带有交叉耦合的平行四腔螺旋滤波器设计

Design of parallel 4-cavity helical filter with cross-coupled structure

针对螺旋滤波器的结构及耦合方式,采用平行四腔的直线形交叉耦合结构,在非相邻的一腔和四腔间添加控制部件,从而引入传输零点以提高带外抑制。用Ansoft HFSS软件设计并制作了一款体积为150 mm×60 mm×70 mm,中心频率为380 MHz的螺旋滤波器。测试结果表明,该滤波器的带内回波损耗大于20 dB,插损小于2 dB,验证了该方法的可行性和实用性。

Against the structure and the coupling method of helical filters, the parallel 4-cavity helical filter with cross-coupled structure by adding control parts between the 1st and the 4th non-adjacent cavities to introduce transmission zeroes to increase out band rejection was proposed. A helical filter with the size of 150 mm ~ 60 mm ~ 70 mm and the center frequency of 380 MHz was designed by Ansoft HFSS and fabricated. The test result shows thatin-band return loss of the filter is higher than 20 dB and the insertion loss is lower than 2dB, the feasibility and practicability of the method are verified.