Design And Debug Of Multiple Couplers

With the vigorous development of microwave, millimeter wave, mobile communication technology makes a spurt of progress. The frequency resources are becoming more and more crowded. People prefer to transmit much more information within a narrow band. Multi-coupler is one of the means of using spectrum resources efficiently, which is widely used in FM radio, antenna combiner technology and military interference in modern communications and adopts a plurality of channels work at different frequency points, resulting a proper isolation between every two channels, and can share one broadband antenna at the same time.The main work in this thesis is mainly reflected in the following aspects:1. Starting from understanding the research background and needs of the multi-coupler and surveying its research status at home and abroad. A comprehensive analysis and research for the multi-coupler is conducted; and introduces some general design method of multiplexer.2. Based on the theoretical analysis of multiplexer and the problem taken into when design. Analyze the interaction between each channel filter when multiplexer is designed, namely the elimination of remaining admittance; at the same time, a kind of low-pass prototype design which has a band negative slope reactance characteristic can be as a starting point. Besides.3. Based on the wideband equivalent circuit of the helical cavity filters, accurate and fast design of a contiguous 24-channel multiplexer in UHF band is realized by full wave-circuit hybrid model. Simply outlines the circuit design of the structure 24-channel multiplexer, and the final structure can be obtained after the circuit is optimized by using distribution optimization method in AWR software. In the entire circuit structure. Besides matching network adopts the manifold network. Each channel filter is connected to the manifold network by a T type junction. Due to a large circuit model, step by step optimization strategy is used. Finally, the 24-channel multiplexer is simulated in the AWR software. Simulated result is good, return loss of common port is kept-20 d B below, transmission characteristics of each channel is overlapped at a insertion loss of-3d B, basically meet the requirements. And I tune physical structure of the worked out single filter by using the method of group delay tuning, tuning results are basically consistent with the theoretical simulation, thereby verify the correctness of the full wave-circuit mixed model4. Based on the required higher and higher targets of multiplexer, hoping that the multiplexer owns lower insertion loss and more compact structure. The thesis uses the view of bionics proposed by the previous researcher and models on the structure principle of breast-feeding cochlea and design a multiplexer; then, it starts from the physical structure of the cochlea to deduce its mechanical model and circuit model step by step. Clarifying how to extract the method of circuit parameter, lastly, design a good transmission performance 24-channel multiplexer simulation example by by using the method of distribution optimization in UHF band.