The Research Of Miniaturized And Low Loss Diplexers

As the key passive components of RF/microwave transceivers,diplexers play an important role in the frequency division duplexing?FDD?systems.It can separate input singnals into two ways,or vice versa.With the quick development of wireless and mobile communication system and the improvement in user's demand,especially the proposal of 5G,higher requirements for diplexer's miniaturization,low insertion loss and high circuit performance are put forward.Therefore,it is of great significance for the research of diplexer with small size and low loss.In this paper,the research work are as follows:1.The diplexer design with stub loaded dual-mode resonator and defected ground structure?DGS?are proposed,the size of the circuit is greatly reduced by using both sides of the substrate to be designed.In addition,the dual mode of SIW resonator is applied to design the diplexer by reasonably arranging the resonator position and coupling structure.The common resonant cavity is used instead of the matching circuit to further reduce the space.The high isolation between the passband is realized by using the inherent orthogonality of two degenerate modes,and the effect on the isolation characteristic is explored by multi-order circuit.2.Based on the SIW dual-mode diplexer in the previous chapter,a SIW balanced diplexer is designed.For the TE_m0n mode,the balanced diplexer is designed using the common mode suppression characteristic of the SIW resonator when the n is an even number.According to the surface current distribution,the Common Mode Rejection Ratio?CMRR?is further improved by the form of a radiation slot on the surface of the diplexer.3.In order to improve the design efficiency of diplexer,aggressive space mapping?ASM?algorithm is used to design a microstrip diplexer.The whole optimization process only needs seven times full wave simulation using HFSS to get the desired results,without large amount of time consuming computation and saving computer resources.The feasibility of the method is verified by circuit measurement.