COMPACT PARALLEL COUPLED-LINE BANDPASS FILTER WITH WIDE BANDWIDTH AND SUPPRESSION OF SPURIOUS

摘要

The re-entrant coupling structure is applied in a parallel-coupled microstrip filter design to ensure a wide bandwidth, compactness, and the suppression of spurious. Fan design graphs are provided to determine the dimensions of each coupled stage. The features and advantages of the proposed circuit are analyzed in detail. Two experimental filters with design bandwidths of 70 and 90% are fabricated to verify the effectiveness of the modified structure.