Dielectric filter using quarter wavelength coaxial dielectric resonators connected in series

A dielectric filter having a plurality of lambda /4 coaxial dielectric resonators in stages, the resonator being filled with a dielectric material between its inner and outer conductors, comprising at least one stage in which the outer conductor of the lambda /4 coaxial dielectric resonator is grounded via a capacitance or inductance. The dielectric filter is embodied as a low-pass filter, high-pass filter or a band-pass filter. As a result, by utilizing dielectric resonators having a desired resonant frequency, it is possible to readily achieve a dielectric filter having an attenuating pole in the neighborhood of the frequency passband and small in insertion loss.