Computer-aided design of finline filters in waveguides below cutoff

摘要

This paper describes a new design of optimized ladder-shaped finline filters in waveguide sections operating below cutoff. While the realization of conventional dielectric resonator filters requires precision machining of individual resonator blocks which must be mechanically adjusted in the reduced size waveguide section, the new design can be manufactured very accurately with photolithographic techniques, and the dimensions are optimally adjusted in a single design procedure. A rigorous field theoretical calculation of the individual waveguide discontinuities includes the interaction of higher-order modes and provides an accurate prediction of the practical filter response.