Researches And Design Of Dielectric Cavity Dual-mode Filter

Modern mobile communication technology has brought human life significant changes. In the development of mobile communication systems, high performances and compact dimensions of RF frontends are in critical demanding. As an important component of RF systems, base station filters are require-d to have low insertion loss, high rejection and compact sizes as well. Coaxial cavity filters are widely used in the base station RF-frontends, providing low loss and high power handling capability, at the expense of large dimension. For further reducing the dimension and insertion loss in addition, dual-mode dielectric cavity filters were proposed and researched, bringing higher Q and lower quality volume ratio.This thesis mainly focuses on the researches and design of dual-mode dielectric cavity filters. After introducing the basic theories of dielectric resonators and microwave filters, detailed structure of dual mode dielectric cavity, coupling structures are presented and studied by electromagnetic simulation.Fi lters containing one cavity(2nd order), two cavities(4th order) and 4 cavities(8th order) are designed,fabricated and measured, respectively. High performances, such as compact dimensions, low insertio nlosses, multiple transmission zeros and high rejections are demonstrated. The results of this work wil be valuable in designing high performance base station RF frontends.