The techniques for EMC measurements used with antennas above 1 GHz have been gleaned from methods used at lower frequencies. The assumptions made in applying these techniques have not been completely validated. This analysis will compare antennas for use above 1 GHz, showing ramifications from use of each type. Measurement methods used above 1 GHz as well as the effects of antenna parameters such as antenna pattern, beamwidth and polarization will be reviewed. Several commonly available 400 antennas will be measured and their results studied. Frequencies from 1 to 18 GHz are considered.