Four-element array antenna based on pattern reconfigurable Yagi-Uda antenna with complementary parasitic elements

In this paper, we propose an array antenna based on radiation pattern reconfigurable elements. Array antennas basically have limited element spacing to suppress grating lobes. This, however, also limits the gain of the array. Since the radiation pattern reconfigurable elements of the proposal suppress grating lobes, wide element spacing is possible. This yields high gain and wide beam scanning angles. We adopt the Yagi-Uda antenna as the antenna element. PIN diode switches are added to the parasitic elements to change director and reflector. Because only one control line pair is directly connected to all parasitic elements, all antenna elements can be concurrently controlled. This control structure is simple and it can be applied to large scale arrays. We design, fabricate, and test a four-element array. Calculations and measurements confirm the generation of two symmetrical radiation patterns.