Design And Realization Of A Duplexer Based On LTCC

With the development of wireless communication technology,the importance of the microwave circuits and systems has become more prominent in communication,navigation,radar and information confrontation.As one of the irreplaceable devices in various systems,the duplexer is mainly used for signal separation and spectrum isolation between channels.The performance of the duplexer device directly affects the frequency response of the system.As more and more types of communication appear,there is a great demand for spectrum resources which are already scarce.As for the system,it's gradually developing towards high integration,multi-function,and miniaturization.At the same time,it puts forward stringent requirement for duplexer on miniaturization,low insertion loss,and wide-band.This article aims to realize a duplexer based on LTCC,describes the present situation of the filter and duplexer,researches and deduces some theories and designs a duplexer based on LTCC using network synthesis method,the device and measures it.The main content of this article is as follows:Firstly,this article introduces the development of filters and duplexers,the types and characteristics of filters and duplexers,works on and deduces some theories of filters and duplexers design.The models of the capacitance and inductance embedded in LTCC are modeled and verified after theoretical analysis.According to the parameters of the duplexer,the duplexer of the article is designed by network synthesis method.According to the parameters,the duplexer can be decomposed into branch filters.The schematic of the duplexer circuit is designed after finishing the schematic design of branch filter.Using the deduced capacitance and inductance models,the three-dimensional model of the branch filters and the duplexer are established.The final model is optimized by the high frequency simulation software based on full-wave.Comparing the measured results tested by the actual devices with the design parameters,and the direction that can be improved and studied in the future is proposed.The low-frequency passband of the duplexer is from DC to 1300 MHz,while the high-frequency passband is from 1650 MHz to 3000 MHz.The insertion loss of the both low passband and high passband are ?1.5dB.The out-band rejection of low-frequency passband is ?33dBc at 1650 MHz,which of the high-frequency passband stands ?30dBc at 1300 MHz.