Abstract
An ultra-wideband (UWB) bandpass filter is proposed based on the hybrid structure of microstrip and coplanar waveguide (CPW). First, the detached-mode resonator is formed on the CPW layer, which composes a quarter-wavelength (lambda/4) multiple-mode resonator (MMR) with a short-stub and a lambda/4 single-mode resonator. Then, two lambda/4 microstrip open-stubs on the top side of the common substrate are introduced for bandwidth enhancement to meet the UWB passband limit. Quasi-elliptic function response and UWB operation are achieved. The simulated and measured results show an excellent agreement. (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2470-2473, 2009: Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24658