# US 5,345,202 A · Dielectric filter comprising a plurality of coaxial resonators of different lengths all having the same resonant frequency

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- Number: US 5,345,202 A
- Document ID: US5345202A
- Status: Granted
- Kind: A
- Application number: 08/124,481
- Filed: 1993-09-22
- Granted: 1994-09-06
- Earliest claimed: 1991-03-25
- Assignees: Sanyo Electric Co., Ltd.
- Inventors: Yasumi Kobayashi; Kousuke Takeuchi; Kachio Ikeda; Kenichi Shibata; Kazuhiko Kuroki
- Web page: https://patentgrep.com/patent/US5345202A

## CPC

- H01P 1/2136: {using comb or interdigital filters; using cascaded coaxial cavities (H01P1/2131, H01P1/2135 take precedence)}
- H01P 1/2053: {the coaxial cavity resonators being disposed parall to each other}
- H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B)

## Abstract

In a dielectric filter according to the present invention, a depressed part is formed by removing a portion of an outer peripheral conductor on the open face side of each of a plurality of one-end face short-circuited type coaxial resonators or a portion of the outer peripheral conductor including a dielectric member. A dielectric substrate having a plurality of capacitance forming electrodes for forming antiresonance capacitances between the electrodes and inner peripheral conductors of the coaxial resonators formed thereon is mounted on the depressed part, and a reactance element for coupling the capacitance forming electrodes is provided on the dielectric substrate.

## Claims

### Claim 1

In an improved dielectric filter comprising a plurality of coaxial resonators each having an outer peripheral conductor and an inner peripheral conductor formed by coating an outer peripheral surface and an inner peripheral surface of a first dielectric member with a conductive member and having one end face short-circuited, the improvement comprising:
at least one of said plurality of coaxial resonators has a length different from those of the other coaxial resonators, and has the same resonance frequency as those of said other coaxial resonators produced by a resonance frequency correcting capacitance forming portion connected to both the inner peripheral conductor and the outer peripheral conductor.

### Claim 2 (depends on 1)

The dielectric filter according to claim 1, wherein said resonance frequency correcting capacitance forming portion is formed by mounting a second dielectric member having a capacitance forming conductor formed thereon on an open surface of said one of said plurality of coaxial resonators.