同轴线型低通滤波器的设计

Design of Coaxial Line Low Pass Filter

该文介绍了同轴线型低通滤波器的设计原理与方法,并以结构二,即同轴线内导体外直径统一,外导体内直径呈阶梯变换实现了截止频率为4GHz的同轴线型低通滤波器。结构二相比于结构一,即外导体内直径统一,内导体外直径呈阶梯变化的优势是其设计简单,体积较小且性能更好。测试结果表明,所制作的同轴低通滤波器有良好的性能指标,在整个通带内插入损耗小于0.4dB,回波损耗大于15dB,在通带外6GHz处的抑制约为36dB,整体满足了设计要求。

This paper introduced the design principle and method of the coaxial line low pass filter,and designed a coaxial low pass filter with 4GHz cut-off frequency,which structure named structure No.2is that the inner conductor's diameter is unified and the outer conductor's diameter is varied in stepped variation.The structure No.2has the advantages of simpler design,smaller size and better performance over the structure No.1,which outer conductor's diameter is unified and the inner conductor's diameter is varied in stepped variation.The test results showed that the filter had good performance with the insertion loss of less than 0.4dB,return loss of more than15 dB in the whole pass band.At 6GHz outside the passband,the superession is about 36 dB,which satisfied overall the design requirements.