一种超宽阻带微带低通滤波器的设计

基于传统阶跃阻抗滤波器,提出了一种易于实现的超宽阻带微带低通滤波器改进设计方案。低阻抗线部分采用扇形微带结构,在同等阶数下,该结构的滤波器与传统阶跃阻抗滤波器相比,具有更紧凑的电路结构以及更好的阻带特性。在滤波器末端并联开路短截线,使得阻带增加额外传输陷波点来抑制寄生通带。利用ADS和HFSS仿真软件对滤波器结构进行优化设计,并进行了实物的加工和测试。实测结果表明,通带3 dB 截止频率为2 GHz,通带内0-1.8 GHz 回波损耗大于20 dB,3-20 GHz 频率范围内的阻带抑制能达到25 dB 以上。

Design of a Microstrip Low-Pass Filter with Ultra-wide Stopband

Based on traditional step impedance filter, an improved design scheme of ultra-wide stopband microstrip low-pass filter is proposed. The sector microstrip structure is used as the low impedance line. Under the same filter''s order, the proposed filter has a more compact circuit structure and better stopband characteristics than the traditional step impedance filter. The spurious passband has been suppressed by using parallel open circuit stub at the end of the filter to increase the extra transmission notch point. The structure of the filter is optimized by using ADS and HFSS simulation software, and physical processing and testing are carried out. The measured results show that the cut-off frequency of the pass band 3 dB is 2 GHz. The return loss is more than 20 dB in the 0-1.8 GHz pass bands, and the stopband rejection of the 3-20 GHz frequency range can reach more than 25 dB.