A Mechanically Beam-Steered Phased Array Antenna for Power-Harvesting Applications [Antenna Applications Corner]

Beam-steered antennas are highly desirable for radio-frequency (RF)- power-harvesting applications. By changing the direction of its main beam, maximum power can be harvested without physically rotating the antenna. This is specifically favorable to power-harvesting applications where the harvesting unit needs to be placed on a planar surface, cannot be rotated, and the available volume is constrained. We present a 2 X 2 beam-steered phased array antenna for RF-power-harvesting applications. The designed antenna array achieves a continuous beam-steering angle of ?3? in the E-plane. Beam steering is realized by mechanically shifting the position of the feeding point. The antenna does not utilize any active elements; thereby, the maximum amount of power can be delivered into the harvesting circuitry. A small and wideband patch antenna element has also been designed and incorporated in the array, which reduces its overall size and enables wide scanning angle impedance matching. At the operating frequency of 2.4 GHz, the size of the array is 0.96 X 0.96 X 0.056 ?. The measured peak gain is 11.3 dBi, and bandwidth is 12.9%.