一、引言 高增益微波天线系统相当庞大,在双工通信时,往往收发共用一付天线。为了达到这目的,一般采用极化去耦或频率去耦的办法,而后者具有较好的去耦比。 本滤波器即为解决收发共用天线时收发讯机去耦之用。为此要求在通带内通过衰减小,阻带内截止衰减大,以防止在发射时过大的功率串入收信机而烧毁晶体检波器或产生有害的 I. INTRODUCTION The high-gain microwave antenna system is quite large. In duplex communication, it usually receives and sends a common antenna. In order to reach this goal, adopt the method of polarization decoupling or frequency decoupling generally, and the latter has better decoupling ratio. The filter is to receive and dispatch the common antenna transceiver decoupling purposes. In order to do so, it is required to pass the attenuation in the pass band to be small, and the attenuation in the stop band should be large so as to prevent excessive power from entering the receiver and burning down the crystal detector or generating harmful