Design Methodology of Multi-frequency Un- Equal Split Wilkinson Power Dividers Using Transmission Line Transformers

In this paper, a new simple design procedure of multifrequency unequal split Wilkinson power dividers (WPDs) is presented. The procedure is based on using N -sections of transmission line transformers, instead of the conventional quarter-wave WPD branches, to realize a WPD that operates at N frequencies. Good isolation is achieved by using lumped resistors without any extra modification to the conventional structure of WPDs. The analysis, design procedure, and mathematical expressions are presented for arbitrary design frequencies, and arbitrary power split ratio. For verification purposes, a 1 : 2 dual-frequency, a 1 : 2 tri-frequency, and a 1 : 2 quad-frequency WPDs are designed and fabricated. The measured results show good agreement with those obtained using the presented design methodology and with full-wave simulated results.