A Low-Profile and Dual-Band Shared Aperture Sparse Array for Beam Scanning Applications

This paper presents a low-profile and dual-band shared aperture sparse array for beam scanning applications. A multi-layer structure is used in the design, and metamaterial grid and fractal slot are used to enhance the impedance bandwidth. The proposed dual-band shared aperture array has a bandwidth wider than 14.5% at C-band and 13.3% at Ku-band. Moreover, Floquet modal analysis and genetic algorithm are used to optimize the Ku-band array, and 56.5% sparse ratio is achieved. The proposed shared aperture antenna array consists of 234 Ku-band cells and 57 C-band cells, and has a scanning range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 30^{\circ}$</tex> at C-band and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 60^{\circ}$</tex> at Ku-band. In the whole scanning range, the transmitting and receiving side-lobe-level is basically lower than -18 dB and -25 dB, respectively. To verify our design, the proposed shared aperture antenna array is fabricated and measured, and the preliminary experimental results are presented.