Compact Planar Four-Sector Antenna Comprising Microstrip Yagi-Uda Arrays in a Square Configuration

In this letter, a simple four-sector antenna configuration is proposed that has a square configuration of microstrip Yagi-Uda arrays and has common parasitic elements with terminations at the corners of the square. The square arrangement of four microstrip Yagi-Uda arrays and commonly shared elements enable downsizing of the antenna, and the termination of commonly shared element enables high front-to-back ratio. From the results of numerical analysis of the radiation pattern, we found that the proposed antenna with termination achieves the high front-to-back ratio of 17 dB, and 10 dB increases compared to that without termination. We also found that the proposed antenna achieves a 50% antenna area reduction compared with the conventional configuration, which shares only the reflector element.