A Single-Layered Broadband Reflectarray Employing 0.15-Wavelength Elements

摘要

A single-layered broadband reflectarray antenna employing 0.15-wavelength elements is proposed and investigated in this letter. The unit cell is constituted by a ring patch inserted with an interior concave arm and arranged in a grid size of 4.5 mm x 4.5 mm, corresponding to only 0.15 wavelength at 10 GHz. Despite such a small grid spacing, a linear phase close to 360 degrees can still be obtained by changing the height of the embedded concave arm, without adjusting the external ring size. A planar reflectarray antenna composed of 2116 unit cells is designed, manufactured, and tested. According to the measured results, the 1 dB gain bandwidth of the reflectarray antenna is 29%, while the peak aperture efficiency is 66%. Besides, satisfactory sidelobe and cross-polarization levels are also achieved. These promising features show a good overall performance of the proposed array and also successfully demonstrate the feasibility of employing 0.15-wavelength element for wideband reflectarray designs.

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