A Compact Low-Profile Reconfigurable Metasurface Antenna With Polarization and Pattern Diversities

A compact low-profile reconfigurable metasurface (MTS) antenna is presented in this letter, occupying an overall size of 0.65λ
₀
× 0.65λ
₀
× 0.067λ
₀
. The proposed antenna is mainly composed of a 3 × 3 square MTS, a ring-shaped pixel structure, a square microstrip patch, a metal ground plane, and a simple feeding network. Through the characteristic mode analysis, two orthogonal degenerate modes are excited to realize the reconfigurable two linear polarizations and one circular polarization (CP). Furthermore, by loading an annular pixel structure around the MTS, the designed antenna can produce the steerable beam directions of ±40° with horizontal polarization, ±20° with vertical polarization, and ±25° with CP in the yz plane. Due to the symmetry of the layout, polarization and pattern diversities can also be realized in the xz plane. The proposed reconfigurable antenna is manufactured and measured to demonstrate the proposed design. The measured results show that the designed antenna acquires polarization and pattern diversities in C-band at the center frequency of 5 GHz, and the test results generally are in consistent with the simulation ones, which demonstrates the superiority of the proposed antenna.