A Novel Method for Generating Planar Wave Based on Dielectric Gratings

The application of conventional reflector-type compact test ranges becomes increasingly difficult at millimeter wavelength. The main problems are the tight surface accuracy requirements for the reflectors and, therefore, the high manufacturing costs. These problems can be overcome by the use of a grating type of compact range in which a planar grating structure is used. This idea is described and its performance is studied with theoretical analyses and measurement at 40 GHz. Simulations of the quiet-zone field are done with a two dimensional finite difference time domain method (FDTD), combined with physical optics (PO) method. In the quiet-zone, the peak-to-peak amplitude ripple is less than 2 dB and the phase ripple is less than 10°. The quiet zone is tested at 40GHz by moving a probe antenna across the quiet-zone with a linear scanner. The quiet zone can be larger than 110mm. It can be used in antennas measurements and scale model RCS measurements.