具有小中心频率比的紧凑型双频带通滤波器

Compact Dual-Band Bandpass Filter with Small Center Frequency Ratio

为实现具有小中心频率比的双频带通滤波器,设计了一种平面双模谐振器及一种紧凑型滤波器拓扑结构。利用该谐振器的频率可控的特性,可实现两个工作频段的中心频率比1∶1.1,利用该拓扑结构引入源负载耦合,实现了具有4个传输零点的双通带响应。加工并测试了该滤波器,两个通带的中心频率为5.2 GHz和5.8 GHz,3 dB相对带宽为5.8%和5.2%,通带内的插入损耗小于0.8 dB,4个传输零点分别位4.52 GHz、5.50 GHz、5.50 GHz和6.50 GHz,实验和仿真结果吻合,验证了结构的有效性。

realize a dual-band bandpass filter with small center frequency ratio,a dual-mode planar resonator and a compact filter topology are designed.Based on the frequency control mechanism of the dual-mode resonator,a very small center frequency ratio of 1∶1.1 is realized.The filter is fabricated and measured.The operating frequencies of the two passbands are 5.2 GHz and 5.8 GHz,the 3 dB bandwidths are 5.8%and 5.2%,the insertion losses of the two bands are less than 0.8 dB,four transmission zeros are generated at 4.52 GHz,5.50 GHz,5.50 GHz and 6.50 GHz.The measurement and simulation are in good agreement,verifying the validity of structures.