Accurate Schiffman-type section design approach for microstrip line Wilkinson power divider

Abstract

In this paper, a novel accurate Schiffman-type (S-type) section design approach is presented for microstrip line Wilkinson power divider. S-type section replaces straight 90° transmission line with compact circuit size and easy fabrication, isolation condition between two output ports is also maintained in microstrip line structure. Mathematical equations for S-type section are derived from even- and odd-mode equivalent circuit analysis, and several selected examples have been proved that: through adjusting the even- and odd-mode characteristic impedances and their electrical lengths of S-type section, proposed Wilkinson power divider provides perfect matching in microstrip line structure; in other words, S-type section could provide self-compensation in microstrip line structure, no extra compensation structure is needed. In experiment, one circuit was fabricated, and experimental results showed good agreement with theoretical results.