HIGH FREQUENCY DEVICE, FILTER, DUPLEXER, COMMUNICATION MODULE, AND COMMUNICATION APPARATUS

摘要

<P>PROBLEM TO BE SOLVED: To achieve a low-loss balance filter by attaining an IDT capacitor having a higher Q value. Ž<P>SOLUTION: A lumped constant balun 12 included in a filter or duplexer is provided with a resonator functioning as a capacitor (IDT capacitor) and the resonance frequency of the IDT capacitor is set higher than the pass-band frequency of the filter. Thereby, the low-loss balance filter having the improved Q value of capacitor can be achieved. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž