The list defines and explains some common key antenna terms: Gain refers to the antenna’s effective radiated power compared to the perfect isotropic antenna model. Efficiency is defined as the ratio of radiated power to supplied power. Polarization is the orientation, either circular or linear, of the EM field. Johanson’s antennas are linearly polarized. Return loss is a measure of antenna match. This can also be expressed as Voltage Standing Wave Ratio (VSWR). Bandwidth refers to the frequency range over which the return loss is acceptable.