ANTENNA PATTERN DISTRIBUTIONS FROM RANDOM ARRAYS
RAND CORP SANTA MONICA CA
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Research concerns the determination of the probability distribution of the electric field resulting from an arbitrary random array of sources or scatterers. The distribution is surprisingly simple, is easily calculated for most interesting array distributions, and has wide generality of application. Specifically, we find the antenna pattern distribution of a synthetic aperture antenna formed by a moving space vehicle emitting pulses randomly in time. However, the results apply not only to synthetic aperture antennas of arbitrary distribution but also to randomly deleted antennas and to chaff, meteor trail, and electron cloud diagnostics as well. The problem is restricted to the study of the far field from n sources, the positions of which are independent identically distributed as Fr. Markovs method is then used to analyze what is essentially a two-dimensional random walk induced by a three-dimensional distribution. It is shown that if the Fourier transform psik of the distribution function Fr can be performed in closed form, then the limiting form of the probability density of the resultant electric field vector is immediately obvious for every frequency and direction of propagation. Finally, the probability density of the resultant power or envelope is determined in closed form, and the correlation between the resultant field at different angles and frequencies is exhibited.
- Radiofrequency Wave Propagation
- Active and Passive Radar Detection and Equipment