A modified wideband Gysel power divider structure

Abstract

Power dividers/combiners are one of the essential and crucial components of the modern RF communication systems since dividing makes RF power amplification easier to handle. As the data rates of the systems increase, the demand for wide bandwidth devices become more urgent and essential. Also, wide bandwidth systems show broadband performance in electronic warfare applications such as jamming. However, for RF power combiners/dividers increasing the bandwidth comes along with an engineering trade-off; the isolation of the divider decreases signifcantly. There are several studies in literature that offer various types of trivial solutions for improving both the bandwidth and the isolation performance of generic Wilkinson and Gysel power divider structures. This work concentrates on the conventional Gysel power divider structure since for high-power applications Gysel divider is preferred mainly for the feasibility of external isolation resistors. We propose a modified Gysel divider structure with a series LC circuit resonant at the center frequency to correct the impedance at the output and the isolation ports and the generic transmission line impedances optimized to adapt to this modification. We both show the interrelations of the capacitor and inductor values and also their relations to the scattering parameters and offer a guideline to choose the appropriate filter for the required application. The experimental results are presented to verify the proposed Gysel divider structure.