Reduction of truncation errors in partial spherical near-field antenna measurements

In this report, a new and effective method for reduction of truncation errors in partial spherical near-field (SNF) antenna measurements is proposed. This method is based on the Gerchberg-Papoulis algorithm used to extrapolate functions and it is able to extend the valid region of the far-field pattern calculated from a truncated SNF measurement up to the whole forward hemisphere. The method is useful when measuring electrically large antennas and the measurement over the whole sphere is very time consuming. Therefore, a solution is considered to take samples over a portion of the spherical surface and then to apply the above method to reconstruct the far-field pattern. The work described in this report was carried out within the external stay of Francisco J. Cano at the Technical University of Denmark (DTU) from September 6th to December 18th in 2010.