A low-profile frequency and polarization reconfigurable circularly polarized water antenna for satellite navigation

A low-profile circularly polarized (CP) antenna with frequency and polarization reconfigurability is presented in this paper, which is a rectangular water patch mounted on a large ground plane with a thin air gap, and etched with a slot on the broad side to achieve circular polarization. Two top-hat probes are used to feed the antenna at its corner, generating both LHCP and RHCP. By varying the height of the water patch, the 3-dB axial ratio (AR) band can be tuned, covering 0.85 GHz to 1.45 GHz (52%), with good impedance match (|S
₁₁
| <; -10 dB) over all AR bands. The proposed antenna has a very low profile of only 0.06λ
₀
and high transparency, and should be useful for satellite navigation.