Examination of a microwave receiving system combining the superconducting filter and trimming

We examined the differences in frequency response between a fabricated filter and a designed filter, and we improved the frequency response of the fabricated filter using trimming. The cable probes approached the respective resonator in a 5-pole Chebyshev superconducting filter, and the resonant frequencies were measured. For the differences in the respective resonant frequencies of the resonators, improvement areas in the filter were found. The filter's response was controlled by trimming of the sapphire and nickel rods. As a result of measuring the resonant frequency in the resonators, one resonator was found to have a 10 MHz lower than the other resonators. Therefore, we adjusted the resonant frequency of the resonator to obtain similar frequencies to the other resonators by trimming the sapphire and nickel rods. After trimming, the passband ripple reduced approximately 3.2 dB and the frequency response of the filter improved. (c) 2005 Published by Elsevier B.V.