Flat Gain Broadband Metasurface Antennas

Modulated metasurface (MTS) antennas can provide a broadside pencil beam at the frequency where cylindrical surface wave (SW) wavelength matches period of impedance modulation. For modulations with constant period, mismatch between SW and imposes limitation on gain-bandwidth product. However, this be overcome by shaping local as function radial distance. Doing so, we generate an annular active region antenna aperture, SW-to-impedance interaction mainly occurs. Such moves from center to circular rim decreases. This article shows that one optimize profile periodicity obtain beams over large bandwidths, while preserving flatness gain versus response good stability phase center. The performances so obtained are really unique for flat based printed technology. Finally, present simple formula product average bandwidth, which gradually blends into already known expression period. establishes absolute limit product, only depends wavelength-normalized radius central frequency.