US-12620711-B2 - Antenna module

US12620711B2US 12620711 B2US12620711 B2US 12620711B2US-12620711-B2

Abstract

An antenna module includes a dielectric substrate, loop antennas, and power feeding wires that transmit high-frequency signals to the antennas. One loop antenna is positioned inside the loop of another in plan view from the winding axis direction. Each power feeding wire has a flat electrode and a via extending along the winding axis. The flat electrodes partially overlap with their respective loop antennas but not with others. At least one via connects to its corresponding flat electrode at a position offset from the antenna in the polarization direction.

Inventors

Kaoru Sudo

Assignees

MURATA MANUFACTURING CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20240927
Priority Date: 20220328

Claims (20)

1 . An antenna module comprising: a dielectric substrate; a first radiation element disposed on the dielectric substrate and having a loop-shaped wiring pattern; a second radiation element disposed inside a loop of the first radiation element when viewed in plan view from a winding axis direction of the first radiation element and having a loop-shaped wiring pattern; and a first power feeding wire and a second power feeding wire that transmit high-frequency signals to the first radiation element and the second radiation element, respectively, wherein the first power feeding wire comprises: a first flat electrode disposed apart from the first radiation element in the winding axis direction; and a first conductor connected to the first flat electrode and extending in the winding axis direction, the second power feeding wire comprises: a second flat electrode disposed apart from the second radiation element in the winding axis direction; and a second conductor connected to the second flat electrode and extending in the winding axis direction, and when viewed in plan view from the winding axis direction, the first flat electrode at least partially overlaps with the first radiation element and does not overlap with the second radiation element, the second flat electrode at least partially overlaps with the second radiation element and does not overlap with the first radiation element, and at least one of the first conductor and the second conductor is connected to the corresponding flat electrode at a position offset from the corresponding radiation element in a first polarization direction of the radiation element.
2 . The antenna module of claim 1 , wherein when viewed in plan view from the winding axis direction, the first flat electrode extends from an overlapping portion with the first radiation element to an outside of the loop of the first radiation element, and the first conductor is connected to the first flat electrode outside the loop of the first radiation element.
3 . The antenna module of claim 1 , wherein when viewed in plan view from the winding axis direction, the first flat electrode extends from an overlapping portion with the first radiation element to an outside of the loop of the first radiation element, and the first conductor is connected to the first flat electrode inside the loop of the first radiation element.
4 . The antenna module of claim 1 , wherein when viewed in plan view from the winding axis direction, the second flat electrode extends from an overlapping portion with the second radiation element to an outside of a loop of the second radiation element, and the second conductor is connected to the second flat electrode outside the loop of the second radiation element.
5 . The antenna module of claim 1 , wherein when viewed in plan view from the winding axis direction, the second flat electrode extends from an overlapping portion with the second radiation element to an inside of a loop of the second radiation element, and the second conductor is connected to the second flat electrode inside the loop of the second radiation element.
6 . The antenna module of claim 1 , wherein when viewed in plan view from the winding axis direction, a winding axis of the first radiation element is inside a loop of the second radiation element, and the first flat electrode and the second flat electrode are disposed on the same side with respect to the winding axis of the first radiation element.
7 . The antenna module of claim 1 , wherein when viewed in plan view from the winding axis direction, a winding axis of the first radiation element is inside a loop of the second radiation element, and the first flat electrode and the second flat electrode are disposed on opposite sides to each other with respect to the winding axis of the first radiation element.
8 . The antenna module of claim 1 , wherein when a length of the loop along a center of the wiring pattern of the first radiation element is L1, a shortest distance between a center of the first conductor and the center of the wiring pattern of the first radiation element is ½ or less of L1.
9 . The antenna module of claim 1 , wherein when a length of a loop along a center of the wiring pattern of the second radiation element is L2, a shortest distance between a center of the second conductor and the center of the wiring pattern of the second radiation element is ½ or less of L2.
10 . The antenna module according to claim 9 , wherein in the second radiation element, when a dimension of the second radiation element in an offset direction of the second conductor is S1, the shortest distance between the center of the second conductor and the center of the wiring pattern of the second radiation element is ½ or less of S1.
11 . The antenna module according to claim 1 , wherein the first radiation element and the second radiation element are disposed at different positions in the winding axis direction in the dielectric substrate.
12 . The antenna module according to claim 1 , further comprising: at least one of a third conductor that connects the first radiation element and the first flat electrode and a fourth conductor that connects the second radiation element and the second flat electrode.
13 . The antenna module according to claim 1 , wherein at least either the first radiation element and the first flat electrode or the first radiation element and the second flat electrode are capacitance-coupled.
14 . The antenna module of claim 1 , further comprising: a ground electrode disposed facing the first radiation element and the second radiation element in the winding axis direction in the dielectric substrate, wherein the first conductor and the second conductor pass through the ground electrode.
15 . The antenna module of claim 1 , wherein at least one of the first conductor and the second conductor is composed of a plurality of flat electrodes and a plurality of vias.
16 . The antenna module according claim 1 , further comprising: a third power feeding wire that transmits, to the first radiation element, a high-frequency signal for radiating a radio wave in a second polarization direction different from the first polarization direction; and a fourth power feeding wire that transmits, to the second radiation element, a high-frequency signal for radiating a radio wave in the second polarization direction, wherein the third power feeding wire comprises: a third flat electrode disposed apart from the first radiation element in the winding axis direction; and a fifth conductor connected to the third flat electrode and extending in the winding axis direction, and the fourth power feeding wire comprises: a fourth flat electrode disposed apart from the second radiation element in the winding axis direction; and a sixth conductor connected to the fourth flat electrode and extending in the winding axis direction.
17 . The antenna module according to claim 16 , wherein when viewed in plan view from the winding axis direction, a winding axis of the first radiation element is inside a loop of the second radiation element, the first flat electrode and the second flat electrode are disposed on opposite sides to each other with respect to the winding axis of the first radiation element, and the third flat electrode and the fourth flat electrode are disposed on opposite sides to each other with respect to the winding axis of the first radiation element.
18 . The antenna module of claim 1 , further comprising: a third radiation element disposed in a region not overlapping with the first radiation element and the second radiation element when viewed in plan view from the winding axis direction, and capable of radiating a radio wave of a frequency band different from the first radiation element and the second radiation element.
19 . The antenna module of claim 18 , wherein the third radiation element is a loop antenna.
20 . An antenna module comprising: a dielectric substrate; and a first antenna element and a second antenna element disposed adjacent to each other on the dielectric substrate, wherein each of the first antenna element and the second antenna element comprises: a first radiation element disposed on the dielectric substrate and having a loop-shaped wiring pattern; a second radiation element disposed inside a loop of the first radiation element when viewed in plan view from a winding axis direction of the first radiation element and having a loop-shaped wiring pattern; and a first power feeding wire and a second power feeding wire that transmit high-frequency signals to the first radiation element and the second radiation element, respectively, the first power feeding wire comprises: a first flat electrode disposed apart from the first radiation element in the winding axis direction; and a first conductor connected to the first flat electrode and extending in the winding axis direction, the second power feeding wire comprises: a second flat electrode disposed apart from the second radiation element in the winding axis direction; and a second conductor connected to the second flat electrode and extending in the winding axis direction, and when viewed in plan view from the winding axis direction, the first flat electrode at least partially overlaps with the first radiation element and does not overlap with the second radiation element, the second flat electrode at least partially overlaps with the second radiation element and does not overlap with the first radiation element, and at least one of the first conductor and the second conductor is connected to the corresponding flat electrode at a position offset from the corresponding radiation element in a polarization direction of the radiation element.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation application of PCT International Application No. PCT/JP2023/005709 filed on Feb. 17, 2023, designating the United States of America, which is based on and claims priority to Japanese patent application JP 2022-051664, filed Mar. 28, 2022. The entire disclosures of the above-identified applications, including the specifications, the drawings, and the claims are incorporated herein by reference in their entirety. TECHNICAL FIELD The present disclosure relates to an antenna module and, more particularly, to a technology for improving antenna characteristics of an antenna module having a plurality of loop antennas. BACKGROUND ART Japanese Unexamined Patent Application Publication No. 2020-36067 (Patent Document 1) discloses a configuration of an antenna device in which a plurality of loop antennas is arranged concentrically. In the antenna device disclosed in Japanese Unexamined Patent Application Publication No. 2020-36067 (Patent Document 1), a power feeder is arranged perpendicular to each loop antenna. By arranging the conductor of the loop antenna and the conductor of the power feeder so as to be orthogonal to each other, occurrence of induced current between the conductors is suppressed. CITATION LIST Patent Document Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-36067 SUMMARY Technical Problem In the antenna device disclosed in Japanese Unexamined Patent Application Publication No. 2020-36067 (Patent Document 1), the power feeder (power feeding wire) extends vertically from a transmitter or a receiver to an antenna conductor. In such a case, since the length of the line of the power feeder is limited, there is a possibility that the impedance between the antenna conductor, the power feeder and a power transmitter/receiver is not sufficiently matched. The present disclosure has been made to solve such a problem, and an object of the present disclosure is to improve the antenna characteristics of an antenna module provided with a plurality of loop antennas. Solution to Problem An antenna module according to the present disclosure includes a dielectric substrate, a first radiation element and a second radiation element disposed on the dielectric substrate and each having a loop-shaped wiring pattern, and a first power feeding wire and a second power feeding wire that transmit high-frequency signals to the first radiation element and the second radiation element, respectively. The second radiation element is disposed inside a loop of the first radiation element when viewed in plan view from the winding axis direction of the first radiation element (first direction). The first power feeding wire includes a first flat electrode disposed apart from the first radiation element in the first direction, and a first conductor connected to the first flat electrode and extending in the first direction. The second power feeding wire includes a second flat electrode disposed apart from the second radiation element in the first direction, and a second conductor connected to the second flat electrode and extending in the first direction. When viewed in plan view from the first direction, the first flat electrode at least partially overlaps with the first radiation element and does not overlap with the second radiation element. When viewed in plan view from the first direction, the second flat electrode at least partially overlaps with the second radiation element and does not overlap with the first radiation element. At least one of the first conductor and the second conductor is connected to the corresponding flat electrode at a position offset from the corresponding radiation element in a first polarization direction of the radiation element. Advantageous Effects In the antenna module according to the present disclosure, high-frequency signals are supplied to a plurality of loop-shaped radiation elements disposed on a dielectric substrate via flat electrodes offset in the polarization direction and vias connected to the flat electrodes. When viewed in plan view from the winding axis direction of the radiation element, each flat electrode does not overlap with any radiation element other than the one to which power is to be fed. With such a configuration, since the length of the line of the power feeding wire and the overlap with the radiation element to which power is to be fed in the first direction can be finely adjusted by adjusting the offset amount of the via from the radiation element, impedance matching can be facilitated. Further, since the flat electrode does not overlap with the radiation element to which power is to be fed when viewed in plan view, deterioration of isolation from other radiation elements can be suppressed. Therefore, in an antenna module provided with a plurality of loop antennas, antenna characteristics can be improved. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a block diagram of a