A frequency‐ and polarization‐reconfigurable cross dipole antenna using liquid metal

A frequency and polarization reconfigurable wideband cross‐dipole antenna is proposed. A λ $\lambda $/4 phase‐shifted ring structure is used to design a reconfigurable frequency and polarization wideband antenna, which is connected to the dipole arm with the liquid metal as a parasitic branch. The antenna consists of a pair of rectangular dipoles, a pair of curved phase‐shifted rings, and a square ring. Two mutually perpendicular rectangular dipole arms are connected by a phase‐shifted ring, which is printed on the upper and lower surfaces. The left‐hand circular polarization and right‐hand circular polarization can be switched by loading liquid metal at different positions of the antenna, and the frequency can be reconstructed by adjusting the length of liquid metal at corresponding positions. The total 3 dB axial ratio bandwidth are 41.27% (1.50–2.28 GHz) and 43.57% (1.49–2.32 GHz), and eight adjustable circularly polarized frequency bands can be obtained at the same time. To verify the proposed design, a reconfigurable antenna is fabricated and measured. The measured results are in good agreement with the simulated results.