Asymmetric 4.77 Three-Way Unequal Filtering Power Divider/Combiner for Communication Systems Application

This study presents a novel three-way unequal filtering power divider/combiner, addressing challenges in unequal power distribution while incorporating filtering functions in communication systems. Wilkinson power divider (WPD) is the traditional power division approach using quarter-wavelength transmission lines [1]. This type of power divider is popularly used in communication systems due to its good electrical isolation and simple structure. The problem with WPD is that its operation requires the use of an externally connected bandpass filter (BPF) to achieve filtering functionality. This leads to increased footprint and increased loss coefficients in a system. In contrast to the traditional design approach involving a BPF, a matching transmission line, and a Wilkinson power divider as separate components, the proposed integrated filtering power divider (FPD) consolidates all three components into a single device, leading to lower footprint and lower loss coefficient in a system. Circuit modelling and electromagnetic (EM) simulations were conducted to ensure alignment between theoretical and practical results. The design demonstrates effective unequal power division at the three output ports while maintaining very good filtering performance. Results show a return loss better than 15 dB and a minimum insertion loss of 1.2 dB. The overall size of the device is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$32.2 \times 50.0 ~\text{mm}$</tex>. This paper contributes to advancements in power divider design by addressing unequal power division challenges and integrating filtering functions. The findings offer a foundation for future developments in advanced power divider/combiner systems, with insights into potential challenges and areas for further improvements.