AbstractIn this work, a new type of wideband coplanar bandpass filter with sharp skirts and large stopband is proposed. The filter exhibits a flat response in the passband, and a steep slope and a high rejection in the stopband. The filter design is based on the use of a broadside‐coupled (BC) coplanar‐waveguide (CPW) directional coupler as a transversal filtering section (TFS). This is performed by conveniently loading two ports of the coupler with shunt stubs, so that the signals in the output port interfere in a way that a bandpass filter response is obtained. The suggested filter scheme has been validated experimentally throughout the design, fabrication, and measurement of a wideband coplanar bandpass filter centered at 2.0 GHz, formed by two TFS connected in cascade. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 294–298, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24029