A small antenna with aerospace application

The reactive power and energy of a spherical radiator are investigated. The radiator may be an actual sphere, or it may be a Gaussian surface fit about a radiator of arbitrary shape supporting Kirchhoff equivalent currents and charges. It is shown that the sphere can be resonant, in the sense of no reactive power, at any ratio of diameter to wavelength. An antenna is described based on the analysis. The design consists of linear elements whose interaction is nonlinear. The antenna is narrowband, sweepable broadband, and has a resonant frequency only indirectly dependent upon its size. The construction is one of properly combined electric and magnetic multipolar sources. For given multipolar dimensions, the resonant frequency is dependent upon the relative magnitudes and phases of the driving currents. The radiation pattern is independent of frequency and the physical size of the antennae.<>