A Novel Wideband Quasi-Yagi Antenna for Base-station Applications

A novel design of a wideband quasi-Yagi antenna with a bear face-shaped driver is proposed. The quasi-Yagi antenna comprises a bear face-shaped driver, a box-shaped reflector, and an octagon-shaped director. A bear face-shaped driver is printed on the top side of the middle layer to improve impedance matching. To further enhance the impedance matching, a wideband balun with a stepped microstrip is employed to feed the two radiating arms. In addition, the proposed octagon-shaped director not only improves impedance matching but also stabilizes the radiation pattern. The box-shaped reflector also plays a critical role in stabilizing the radiation pattern. The measurement results show that the proposed antenna achieves an extensive bandwidth from 1.7 GHz to 3.6 GHz (72%) for the impedance matching is less than -15 dB and a stable high gain of 8.9 +/- 0.9 dBi. Additionally, the designed antenna has a stable 3-dB beamwidth of 62 +/- 5 degrees in the horizontal plane. Therefore, this antenna can be suitable for base-station applications.