An interrange comparison in support of the characterisation of space antenna systems and payload testing

The construction at Matra Marconi Space Portsmouth of a new 1-50 GHz, 22 m by 8 m scan area planar near-field antenna measurement system, taken together with the existence of the large spherical near-field range on the same site, has presented opportunities to compare results obtained in two very different antenna measurement facilities. This paper gives a comparative description of the facilities, and an overview of the measurement process in each range as applied to the measurement of spaceborne antennas. Results of a study undertaken to establish the similarity between results obtained by each range when measuring the same instrument are then summarised. The results show encouraging similarity given that the measurement geometry, RF subsystems, control computers, positioner hardware, near field-far field transform software, software correction techniques, alignment correction methods and alignment measurement procedures are different in each facility. It should also be remembered that the planar and spherical techniques are optimised for different classes of antenna