An Antenna Array with Contactless Feeding Design Using MetaCoax Coupler

In this paper, contactless capacitively coupled PCB-to-PCB couplers, referred to as MetaCoax, are used to design a feeding layer with beamforming electronics for an <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$8\times 8$</tex> element circularly polarized antenna array. The simulated performance of the antenna array, both with and without the feeding layer, shows nearly identical results. The antenna with the feeding layer achieves a 15% bandwidth, with active reflection coefficients of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\leq-10$</tex> dB and axial ratios of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\leq 3$</tex> when scanning within a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 60^{\circ}$</tex> scan volume. This is accompanied by a gain reduction of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\leq 0.4$</tex> dB compared to a directly fed antenna (i.e., without the feeding layer).