Highly Selective Quasi-elliptic Function Filters

Recently, with the development of wireless communication, the requirement of filter's performance for wireless communication is becoming harder and harder. The transmission zeros(TZ) of Quasi-elliptic function filter could be placed in any position, so the attenuation out of band is controllable, then a high selection performance could get. The design method can be also applied in all kinds of transmission-line filter and in all kinds of filter made by different material such as LTCC. It can be used the frequency range from RF to millimeter-wave.The aim of this paper is to study the generalized chebychev transfer function and the synthesis of coupling matrix and is to give the design method.The main works are as follows:1. Introduces the basic theory on microwave filter2. Introduces the design basis on quasi-elliptic function filter, concluding the relation between phase and TZ.3. Describes the synthesis of the coupling matrix. Through locateing the TZ , configure the transfer and reflection function polynomials,geting the coupling matrix.4. Gives some design examples.