Dielectric filter having coupling electrodes for connecting resonator electrodes, and method of adjusting frequency characteristic of the filter

摘要

A tri-plate type dielectric filter having a dielectric substrate (24, 30, 32), a plurality of resonator electrodes (18) embedded in the substrate, and coupling electrodes (22, 26) formed within the dielectric substrate, for electrically connecting the resonator electrodes, so as to provide capacitors (36, 38) each between adjacent ones of the resonator electrodes. The resonator electrodes may take the form of parallel elongate strips each providing a stripline type λ/4 or λ/2 TEM mode resonance circuit. One end of each strip is exposed on an outer surface of the substrate (30, 32). This end of each strip is trimmed to adjust the resonance frequency of the resonance circuit.