JP2012215455A - Wide coverage radar apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wide coverage radar apparatus minimizing an influence to the utmost which radiation characteristics of a transmitting antenna and a receiving antenna receive from an upper end portion of a metallic housing on which a radome is placed.SOLUTION: A wide coverage radar apparatus 100 comprises: an antenna unit 110 having a substrate 111, a transmitting antenna 112 and a receiving antenna 113 disposed at opposite both end portions of the substrate 111, and a supporting body 114 on which the substrate 111 is placed; a radome 120 for covering the antenna unit 110; and a metallic housing 130 for storing the antenna unit 110. In the housing 130, a groove 133 for placing and fixing the radome 120 at an upper end thereof is formed. The upper end of the groove 133 is on a lower side than a surface of the substrate 111 on which the transmitting antenna 112 and the receiving antenna 113 are disposed.

Description

  The present invention relates to a radar apparatus provided with a radome that accommodates at least a transmission antenna and a reception antenna, and more particularly to a wide coverage radar apparatus in which a transmission antenna and a reception antenna have wide directivity.

  The radar apparatus detects the distance and direction to the object by reflecting the transmitted wave radiated from the transmitting antenna by the object and receiving the reflected wave by the receiving antenna. In recent years, such a radar device is mounted on an automobile and used to detect an obstacle in a traveling direction. A radar device or the like mounted on an automobile is required to have a wide coverage area for widening an angle range to be measured and a small size for reducing an installation space. For this reason, the transmitting antenna and the receiving antenna are housed in one radome to reduce the size and increase the coverage, but the transmission / reception isolation between the transmitting antenna and the receiving antenna, which is a problem at that time, is achieved. Improvement is required. As a conventional technique for improving such transmission / reception isolation, for example, there is one disclosed in Patent Document 1.

  In addition, in order to increase the measurement accuracy of the radar apparatus, the development of a radar apparatus using a broadband high-frequency signal as a transmission wave has been advanced. In recent years, there has been a demand for applications such as parking assistance and blind spot detection as a need for a radar device mounted on an automobile. In such an application, it is required to detect an object at a very short distance. However, if such a request is to be realized by a conventional radar device, it is necessary to mount a large number of radar devices on an automobile. . However, since the space in which the radar apparatus can be mounted is limited, a wide coverage radar apparatus that can measure a wide angle range with one radar apparatus is required. Hereinafter, the angle range to be measured is referred to as “angle coverage”.

  In a wide coverage radar apparatus with a wide angle coverage, a wide coverage antenna with a wide beam width is used as a transmission antenna and a reception antenna. The wide coverage radar device can detect an object at a very short distance due to its wide angular coverage, but the isolation between the transmitting antenna and the receiving antenna is not sufficient. Then, there is a possibility that the received wave reflected by the object at a short distance interferes with the transmission wave and cannot detect the object.

  Since the coupling between the transmitting antenna and the receiving antenna generally decreases as the distance between the antennas increases, isolation can be increased by increasing the distance between them as much as possible. . In a small radar device in which a transmitting antenna and a receiving antenna are mounted and integrated in a single substrate and stored in a radome, in order to increase the distance between the transmitting antenna and the receiving antenna, Naturally, the antennas are arranged separately at both ends of the opposing substrates.

JP 2010-210297 A

  Since the transmitting / receiving antenna used in the conventional radar apparatus has a relatively high directivity, the influence of a structure or the like in the substantially horizontal direction of the antenna has not been a problem. However, in a wide coverage antenna, if there is a metal object in a substantially horizontal direction, it may be affected. In particular, when the antennas are arranged at opposite ends of the substrate in order to increase the isolation between the transmitting antenna and the receiving antenna, each antenna comes close to the end of the radome. Since the end portion of the radome is placed and fixed on the upper end portion of the metal casing, the transmitting antenna and the receiving antenna are close to the upper end portion of the metal casing. As a result, the radiation characteristics of each antenna are strongly influenced by the upper end of the metal casing, and there is a problem that a suitable radiation characteristic cannot be obtained.

  The present invention has been made to solve the above problems, and has a wide coverage radar apparatus in which the radiation characteristics of the transmitting antenna and the receiving antenna are reduced as much as possible from the upper end of the metal casing on which the radome is placed. The purpose is to provide.

  A first aspect of the wide coverage radar apparatus of the present invention is a wide coverage radar apparatus that transmits and receives a high-frequency signal to detect an object in a predetermined angle range, and is arranged on a substrate and the substrate. An antenna unit comprising a transmitting antenna and a receiving antenna, and a support for fixing the transmitting antenna and the receiving antenna, a metal casing for mounting the antenna unit, and covering the antenna unit A radome fixed to the metal casing, the radome when the transmitting antenna and the receiving antenna are arranged as the antenna surface, and the radiation direction of the transmitting antenna is an upper side. The uppermost end of the metal casing for fixing the antenna is located below the antenna surface.

  In another aspect of the wide coverage radar apparatus of the present invention, an uppermost end of the metal casing is at least 2.5 mm below the antenna surface.

  In another aspect of the wide coverage radar apparatus of the present invention, a groove for fitting and fixing the end of the radome is formed at the uppermost end of the metal casing.

  In another aspect of the wide coverage radar apparatus of the present invention, the end of the radome is fixed to the inner surface of the groove with a predetermined adhesive.

  In another aspect of the wide coverage radar apparatus of the present invention, the groove includes an inner wall portion standing on the antenna unit side, an outer wall portion facing the inner wall portion, the inner wall portion and the outer surface. It is formed by the groove bottom part between wall parts, It has the width | variety of at least 2.5 mm between the said inner wall part and the said outer wall part, It is characterized by the above-mentioned.

  According to another aspect of the wide coverage radar apparatus of the present invention, a notch for fitting with the inner wall is formed at the end of the radome, and the upper end of the inner wall and the cut It is characterized in that the bottom of the notch is in contact.

  Another aspect of the wide coverage radar apparatus according to the present invention is characterized in that an antenna unit mounting portion for mounting the antenna unit is provided on an inner surface of an upper end of the metal casing.

  Another aspect of the wide coverage radar apparatus of the present invention is characterized in that a gap of at least 0.5 mm is provided between a side surface of the antenna unit and the inner wall portion.

  In another aspect of the wide coverage radar apparatus of the present invention, a height from the antenna surface to the radome inner surface is determined by a height from a bottom portion of the antenna unit placement portion to an upper end of the inner wall portion. It is characterized by being.

  According to the present invention, it is possible to provide a wide coverage radar apparatus in which the radiation characteristics of the transmitting antenna and the receiving antenna are affected as much as possible from the upper end of the metal casing on which the radome is placed.

It is sectional drawing which shows the structure of the wide coverage radar apparatus of 1st Embodiment. It is an expanded sectional view showing composition of a wide coverage radar device of a 1st embodiment. It is an expanded sectional view for demonstrating the positional relationship of an antenna unit and a housing.

  A wide coverage radar apparatus according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. Each component having the same function is denoted by the same reference numeral for simplification of illustration and description.

(First embodiment)
A wide coverage radar apparatus according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a configuration of a wide coverage radar apparatus 100 according to the present embodiment, and is a cross-sectional view seen from a plane perpendicular to the surface of a substrate on a line connecting a transmitting antenna and a receiving antenna. FIG. 2 is an enlarged cross-sectional view showing one end of the cross-sectional view shown in FIG.

  The wide coverage radar apparatus 100 includes an antenna unit 110 having a substrate 111, a transmitting antenna 112 and a receiving antenna 113 disposed at opposite ends of the substrate 111, and a support body 114 on which the substrate 111 is placed. And a radome 120 that covers the antenna unit 110 and a metal casing 130 that houses the antenna unit 110. The antenna unit 110 is housed in a space surrounded by the housing 130 and the radome 120. The support 114 is arranged to shield electromagnetic waves radiated from the substrate 111 from reaching components arranged below the support 114. In this embodiment, the support 111 is placed. It also serves as a role.

  The radome 120 has an upper lid part 121 and a side wall part 122 formed on the periphery of the upper lid part 121. The housing 130 has a housing bottom portion 131 and a housing wall portion 132 standing on the periphery of the housing bottom portion 131, and a groove portion 133 is formed on the upper end of the housing wall portion 132 for mounting and fixing the radome 120. ing. The groove part 133 has a structure formed in a U shape by a groove bottom part 134, an inner wall part 135, and an outer wall part 136.

  The radome 120 is fixed to the housing 130 by fitting the end 123 of the side wall 122 into the groove 133. Further, in the vicinity of the end portion 123 of the side wall portion 122 of the radome 120, a notch portion 124 having a notch on the inner surface side is formed. The notch 124 of the radome 120 is formed so as to be fitted to the inner wall part 135 of the housing 130, and the bottom part 124 a of the notch part 124 is placed on the upper end of the inner wall part 135.

  A U-shaped groove 133 formed at the upper end of the housing wall 132 is formed so as to enhance the adhesiveness with the end 123 of the radome 120. The radome 120 is fixed to the housing 130 by injecting an adhesive into the contact surface between the end 123 and the groove 133. By making the fitting part with the end part 123 of the radome 120 into the U-shaped groove part 133, the adhesive surface with the end part 123 can be enlarged. The width between the inner wall part 135 and the outer wall part 136 is preferably at least 2.5 mm. Thereby, while improving the adhesive strength of the edge part 123 and the inner surface of the groove part 133, a sealing performance can be improved, and the high watertightness to the inside by the radome 120 and the housing 130 can be maintained.

  In order to further improve the adhesion to the end 123 of the radome 120, the width of the groove 133, that is, the interval between the inner wall 135 and the outer wall 136 is preferably set to at least 2.5 mm. Thereby, even if the contact surface with the groove part 133 of the radome 120 has variations (deformation or surface roughness), the adhesive can sufficiently wrap around the groove part 133 to obtain high adhesiveness. In addition, as a means for fixing the radome 120 to the housing 130, it may be fixed using screws instead of the adhesive. Alternatively, fixing with an adhesive and fixing with screws may be used in combination.

  In the wide coverage radar apparatus 100 of the present embodiment having the above-described configuration, the upper end of the groove 133 is the surface of the substrate 111 on which the transmitting antenna 112 and the receiving antenna 113 are disposed (hereinafter referred to as an antenna surface). It is characterized by being on the lower side. The positional relationship in the height direction between the antenna surface and the groove 133 is shown in FIG. As shown in the figure, the wide coverage radar apparatus 100 of the present embodiment is configured such that the end portions of the inner wall portion 135 and the outer wall portion 136 of the groove portion 133 are located below the antenna surface. Yes. Here, “below the antenna surface” means the side opposite to the radiation direction of the transmitting antenna 112 with respect to the antenna surface.

  The groove part 133 of the housing 130 has a periodic structure in which an inner wall part 135 and an outer wall part 136 made of metal are arranged at a predetermined interval. If such a metal periodic structure is present on the antenna surface, the radiation characteristics of the transmitting antenna 112 and the receiving antenna 113 may be strongly affected. For example, when the use frequency band of the wide coverage radar apparatus 100 is an ultra-wide band, the periodic structure of the groove 133 may cause deterioration in antenna characteristics such as a decrease in gain in a specific frequency band. Therefore, in the wide coverage radar apparatus 100 of the present embodiment, the housing 130 is formed so that the upper end of the groove 133 is below the antenna surface so that such a metal periodic structure does not exist on the antenna surface. ing. Thereby, the influence which the groove part 133 has on a radiation characteristic is suppressed.

  By forming the groove 133 as described above, the housing 130 does not exist on the antenna surface and the upper side (radiation direction of the transmitting antenna 112), and no metal exists. As a result, the influence of the radiation characteristics of the transmitting antenna and the receiving antenna from the metal housing 130 can be reduced as much as possible. Preferably, the upper ends of the inner wall portion 135 and the outer wall portion 136 are at least 2.5 mm below the antenna surface.

  Further, an antenna unit mounting portion 137 is formed in the housing wall portion 132 by cutting out the inner surface side. An end of the antenna unit 110 is placed on the antenna unit placement portion 137. By forming the antenna unit mounting portion 137 for stably mounting the antenna unit 110 in the housing 130, the distance between the upper lid 121 of the radome 120 fixed to the housing 130 and the antenna surface is stable. To be determined. That is, if the height from the antenna surface to the inner surface of the upper lid 121 of the radome 120 is H, the antenna unit mounting portion 137 may be formed so that the height H becomes a predetermined value. The radome 120 is positioned when the height from the notch lower portion 124a of the radome 120 to the inner surface of the upper lid 121 is determined to be a predetermined value from the bottom of the antenna unit mounting portion 137 of the housing 130 to the inner wall portion. This can be done with high accuracy by determining the height to the upper end of 135 to a predetermined value.

  In the wide coverage radar apparatus 100 of the present embodiment, the end portion of the support body 114 of the antenna unit 110 is placed on the antenna unit placement portion 137. It is preferable that there is no gap as much as possible between the side surface of the antenna unit 110, that is, the side surface of the support body 114 and the side surface of the support body receiving portion 137. If a large gap is formed between the side surface of the support body 114 and the side surface of the support body receiving portion 137, the antenna characteristics may be adversely affected.

  On the other hand, if the structure is such that there is no gap between the side surface of the support body 114 and the side surface of the support body receiving portion 137, there is a problem that it becomes difficult to attach or remove the antenna unit 110 to or from the housing 130. Arise. It is preferable to provide a gap of at least 0.5 mm between the side surface of the support body 114 and the side surface of the support body receiving portion 137.

  As described above, the wide coverage radar apparatus 100 of the present embodiment has a structure in which the antenna unit 110 and the radome 120 are integrated with the housing 130, and the highest position of the metal housing 130. The upper end of the groove 133 is formed so as to be lower than the antenna surface. As a result, no metal is present on the antenna surface or higher.

  The wide coverage radar apparatus 100 having the above-described structure reduces the deterioration of the radiation characteristics of the transmission antenna 112 due to the influence of the housing 130 as much as possible, and also disturbs the reception characteristics of the reception antenna 113. Thus, it is possible to realize radar characteristics with a wide band and a wide coverage. The wide coverage radar apparatus 100 of the present embodiment is particularly suitable for being mounted on a vehicle because the antenna unit 110 is easily covered with the housing 130 and the radome 120 and can be reduced in size.

  The description in the present embodiment shows an example of the wide coverage radar apparatus according to the present invention, and the present invention is not limited to this. The detailed configuration and detailed operation of the wide coverage radar apparatus according to the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

100 Wide Cover Radar Device 111 Substrate 112 Transmitting Antenna 113 Receiving Antenna 114 Support 110 Antenna Unit 120 Radome 121 Upper Cover 122 Side Wall 123 End 124 Notch 130 Housing 131 Housing Bottom 132 Housing Wall 133 Groove 134 Bottom portion 135 Inner wall portion 136 Outer wall portion 137 Antenna unit placement portion

Claims (9)

A wide coverage radar device that transmits and receives a high-frequency signal to detect an object in a predetermined angle range,
An antenna unit comprising a substrate, a transmitting antenna and a receiving antenna disposed on the substrate, and a support for fixing the transmitting antenna and the receiving antenna;
A metal housing for mounting the antenna unit;
A radome that covers the antenna unit and is fixed to the metal casing,
When the radiation direction of the transmitting antenna is the upper side, and the surface of the substrate on which the transmitting antenna and the receiving antenna are arranged is an antenna surface, the uppermost end of the metal casing that fixes the radome is the antenna surface. A wide-area radar device characterized by being on the lower side. 2. The wide coverage radar apparatus according to claim 1, wherein an uppermost end of the metal casing is at least 2.5 mm below the antenna surface. The wide coverage radar apparatus according to claim 1 or 2, wherein a groove for fitting and fixing an end of the radome is formed at an uppermost end of the metal casing. The wide area radar device according to claim 3, wherein an end of the radome is fixed to an inner surface of the groove with a predetermined adhesive. The groove portion is formed by an inner wall portion standing on the antenna unit side, an outer wall portion facing the inner wall portion, and a groove bottom portion between the inner wall portion and the outer wall portion, 5. The wide area radar apparatus according to claim 3, wherein the radar apparatus has a width of at least 2.5 mm between an inner wall portion and the outer wall portion. The radome has an end formed with a notch for fitting with the inner wall, and the upper end of the inner wall is in contact with the bottom of the notch. The wide coverage radar apparatus according to claim 5. The wide covering according to any one of claims 1 to 6, wherein an antenna unit mounting portion for mounting the antenna unit is provided on an inner surface of an upper end of the metal casing. Area radar equipment. The wide coverage radar apparatus according to claim 7, wherein a gap of at least 0.5 mm is provided between a side surface of the antenna unit and the inner wall portion. The height from the antenna surface to the radome inner surface is positioned by the height from the bottom of the antenna unit placement portion to the upper end of the inner wall portion. Wide coverage radar device.

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