Ultra-wideband bandpass filter using broadband planar Marchand balun

摘要

A novel ultra-wideband (UWB) bandpass filter using a planar Marchand balun is proposed. Owing to the different input/output impedances of the planar Marchand balun, the UWB bandpass filter has an adjustable fractional bandwidth from 74 to 114%, by cascading two planar Marchand baluns based on the transversal filter concepts. Detailed design and synthesis procedures for the UWB bandpass filter are provided.