ABSTRACT
This chapter describes the fundamental theory and design of ultra-wideband (UWB) antenna systems that are developed for the radiation and reception of impulse-type nonsinusoidal electromagnetic waves The use of a sinusoidal carrier in radar and radio communications is traceable to Maxwell’s equations, which are space and time dependent. Practical radio transmission became feasible when Marconi improved the efficiency of radiation of the Hertzian electric dipole by introducing the resonating dipole, or the half-wave dipole. The incentive for a large operating bandwidth is to achieve a high resolution capability in radar and a high transmission rate of information in communications. The use of a sinusoidal carrier and the available technology restricted the increase of the allowable operating bandwidth. The disappearance of resonance effect with increasing bandwidth applies to the conventional technology that is based on the use of a sinusoidal carrier. The large-current radiator is a UWB antenna that can be used for the efficient radiation of impulse-type nonsinusoidal electromagnetic waves.
