A High Gain and Uniform Power Mushroom Antenna Using Metasurface

In this study, we present a simple feed-aperture coupled antenna with a high gain and flat-top radiation pattern for microwave power transmission (MPT) applications involving misalignment. A 4 x 4 mushroom structure is proposed to suppress the back-lobe radiation and to achieve the high gain of the aperture-coupled antenna. Additionally, to improve the flat-top radiation pattern and circular polarization (CP), an array 4 x 4 metasurface is employed to obtain an equal electric field in the propagation direction. The overall dimensions are 2.13 lambda(0) x 2.13 lambda(0) x 0.228 lambda(0) at 5.8 GHz. The measurement results show that the impedance bandwidth of <-10 dB of 5.5 - 6 GHz (8.69 %), a maximum realized left-hand circular polarization (LHCP) gain of 10.4 dBi with flat-top beamwidth (1-dB) of 36 degrees and 38 degrees for E and H plane, respectively. Moreover, the proposed transmitter antenna is tested in a realistic MPT indicating an advantage of radiating uniform power of 10 mW in the diameter range of 80 mm.