RESONATOR, DUPLEXER, AND COMMUNICATION DEVICE

PROBLEM TO BE SOLVED: To provide a resonator corresponding to a plurality of frequency bands by expanding the frequency variable range when compared with general variable frequency duplexers, and to provide a duplexer and a communication device.SOLUTION: Frequency characteristics are changed continuously by using a resonator of a hollow conductor. A duplexer having a transmission side resonator for passing a transmission signal with low loss at the transmission frequency and attenuating a reception signal at the reception frequency, and a reception side resonator for attenuating a transmission signal at the transmission frequency and passing a reception signal with low loss at the reception frequency, and separating the transmission signal and reception signal is constituted of a resonator of a hollow conductor. Consequently, the frequency variable range of the duplexer can be expanded, and the number of components can be reduced.