Radiation pattern of a reflector antenna from near field measurements over the focal region of a coupled lens or offset reflector

A method is proposed which uses a microwave lens or an offset reflector instead of a front-fed reflector. The lens focuses the incident field on the other side of the antenna under test. Thus the feed and the probe do not interfere with each other. For the offset reflector case to work, the reflector has to have analogous focal region properties to a front-fed parabolic reflector. Using M. Hoque et al.'s (1984) model, the authors show how the offset reflector scheme is possible. The technique is expected to be valuable for compact ranges although the feasibility of the method and practical near-field separation distance between the two reflectors are still to be determined.