DUAL-MODE FILTER

Japanese Patent JP3966197

B2

PROBLEM TO BE SOLVED: To solve the problem in a dual-mode filter that at least one or more frequency correcting screws have been necessary to be inserted into a cavity resonator other than a coupling screw between orthogonal modes in order to correct the difference resonant in frequency between two orthogonal modes.
SOLUTION: To reduce the loss of filter characteristics, the dual-mode filter is made to have a structure in which a recess or a projection, or both, are provided on a circle on entrance and exit coupling holes 3a, 3b in a cavity resonator in order to correct the difference in resonant frequency between the two orthogonal modes, so that frequency correcting screws 6a, 6b are not required. To separate the coupled orthogonal modes to easily obtain filter characteristics, for a center coupling hole 4 for coupling the dual-mode cavity resonators, a long and narrow coupling hole having a wide surface in a vertical direction at its center portion is provided on its center portion to propagate a horizontal electric field n2, and two long and narrow coupling holes each having wide surface in a horizontal direction are provided at its both sides portion to propagate a horizontal electric field n1.

Taro Hiraike
Hiroyuki Omine
Naofumi Yoneda

JP2003075287A

August 29, 2007

March 19, 2003

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Mitsubishi Electric Corporation

H01P1/208; H01P1/205; H01P7/06; (IPC1-7): H01P1/208; H01P1/205; H01P7/06

JP62169501A
JP2000353905A
JP51016094A
JP60253301A

US5886594

Shogo Takahashi
Tadahiko Inaba
Kanako Murakami
Nakatsuru Kazutaka

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