Low-Profile Compact Circularly-Polarized Antenna Based on Fractal Metasurface and Fractal Resonator

A novel low-profile and compact circularly-polarized (CP) antenna has been proposed and comprehensively investigated based on the combination of fractal metasurface and fractal resonator. The Hilbert shaped reactive impedance surface has improved the antenna performance in terms of low substrate thickness and good front-to-back ratio, and the Wunderlich-shaped fractal complementary split ring resonator with strong space-filling property achieves the CP property and further size reduction. For application, a CP antenna working at the Wimax band is numerically and experimentally studied. The results indicate that the proposed antenna achieves a compact layout of 40 mm ×45 mm ×2.5 mm at 3.5 GHz, a relative wide bandwidth of more than 1.86% and also a comparable gain of about 6.3 dBic. The strategy does not require any metallic via holes, sophisticated feeding networks or truncated corners, predicting promising applications in portable communication systems.