基于分离指标的宽阻带低通滤波器设计

Design of Broad-stopband Low-pass Filter Based on Separating Specifications

摘要:

常见的开路短截线和阶跃阻抗结构在微带低通器设计中较为成熟,但是这些结构的低通滤波器受到寄生通带的影响,阻带不够宽;提出了一种基于分离指标的宽阻带低通滤波器设计方法,利用计算机仿真软件ADS,对常见的阶跃阻抗低通滤波器进行结构改进;该方法将低通滤波器设计指标重点分为滚降率和宽阻带抑制两部分,分别利用椭圆滤波器和巴特沃斯滤波器的本身特性实现设计目的,最后进行级联优化;此结构综合设计方法简单严谨,易于实现,改进的低通滤波器性能优越,实现了宽阻带的设计需求,通带0~3 GHz,插入损耗<0.5 dB,阻带4~12 GHz,抑制>45 dB。

Abstract:

Conventional planar low-pass filters often suffer from the problem of spurious passbands,though the design technology is mature. It presents a novel low-pass filter with broad stopband, which is a optimal structure realized by the way of separating specifications and ADS. Attenuation rate and stopband are designed respectively by using elliptic filter and butterworth filter before optimizing. The proposed low-pass filter has the advantage of design process and broad stopband. The insertion loss is less than 0.5 dB from DC to 3 GHz and S21 is less than -45 dB within the broad stopband from 4 GHz to 12 GHz.