Balanced-to-unbalanced Bagley Power Divider with Input-reflectionless Filtering Characteristics

Abstract

A novel balanced-to-unbalanced (BTU) Bagley power divider (BPD) with inputreflectionless filtering characteristics is proposed. It features a balanced input port and three singleended output ports, which is difficult to achieve by means of conventional BTU power dividers. The filtering characteristics are achieved by parallel coupled lines. To further improve the differential-mode filtering selectivity, stepped impedance resonators are applied to introduce two transmission zeros near the passband. The input-reflectionless characteristic in the bandstop region is achieved by loading absorptive branches. For verifying the proposed power divider topology, a prototype of microstrip BTU Bagley power divider operating at 1.0 GHz is designed and fabricated with 3-dB filtering bandwidth of 72%. Furthermore, 10-dB input-reflectionless bandwidth covers the full measurement frequency from 0 to 2.5 GHz. Good agreement between the simulation and measurement validated the proposed method.