Compact Circularly Polarized Antennas Combining Meta-Surfaces and Strong Space-Filling Meta-Resonators

Reduced-size single-feed circularly-polarized (CP) patch antennas are proposed and investigated based on the strategy of combining meta-surfaces and meta-resonators owning strong space-filling capability. They all comprise a slot-loaded square patch printed over a well designed reactive impedance surface (artificial meta-surface with magnetic response at the resonant frequency) for improved antenna performances and size reduction. The complementary crossbar fractal tree (CCFT) slot and three-turn complementary spiral resonators (TCSRs) with asymmetric gap orientation are employed as meta-resonators to render the antennas to radiate CP waves in single-band or dual-band operation and to facilitate further miniaturization. Numerical and experimental results indicate that these antennas owning a maximum size of 0.262λ₀ × 0.262λ₀ around 3 GHz exhibit a comparable impedance and axial ratio (AR) bandwidth over 1.05% and high gain of more than 4.15 dBic, predicting promising applications in portable and handheld communication systems.