The group delay one definite form dielectric filter inside band uses that the deformation compensating die amplifier

摘要

PROBLEM TO BE SOLVED: To provide an in-band group delay constant type dielectric filter with a small loss, having prescribed group delay characteristics and a small size. SOLUTION: This in-band group delay constant type dielectric filter is provided with a plurality of dielectric coaxial resonators 104, 105 whose resonance frequency is variable, a coupling circuit that couples the dielectric coaxial resonators 104, 105 and an input output terminal 101 that is coupled with the dielectric coaxial resonators placed at both ends of a plurality of the dielectric coaxial resonators that are coupled. The coupling circuit utilizes coupling capacitance formed by copper plating electrodes 103 placed on an alumina-made coupling base 102, for example. Both group delay deviation and amplitude deviation between the input and output terminals are kept within a prescribed deviation respectively at a specified band decided by a center frequency, and its surrounding frequencies and minimum value of the group delay time are selected so as to be the specified prescribed delay time or longer.