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

A novel balanced-to-unbalanced (BTU) Bagley power divider (BPD) with input-reflectionless filtering characteristics is proposed. It features a balanced input port and three single-ended 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.