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
$4\times4$
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
$4\times4$
metasurface is employed to obtain an equal electric field in the propagation direction. The overall dimensions are
$2.13\lambda _{0} \times 2.13\lambda _{0} \times 0.228\lambda _{0}$
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° and 38° 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.