Novel Ultra-Wideband Filter Using Coplanar-Waveguide-To-Microstrip Transition and Stubs

This letter presents a novel ultra-wideband (UWB) filter using coplanar-waveguide (CPW)-to-microstrip transition and stubs. The proposed filter is implemented by the CPW series stubs and microstrip shunt stubs. The transition includes a via that not only connects the series and shunt stubs but also can improve the out-of-band rejection. The proposed filter has been analyzed, verified, and fabricated. Both simulation and measurement results demonstrate the higher rejection cutoff frequencies above 18 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2269–2271, 2013