UWB BPF with triple notched bands using interdigital coupled-line and three QWR coupling short stubs

In this article, a compact ultrawideband microstrip bandpass filter with triple narrow notched bands and wide stopband is proposed utilizing interdigital coupled-line and three quarter-wavelength resonator (QWR) coupling short stubs loaded in the 50- feedlines. The short stubs can improve the passband performance and create new transmission zeros in the upper-stopband. The coupling QWR is studied and used to generate the desired notched band and deepen the stopband. By simply adjusting the dimensions of the QWRs, the center frequencies of the notched bands can be allocated at 3.6, 5.2, and 5.8 GHz, respectively. Good insertion/return losses and wide stopband are achieved as demonstrated in both simulation and experiment. (c) 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2874-2876, 2013