Research On Key Technologies Of The Design Of Multiplexer

The multiplexer is the key component in transceiver for modern wireless and mobile communication system. In recent years, with the development of modern communication technology, emerging a variety of communication systems and the frequency has been used densely. If we construct the transceiver systems for every frequency, the resources must be wasted on one hand and it will cause unnecessary interference to other systems on the other hand. So, it is necessary to use the multiplexer to construct the integrated transceiver systems for multifrequency.There are two major types of multiplexer. One is the same frequency multiplexer, and the other one is the different frequency multiplexer. The same frequency multiplexer combines the same frequency signal, while the different frequency multiplexer combines the different frequency signal. Combining the same frequency signal is generally used the inverse process of the power divider. While the filters are the components of the different frequency multiplexer. Therefore, this paper firstly studies the basic theory of filter and power divider, and it will be applied in the design of multiplexer.Based on the theoretical basis of the above, three different types of multiplexer are designed in this paper. The first one is the dual-band cavity multiplexer for the design of mobile communication bands, which has a wide application. The dual-band cavity multiplexer is composed of two bandpass filters with different frequency. The second one is the tri-band microstrip multiplexer. It is composed of three bandpass filters with different frequency and three two-way equal-spit Wilkinson power dividers, which are connected to each bandpass filter’s input. The bandpass filters consist of the open-loop resonator and they couple to both sides of the input and output, respectively. The multiplexer can combine the signal that it comes from different array antenna systems. The last one is the LC multiplexer for the design of low frequency, small dimension and wideband. It consists of three same VHF bands and one UHF band circuts, and it can be applied in some communication systems to combine the same frequency and different frequency signal at the same time.