US-12627041-B2 - Antenna device

US12627041B2US 12627041 B2US12627041 B2US 12627041B2US-12627041-B2

Abstract

In a conventional antenna device, transmission radio waves transmitted from a transmitting antenna traveling directly to a receiving antenna are blocked by a shield wall disposed between the receiving antenna and the transmitting antenna. However, some of the transmission radio waves are diffracted at the edge of the shield wall and enter the receiving antenna as diffracted waves, affecting the reception of the reception radio waves. In view of this, the shield wall and a polarized wave converter unit are disposed between the transmitting antenna unit and the receiving antenna unit. As a result, vertically polarized wave components of the diffracted waves are converted by the polarized wave converter unit to circularly polarized wave components that are less affecting the reception of the reception radio waves in the receiving antenna, and the diffracted waves are prevented from affecting the receiving operation of the receiving antenna.

Inventors

Shunichi Ikeda
Narihiro NAKAMOTO
Hiromasa Nakajima
Tomohiro Takahashi
Toru Fukasawa
Naoya Noguchi

Assignees

MITSUBISHI ELECTRIC CORPORATION

Dates

Publication Date: 20260512
Application Date: 20240624

Claims (13)

1 . An antenna device comprising: a transmitting antenna unit to transmit transmission radio waves of circular polarization; a receiving antenna unit to receive reception radio waves of circular polarization; a shield wall disposed between the transmitting antenna unit and the receiving antenna unit to block the transmission radio waves transmitted from the transmitting antenna unit toward the receiving antenna unit; and a polarized wave converter unit disposed between the shield wall and the receiving antenna unit to convert, among the transmission radio waves, vertically polarized wave components having a polarized wave plane orthogonal to the shield wall into circularly polarized waves having a rotation direction different from that of the reception radio waves to be received by the receiving antenna unit.
2 . The antenna device according to claim 1 , wherein the transmitting antenna unit and the receiving antenna unit each include a plurality of antenna elements, and the polarized wave converter unit is configured such that a sum of amounts of the transmission radio waves transmitted from the plurality of antenna elements included in the transmitting antenna unit leaking into the plurality of antenna elements included in the receiving antenna unit is below a predetermined value.
3 . The antenna device according to claim 2 , wherein choke grooves extending in a direction orthogonal to a direction in which the transmitting antenna unit and the receiving antenna unit are arranged and having a depth corresponding to ¼ of a wavelength of the transmission radio waves are provided on a surface of the shield wall.
4 . The antenna device according to claim 2 , wherein the shield wall comprises a dielectric substrate and antenna elements supported by the dielectric substrate to receive the transmission radio waves.
5 . The antenna device according to claim 1 , wherein choke grooves extending in a direction orthogonal to a direction in which the transmitting antenna unit and the receiving antenna unit are arranged and having a depth corresponding to ¼ of a wavelength of the transmission radio waves are provided on a surface of the shield wall.
6 . The antenna device according to claim 1 , wherein the shield wall comprises a dielectric substrate and antenna elements supported by the dielectric substrate to receive the transmission radio waves.
7 . An antenna device comprising: a transmitting antenna unit to transmit transmission radio waves of circular polarization; a receiving antenna unit to receive reception radio waves of circular polarization; a shield wall disposed between the transmitting antenna unit and the receiving antenna unit to block the transmission radio waves transmitted from the transmitting antenna unit toward the receiving antenna unit; and a polarized wave converter unit disposed between the transmitting antenna unit and the shield wall to convert circularly polarized waves of the transmission radio waves into horizontally polarized waves having a polarized wave plane parallel to the shield wall.
8 . The antenna device according to claim 7 , wherein the transmitting antenna unit and the receiving antenna unit each include a plurality of antenna elements, and the polarized wave converter unit is configured such that a sum of amounts of the transmission radio waves transmitted from the plurality of antenna elements included in the transmitting antenna unit leaking into the plurality of antenna elements included in the receiving antenna unit is below a predetermined value.
9 . The antenna device according to claim 8 , wherein choke grooves extending in a direction orthogonal to a direction in which the transmitting antenna unit and the receiving antenna unit are arranged and having a depth corresponding to ¼ of a wavelength of the transmission radio waves are provided on a surface of the shield wall.
10 . The antenna device according to claim 8 , wherein the shield wall comprises a dielectric substrate and antenna elements supported by the dielectric substrate to receive the transmission radio waves.
11 . The antenna device according to claim 7 , wherein choke grooves extending in a direction orthogonal to a direction in which the transmitting antenna unit and the receiving antenna unit are arranged and having a depth corresponding to ¼ of a wavelength of the transmission radio waves are provided on a surface of the shield wall.
12 . The antenna device according to claim 7 , wherein the shield wall comprises a dielectric substrate and antenna elements supported by the dielectric substrate to receive the transmission radio waves.
13 . The antenna device according to claim 7 , wherein the transmitting antenna unit and the receiving antenna unit each include a plurality of antenna elements, and the polarized wave converter unit is configured such that a sum of amounts of the transmission radio waves transmitted from the plurality of antenna elements included in the transmitting antenna unit leaking into the plurality of antenna elements included in the receiving antenna unit is below a predetermined value.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a Continuation of PCT International Application No. PCT/JP2022/000635, filed on Jan. 12, 2022, which is hereby expressly incorporated by reference into the present application. TECHNICAL FIELD The present disclosure relates to an antenna device. BACKGROUND ART In an antenna device with a transmitting antenna and a receiving antenna separately provided, the transmitting antenna and the receiving antenna are sometimes arranged close to each other from a viewpoint of limitation of installation space, downsizing of the device, and the like. When such an antenna device is used in a time-division duplex system, in which transmission of transmission radio waves and reception of reception radio waves are performed in a time-division manner, isolation between the transmission radio waves and the reception radio waves is ensured. However, when the antenna device is used, for example, in a frequency-division duplex system, in which the transmission of the transmission radio waves and the reception of the reception radio waves may be performed simultaneously, the transmission radio waves may interfere with the reception radio waves or become a disturbance to the receiving antenna for receiving radio waves. This may degrade the performance of the antenna device. As an example of preventing the transmission radio waves from affecting the reception radio waves when the transmitting antenna and the receiving antenna are placed close to each other, Patent Document 1 discloses an antenna device in which the transmission radio waves traveling from the transmitting antenna to the receiving antenna are blocked and prevented from affecting the reception radio waves by providing a shield wall composed of a metal or a wave absorber between the transmitting antenna and the receiving antenna. PRIOR ART DOCUMENTS Patent Documents [Patent Document 1] Japanese Unexamined Patent Application Publication No. H10-126146 SUMMARY OF THE INVENTION Problems to be Solved by the Invention In the antenna device disclosed in the above Patent Document 1, the shield wall disposed between the receiving antenna and the transmitting antenna can block the transmission radio waves that travel directly from the transmitting antenna to the receiving antenna. However, there remains a problem that some of the transmission radio waves are diffracted at the edge of the shield wall, and enter the receiving antenna as diffracted waves, thereby affecting a receiving operation of the reception radio waves. The present disclosure is made to solve the above-mentioned problem and aims at obtaining an antenna device capable of suppressing adverse effects on the reception of the reception radio waves by the receiving antenna, the adverse effects being caused by the diffracted waves which are generated by the diffraction of the transmission radio waves radiated from the transmitting antenna at the edge of the shield wall disposed between the receiving antenna and the transmitting antenna. Means for Solving Problem An antenna device according to the present disclosure includes: a transmitting antenna unit to transmit transmission radio waves of circular polarization; a receiving antenna unit to receive reception radio waves of circular polarization; a shield wall disposed between the transmitting antenna unit and the receiving antenna unit to block the transmission radio waves transmitted from the transmitting antenna unit toward the receiving antenna unit; and a polarized wave converter unit disposed between the shield wall and the receiving antenna unit to convert vertically polarized wave components of the transmission radio waves into circularly polarized wave components having a rotation direction different from that of the reception radio waves to be received by the receiving antenna unit. The antenna device according to the present disclosure includes: a transmitting antenna unit to transmit transmission radio waves of circular polarization; a receiving antenna unit to receive reception radio waves of circular polarization; a shield wall disposed between the transmitting antenna unit and the receiving antenna unit to block the transmission radio waves transmitted from the transmitting antenna unit toward the receiving antenna unit; and a polarized wave converter unit disposed between the transmitting antenna unit and the shield wall to convert circularly polarized waves of the transmission radio waves into horizontally polarized waves having a polarized wave plane parallel to the shield wall. Effects of the Invention The antenna device according to the present disclosure includes the polarized wave converter unit disposed between the shield wall and the receiving antenna unit to convert the vertically polarized wave components of the transmission radio waves to the circularly polarized wave components that have a rotation direction different from that of the reception radio waves to be received by the rec