Microstrip Complementary Duplexer

The twenty-first century is the century of rapid development of science and technology. Communication technology advances every day, therefore it means that the requirements for technology are higher and higher.Filters are used as an integral part of the communication system, so for high performance, high noise immunity and smaller size and other requirements are increasingly prominent. The duplexer used as a common part of the transceiver end of a communication system, its high performance directly determines the quality of transmission and reception signals, so the research on diplexer has not stopped.The author designs the diplexer according to the actual needs of engineering and writes this paper based on process and measurement; The main work of this paper is researching the characteristics of microstrip lines and suspension lines and setting up the simulation model to obtain a diplexer which the passband is respectively DC-3.4GHz and 3.6GHz-5GHz, then takes a comparative study with the simulation model and the material object. The details are as follows:Firstly, do overview of the filter and diplexer’s research status, and introduce the main contents of this article.Secondly, introduce the fundamental theoretical knowledge of the microstrip line, strip line suspended and a variety of filters this document referred to in detail.Thirdly, create some models to simulate in ADS with microstrip line structures based on theory above and analyze the feasibility of the model structures.Fourthly, according to the feasibility of model structure in ADS, set up suspension line structure simulation model in the CST. Through connecting the lowpass filter and bandpass filter, highpass filter respectively; finally obtain three kinds of structure: The first is a lowpass filter with a tuning fork resonant structure in the form of a bandpass filter to constitute a duplexer. The second is the lowpass filter with an I type resonant structure in form of a bandpass filter to constitute a duplexer. The third one is a lowpass filter with a highpass filter to constitute a duplexer. Compare the results obtained by the three structures, process and measure the first and the third kind of structure, compare with the simulation results.Finally, summarize the research results.