| 摘要 |
<p>A microstrip tunable filter wherein coupling sections (5 1 ,5 2 ,5 3 ) are formed in an input/output line along its lengthwise direction, each coupling section including a gap (G5 1 ,G5 2 ,G5 3 ) formed in the input/output line and coupling electrodes (E5a 1 ,E5b 1 ,E5c 1 ) arranged in the gap in the longitudinal direction of the input/output line; and resonators (4 1 ,4 2 ) capable of varying the resonance frequency are connected to the input/output line at the positions between adjacent ones of the coupling sections. Switch means (7 1 ,7 2 ,7 3 ) are provided for selectively grounding the coupling electrodes of the coupling sections or selectively short-circuiting the coupling electrodes and the input/output line, and resonance frequency varying means (4m 1 ,4m 2 ) are provided for varying the resonance frequency of the one or more resonators in association with the switch means.</p> |
