In the context of phased arrays, a standard linear array (SLA) is a uniform linear array (ULA) of interconnected transducer elements, e.g. microphones or antennas, where the individual elements are 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.
Grating lobes are identical to aliasing that occurs in time series analysis for an under-sampled signal.
Because the beam pattern (or array factor) of a linear array is the Fourier transform of the element pattern,[2] the sampling theorem directly applies, but in the spatial instead of spectral domain.
The discrete-time Fourier transform (DTFT) of a sampled signal is always periodic, producing "copies" of the spectrum at intervals of the sampling frequency.
The analog of radian frequency in the time domain is wavenumber,