A Circularly Polarized Heterogeneous Antenna Array for Wide Elevation Angle Scanning and Full Azimuthal Coverage

In this letter, a circularly polarized (CP) wide-angle scanning heterogeneous antenna array is proposed. The array is composed of one top CP element and six side CP elements, with the top element in the shape of a crossed dipole loaded with parasitic fan-shaped patches and the side element in the shape of loop dipole loaded with internal parasitic loops. Both elements can achieve wide impedance bandwidth (IBW) and axial ratio bandwidth (ARBW) when operating independently. The optimized array resonates at 3.5 GHz, achieving an IBW and ARBW overlapped bandwidth of 17.2% (3.2–3.8 GHz). By adjusting the amplitude and phase of seven feeding ports, the array can achieve an elevation scan from −60° to 60° ( θ angle) at any azimuthal angle within the operating bandwidth. Besides, during scanning, the axial ratio (AR) in the main lobe remains below 2.7 dB, and the gain fluctuation does not exceed 2.9 dB. Compared with the previous wide-angle scanning arrays, the proposed design combines different antenna elements to form a heterogeneous array, realizing both wide-angle scanning and good AR with only seven elements.