Theory and Design of a Flexible Coupled-Line Based Ultra-Wideband Wilkinson Power Divider

Abstract: This article proposes the design scheme of an ultrawideband Wilkinson Power Divider (WPD). A detailed even and odd-mode analysis is carried out to derive closed-form design equations for the determination of design parameters. The design equations demonstrate that the proposed design theory indeed exhibits a bandpass behavior. Moreover, an interesting feature is a simple equation-derived resistive isolation network for achieving a wideband isolation between the two output ports. The concept of a defected ground is also employed to achieve compactness in design and for achieving realizable values of the design parameters. After analyzing power division in terms of reflection and isolation, a prototype has been designed on RO4003C substrate. The simulated and measured results show excellent agreement with an ultra-wide fractional bandwidth of 82% and port-to-port isolation over a fractional bandwidth more than 100%.