Cylindrical multi-sector antenna with self-selecting switching circuit

Sector antennas provide many advantages such as when combined with a narrow beam antenna, they become particularly effective in achieving high-speed w ireless communication systems and they aid in simplifying the structure. Th ese antennas have a drawback in that as the number of sectors increases, th e antenna size rapidly increases. Therefore, downsizing the sector antenna has become a major research topic. A promising candidate is utilizing a pha sed-array type antenna; however, this antenna requires a phase-shifter circ uit for beam scanning and generally the feeding circuit for this type of an tenna is very complicated. To address these issues, we propose a self-selec ting feeding circuit that is controlled by the same control circuit and is operated similarly to the conventional single port n-th throw (SPNT) switch . We fabricated a small cylindrical 12-sector antenna at 19 GHz employing t he proposed feeding circuit for verification purposes. Furthermore, this pa per clarifies the design method of this feeding circuit where the antenna d iameter is 71 mm, and the results clearly show that the gain is more than 1 2 dBi.