Resonant element and high frequency filter, and wireless communication apparatus equipped with the resonant element or the high frequency filter

摘要

A resonant element that causes a signal input from an input terminal to resonate at a predetermined resonance frequency and outputs it to an output terminal is provided. The element has a transmission line series including a plurality of transmission lines connected in series with each other and intersecting with a hotline connecting the input terminal and the output terminal and a plurality of switches. At least one of one end and the other end of the transmission line series is a grounded end. The resonant element having first and second end side, each end side having a first transmission line and a second transmission line connected to a switch having a grounded end. The resonance frequency is switched by turning on/off the switch to change the sum of the lengths of the transmission lines through which the signal passes.