Spurious Response Suppression in Broadband and Introduction of Attenuation Poles as Guard Bands in Printed-Circuit Filters

Abstract

We report here a novel structure of the printed-circuit bandpass filter that can suppress spurious responses over a wide frequency range. In the filter reported in this paper, we show a very simple technique, by which the spurious responses up to the 4th order are successfully suppressed. In addition to such a spurious suppression, we adopt one more function that can produce sharp attenuation poles near the passband as the guard bands. These theoretical results are confirmed by experiments.