Design of Coupled-Line Wilkinson Power Divider for UMTS mobile applications

A power divider is a critical passive device, which is commonly used in microwave systems. This microwave component splits the input power, evenly or unevenly, into several smaller output powers. In this paper, we present a design of a coupled-line Wilkinson power divider (WPD) for UMTS mobiles applications. This divider consist two ($\lambda / 4$) transmission lines and an isolation resistor R, which is connected between output ports. The main disadvantage of this structure is large size and narrow band, especially at lower frequencies. The proposed design composed a signal coupled line to replace the two ($\lambda / 4$) transmission lines in conventional WPD and one isolation resistor R. The use of a coupled line, in our WPD, offers many advantages compared to the standard WPD including compact size, wide bandwidth, low profile and high isolation. The design was printed on a Rogers RO4003C with an $\varepsilon_{r}=3.55$ and a thickness of 0.813 mm. Simulations results indicate that the proposed WPD presents low return losses in all ports and high isolation between output ports over the third-generation mobile band.