Multimode Resonators and Their Filter Applications

Abstract

The design methods of microwave filters using multimode resonators can generally be divided into two categories One is to design the structure and resonant frequencies of the multimode resonator first and then the couplings to input/output ports are adjusted to complete the design The other is to use approximate or exact synthesis methods to derive all the component values of the filter directly This thesis mainly studies the first method and focuses on the effects and designs of the resonant frequencies and characteristic impedances of commensurate step-impedance resonators It is found that not only the resonant frequencies but also the characteristic impedances of the multimode resonators are very important design parameters Design graphs and tables are created to help the design of these kinds of multimode resonator filters Furthermore it is proposed to replace commensurate resonators with non-commensurate ones or shunt short-stub resonators in order to reduce the overall filter size By keeping the resonant frequencies and the characteristic impedance of the first transmission-line section unchanged it is found the passband responses are still good after these replacements Finally all the above studies are verified by electromagnetic simulations and real circuit measurements

Date of Award	2020
Original language	English
Supervisor	Chih-Ming Tsai (Supervisor)