Compact Bandpass Filter with Wide Upper-end Stopband

Abstract

A compact band pass filter with wide upper-end stop band is discussed in this paper. To obtain wide stop band and spurious suppression, two open stubs are loaded on both the input and output feeding lines. Based on the proposed topology, a prototype was fabricated to achieve band pass application around 2.4 GHz and the wide stop band applications from 3.08 to 8.43 GHz at upper band with a rejection level of nearly 20 dB. Experiment results demonstrate the designed filter available.