Compact Six-Sector Antenna Employing Three Intersecting Dual-Beam Microstrip Yagi–Uda Arrays With Common Director

A novel compact planar six-sector antenna suitable for wireless terminal is presented. Our new antenna design yields low-profile and extremely compact multisector antennas since it allows microstrip Yagi-Uda array antennas to share director elements. Two microstrip Yagi-Uda array antennas are combined to form a unit linear array that has feed elements at both ends, only one of which is excited at any one time, and the other is terminated. A numerical analysis shows that applying a resistive load to the feed port of the terminated element is effective in reducing the undesired radiation. The radiation pattern of a six-sector antenna, which employs three intersecting unit linear arrays, is investigated, and the optimum termination condition is identified. From the results of measurements, it is found that our antenna achieves high gain, at least 10 dBi, even though the undesired radiation is suppressed. It is shown that the radiation pattern suitable for a six-sector antenna can be obtained even with a 1.83 wavelength diameter substrate, i.e., the area is 75% smaller than that of a regular antenna with six individual single-beam microstrip Yagi-Uda arrays in a radial configuration