Design and Performance Comparison of Novel High Q Coaxial Resonator Filter for Ka-band High Throughput Satellite

Abstract

The filters deployed in the satellite are high-performance filters that have very stringent in-band and out of band performance. They require high Q resonators with spurious free-range for their realization. But, the Q factor decrease with an increase in frequency. Currently, Ka-band high throughput satellite uses cavity filters in its payload because of its known performance and well-established realization process. This thesis presents novel high Q filters, which provide an alternative to conventional cavity filters. The Ka-band filters developed using two different technologies. The first is a fully tunable Non-radiative dielectric waveguide filter, and the second is the High Q coaxial resonator filter. For the first time, high Q TM012 mode of the coaxial resonator used at Ka-band for filter realization. The direct and crosscoupled filters have designed to demonstrate the concept of higher-order modes of the coaxial resonator for filter development. The high power analysis has done for the identical configuration cross-coupled coaxial resonator and cavity filter; compare their performance over operating temperature from -150C to 650C. These filters fabricated from metal and their frequency drift depend on the coefficient of thermal expansion of metal, which should be minimum to have a stable response in the space environment. The analytical tool used to minimize the frequency drift of the coaxial resonator filter and compensate it over the operating temperature. The temperature-compensated coaxial resonator filter has developed with this tool, and its performance is compared with the identical uncompensated filter. This temperature-compensated filter provides more design margin without increasing the complexity.