A parallel coupled-line bandpass filter with wide stopband using slotted ground structures

This letter proposes a parallel coupled-line bandpass filter (BPF) using the folded slotted ground structures (SGSs) to improve the wide stopband. It is shown that the designed folded SGS has a very small area in comparison of previous works. The folded SGS exhibits a dual stopband characteristic owing to the bandgap resonant characteristic of SGS to suppress the harmonic frequency of the parallel coupled line BPF. Good agreement with electro-magnetic simulation and measurement is demonstrated. (c) 2006 Wiley Periodicals, Inc.