Geometrical Modeling of Strip-Loaded CPW and Its Application to All CPW Air-Bridge Free Wilkinson Power Dividers

Abstract

This paper presents a generalized geometrical equivalent circuit model for a strip-loaded coplanar waveguide (CPW) that carries the even and odd modes simultaneously. The proposed model enables the analysis, sets the design requirements, and defines the constraints of the realization of an air-bridge free all CPW Wilkinson power divider (WPD). To overcome these constraints, this paper proposes two implementations. The first one engineers the dispersion relation of the odd mode to provide a slow-wave factor that compensates the difference in the electrical lengths with the even mode, while the second implementation deploys the floating strips as electrical air-bridges. The proposed power dividers are designed to operate at 2.4 GHz. Measurements, which are in good agreement with the EM simulations, confirm the theoretical predictions.