The Present Technology of Impluse Radars

TLDR: In this article, the authors present an antenna dilemma resulting from operation with instantaneous bandwidths greater than a decade, and present a solution to the very practical problem of obtaining a large energy content in an impulsive radiation is achieved by temporal-spatial compression.

Abstract: : From the birth of radar there has been a steady trend to increase the radiated bandwidth to obtain high resolution, extreme accuracy, target identification, and fine imagery. The ultimate radiated waveform to achieve these goals is an impulse. The present capability of generating multimegawatt subnanosecond impulsive waveforms is discussed including future limitations on the maximum peak power. A theoretical discussion of radiation and reception of impulse waveforms, as well as the experimental responses of selected antennas, is given. The paper presents an antenna dilemma resulting from operation with instantaneous bandwidths greater than a decade. Because of the antenna's inherent limitations, other transient waveform responses are also discussed including a ramp (double integrated impulse) and a monocycle (differentiated impulse) radar. MTI (Moving Target Indicator) operation is discussed showing that target blind velocities do not occur as with conventioal MTI radars. A solution to the very practical problem of obtaining a large energy content in an impulsive radiation is achieved by temporal-spatial compression. Here, a dispersive antenna is employed as a pulse compression network resulting in enhanced electromagnetic field intensity. Finally, some short-range impulse radar backscatter is shown for several targets. (Author)