Abstract

A new miniature design of a highly selective lowpass filter based on a suspended substrate with a two-sided stripline pattern has been developed. The filter frequency response slope (cutoff attenuation rate) and stopband attenuation depth are determined by transmission zeros, the number of which is equal to the filter order. An experimental prototype of a fifth-order lowpass filter on 0.5-mm-thick alumina substrate with dielectric permittivity ε = 9.8 has been synthesized with the aid of numerical electrodynamic analysis of a three-dimensional model. The cutoff frequency of the filter passband at a –1-dB level is f_c = 1.75 GHz. The stopband width at a –100-dB attenuation level reaches 4.4f_c.

中文翻译：

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具有超过100dB宽阻带衰减的高选择性带状线低通滤波器

摘要

已经开发了一种新的微型设计，该设计基于具有双面带状线图案的悬浮基板的高选择性低通滤波器。滤波器频率响应斜率（截止衰减率）和阻带衰减深度由传输零决定，传输零等于滤波器阶数。借助三维模型的数值电动力学分析，合成了介电常数ε= 9.8的0.5毫米厚氧化铝基板上的五阶低通滤波器的实验原型。滤波器通带在–1 dB处的截止频率为f _c = 1.75 GHz。在–100 dB衰减水平下的阻带宽度达到4.4 f _c。