Computer-generated hologram and its use for submm-wave antenna measurement

Computer-generated holograms (diffractive elements) can be used for shaping millimeter-wave beams, e.g., for producing a plane wave in a compact space. An amplitude hologram has earlier been demonstrated to be able to form arbitrary beams at 310 GHz and has proven to be a feasible alternative as a focusing element in a compact antenna test range (CATR) at mm-wavelengths. It was used successfully for Odin satellite antenna tests at 119 GHz. In a recent study we have designed and constructed a compact antenna test range for 322 GHz and measured the ADMIRALS representative test object, which is a 1.5-meter offset paraboloid antenna.