Effect of support strut diffraction on reflector surface profile assessment

The phase-imaging properties of microwave holographic processing are used to provide an inward-looking reconstruction of support strut diffraction and its effect on reflector surface profile assessment. Measured near-field data are employed to illustrate the contribution made by the support strut geometry to the apparent profile error for a 2.5 m reflector antenna operating at 10 GHz. The relative significance of real profile errors and those deriving from strut effects are studied by using a diffraction model. It is concluded that certain configurations of support struts can give rise to significant modification of the effective profile error distribution.