Miniaturized High-Performance Metasurface Antenna Embedded in Cross-Shaped Strips

Abstract

A miniaturized high-performance metasurface (MTS) antenna with cross-shaped strips is designed, which can be applied to wireless communication systems. The resonant frequency of the main mode of the proposed MTS is reduced by embedding a 2 × 2 cross-shaped strip array in the gaps of the 3 × 3 circular MTS array, resulting in a lower operating frequency and miniaturization. The main mode of the MTS and the probe mode are excited simultaneously by the L-probe structure, resulting in a dual-mode resonance for a broadband performance. The entire design mechanism of the antenna is explained analytically through characteristic mode analysis (CMA) method. Additionally, the cross-polarization levels in H-plane are effectively suppressed by a metal via positioned at the MTS center. Measured results show a wide impedance bandwidth of 32.6% (reflection coefficient ≤ −10 dB) with an MTS size of 0.44λ₀ × 0.39λ₀ (where λ₀ is the free-space wavelength of 6.6 GHz). The achieved peak gain is 7.1 dBi, with a 2 dB gain bandwidth of 36% (5.25-7.55 GHz) and a low cross-polarization level below -20 dB.