The measurement of monopulse tracking nulls in a planar near-field antenna range

Monopulse antennas typically have a sum and two difference channels allowing for the accurate tracking of radar targets. Measuring the radiation patterns of these three channels often include establishing the electrical boresight of the antenna. Planar near-field test systems allow for the accurate determination of difference pattern nulls and locations. In this paper we present an iterative process requiring the use of all three channels to achieve an accurate null depth and location result. The impact of near-field truncation on the boresight pointing angle is also addressed and achievable accuracy numbers are presented.