Research On High Temperature Superconducting Filter Technology Based On Multimode Resonators

Microwave filters are commonly used classic devices in communications,radars,navigation systems,etc.,and are also one of the main research directions for national core electronics,high-end general chips,and infrastructural software products.Among them,the high temperature superconducting(HTS)filter with extremely low loss,high selectivity and high out of band rejection has become one of the core devices of electronic information system reinforcement and defense,and has a very broad application prospect in national defense weapon equipment,communication and electronic system,economy and society.The related theories and technical researches are undoubtedly the frontier field of microwave passive components,and it is also one of the key research contents in the current key technology directions such as mobile communications and satellite communications.In this thesis,researches on high-temperature superconducting filter technology based on multimode resonators are carried out,and a series of high-performance wideband,dual-passband,triple-passband and triple-passband balanced,quad-passband miniaturized high-temperature superconducting filters are designed and realized.This thesis mainly completes the following three aspects of research content and innovation:1.A general design method of stepped impedance type/stub-loaded stepped impedance type resonators based on self-coupled structure is proposed,and the characteristics of self-coulped stepped impedance resonator under different conditions such as central short-circuit stub loaded and central open-circuit stub loaded are studied.Compared with traditional stepped impedance resonators and stub-loaded resonators,this structure significantly reduces the geometric size of the circuit and improves the relative design freedom.The resonance characteristics of the three resonator structures are analyzed in detail.Based on the above three new resonators,triple-mode triple-passband,quad-mode quad-passband,and quad-mode wideband high-temperature superconducting filters have been designed and implemented.By using electromagnetic hybrid coupled,source load coupled and other methods,excellent out of band suppression,isolation between passbands,miniaturization and other characteristics are obtained.2.A general design method of cross-type stepped impedance resonators is proposed.Firstly,a design method based on cross-type stepped impedance semi-symmetrical multi-mode resonator is proposed.By introducing a high impedance line and a capacitive load coupled line structure between resonators,flexible control of multiple independent passband coupling coefficients is obtained.The "coupled+tapped" hybrid doubly feedline structure achieves the rated quality factor required for multiple passbands.This method breaks through the problems of high isolation between passbands and difficult flexible control of passband bandwidths.A cross-type stepped impedance semi-symmetric triple mode high temperature superconducting filter is designed and implemented,The center frequencies and bandwidths of the three passbands can be relatively independent controlled,and the superior performance of miniaturization,high selectivity and low insertion loss is achieved,which verify the correctness and effectiveness of the method.The design method of cross-type stepped impedance omni-symmetrical structure multimode high temperature superconducting balanced filter is presented.A cross-type stepped impedance omni-symmetrical triple-mode HTS filter is designed and implemented.A balanced structure filter with a wide range of high common-mode rejection and independent controllability of passbands' center frequencies and bandwidths under differential-mode excitation is obtained.Better crosstalk noise suppression performance is achieved.3.The concept of the dual-mode composite left-handed transmission line is introduced,and the equivalent circuit model of dual-mode high-temperature superconducting filter based on a composite left-handed transmission line is given,and the research and analysis of independent control mechanism of center frequencies and bandwidths are carried out.Using this model method,a dual-band high-temperature superconducting filter was designed and realized,and the superior performance of the two passband center frequencies and bandwidths were independently controllable,ultra-compact(one-fifth of the original size),and verified The accuracy and effectiveness of the model are verified.