Design Of Balanced Diplexer And Quadruplexer Based On SLR

The popularization of intelligent communication equipment has promoted the rapid development of wireless communication technology,and the updated mobile communication equipment puts forward new requirements on the working capacity and transmission efficiency of the wireless communication system.Therefore,passive components such as filters,diplexers and multiplexers,which are important components of the front-end of the radio frequency system,have also entered a new stage of development.At the same time,with the increase in communication demand and the surge in the number of users,the electromagnetic environment has deteriorated sharply,and electromagnetic interference has become more common.While affecting normal communication activities,it also brings potential risks to the security of the communication system.In order to cope with the problem of the shortage of spectrum resources,frequency bands are divided more carefully,leading to increasingly serious problems of signal fading and mutual interference between frequency bands,which puts the security of radio frequency microwave communication systems at risk.Meanwhile,the development of scientific computer technology and integrated technology has provided new opportunities for the development of microwave radio frequency passive devices.Design of a compact,high performance,low cost and high integration of passive devices may speed up the conversion to the application.Based on the research background,this paper proposes a differential diplexer and multiplexer based on SLR.Under the premise of achieving better frequency selectivity and anti-electromagnetic interference,it improves the frequency utilization and is suitable for multi-signal complex circuits in the communication.The contents are as follows,1.In order to explore and compare the common mode suppression of the L-shaped differential feedlines and the U-shaped differential feedlines,two differential dual-band filters based on the L-shaped feedlines and the U-shaped feedlines are proposed respectively.Among them,the dual-bandBPF with L-shaped differential feedlines is implemented based on split ring resonators(SSRs).The differential mode frequencies are located at 1.58 GHz and 2.44 GHz,and the center frequency and bandwidth are independently controllable,and the common mode insertion loss is better than 18 dB;The U-shaped differential dual-bandBPF adopts stepped impedance resonators and has seven transmission zeros.The simulated and measured results show the frequency band selectivity is superior and the common mode suppression can reach 40 dB.2.A differential diplexer based on U-shaped microstrip-slot feedlines and stub-loaded resonator(SLR)is proposed.The working characteristics of the proposed SLRs are explained based on the odd mode and the even mode.The center frequency of the differential mode and the position of transmission zeroes can be controlled easily so that the resonator can work at different frequencies,which produces two passbands without affecting each other.Afterwards,the working mechanism of the U-shaped differential feedelines is explained,and the realization process of the anti-interference characteristics of the differential diplexer is explained in detail.3.Based on the work of the differential diplexer,a microstrip differential quadruplexer is presented.By showing the electromagnetic coupling relationship between the various parts,the schematic diagram of the electric field,and current distribution,the design concept and idea of the differential quadruple are introduced,and the simulation results are compared with the help of different simulation softwares.Finally,the proposed microstrip differential quadruplexer is fabricated and tested.The measured differential mode center frequencies are3.02 / 3.26 / 3.70 / 4.05 GHz,and the insertion losses are 1.86 / 1.61/ 1.77 / 1.65 dB respectively,which proves the feasibility of our design.