CMA of Non-uniform Metasurface Circularly-Polarized Slotted-Patch Antenna with L-Shaped Feed Structure

This research presents a non-uniform metasurface (MTS) scheme circularly-polarized slotted-patch (CPSP) antenna for modern cellular technology. The proposed non-uniform MTS CPSP antenna was combined with non-uniform MTS scheme (upper-layer substrate) and slot-coupled feed (lower-layer substrate). The slot-coupled feed comprised of the L-shaped microstrip-line feed and rhombus-slotted ground plane. The non-uniform MTS scheme was characterized using characteristic mode analysis (CMA). The CP mode at 4.6 GHz (center frequency) was realized by two orthogonal modes (modes 1 and 2). To achieve wide return loss bandwidth (RLBW), the use of the different sizes (two sizes) of square-shaped MTS unit cells was adopted. The simulated RLBW and axial ratio bandwidth (ARBW) results achieved 34.78% (between 4.1 – 5.7 GHz) and 5.65% (between 4.43 – 4.69 GHz). The optimal gain of right-hand circular polarization was 3.56 dBic at 4.35 GHz, rendering this proposed non-uniform MTS CPSP antenna is functional for wireless communications.