A look at the small antenna design problem from a practitioner's viewpoint

Designing small antennas is a very challenging problem, which has received the attention of a whole host of workers during the last five decades. It was recognized very early on, by researchers such as Chu, Harrington and their contemporaries, that there are some fundamental limits of realizable gain, bandwidth and efficiency of small antennas that are determined by the size of the sphere within which the antenna can be embedded, and that these limits cannot be overcome by using different materials or geometrical configurations of the antenna so long as it remained confined within the given sphere. Small antennas which attempted to “fill” the space within the sphere to reach the Chu-Harrington limit were designed by many workers, one of the principals among them being Best [1, 2]. Some of Best's designs are shown in Fig.1.