Высокоселективный полосковый фильтр нижних частот с уровнем заграждения более 100 dB в широкой полосе

Abstract

A new miniature strucuter of a highly selective low-pass filter (LPF) on a suspended substrate with a double-sided topology of stripline conductors has been proposed. The steepness of the slope of the frequency response of the filter and the depth of the stopband are determined by the zeros of the transmission coefficient, which number is equal to the order of the filter. The synthesis of a fifth-order low-pass filter prototype on a 0.5-mm thick alumina substrate with a relative permittivity εr = 9.8 was performed by numerical electrodynamic analysis of its 3D model. The filter passband cut-off frequency at the level of –1 dB fc = 1.75 GHz, and the length of the stopband at the −100 dB level extends to a frequency of 4.4 fc.