The main works are as follows : 1 . the paper systematically describes basic concepts and theories that form the foundation for design of general microwave filters . the topics will cover filter transfer function , lowpass prototype filters , frequency transformations , immittance inverters and the passband insertion loss under the influence of the dissipation of filter elements 2 现总结如下: 1 .对微波滤波器的设计理论进行系统的分析,阐述了微波滤波器的传输函数、低通原型、频率变换、倒置变换器以及元件损耗对带内插损的影响等方面。