Patent ID: 7518473

Claim:
A design method for designing broadband filters using finite-width conductor-backed coplanar waveguide structures comprising: Determining the ratios of length (L), width (W), and thickness (H) of dielectric material, the width (Ws) of metallic signal waveguide, the width (Wg) of metallic ground waveguides, the width (Wd) of dielectric material without covering by metallic ground waveguides, the distance (G) between metallic signal waveguide and metallic ground waveguides based on center frequency of the desirable frequency band, number of electromagnetic modes, mode matching, mode coupling, and conversion efficiency of modes; Specifying a configuration of via holes including the radius or cross section and height of metallic connecting posts and the locations of these via holes between the metallic ground waveguides, and metallic back conductor, for producing a plurality of equivalent resonant cavities with specific resonant frequencies; therefore part of the energy of a plurality of electromagnetic modes with the specific frequencies coupled from the metallic signal waveguide to the metallic ground waveguide, and subsequently converted to a different plurality of electromagnetic modes conducted through the conducting posts of the via holes, and dissipated to the metallic back conductor, thereby establishing the filtering effect.