High bandwidth planar power divider

Abstract

The power dividers are one of the most ubiquitous passive circuit elements in RF/Microwave applications. They are widely used in antenna arrays, balanced amplifiers, mixers, frequency multipliers etc. as power combiners or splitters. The Wilkinson power divider (WPD) and the Gysel power divider (GPD) are the two most useful of all the power dividers because of it low insertion loss, matched ports and isolated outputs ports. The conventional WPD has a simple structure and good performance except that its bandwidth, especially the isolation bandwidth, is limited. Therefore, this thesis aimed at exploring the ways to enhance this Figure of Merit (FOM). To that end, a combination of the GPD and WPD architectures with a single isolation resistor is proposed as one of the methods to achieve higher isolation bandwidth. Simulation results indicate that for 15dB reference, a return loss bandwidth of 72% is possible as compared to 36% for the conventional methods. Furthermore, a WPD utilizing the concept of port extension is also proposed that provides complete DC isolation along with a higher bandwidth. This technique is fully planar and does not require any extra lumped element in the isolation network to achieve a measured isolation bandwidth of 62%.