Mutual Coupling Effects in Thinned Antenna Arrays

The reduction of mutual coupling effects is one interesting advantage of thinned antennas for phased array systems. This paper deals with the reflection coefficients and the antenna gain both as functions of the degree of thinning in statistically highly-thinned arrays. Appropriate statistics are derived, discussed, and experimentally tested. In the resulting probability distributions the variance is approximately proportional to the degree of thinning ¿ and nearly independent of the scan direction. For example, if a ¿=0.1 the total reflected power is always less than 10% of the input power and the maximum deviation of the antenna gain function, normalized to the number of radiating elements, from the gain function of an isolated element amounts to 1 dB only.