DIELECTRIC FILTER, ANTENNA SHARING UNIT AND COMMUNICATION UNIT

摘要

PROBLEM TO BE SOLVED: To provide a filter which can easily adjust impedance and can make an inhibition band to be wide in the filter, having a band inhibition characteristic near resonance frequency of a resonator. SOLUTION: A transmission line between input/output terminals 101 and plural resonators 103a and 103b are connected via capacitors 102a and 102b, and capacitance of the capacitors 102a and 102b are set to have different values. Thus, the frequencies of attenuation poles, which appear in the same number as for the resonators 103a and 103b, can be adjusted independently. The capacitors of the capacitors 102a and 102b can be varied according to different impedances in the input/output terminals. Thus, impedance matching can be executed sastisfactorily.