A Wireless Power Transmitter With Uniform Power Transfer Coverage
Chuang Kai Wang, Bing Jie Xiang, Shao Yong Zheng, Kwok Wa Leung, Wing Shing Chan, Yuan An Liu
Abstract
To avoid the performance deterioration caused by the changing placement angle of a receiving antenna, a wireless power transmitter with uniform power transfer coverage is preferred. The utilization of a transmitting antenna with flat-top radiation patterns is the most effective approach. However, the existing antennas with flat-top radiation patterns usually are complex structures and bulky sizes. To mitigate these problems, a rectangular dielectric resonator antenna (DRA) is proposed to obtain flat-top radiation patterns for the first time. Flat-top patterns are realized in both the E and H planes by combining the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">119</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sup> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">133</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sup> modes of a rectangular DRA. For validation, both linearly polarized (LP) and circularly polarized (CP) flat-topped DRAs operating at 5.2 GHz were designed, fabricated, and tested. Reasonable agreement between the measured and simulated results is observed. For the LP design, stable flat-top patterns can be maintained from 5.18 GHz to 5.24 GHz. Across the operating frequency band, the measured 3-dB beamwidths are 86° and 58° in the E and H planes, respectively, with the side lobe levels lower than -13.9 dB. For the CP design, similar flat-top radiation patterns can be found. To demonstrate the effectiveness of the proposed transmitting antenna, the LP design is used to construct a wireless power transmitter, which can provide more power and also uniform power coverage within the desired angular sector.