Generalized Cut Chebyshev Directional Coupler Diplexer Developed

This gave emphasis to the synthesis and design of the general Chebyshev filters and duplexers, and studied the related theories and technologies.Firstly, the synthesis and design of the conventional filters (Butterworth, Chebshev, Cauer) and frequency transformation were given as the basic theories. Further more, the theory of the general Chebshev filters with arbitrary transmission zeros was introduced. And transforming the wheel canonical prototype to the cascaded triplet prototype, the cascaded quadruplet prototype, the folding prototype and the box prototype applies the matrix rotations. Lastly, the examples were given for explaining the synthesis and annihilation theories.Additionally, the method was used to design the general Chebshev duplexer for coupling direction at 751MHz~782MHz. In the first instance, the effective coupling matrix was synthesized based on the required configuration and the synthesis theory of the filters given before. Then, in the sake of decreasing the volume and inter loss, the duplexer consists of the coaxial SIR filters. Ultimately, convenient for the signal surveillance, a coaxial directional coupler was designed.Finally, the result of the simulation and experimentation were matched very well. Simultaneously, the validation and efficiency of the MATLAB program was demonstrated. It would be helpful in engineering application.