Size-Reduction of Dual-Wideband Bandpass Filters Using Bridged-T Coils

In this paper, reduced-sized dual-wideband bandpass filter designs using bridged-T coils are proposed. The bridged-T coil can be designed as a wideband lumped-element equivalent of the transmission line, and it is used to replace all or part of the transmission line sections in a conventional dual-wideband bandpass filter for very efficient circuit size reduction. The tradeoff between circuit size and insertion loss is investigated, and practical design examples are presented to demonstrate the filter performance.