Abstract :
The kinematic properties of an array of transmitting antennas that are transiently excited by a sequence of modulated pulses, with high repetition rate, are explored. The arrayʹs parameterization is carried out via the energy radiation pattern. It is shown that the energy radiation pattern can be decomposed into a set of different types of beam contributions, defined over a beamskeleton, which is determined by the arrayʹs physical and excitation parameters. The different types of beams are main beams, gratinglobe beams and cross-pulsed lobe beams, each corresponding to a different pulsed interference mechanism. While grating lobes are timeharmonic phenomena, cross-pulsed lobes are unique for excitation with a pulsed sequence. The different beam types set limits for array sparsity in terms of the arrayʹs physical and excitation parameters. The arrayʹs directivity is introduced as a figure of merit of its performance and to demonstrate the resulting effect of the time-domain excitation characteristics. The arrayʹs parameterization can be used with any type of excitation --- from extreme narrow band (time-harmonic) to extreme ultra-wideband (transient/short pulsed) excitation. For timeharmonic excitation, the resulting characterization matches that of the classical frequency domain antenna theory.
