Reflectionless Bandpass Filters Using Two Dual Bandpass Filters

A reflectionless filter is designed based on the dual‐circuit theory. Two types of reflection‐less filters are presented for this methodology. The proposed configuration consists of two dual branches. Two dual‐bandpass filters are used in two branches of the structure, which are connected using Wilkinson‐like power dividers. Out‐of‐phase reflected signals from each of the two branches are delivered to a resistor, resulting in a reflectionless port. A coupled line bandpass filter is fabricated and measured to verify the presented configuration and design equations. There is a good agreement between theory and measurement.