ABSTRACT In this article, a SIW‐SSPP based bi‐directional LWA has been proposed. The presence of a transition structure between SSPPs lines and traditional lines makes it difficult to precisely extract and analyze the dispersion characteristics of LWAs. A general SOC technique is proposed to accurately calculate the propagation constant of SSPPs LWAs using network theory. The antenna's two symmetric beams enable high‐rate, continuous scanning over a wide angular range using an SSPP slow‐wave mod