Antenna Far Field Distances

Antenna specifications can seem confusing or worse yet, can be misinterpreted. Of all the salient antenna specifications, antenna gain seems to present the biggest problem. The antenna gain provided in data sheets is generally understood to be valid in the so-called “far-field” region. In this region the field energy primarily consists of radiated RF with an angular  field distribution that tends to be independent of distance from the antenna and a field level that is inversely proportional to the separation between the antenna and EUT.