Duplexer Design And Implementation

In the wireless communication system, we need to receive and transmit the radio signal through antenna. If the receiver and transmitter antennas are configured independently, not only increases the cost but also increases the size and the transmitting antenna and receiving antenna signals will interfere with each other, duplexers is the key to solving this problem. So the duplexer has important research significance.In this paper, work was done as follows:First, this paper summarizes the basic theory and implementation methods of filter design which used in the duplexers, the duplexer described the structure of the duplexers briefly, detailed the performance parameters of the duplexer, analyzed the relationship between the performance parameters and filter and analyzed the high-frequency characteristics of the device which used in the duplexer;Second, on the basis of the research of the filter, duplexer design method, in order to design a duplexer which high frequency channel is150MHz-155MHz, low frequency channel is45MHz-50MHz, insertion loss is less than0.5dB, isolation is greater than20dB, we use ADS for simulation design. In the design, this paper presents four programs, and used ADS to simulate each program and analyzed the advantages and disadvantages of various options in insertion loss, isolation and group delay, etc.; this paper also analyzed the stability of the duplexers. These papers selected the better one to carry out;Third, this paper used discrete components to achieve duplexer, first to achieve a high-pass and low-pass filters, and tested them. Then we combined the filters to become a duplexer and used a network analyzer to test it. We finally archive the duplexer which meets the design requirements; Fourth, this paper summarized the work carried out on, illustrated the problems which exist in the work and proposed directions for further improvement.