Metamaterial-Based Wide-Angle Scanning Circularly Polarized Phased Array With Stable Gain

In this paper, a wide-angle scanning circularly polarized phased array with stable gain is proposed. The proposed antenna array is composed of truncated microstrip antennas, four rows of mushroom metamaterials, and two tensor holographic metasurfaces. The mushroom metamaterials generate TM10 mode on the same plane as the antenna elements, compensating for the imbalance between horizontal and vertical polarization when the beam pattern of the phased array is steered to a wide-angle point. Meanwhile, the tensor holographic metasurfaces convert surface waves into circularly polarized leaky waves, which superimpose on the radiation of the antenna array, thereby improving the axis ratio and increasing the realized gain. Furthermore, an eight-element linear phased array with the circularly polarized and scanning gain enhanced metamaterials are fabricated. The measured results show that the axial ratio of the proposed wide-angle scanning antenna array remains below 3 dB, the scanning range is from −60° to 65°, and the gain fluctuation is less than 1.8 dB in the operating frequency range 10.1-10.7 GHz. In general, the proposed antenna array loaded metamaterials have the advantages of stable scanning gain, low profile and easy to fabricate, thus satisfying the requirements of satellite and radar applications.