Feasibility of Microstrip Wilkinson Power Dividers on FR4 Substrates for L-Band (1-2 GHz) Applications

1. Introduction Microstrip structures are very popular choices both for circuits and antennas. Wilkinson power dividers in microstrip form are indispensable components for printed antenna array feeding networks. In principle, low loss specialized microwave sub-strates are used for best results. However, since substrate cost is the dominant factor for microstrip passive circuits [1], there is a need to use cheaper materials such as FR4 without compromising the performance. In this paper, the feasibility of using FR4 is investigated via the testing of Wilkinson power dividers operating in portions of the L-band (1-2 GHz). The 1-2 GHz band serves significant wireless applications such as cellular mobile [2] and mobile satellite data [3]. The principles of the Wilkinson power divider operation, microstrip implementation and fabrication details are given in section 2. Results are given in section 3 using a divider built on Duroid as a performance benchmark. A discussion on FR4 tolerances and potential consequences on amplitude and phase errors is also included in Section 4.