Design And Realization Of Electrically Tunable Microwave Filter

The Microwave circuit theory and technology research of electrically tunable filters belongs to the current international direction of microwave circuit frontier technology and national core electronics,high-end general chips and infrastructural software;It is one of the core devices to achieve miniaturization,multi-function,low cost and iterative upgrade of various radio systems;It can replace the traditional filter bank,which is an indispensable key component to realize the frequency agility function of radio system,and can effectively improve the efficiency of our radar,communication and other electronic systems;It is an important part of the new generation of electronic reinforcement technology system,which can greatly improve the anti-penetration and self-protection ability of electronic system,and has very important scientific value and popularization and application value.This paper focuses on the design and implementation of microwave electrically tunable filter.Based on microstrip lines and Substrate Integrated Waveguide(SIW),a variety of microwave electrically tunable filter are proposed and implemented.The main work and results of this article are divided into the following three aspects:1.The theory and technology of electrically tunable filters based on microstrip lines and SIW structure at home and abroad are systematically studied,compared and analyzed,as well as the basic design principles and implementation methods of controlling the central frequency adjustment range and bandwidth of electrically tunable filters.In view of the problems of narrow single-mode single parameter adjustment range,the design idea of electrically tunable filters with wide central frequency tuning range,multi-mode SIW frequency adjustable and single-mode SIW three parameters adjustable is proposed.2.A design method of electrically tunable filters with microstrip parallel coupled line direct feeding is proposed,which realizes a variety of electrically tunable filters with wide frequency adjustment range,which not only significantly improves the adjustable center frequency of the electrically tunable filters range,but also satisfies the requirements of the external Q value in the entire frequency adjustment range,and significantly improves the selectivity and out-of-band suppression level of the filter;On the basis of direct feed,a method of dual-mode segmented superposition and switching is proposed,and an ultra-wide passband electrically tunable filter with a "dual-mode+" center frequency width is designed and implemented;An electrically tunable balanced filter is designed and implemented,which solves the problem of interference suppression in complex electromagnetic environments.3.A design method of multimode SIW frequency tunable filters using PIN diodes to reconstruct electromagnetic boundary conditions is proposed,and a dual-mode SIW frequency electrically tunable filter is implemented,which significantly improves the in-band selectivity of the filter and out-of-band suppression levels;A design method of single-mode three parameter electrically tunable filter based on varactor diode loaded SIW is proposed,and an electrically tunable filter with adjustable frequency,bandwidth and transmission zero position is realized based on this method,which breaks through the technical difficulty of single adjustable parameters of SIW electrically tunable filter.