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. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 159–162, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22065 [ABSTRACT FROM AUTHOR]