there are hundreds of different types of "antennas", each with their own best uses. A "NEAR FIELD PROBE" can i suppose be thought of as an "antenna", although often they could better be described as a "magnetic loop", or as a "short capacitive coupler". The will NOT work well at any distance, so if you are trying to measure a field strength at 3 meters away, they will be useless. They ARE useful for pinpointing on a board or along a housing cover, exactly where the greatest amount of RF leakage is happening.