An active array for UHF compact range illumination

The use of the reflector fed compact range for generating an approximation to a plane electromagnetic wave is well established for radiative EMC testing and for antenna measurements at frequencies in the GHz region. Extension of this technique into the VHF-UHF frequency range poses problems. In this frequency range control of the aperture illumination is better achieved by using an array antenna. Antenna arrays have the advantage that their dimensions may be smaller than those of a paraboloidal reflector over the frequency range of interest, since they are not limited by geometrical optics. A further advantage is that, by means of an active feed network, the size and quality of the quiet zone may be optimised to suit the geometry of the device under test. Such an active array has been developed at the University of Bradford and is described in the paper