Broadband Dual-Polarized Antenna Using Metasurface for Full-Duplex Applications

In this letter, a broadband dual-polarized metasurface-based antenna is proposed for in-band full-duplex applications. The design concept exploits the wideband and low-profile features of a metasurface, as well as its structural symmetry to implement the differential-fed scheme for high isolation. An antenna design operating at 3.5 GHz is optimized, fabricated, and tested. The prototype with dimensions of 0.97λ
_min
× 0.97λ
_min
× 0.078λ
_min
(λ
_min
is the free-space wavelength referring to the lowest operational frequency) achieves a 10 dB return loss bandwidth of 28.4% (2.93-3.90 GHz) and an interport isolation of >43 dB. The far-field measurements indicate that the antenna exhibits broadside radiation with a realized gain of >8.0 dBi and low cross-polarization level of <; -30 dB within the wide operational bandwidth.