Bandpass Diplexer Design And Debugging Engineering Research

Recently, with the fast development of wireless communication, the electromagnetic frequency used by wireless communication becomes very narrow. So, the requirement of filter's performance for wireless communication is becoming harder and harder, this means that the filter should have enough attenuation out of band, besides the common requirement of small size, high selection and low insert loss. Usually the General Cheyshev filter is used to meet these hard requirements.The transmission zeros of the General Chebyshev filter could be placed in any position, so the attenuation out of band is controllable, then a high selection performance could be obtained. In addition, through some special cross couple, the complex transmission zeros could be formed to improve the group delay response and decrease the distortion.The basic principle, the basic structure, the realization form and the debugging method of the band-pass diplexer is studied in this thesis in detail. As an example, a coaxial housing diplexer is designed with two General Chebyshev filters using the foldaway topology.The emphasis is on the procedure of synthesis the couple matrix of the General Chebyshev filter and the realization of the couple matrix. The diplexer electric circuit simulation methods as well as the diplexer debugging method are also discussed in detail.