Parallel coupled CPW filters for spurious band suppression

Abstract

Modified coplanar waveguide (CPW) edge‐coupled band‐pass filters with floating conductor strips printed below the coupled‐line sections are proposed. These structures allow one to suppress the first undesired spurious passband associated with the nonhomogeneous nature of the dielectric in CPW structures. Also, tight coupling levels can be easily achieved. An optimization code based on a fast quasi‐TEM solver is used to optimize the dimensions of the filter sections, in such a way that final dimensions are obtained in less than 1 min. A couple of filters have been built and measured to illustrate the theory. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1094–1097, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25135