Development of Design Procedure for Compact Planar Ultra-Wideband (UWB) Bandpass Filters

We have reported a compact planar-type UWB bandpass filter with tightly coupled E-shaped electrodes in Ref [1]. In this paper, a useful and practical design procedure for this filter is developed, and explained in details with full-wave simulations. In addition, the resulting model designed by the introduced procedure is demonstrated experimentally to confirm the theoretical predictions. Furthermore, the design procedure is applied to several models with different substrate parameters, and a super-compact filter is designed on the substrate with the relative permittivity of 10 and thickness of 0.5 mm, whose dimensions, 2.7 mm x 2.01 mm x 0.5 mm (filter body) correspond to 24.4 % size reduction from the initial mode; reported in Ref [1].