US-12627036-B2 - Antenna device with attachment member and attachment structure for antenna device

US12627036B2US 12627036 B2US12627036 B2US 12627036B2US-12627036-B2

Abstract

An antenna device with an attachment member includes an antenna including a radiation plate provided with radiation face that radiates vertically polarized waves, a housing portion that houses the antenna, an attachment member that attaches the housing portion to a vehicle, and a metal fixing portion that is formed in an elongated shape to one end of the attachment member, that abuts a back face of the housing portion facing toward an opposite side to the radiation face, and that fixes the housing portion. Viewed from a thickness direction of the radiation plate, the fixing portion is disposed between a first region formed to the back face on one side in the extension direction of a first straight line, and a second region formed to the back face on another side in the extension direction of the first straight line.

Inventors

Toshiki SAYAMA
Hideaki Shoji
Yusuke Kato

Assignees

AGC Inc.

Dates

Publication Date: 20260512
Application Date: 20240611
Priority Date: 20211214

Claims (20)

1 . An antenna device with an attachment member comprising: an antenna including a radiation plate provided with a radiation face that radiates linearly polarized waves of a prescribed frequency band; a housing portion that houses at least a portion of the antenna; an attachment member that attaches the housing portion to a vehicle; and metal fixing portions that are formed in an elongated shape to one end of the attachment member, that abuts a back face of the housing portion on an opposite side of the radiation plate to the radiation face side, and that fixes the housing portion, wherein when a first straight line defined as passing through a centroid of the radiation plate in a vibration direction of the linearly polarized waves when viewed from a thickness direction of the radiation plate, and a second straight line defined as being orthogonal to the first straight line and passing through the centroid, and with each of the fixing portions disposed with its length direction along an extension direction of the second straight line, then viewed from the thickness direction of the radiation plate, each of the fixing portions is disposed between a first region formed to the back face on one side in the extension direction of the first straight line, and a second region formed to the back face on another side in the extension direction of the first straight line.
2 . The antenna device with the attachment member of claim 1 , wherein viewed from the thickness direction of the radiation plate, the fixing portion is disposed such that a length direction axial line of the fixing portion overlaps with the second straight line.
3 . The antenna device with the attachment member of claim 1 , wherein viewed from the thickness direction of the radiation plate, a feed point of the antenna is disposed on the first straight line at a different position to the centroid.
4 . The antenna device with the attachment member of claim 1 , wherein the antenna includes a ground conductor plate on an opposite side with respect to the radiation plate to the side where the radiation face is disposed, with a dielectric substrate interposed between the ground conductor plate and the radiation plate.
5 . The antenna device with the attachment member of claim 4 , wherein a width W of each of the fixing portions in the extension direction of the first straight line is set so as to satisfy a relationship equation with respect to a length L P of the ground conductor plate in the extension direction of the first straight line: 0.01 ≤ W / L S ≤ 0.75 .
6 . The antenna device with the attachment member of claim 4 , wherein a region of overlap between the first region and the ground conductor plate and a region of overlap between the second region and the ground conductor plate have substantially the same shape and substantially the same surface area as each other.
7 . The antenna device with the attachment member of claim 1 , wherein the antenna is a slot antenna including a slot extending along the second straight line.
8 . The antenna device with the attachment member of claim 7 , wherein a width W of each of the fixing portions in the extension direction of the first straight line is set so as to satisfy a relationship equation with respect to a length L S of the radiation plate in the extension direction of the first straight line: 0.01 ≤ W / L P ≤ 0.75 .
9 . The antenna device with the attachment member of claim 7 , wherein a region of overlap between the first region and the radiation plate and a region of overlap between the second region and the radiation plate have substantially the same shape and substantially the same surface area as each other.
10 . The antenna device with the attachment member of claim 1 , wherein: the housing portion includes a protruding portion that protrudes along the second straight line viewed from the thickness direction of the radiation plate; and an attachment portion is formed to the protruding portion for attaching the fixing portions to the housing portion through a metal fastening member.
11 . The antenna device with the attachment member of claim 1 , wherein viewed from the thickness direction of the radiation plate the fixing portion has line symmetry with respect to the second straight line.
12 . The antenna device with the attachment member of claim 1 , wherein: each of the fixing portions includes an opening portion open in a plate thickness direction at a vicinity of the centroid; and a connecter for electrically connecting to a feed point of the antenna is inserted into the opening portion.
13 . The antenna device with the attachment member of claim 1 , wherein the attachment member is formed from metal.
14 . The antenna device with the attachment member of claim 1 , wherein the attachment member is integrally formed.
15 . The antenna device with the attachment member of claim 1 , wherein the attachment member includes a metal extension portion that extends in a direction separating from the radiation plate.
16 . The antenna device with the attachment member of claim 15 , wherein an angle formed between the extension portion and the radiation face is in a range of from 20° to 160°.
17 . An attachment structure for an antenna device wherein: in a state in which the attachment member of claim 15 is attached to the vehicle; and an extension direction that the extension portion extends in is in a range of from −30° to 70° with respect to a horizontal plane.
18 . An attachment structure for an antenna device, wherein: the radiation face of an antenna of claim 1 is provided so as to be within ±15° with respect to a vertical direction in a state in which the attachment member is attached to the vehicle.
19 . The attachment structure for the antenna device of claim 17 , wherein: the first straight line is disposed so as to be in a range of ±15° with respect to an up-down direction of the vehicle; and the prescribed frequency band includes a 5.8 GHz band or a 5.9 GHz band.
20 . The attachment structure for the antenna device of claim 19 , wherein the antenna is a V2X antenna.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation application of International Application No. PCT/JP2022/045566 filed Dec. 9, 2022 the disclosure of which is incorporated herein by reference in its entirety. Further, this application claims priorities from Japanese Patent Application No. 2021-202862 filed Dec. 14, 2021, the disclosure of which is incorporated herein by reference in their entirety. TECHNICAL FIELD The present invention relates to an antenna device with an attachment member and to an attachment structure for an antenna device. RELATED ART In accordance with recently improved levels of self-driving, there is a tendency to install vehicles with a communication system to implement Vehicle to Everything (V2X), such as vehicle-to-vehicle communication and roadside-to-vehicle communication and, for example, progress is being made to enable the acquisition of various safety related information from outside the vehicle utilizing the transceiving of narrow-band wavelength radio waves in a 5.9 GHz band. In such a vehicle communication system there is, in particular, a demand for V2X antennas capable of transceiving vertically polarized radio waves of a frequency band satisfying a V2X communication standard (a 5.8 GHz band (Japan) or a 5.9 GHz band (Europe/USA) at a desired gain. Moreover, in a V2X antenna installed in a vehicle, there is a demand for stable directionality capable of implementing a desired antenna gain over a range of ±90° (180°) in a horizontal plane, left and right of a center of a vehicle forward direction (vehicle progression direction). Japanese Patent Application Laid-Open (JP-A) No. 2019-75644 discloses an antenna for use in V2X communication disposed inside a vehicle cabin such that a radiation face of a radiation element faces toward a front glass or toward a rear glass. However, preferably a metal bracket is employed for stably fixing to a vehicle from a vehicle cabin inside such that a radiation face of a V2X antenna faces toward a windshield or rear glass. However, when a linearly polarized wave antenna such as a V2X antenna is fixed using such a metal bracket, the transceiving properties (gain) of radio waves are changed by the metal, reducing the antenna gain, and giving rise to a concern that desired directionality might no longer be obtained. SUMMARY In consideration of the above circumstances, an object of the present invention is to obtain an antenna device with an attachment member and an attachment structure for an antenna device that are capable of attaching an antenna stably to a vehicle while also enabling a drop in antenna gain to be suppressed and enabling desired directionality to be implemented. An antenna device with an attachment member according to the present invention includes an antenna including a radiation plate provided with radiation face that radiates linearly polarized waves of a prescribed frequency band, a housing portion that houses at least a portion of the antenna, an attachment member that attaches the housing portion to a vehicle, and a metal fixing portion that is formed in an elongated shape to one end of the attachment member, that abuts a back face of the housing portion on an opposite side of the radiation plate to the radiation face side, and that fixes the housing portion. When a first straight line defined as passing through a centroid of the radiation plate in a vibration direction of the linearly polarized waves when viewed from a thickness direction of the radiation plate, and a second straight line defined as being orthogonal to the first straight line and passing through the centroid, and with the fixing portion disposed with its length direction along an extension direction of the second straight line, then viewed from the thickness direction of the radiation plate, the fixing portion is disposed between a first region formed to the back face on one side in the extension direction of the first straight line, and a second region formed to the back face on another side in the extension direction of the first straight line. An antenna device with an attachment member according to the present invention enables an antenna to be stably attached to a vehicle while also enabling a drop in antenna gain to be suppressed and enabling desired directionality to be implemented. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a plan view viewed from a vertical direction of a vehicle attached with an antenna device with an attachment member according to a first exemplary embodiment. FIG. 2 is an exploded cross-section illustrating an antenna device with an attachment member according to the first exemplary embodiment in a state attached to a windshield, and illustrates a section along A-A of FIG. 1. FIG. 3 is an exploded perspective view illustrating an antenna device with an attachment member according to the first exemplary embodiment looking diagonally from the rear. FIG. 4 is a perspective view of an antenna device with a