IEC TR 63099-3:2022 provides technical information about the methods for an antenna near-field measurement in the terahertz-wave band. The methods are applied to the frequency bands above 100 GHz, which has potential for use in terahertz wireless communication. The methods consist in measuring the amplitude and phase distributions of the electromagnetic field at the near-field range of on-chip antenna devices which integrate RF and IF components. This document also gives examples of the far-field pattern calculated from the measured near-field pattern.