Design Of Miniaturized Orthomode Transducer

With the vigorous development of modern wireless communication industry,the demand for microwave communication system capacity is increasing,and spectrum resources are non-renewable and scarce resources.Therefore,how to improve the frequency utilization efficiency is one of the focuses of wireless communication technology research.OMT technology is one of the important technologies to realize high capacity information transmission in communication systems such as satellite communication.this thesis is to study the design of miniaturized orthomode transducer.Firstly,this thesis introduces the research background of orthomode transducer and analyses the research status of orthomode transducer with different structures at home and abroad,as well as the product performance requirements of orthomode transducer in the industry.It also makes a theoretical analysis of the electromagnetic wave transmission form and impedance transformation principle of waveguide structure,which provides an important theoretical basis for the high performance design of orthomode transducer.Secondly,in this thesis,a Ka dual-band orthomode transducer is analyzed and designed.The design goal is to broaden the bandwidth as much as possible on the basis of ensuring good performance of return loss and isolation.In this thesis,commercial high frequency simulation software CST is used to analyze and design,and the influence of key structural parameters on performance is analyzed.The simulation results of final parameter optimization show that the return loss in two operating bands is less than-20 dB and the isolation of port is more than 75 dB.Thirdly,a Ku-band orthomode transducer is also analyzed and designed to improve the performance of return loss and port isolation as far as possible within the limited operating frequency band.Similarly,CST software is used to optimize the simulation and sensitivity analysis of structural parameters.The measured results show that the return loss is better than-25 dB,the isolation in low frequency band is greater than 80 dB,and the isolation in high frequency band can reach 110 dB.Finally,the dissertation compares the above two miniaturized orthomode transducer with the industrial production standards.Both design models meet the performance requirements of practical engineering indicators,and have good engineering practical value in satellite communication and microwave communication antenna feed subsystem.