超宽带交指腔体滤波器的设计

Design of Ultra Wideband Interdigital Cavity Filter

该文介绍了交指型腔体滤波器的设计步骤并分析其制作难点,并根据该步骤设计出一款通带为10.2~16.7 GHz的宽带带通滤波器。提出了一种新型滤波器抽头结构,该结构通过在进线处添加金属方块提高了输入端与第一阶谐振腔之间的耦合,拉低了滤波器外部品质因数(Qe),实现了超宽带的设计。结果表明,在通带(10.2~16.7 GHz)内,滤波器样品电压驻波比(VSWR)<1.7,插入损耗<1.5 dB,带外抑制良好,满足工程需求。

The design steps of interdigital cavity filter are introduced and its fabrication difficulties are analyzed in this paper.Based on the design steps,a broadband band-pass filter with a passband of 10.2-16.7 GHz was designed.A novel filter tap structure is proposed,which improves the coupling between the input and the first resonant cavity by adding a metal block at the position of the incoming line,reduces the external Q of the filter,and realizes the ultra-wideband design.The result shows that the voltage standing wave ratios(VSWR)of filter prototype is less than 1.7,insertion loss is less than 1.5 dB in the passband(10.2-16.7 GHz)and the out-of-band suppression is good,meeting the engineering requirements.