Research Of Compact Plnar Passband Filter And Superconducting Filter Based On Loaded-stub

With the development of wireless communication services, it has brought greatconvenience to people’s communication and their life. However, it also has proposed newrequirements for the development of wireless communication system, which includeshigh-integrated circuits and high anti-interference ability. Thus, the designs of passivecomponents in wireless communication circuit such as filters are faced with greaterchallenges. Miniaturization filters are conducive to the integration, which will improve theeffective use of the radio frequency circuit. One of the effective methods is to use multi-moderesonators (MMRs) generated by stub-loaded method. Compared to the conventionalmulti-stage cascaded microstrip structure, with some circuit area, the number of resonators isreduced by MMRs. Meanwhile, the high-temperature superconducting structures have manyadvantages such as lower passband insertion loss, larger passband rejection, steeper passbandedge. While international research scholars have published many papers on multi-moderesonators, but the theory of MMRs is not thorough. It remains to be further studied,especially in applying MMRs to the design of high temperature superconducting structures.Firstly, the stub-loaded method and the theory of microwave filter design have beendiscussed in this paper. Further, a series of band-pass filters (BPFs) and high-temperaturesuperconducting structures have been designed and implemented based on this theory. Doublestub-loaded structure has been proposed in Chapter III, which acts as a three-mode resonator.When electrical lengths of double stubs vary, the resonant frequencies will be changed.Moreover, the design graph between the electrical lengths of double stubs and the resonantfrequencies has been developed. Making full use of the graph, two tri-mode dual-band BPFshave been designed; The chapter IV studies a multi stub-loaded structure, which has beenutilized to design a broadband multi-mode BPF, and the transmission zeros and wide stopbandcharacteristics has been analyzed in detail; A dual-mode split ring resonator (SRR) has beenstudied in Chapter V. Meanwhile, the multimode split ring resonator has been searched basedon the dual-mode split ring resonator. Combined with high-temperature superconductingmaterials, a dual-band structure of high-temperature superconductivity has been designed. theactual simulation and test have been used in all above designs, which have verified thefeasibility of the stub-load method to design filter.