Filter device, antenna apparatus, and antenna module

Patent metadata

Field	Value
Publication number	US-12555900-B2
Application number	US-202418596816-A
Country	US
Kind code	B2
Filing date	Mar 6, 2024
Priority date	Nov 22, 2021
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

A filter device includes a first LC series resonator to resonate in series at a first series resonant frequency with a first inductor and a first capacitor, and a second LC series resonator to resonate in series at a second series resonant frequency with a second inductor and a second capacitor. The first and second LC series resonators are connected in parallel and resonate in parallel at a parallel resonant frequency. The second series resonant frequency is lower than the first series resonant frequency. The parallel resonant frequency is between the first and second series resonant frequencies.

First claim

What is claimed is:

1 . A filter device comprising:
a first series resonator to resonate in series at a first resonant frequency with a first inductor and a first capacitor connected in series to the first inductor; and a second series resonator to resonate in series at a second resonant frequency with a second inductor and a second capacitor connected in series to the second inductor; wherein the first series resonator and the second series resonator are connected in parallel to each other and resonate in parallel at a third resonant frequency; the second resonant frequency is lower than the first resonant frequency; and the third resonant frequency is between the first resonant frequency and the second resonant frequency.

2 . The filter device according to claim 1 , wherein the first inductor and the second inductor are magnetically coupled to each other.

3 . The filter device according to claim 2 , wherein the first inductor and the second inductor are coupled to each other in positive polarity.

4 . The filter device according to claim 2 , wherein the first inductor and the second inductor are coupled to each other in subtractive polarity.

5 . The filter device according to claim 1 , wherein the first inductor is a parasitic inductance.

6 . The filter device according to claim 1 , wherein the filter device is provided in an antenna apparatus capable of radiating the first resonant frequency and the second resonant frequency as resonant frequencies.

7 . The filter device according to claim 1 , wherein the filter device is an integrated component.

8 . The filter device according to claim 1 , further comprising a third capacitor or a third inductor that is connected in parallel to the first series resonator and the second series resonator.

9 . The filter device according to claim 7 , further comprising:
a third capacitor or a third inductor that is connected in parallel to the first series resonator and the second series resonator; an input terminal connected to one end of the first series resonator and one end of the second series resonator; and an output terminal connected to another end of the first series resonator and another end of the second series resonator; wherein the third capacitor or the third inductor is connected between the input terminal and the output terminal as a separate element.

10 . An antenna apparatus comprising:
a first feed circuit to receive or output a radio frequency signal; a first antenna to radiate the first resonant frequency or the second resonant frequency as resonant frequencies; and the filter device according to claim 1 , the filter device being between the first feed circuit and the first antenna.

11 . The antenna apparatus according to claim 10 , wherein the first inductor and the second inductor are magnetically coupled to each other.

12 . The antenna apparatus according to claim 11 , wherein the first inductor and the second inductor are coupled to each other in positive polarity.

13 . The antenna apparatus according to claim 11 , wherein the first inductor and the second inductor are coupled to each other in subtractive polarity.

14 . The antenna apparatus according to claim 10 , wherein the first inductor is a parasitic inductance.

15 . The antenna apparatus according to claim 10 , wherein the filter device is an integrated component.

16 . An antenna module comprising:
a first antenna apparatus; and a second antenna apparatus; the first antenna apparatus including:
a first feed circuit to receive/output a radio frequency signal;
a first antenna to radiate a first resonant frequency and a second resonant frequency as resonant frequencies; and
a filter device between the first feed circuit and the first antenna;
the filter device having a passband in a first frequency band, a passband in a second frequency band lower than the first frequency band, and an attenuation band in a third band between the first frequency band and the second frequency band; the filter device including:
a first series resonator to resonate in series at the first resonant frequency in the first frequency band with a first inductor and a first capacitor connected in series to the first inductor; and
a second series resonator to resonate in series at the second resonant frequency in the second frequency band with a second inductor and a second capacitor connected in series to the second inductor;
the first series resonator and the second series resonator being connected in parallel and resonating in parallel at a third resonant frequency in the third frequency band;
the second antenna apparatus including:
a second feed circuit to receive/output a radio frequency signal; and
a second antenna to radiate the third resonant frequency as a resonant frequency;
the first antenna apparatus and the second antenna apparatus being adjacent to or in a vicinity of each other.

17 . The antenna module according to claim 16 , wherein the first inductor and the second inductor are magnetically coupled to each other.

18 . The antenna module according to claim 17 , wherein the first inductor and the second inductor are coupled to each other in positive polarity.

19 . The antenna module according to claim 17 , wherein the first inductor and the second inductor are coupled to each other in subtractive polarity.

20 . The antenna module according to claim 16 , wherein the first inductor is a parasitic inductance.

Assignees

• Murata Manufacturing Co

Inventors

• Tachibana Shinya

Classifications

• H03H7/175

  Series LC in series path (H03H7/1783 takes precedence) · CPC title

• H03H7/0115 Primary

  comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title

• H01Q1/521

  reducing the coupling between adjacent antennas · CPC title

• H03H2001/0085

  Multilayer, e.g. LTCC, HTCC, green sheets · CPC title

• H03H7/09

  Filters comprising mutual inductance · CPC title