Design Of Compact Dual-polarized Diplexer

As the data transmission capacity of 5G and next-generation communication systems continues to rise,the performance of communication systems must also be improved to meet the increasing demand for wireless communication.A good option is " co-channel dual-polar(CCDP)" transmission system,which uses two different modes of polarization,horizontal and vertical,so that the signal streams are transmitted in the same frequency band and does not affect each other.In general,CCDP systems are implemented using an integrated dual-polarized antenna with an Ortho-Mode Transducer(OMT)connected to two diplexers.The OMT can separate the signals of different polarization modes,while the diplexer can separate the signals of different frequency bands under the same polarization mode.The function of polarization separation and frequency multiplexing of the dual polarization antenna transceiver system can be realized when the two discrete devices work together.At the same time,the miniaturization and integration of communication equipment is also an increasing demand of communication system.This paper starts with the miniaturization design of the diplexer.A K-band branchwaveguide diplexer is designed.The branch-waveguide coupler is chosen as its common junction and the channel filter adopts the topological structure of double CT.The structure of the whole diplexer is extremely compact.The simulation results show that it has good performance.Further,to meet the requirements of miniaturization and integration,a design method of dual-polarized diplexer is proposed in this paper,the diplexer can duplex the horizontally polarized signal and the vertically polarized signal respectively,and has the function of polarization separation.Finally,a dual polarized-diplexer working in Ka band is designed and fabricated as a verification example.The measured results are in good agreement with the simulation results,which verifies the effectiveness of the design method.