The radiative properties of electrically-small antennas

The radiative properties of electrically-small antennas are examined using the theory given by Wheeler, Chu, and Harrington. This theory predicts fundamental limitations on the bandwidth of such antennas. Some approximations are made in the theory; these approximations are examined. Several electrically-small antenna designs are evaluated in terms of how close they come to attaining the predicted fundamental limit of bandwidth. Also, the ideas upon which these designs are based are discussed. Finally, a technique for the measurement of the radiation and and the radiation efficiency of electrically-small antennas is reviewed and discussed with emphasis on the accurate separation of conduction and radiation losses