一种全容性耦合直线型介质波导滤波器的设计

Design of A Full Capacitive Coupled Linear Dielectric Waveguide Filter

文中设计了一种新型的全容性耦合直线型介质波导滤波器,由两个深的容性盲孔和一个浅的调试盲孔组成容性耦合结构,产生弱感性耦合,使得通带高端产生传输零点,从而解决了一般直线型耦合滤波器难以实现交叉耦合传输零点的问题,并满足了工业应用对滤波器外形“直入直出”的需求。依照仿真对滤波器进行实物加工,测试的滤波器中心频率3.5 GHz,当频率在3.42~3.58 GHz时,带内插入损耗小于1 dB,回波损耗小于15 dB,在带外频率3.8 GHz处产生传输零点。测试结果与仿真结果高度吻合,验证了该滤波器结构简单、易于调谐、滤波性能良好,能够满足基站通信的应用需求。

This paper designs a new kind of the capacitive coupling linear dielectric waveguide filter.Two deep blind holes and a shallow adjustment blind hole build up the capacitive coupling structure,which produces weak inductive coupling,causing the transmission zeros at the passband high-end,solving the problem that the general linear coupling filter is difficult to realize cross coupling transmission zeros,and meeting the filter shape requirement of“straight-in-straight-out”in industrial applications.According to the simulation,the filter is processed in real object.The center frequency of the tested filter is 3.5 GHz.When the frequency is at 3.42~3.58 GHz,the in-band insertion loss is less than 1 dB,the return loss is less than 15 dB,and the transmission zero is generated at 3.8 GHz out-of-band frequency.The test results are in good agreement with the simulation results,verifying that the filter has the advantages of simple structure,easy tuning and good filtering performance,and can meet the application requirements of base station communication.