E.V. Urzhumtsev - Research Scientist, JSC «Corporation «Vega» (Moscow). E-mail: eurgumcev@gmail.com

The object of study in this paper is linear equidistant array of point isotropic antennas that synchronously radiate impulses of uniform amplitude and shape. The array is called video pulse antenna array if ultrawideband video pulses excite its elements. The matter of study in this paper are the directional characteristics of such array in case there are random errors in the distribution of time delays of exciting pulses. Impossibility of using expressions known from classic statistic antenna theory for estimation of directivity characteristics of such arrays provides urgency of the paper matter. This impossibility can be explained by the fact that classic antenna theory uses expressions containing complex amplitudes of monochromatic signals. Arrays radiating impulses of arbitrary shape (especially ultrawideband impulses) cannot be described this way. The aim of this paper is studying of the effect of the value of dispersion of time delays distribution on the array\'s directional characte-ristics: energetic directivity diagram (EDD) and the reduction of energetic directive gain. Obtained expression for EDD of a video pulse antenna array shows the effect of correlation between impulses initiated near the view-point by different array elements on this characteristic. In case the excitation of array elements is done in random moments of time, and the statistical law of time delays distribution and self-correlation function of the signals radiated by array elements are known, the expression for mean EDD of array can be obtained. The model of linear array of antennas radiating monochromatic signals affected by the errors in the distribution of time delays of ex-citation signals is studied. Self-correlation function of radiated signals, the expression for mean value of this function and the expressions for mean EDD and the reduction of energetic directive gain are obtained. To verify correctness of obtained expressions plots of EDD and directive gain reduction diagrams derived using these expressions, expressions known from statistic antenna theory and by means of averaging of large amount of realizations of these characteristics are compared. The comparison results show convergence of obtained results with the results obtained by numerical simulation. Unlike expressions known from statistic antenna theory the obtained expressions results accuracy doesn\'t depend on the value of dispersion of phase errors distribution (which is equivalent to the dispersion of time delays error distribution). Obtained dependencies can be used while studying of directional characteristics of antenna array regardless of the shape of signals radiated by its elements and of the value of dispersion of time delays error distribution. However in case of radiating monochromatic signals and small values of dispersion of phase errors expressions known from statistic antenna theory provide the same accuracy being easier to compute.

 

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