| 摘要 |
PROBLEM TO BE SOLVED: To improve the receiving performance of a necessary signal by preventing signal with frequencies whose reception is not desired from being picked up by a low nose frequency converter (LNB) device for two-way communication. SOLUTION: A substrate 5 is arranged at the position of a short face set toλ/4 behind a probe 2 of a waveguide 1, and the short face is constituted of a ground pattern 6 on the front face of the substrate 5, and a slot 7 matched with the frequencies of a signal whose reception is not desired is provided so that a signal which should received is reflected, and a signal whose reception is not desired is transmitted through the slot 7 without being reflected. A series resonance circuit (trap) for absorbing the signal with frequencies whose reception is not desired, a terminating circuit for terminating this signal, or a short circuit for short-circuiting this signal are formed in a conductive pattern 8 on the back face of the substrate 5, so that the signal whose reception is not desired is absorbed and extinguished.
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