A Wide-Angle Scanning Circularly Polarized Shared Aperture Array with Low Scan Loss Capability

A wide-angle scanning circularly polarized (CP) shared-aperture array is presented in this paper. The proposed dual-band shared-aperture element consists of a dual CP stacked patch antenna and a single CP
$\bar{u}$
-slot patch antenna. To alleviate the scanning gain drop when beam steering in a wide range, a beam-shaped method is proposed. By employing the metal cavity and bent metal pins, a vertical current can be induced and the radiation pattern can be reshaped. As a result, a dip is introduced to the boresight of the element pattern and the gain at large angles can be improved, which is beneficial to achieve a lower scan loss in a wider scanning range. Based on this shaped-beam element, an eight-element linear array is fabricated and measured. The proposed array can steer the main beam from -65° to +65° and -60° to +60° at dual band with a small average scan loss of 2.2dB and 2.5dB, respectively. The measured results are consistent with the simulated ones.