A Study Of Dual-Band Frequency Multiplier At X And Ku Bands

In space-limited platforms,for example modern vessels and aircrafts,how to construct multi-band and multi-functional front-end systems with improved volume,weight,power consumption and performance is a great challenge.Also,it is an important problem that needs to be solved urgently in the development of the multi-functional front-end systems.The study aims at discussing the realization of a dual-band frequency multiplier with high performance in multi-functional front-end systems;the study is of great significance in wireless communications.In this thesis,a novel dual-band frequency multiplier at X and Ku bands is proposed and studied.By introducing the development of traditional single-band frequency multipliers as well as dual-band/multi-band frequency multipliers,operation mechanisms of the frequency multiplier are discussed,and its theory is analyzed.Contributions of this work include:(1)A novel wideband branch-line balun with all-ports matching and isolation between the balanced ports is proposed.The proposed balun can not only be used in power dividing systems,but also power combining systems,for example in balanced mixers,frequency multipliers,power amplifiers and antenna feeding systems,which has importantly practical value.(2)Topology of the dual-band frequency multiplier at X and Ku bands is discussed,where the doubler at X band is the use of frequency multiplication technique and the tripler at Ku band is based on the frequency mixing.The push-push structure is introduced to build the frequency doubler for harmonic rejection.The mixers,cascaded after the push-push structure,are utilized to generate the third harmonic by mixing the fundamental signal and its second harmonic.(3)Different function modules,including the impedance matching network,bias circuits and the input and output baluns,are designed,respectively.The frequency doubler and tripler are simulated simultaneously in Agilent ADS software to evaluate the performance.A prototype of the dual-band frequency multiplier is finally implemented.Experiments are carried out to confirm the performance.