A Pattern Reconfigurable Microstrip Patch Antenna with Broadside and Conical Beams

keywords:microstrip patch antenna  pattern reconfigurable  conical beam  broadside beam

Abstract:In this article, a novel microstrip patch antenna with reconfigurable patterns of broadside and conical beams is pres- ented, which has low gain variation in azimuth plane and designable pointing angles in the mode of the conical beam. First, a row of shorting posts is introduced at the center of a patch antenna. When the two feeding probes at both sides of the shorting posts are out-of-phase, the current on patch is in the same direction, and thus a broadside beam is radiated. When the two feeding probes are in-phase, the current on patch has opposite directions, and thus a conical beam is radiated. Next, the spacing between the row of shorting posts and the edge of the patch is optimized to adjust the current distribution, so that the gain variation of the conical beam in azimuth plane is reduced. Finally, four additional shorting posts are added in the diagonal direction of the patch. By con- trolling the position and the size of these posts, the physical size of the patch in one designated frequency could be tuned. In this way, conical beams with different pointing angles are obtained. Through full-wave simulation, three patches with switchable broad- side and conical beams are displayed. The beam-pointing angles of the conical beams are designed as 55°, 50°, and 45° with small gain variation in azimuth plane, respectively.