| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter which can be downsized and can particularly be space-saved, and through which a balanced signal can be transmitted over a broadband in a state with an excellent balance characteristic. SOLUTION: A second resonator 2 comprises a pair of 1/4 wavelength resonators 21, 22 interdigitally coupled to each other. A first resonator 1 also comprises a pair of 1/4 wavelength resonators 11, 12 interdigitally coupled to each other. In a pair of the 1/4 wavelength resonators 21, 22, one balanced terminal 4A is connected to the 1/4 wavelength resonator 21, and the other balanced terminal 4B is connected to the other 1/4 wavelength resonator 22. The first and second resonators 1, 2 are resonated at a second resonance frequency f<SB>2</SB>lower than a resonance frequency f<SB>0</SB>in a pair of the 1/4 wavelength resonators 21, 22 interdigitally coupled to each other so that the first and second resonators 1, 2 are electromagnetically coupled to each other. A pair of the 1/4 wavelength resonators 11, 12 and a pair of the 1/4 wavelength resonators 21, 22 are all laminated and arranged in the same direction. COPYRIGHT: (C)2007,JPO&INPIT
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