Design Improvements and Performance of the Bifocal Microwave Microscope

The Bifocal Microwave Microscope dual reflector antenna was invented to allow standoff focusing for nearfield imaging radar applications [1] . It is designed in similar fashion to the Bifocal Scanning Reflector [2] , [3] , but instead of having two perfect foci on either side of the boresight axis, the two foci both lie on the symmetry axis, each corresponding to a perfect image points on the axis. Two perfect image points are possible when two degrees of freedom - two reflectors – are used. With two perfect foci, the optical aberrations for other image points between them are of even order, leading to relatively large focal region bounded by the perfect foci. A focal volume (as opposed to focal plane) array – or a moving synthetic array with fixed reflector and small moving feed – would be able to precisely illuminate a large focal region, point by point.