An outline of indirect holographic methods for antenna measurements and microwave imaging

Indirect microwave holographic techniques offer a simple, low cost technique for a range of microwave measurements including the determination of antenna characteristics and the ability to provide good quality images of passive objects. This work provides a brief outline of the basic theory of indirect microwave holography and how it can be used for the reconstruction of scattered complex fields at the measurement plane and how these results can be back propagated to provide the scattered fields at any preselected observation plane. It provides an outline of the different techniques required for antenna measurement and the imaging of passive objects. It demonstrates how indirect holography can be used to determine the far field radiation pattern of a high gain antenna and reconstruct the complex antenna aperture fields. This work also demonstrates the use of indirect holography for the imaging of passive objects. The techniques described have been validated by experimental results on a range of objects including buried objects.