A Compact Design of Co-Aperture Dual-Sense Circularly Polarized Antenna

A circularly polarized (CP) antenna for simultaneous transmit (Tx) and receive (Rx) communication systems with dual-sense characteristics is proposed in this paper. The proposed antenna occupies a 2 × 2 unit-cell metasurface (MS) as the primary radiating aperture, and an asymmetric patch as the CP source of the whole antenna structure. The antenna has two port excitations for dual-CP operation. The final design has compact dimensions of 0.36λ × 0.36λ × 0.02λ (λ is the free-space wavelength at the center operating frequency) with an operating bandwidth of 1.6% (2.45–2.49 GHz). Within this band, the antenna exhibits very high isolation of greater than 32 dB and the peak gain is about 6.0 dBi.