Low-sidelobe phased array characteristics using planar near-field scanning

A low-sidelobe phased-array antenna was investigated both theoretically and experimentally using the planar near-field scanning technique at a distance of less than one wavelength from the antenna aperture. The theory was applied to a monopole phased array, and it was shown that a theoretical V-dipole probe can accurately model the observed experimental array performance using a waveguide probe. The presence of nonpropagating grating lobes in the plane-wave spectrum has been observed using theory and measurements. Results indicate that the near-field sample spacing must be chosen such that aliases of the grating lobes do not appear in the visible space region. The theory presented can also be applied in the radiating near-field region and to other array thin-wire elements such as dipoles.<>