Transmission-Line Bandpass Filter Structures With Infinite Reflectionless Range

This article is to present a complete method to design transmission-line reflectionless filters. Our approach can be used to accord a transmission-line filter to feature an infinite frequency range of reflectionless response. It can be applied to reflectionless filter prototypes consisting of filtering and matching sections that comply the Cauer topology. Hence, it does not limit by the filter order and/or the filter response type. Design equations supporting our approach are provided, and their applications to actual filter designs will be elaborated via various filter examples with distinct features. The measurements authenticate our design approach.