The Research Of High-performance Novel Planar Bandpass Filter Based On Stub-loaded Method

Since the beginning of the21st century, wireless communication technology has beendeveloped rapidly, which makes new challenges to the RF circuit and system design, and putsforward higher requirements for the performance of the RF filter. Slotline filters and hightemperature superconducting filters, which are two new types of planar filters, have manyadvantages relative to conventional microstrip filters. Slotline filters have much largerpower-handling capability than microstrip filters have while high temperaturesuperconducting filters have lower insertion loss better frequency selectivity and morecompact size than microstrip filters have. The two new types of planar filters have causedwide concern in the international community and many scholars dedicated to research in thisarea, but the theory of the two new types of planar filters is not yet mature. Stub-loadedmethod is one of mature methods using in microstrip filter design. The article gives a detailstudy on the design theory and methods of slotline filters and high temperaturesuperconductor filters, after that, novel kinds of high performance slotline filters and hightemperature superconducting filters is designed and implemented.The major research work of the article is summarized as follows:(1) We research on the splitting of degenerate modes of slotline loop resonator, after that,a compact slotline dual-mode filter with slotline stub loading is designed and implemented.(2) The physical characteristics of high temperature conductors are analyzed, after that, acompact high temperature conducting dual-band filters with stub loading is designed andimplemented.(3) We research on the characteristics of high-order harmonic frequencies of stepimpedance resonator(SIR), after that, a compact SIR high temperature conducting triple-bandfilters with stub loading is designed and implemented.