Modeling of conductor, dielectric loaded resonators, filters and double ridge waveguide T-junctions.

摘要

Tremendous growth in wireless communications has resulted in increasingly crowded frequency spectrum. As a result, a large number of high selectivity, high rejection narrow bandwidth microwave filters and wide-band T-junctions are highly demanded by the systems. Efficient and accurate computer aided design (CAD) tools are vital for the design of these components. This dissertation is therefore devoted to develop a series of efficient, accurate, general simulation and modeling methods and state of art designs of these components.; New classes of microwave cavity filters, dual mode conductor loaded resonator filters and dielectric combline resonator filters, are introduced. Rigorous mode matching method is used to model the generalized configurations of the new type resonators and filters in both cylindrical and rectangular enclosures. A series of new configurations of conductor and dielectric loaded resonator filters with improved spurious free performance are presented. The modeling of the generalized multilayer cylindrical uniaxial anisotropic (isotropic) dielectric loaded resonator structure is developed. Ultra-high Q sapphire resonators operating in whispering gallery mode (WGM) are analyzed. Effects of enclosure on unloaded Q, and the support structures on spurious free window are investigated. Vibrational frequency sensitivity of the WGM mode is accurately determined by incorporating the perturbation technique. A new ultra-stable sapphire resonator structure with round side wall is presented and modeled. Rigorous modeling of generalized re-entrant coaxial cavity, shielded stripline, double ridge waveguide and their discontinuities is established. The configuration of generalized double ridge waveguide T-junction is proposed. A new full-wave analysis method for modeling of the proposed double ridge waveguide T-junction and other complicated multi-port network problems is introduced and presented. The theories are verified by comparing the computed results with that by other methods and experimental data. A number of high performance slot coupled conductor, dielectric loaded and coaxial resonator filters are precisely designed. Excellent measured responses are obtained.