Broadband and Low-Profile Penta-Polarization Reconfigurable Metamaterial Antenna

In this paper, a penta-polarization reconfigurable antenna with mushroom-type metamaterial loading is proposed, which can operate in x-direction linear polarization (x-LP), y-LP, 45°-LP, left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). In order to realize polarization reconfigurability, a dual-port dual LP mushroom antenna excited by crossed H-shape slot is designed by characteristic mode analysis (CMA). Through shifting the states of PIN diodes on the reconfigurable feeding network, the amplitude and phase distributions of two ports of the dual LP antenna can be dynamically controlled and the five polarization modes can be achieved. A prototype with a profile of 0.06λ
₀
at 5.2 GHz (λ
₀
is the operated wavelength in free space) is simulated and measured. The measurement results exhibit a wide impedance bandwidth over 33.2% for LPs and over 38.7% for CPs. In addition, the measured axial ratio bandwidths are 28.0% for LHCP and 30.3% for RHCP, and the maximum measured boresight gains of all modes are higher than 8.2 dBi. The simulated and measured results verify that the proposed antenna can achieve a balance between low-profile and broadband on the basis of penta-polarization reconfigurability. The proposed antenna can be applied to polarization diversity and C band satellite communication.