Standard linear array

A standard linear array (SLA) is a linear array of interconnected transducer, e.g. microphone or antenna, elements where the individual elements are uniformly weighted (un-tapered) and arranged in a straight line spaced at one half of the smallest wavelength of the intended signal to be received and/or transmitted. The reason for this spacing is that it prevents grating lobes in the visible region of the array.

Intuitively one can think of a linear array of elements as spatial sampling of a signal in the same sense as time sampling of a signal. Per Shannon's sampling theorem, the sampling rate must be at least twice the highest frequency of the desired signal. The analog of radian frequency in the time domain is wavenumber, $k={\frac {2\pi }{\lambda }}$ radians per meter, in the spatial domain. Therefore the spatial sampling rate, in samples per meter, must be $\geq 2{\frac {samples}{cycle}}\times {\frac {k{\frac {radians}{meter}}}{2\pi {\frac {radians}{cycle}}}}$. Therefore the sampling interval, in meters per sample, must be $\leq {\frac {\lambda }{2}}$.