Research On Broadband Balanced Filtering And Power Division Network Circuits

Radio frequency(RF)circuits and integrated circuits are becoming much more densed space which allow multi-signals transmit with the development of wireless communication technology.More function,miniaturization and modularization influence the electromagnetic between circuit noodes and crosstalk from substrate coupling deeply.Compared with single-ended technology,balanced circuits have good common-mode rejection that leads to relatively high imuunity to environment noise.Therefore,the balanced circuits have obtained much more attention for the building of communication system.Filters with frequency-selectivity characteristic and power dividers with signals dividing and combining,which are widely used in microwave communication?electronic countermeasures?microwave measurement and frequency synthesizer,are indispensable n many communication and radar systems.It is very important to study on banlanced filters and power dividing/combining networks.According to the hot topics and difficuilt problems in balanced circuits,this thesis is focused on the integration of transversal signal-interference concepts and novel transmission line to explore new technqieus for achieving wideband and good performances.The main contribution of this work is summarized as below:1.The analysis and design of ultra-wideband differential filters based on transversal signal-interference concepts:Firstly,introduce the transversal signal-interference concepts and deduce mixed-mode S-parameter of four ports balanced circuits.Then,accomplishing design and fabrication of two kind differential filters which apply the 180° phase shifter and the theoretical model of transversal filter structure.Wideband differential mode transmission bandwidth and common mode rejection can be realized due to signals flow through different transmission lines combined and cancelled.These works have been published in Applied Computational Electromagnetics Society.2.The analysis and design of wideband balanced network using double-sided parallel-strip line:Firstly,the characteristic of the transmission line of DSPSL and deduce mixed-mode scattering matrix of six-port balanced networks is introduced.Then,the phase inverter based on DSPSL without frequency sensitivity was analyzed and designed.Based on above analysis,half-wavelength open stubs are loaded to achieve wider common mode suppression.These works have been published in IEEE Transactions on Microwave Theory and Techniques,IEEE Microwave and Wireless Components Letter,and applied one patent for wideband balanced network based on DSPSL.3.The analysis and design of wideband filtering power divider using coupled lines and one wideband balanced network:Three novel filtering power dividers with wide frequency band harmonic suppression and one wideband balanced network with improved upper stopband are proposed.Coupled lines are used to replace A/4 impedance transformer and implemented the filtering function more efficiently.In addition,wide upper stopband can be obtained by introducing the multiple transmission zeros realized by the stepped coupled lines.Finally,a planar balanced network with wideband common mode suppression and high isolation is designed and fabricated.These works have been submitted to IEEE Transactions on Microwave Theory and Techniques,IEEE Transactions on Components Packaging and Manufacturing Technology.