Dielectric filter.

摘要

Coupling capacitors (C1-C3) are connected between an input end (1) and an output end (2), a resonator (R1, R2) is connected between each of the coupling capacitor and the ground, and a capacitor (C4, C5) and a switch (S4, S5) are connected between one end of each resonator and the ground. When the capacitor is off, the frequency is set to the resonance frequency of the resonator, and when the switch is turned on, the capacitor is connected parallel to the resonator, so that the resonance frequency is shifted to a lower value, whereby a dielectric filter having multiple frequencies can be obtained.