To provide an electronic tuning bandpass filter which has little insertion loss, a steep out-of-band attenuation characteristic and an optional narrow band to wide band passage characteristic, does not cause distortion due to a nonlinear element, or the like, and controls a resonance frequency having both a characteristic of a resonance (antiresonance) transmission line type bandpass filter, for example, such as an interdigital filter structure and a characteristic of a YIG tuning type filter, etc., that continuously vary an optional frequency.
A piece of crystal for generating a resonance magnetostatic wave mode is installed between the vicinity of the maximum current point of a line of a transmission line resonator and a ground side, and a transmission line type resonance element is included, which controls the resonance frequency of the line by changing an equivalent inductance of the line due to the application of a direct current magnetic field from over the line and due to a change in a permeability that occurs before and after the resonance mode.
| JPH0258401A | 1990-02-27 | |||
| JPS6167301A | 1986-04-07 | |||
| JP2004537905A | 2004-12-16 | |||
| JPS483154A |
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