewed from the back surface (the surface facing the dielectric substrate 100), and FIG. 4 is a schematic cross-sectional view taken along line AA in FIG.

  As shown in FIG. 3, grooves 231 and 232 are formed on the back surface of the shield member 200 in portions covering the feed lines 131 and 132, and grooves 241 to 245 are formed in portions covering the high-frequency connection lines 141 to 145. Each is formed. When the shield member 200 is overlaid on the dielectric substrate 100 by the grooves 231, 232, 241-245, the shield member 200 and the ground pattern 150 are in contact with each other, while the shield member 200, the feed lines 131 and 132, and the high frequency Contact with the connection lines 141 to 145 is prevented. It is also possible to reduce the weight of the shield member 200 by forming some groove portions in other portions.

  FIG. 5 is a block diagram for explaining a connection relation of each circuit included in the antenna device according to the present embodiment.

  As shown in FIG. 5, the antenna device according to the present embodiment autonomously transmits a radio signal, receives the reflected signal, demodulates the received reflected signal, and supplies it to an external circuit. It is a device for measuring the distance to.

  The high frequency signal to be transmitted is generated by superimposing the pulse signal P from the pulse generation circuit 181 on the carrier signal C generated by the oscillation circuit 161. The pulse generation circuit 181 is a part of a baseband circuit formed in the sub-substrate 180. Such superposition operation is performed by the modulation circuit 161 a included in the output circuit 162, and the output is amplified by the power amplifier 161 b included in the output circuit 162 and then supplied to the transmission-side patch array antenna 110. Here, the carrier signal C supplied from the oscillation circuit 161 to the output circuit 162 (modulation circuit 162a) and the signal supplied from the output circuit 162 (power amplifier 162b) to the transmission side patch array antenna 110 are both high frequency signals. These transmissions use high-frequency connection lines 141 and 142, respectively. As described above, both the high-frequency connection lines 141 and 142 are formed on the radiation surface 100 a side of the dielectric substrate 100, and are therefore covered by the shield member 200. However, since the groove portions 241 and 242 are interposed between the shield member 200, the connection lines 141 and 142 and the shield member 200 do not contact each other.

  On the other hand, the reflected signal received by the receiving side patch array antenna 120 is amplified by the LNA 163 and then distributed to two signals whose phases are different by 90 degrees by the 90 degree phase shifter 164a included in the mixer circuit 164. The distributed signal is supplied to the first mixer 164b and the second mixer 164c, respectively, and demodulated by mixing with the carrier signal C from the oscillation circuit 161. The demodulated signals are supplied to intermediate frequency circuits 182 and 183 formed in the sub-board 180, respectively, are subjected to predetermined processing, are supplied to the signal processing circuit 184, and are supplied from the pulse generation circuit 181. By comparing with the signal P, the distance to the obstacle is calculated. The calculation result is supplied to an external circuit (not shown).

  Although not particularly limited, such an antenna device is preferably used as an on-vehicle short range radar device. If the antenna device according to the present embodiment is used as an on-vehicle short range radar device, for example, as shown in FIG. 6, the short range radar device 20 accurately detects the distance D between the host vehicle 10 and the preceding vehicle 11. Therefore, it is possible to perform pre-crash control such as alerting the driver, and further detecting that an unavoidable collision is imminent and tightening the seat belt.

  Next, the configuration of the dielectric substrate 100 will be described in more detail.

  FIG. 7 is a schematic plan view showing the structure of the main part on the radiation surface 100a side of the dielectric substrate 100 in more detail. In FIG. 7, the ground pattern 150 is not shown in consideration of the visibility of the drawing. FIG. 8 is a schematic plan view showing the structure of the main part on the component mounting surface 100b side of the dielectric substrate 100 in more detail. In FIG. 8, the sub-substrate 180 is not shown in consideration of the visibility of the drawing.

  As shown in FIG. 7, the high-frequency connection lines 141 to 145 formed on the radiation surface 100a are connected to corresponding high-frequency circuits mounted on the component mounting surface 100b through one or two through-hole electrodes, respectively. ing. More specifically, the high-frequency connection line 141 is connected to the oscillation circuit 161 through the through-hole electrode 141a, and is connected to the output circuit 162 through the through-hole electrode 141b. The high frequency connection line 142 is connected to the output circuit 162 through the through-hole electrode 142a. Furthermore, the high frequency connection line 143 is connected to the LNA 163 via the through-hole electrode 143a. The high-frequency connection line 144 is connected to the LNA 163 through the through-hole electrode 144a and is connected to the mixer circuit 164 through the through-hole electrode 144b. The high-frequency connection line 145 is connected to the oscillation circuit 161 via the through-hole electrode 145a, and is connected to the mixer circuit 164 via the through-hole electrode 145b.

  The portions where the through-hole electrodes are provided are all surrounded by a region where the high-frequency circuit (161 to 164) is mounted on the component mounting surface 100b side, that is, the ground patterns 171 to 174 as shown in FIG. Located in the designated area. As described above, the routing of the high-frequency connection lines connected to the high-frequency circuits (161 to 164) is not performed planarly on the component mounting surface 100b of the dielectric substrate 100, but on the back surface as viewed from the component mounting surface 100b. After being drawn out to the radiation surface 100a side, it is drawn around on the radiation surface 100a side. For this reason, a high frequency connection line is not formed on the component mounting surface 100b side, and as a result, unnecessary radiation from the component mounting surface 100b side is significantly reduced. This eliminates the need to cover the component mounting surface 100b side with a shield member or the like, thereby suppressing an increase in the number of components and an increase in the size of the entire apparatus.

  Moreover, according to the above configuration, each high-frequency circuit (161 to 164) can be completely surrounded by the annular ground patterns 171 to 174. For this reason, as shown in FIG. 9, each high-frequency circuit (161 to 164) can be covered with the conductive shield cases 191 to 194 without any gaps. That is, as shown in FIG. 10 which is a partial cross-sectional view, it is possible to bring the entire peripheral edge portion of the shield cases 191 to 194 into contact with the annular ground patterns 171 to 174 and to obtain a very high shielding effect. Become.

  As described above, the antenna device according to the present embodiment includes the shield member 200 that covers the radiation surface 100a of the dielectric substrate 100. The shield member 200 covers the feed lines 131 and 132, and the dielectric substrate. Since the high-frequency connection lines 141 to 145 drawn to the radiation surface 100a side of 100 are covered, it is not necessary to cover the component mounting surface 100b side with a shield member or the like. Thereby, it becomes possible to reduce the influence of noise due to unnecessary radiation while suppressing an increase in the number of parts and an increase in the size of the entire apparatus.

  In addition, it is not necessary to route lines for connecting the high-frequency circuits on the mounting surface of the high-frequency circuit, and each high-frequency circuit (161 to 164) can be completely surrounded by the annular ground patterns 171 to 174. The cases 191 to 194 can cover the high-frequency circuits (161 to 164) without gaps, and can effectively shield unwanted radiation generated from the high-frequency circuits (161 to 164).

  In addition, since the opening of the shield member 200 is divided into the transmission-side opening 210 and the reception-side opening 220, the transmission-side patch array antenna does not reach an obstacle (for example, a preceding vehicle) to be measured. It is possible to significantly reduce the radio waves directly input from 110 to the receiving side patch array antenna 120. That is, it is possible to reduce a decrease in reception gain, such as a reflected signal reception interference from a short distance due to a direct sneak in a transmission radio wave and a decrease in the minimum detection distance.

  In the above embodiment, the high-frequency connection lines 141 to 145 are routed on the radiation surface 100a side of the dielectric substrate 100, but the same applies to the baseband signal line that connects the baseband circuit and the high-frequency circuit. It is desirable to draw out to the radiation surface 100a side of the dielectric substrate 100 through the through-hole electrode, and to draw around on the radiation surface 100a side. According to this, since the baseband signal line is also covered by the shield member 200, the influence of unnecessary radiation can be further reduced, and it is necessary to form almost wiring on the component mounting surface 100b of the dielectric substrate 100. Therefore, the structure of the component mounting surface 100b can be greatly simplified.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

  For example, the antenna device according to the above embodiment includes both the transmission-side patch array antenna 110 and the reception-side patch array antenna 120, but the present invention is applied to a transmission-only antenna device including only the transmission-side patch array antenna. It is also possible to apply to a receiving-only antenna apparatus having only a receiving-side patch array antenna.

  In the antenna device according to the above-described embodiment, the shield member 200 is provided with a groove for preventing contact. However, as long as the contact between the shield member 200 and the high-frequency connection lines 141 to 145 can be prevented, such a groove is provided. Is not required. For example, some protrusions may be provided on the shield member 200 instead of providing the groove portions, so that the main surface of the shield member 200 and the radiation surface 100a of the dielectric substrate 100 may be slightly separated.

It is the schematic perspective view which shows the antenna device by preferable embodiment of this invention, (a) is the figure seen from the radiation | emission surface side diagonal direction, (b) is the figure seen from the back surface side diagonal direction. 1 is an exploded perspective view of an antenna device according to a preferred embodiment of the present invention. It is the schematic plan view which looked at the shield member 200 from the back surface (surface which faces the dielectric substrate 100) side. FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 3. It is a block diagram for demonstrating the connection relation of each circuit contained in the antenna apparatus by preferable embodiment of this invention. It is a schematic diagram for demonstrating the example using the antenna apparatus by preferable embodiment of this invention as a vehicle-mounted radar apparatus. 2 is a schematic plan view showing in more detail the structure of the main part of the dielectric substrate 100 on the radiation surface 100a side. FIG. 3 is a schematic plan view showing in more detail the structure of the main part on the component mounting surface 100b side of the dielectric substrate 100. FIG. It is a schematic perspective view which shows the state which covered the high frequency circuit (161-164) with the shield cases 191-194. It is a fragmentary sectional view which shows the state which covered the high frequency circuit (161-164) with the shield cases 191-194.

Explanation of symbols

10 own vehicle 11 preceding vehicle 20 short-range radar device 100 dielectric substrate 100a radiation surface (the other surface)
100b Component mounting surface (one surface)
DESCRIPTION OF SYMBOLS 110 Transmission side patch array antenna 120 Reception side patch array antenna 131,132 Feed line 141-145 High frequency connection line 141a, 141b, 142a, 143a, 144a, 144b, 145a, 145b Through-hole electrode 150 Ground pattern 161 Oscillation circuit 161a Modulation circuit 161b Power amplifier 162 Output circuit 162a Modulation circuit 162b Power amplifier 163 LNA
164 Mixer circuit 164a 90 degree phase shifter 164b First mixer 164c Second mixer 171 to 174 Ground pattern 180 Sub board 181 Pulse generation circuit 182 and 183 Intermediate frequency circuit 184 Signal processing circuit 191 to 194 Shield case 200 Shield member 210 Transmission Side opening 220 Reception side opening 231, 232, 241-245 Groove 300 Fixing screw

Claims (7)

A dielectric substrate in which a high-frequency circuit is mounted on one surface, a patch antenna on the other surface, a feed line connected to the patch antenna, and a high-frequency connection line connected to the high-frequency circuit;
An antenna device, comprising: a shield member provided on the other surface side of the dielectric substrate and covering at least a part of the feed line and the high-frequency connection line.   2. The antenna device according to claim 1, wherein the high-frequency connection line is led out from the one surface side of the dielectric substrate to the other surface side through a through-hole electrode.   The patch antenna includes a transmission-side patch antenna and a reception-side patch antenna, and the shield member includes an opening that exposes the transmission-side patch antenna and an opening that exposes the reception-side patch antenna. The antenna device according to claim 1, wherein the antenna device is provided.   4. The antenna device according to claim 1, wherein a ground pattern surrounding the high-frequency circuit is provided on the one surface of the dielectric substrate. 5.   The antenna device according to claim 4, further comprising a shield case that covers the high-frequency circuit so as to be in contact with the ground pattern.   The antenna device according to any one of claims 1 to 5, wherein a groove for preventing contact is formed in a portion of the shield member that covers the feed line and the high-frequency connection line. Of the other surface of the dielectric substrate, a region covered with the shield member is provided with a ground pattern in contact with the shield member over almost the entire surface except the periphery of the power supply line and the high-frequency connection line. The antenna device according to claim 6.

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