Compact Directional Button Antenna Based on Curved Metamaterial for On-Body Wireless Power Transfer

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compact directional button antenna based on curved Artificial Magnetic Conductor (AMC) is proposed to integrate easily into clothing for on-body wireless power transfer (WPT). The antenna is fed by the microstrip line, and a curved 3 × 3 AMC cells are adopted to reduce the horizontal size and reduce the spacing between the monopole and reflector. The monopole is loaded by two substrates, one is directly connected and has the same radius, while the other has a larger radius. An efficient design method is employed for the curved AMC cells such that the resulting radiation characteristics remain unaffected compared to those of the flat one. Finally, the influence of the human body is studied by using a human arm model.