COMPACT AND LOW-INSERTION-LOSS DUAL-MODE PATCH FILTER WITH SPUR-LINES

摘要

A compact microstrip dual-mode bandpass filter with inserted spur-lines at the edge of the patch is proposed. In order to obtain a low insertion loss, the proposed filter has no coupling gaps. Also, it has a size reduction of about 45% at the same resonant frequency as compared conventional dual-mode bandpass filters. Feed lines with offset are applied to ensure a minimal mismatch. From the measured results, the dual-mode filter has a 0.58-dB insertion loss at 1.27 GHz with 12% bandwidth.