Metasurface-based antenna excited by the slotted radiator

A dual wideband metasurface (MS)-based antenna operating in triple modes is proposed for circularly polarized (CP) operation and these two bands can be controlled independently. The antenna consists of a cross-slot antenna and an MS to generate a dual band at about 3.5 and 5.2GHz. In the low-frequency band, the large cross-slot radiator (CSR) and the MS are used to generate CP radiation by exciting the degenerate modes of TM10 and TM01. In the high-frequency band, the small CSR and the MS form a cavity, and the small CSR serves as a feeding element to excite two groups of orthogonal degenerate modes, i.e. the first group being TM10 and TM01, and the second being TM12 and TM21, alternately for wideband CP radiation. Simulation and measurement are used to study and design the MS slot antenna. Measured results show that the MS slot antenna has a dual operating band of 3.27-3.87GHz (0.6GHz, 16.8%) and 4.41-5.95GHz (1.54GHz, 29.7%), peak gains of 6.3 and 7.9 dBic within the low- and high-frequency bands. This antenna has the advantages of simple single feeding, simple structure, high gains, and dual independent bands.