| 摘要 |
PROBLEM TO BE SOLVED: To select a resonance frequency and to stop a transmission signal without any deterioration in noise index by arranging a resonance rod, which penetrates a housing part at the extension part of an input part, and putting the resonance rod in and out between the housing and input pattern. SOLUTION: A reception signal is a signal of, for example, 12GHz. A transmit signal, on the other hand, has a plane of polarization 90 deg. different from that of the reception signal, but is a signal of 14GHz and has a level >=110db higher than the reception signal. The resonance rod 13 penetrating the housing part 3 is arranged below the input pattern 11 and put in and out to form a series resonance circuit, shown by an equivalent circuit, of an inductive component which is proportional to the length of the resonance rod 13 and a capacitive component generated between the resonance rod 13 and input signal pattern (a). The series resonance circuit is a waveguide type resonance circuit and has high selectivity, so that a transmission signal component is sufficiently attenuated by adjusting the resonance frequency to 14GHz to eliminate the saturated operation state of an amplifying element.
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