A broadband tunable power divider for array beam-forming network

Abstract

In this paper, a broadband tunable power divider (TPD), whose power division ratio (PDR) can be theoretically tuned from -∞ to +∞, is proposed. The new design is based on a Wilkinson power divider, a branch line coupler, and a new combination of phase reconfigurable synthesized transmission lines (PRSTLs) that comprises varactor diodes as the phase shifters (PSs). The operating principles and design equations will be provided with thorough discussion. For proof-of-concept demonstration, a prototype was designed at 2.4 GHz. The performance in the measurement is summarized as follows: the operating bandwidth = 25% (2.1 GHz - 2.7 GHz), very wide PDR tuning range of ±29 dB, maximum insertion loss = 1.6 dB, and switchable output phase of 0⁰ or 180⁰.