基于T型双模谐振器的新型三通带滤波器设计

Design of a novel triple-band filter based on T-type double-mode resonator

提出了一种新型通带可控、损耗较低的紧凑型三频带通滤波器结构。该滤波器由三个四分之一波长谐振器组成,改变谐振器中3个相对独立的谐振路径长度有助于独立控制每个通带,根据通带两侧的期望阻带频率控制传输零点。设计并制作了一款小型三通带滤波器实物。仿真结果表明,3个通频带中心频率分别是0.84,1.59,2.63 GHz,-3 dB相对带宽分别为63.1%(0.45~0.98 GHz),16.4%(1.48~1.74 GHz),6.8%(2.55~2.73 GHz),插入损耗分别为0.07,0.23,0.43 dB,每个通带的回波损耗都优于20 dB。实物测试结果与仿真结果基本一致。

A novel and compact structure was proposed for triple-band bandpass filter with controllable passband and low loss.The filter was composed of three quarter-wavelength resonators.It helps for independent passband control by tuning the length of three relatively independent resonance paths in the resonator.The transmission zeros were controlled according to the expected stopband frequency on both sides of the passband.The compact triple-band filter was designed and manufactured.Simulation results show that the central frequencies of the three passbands are 0.84,1.59,2.63 GHz with-3 dB fractional bandwidth of 63.1%(0.45-0.98 GHz),16.4%(1.48-1.74 GHz),6.8%(2.55-2.73 GHz)and insertion loss of 0.07,0.23,0.43 dB respectively.The return loss of each passband is better than 20 dB.The measured results are consistent with the simulation results.