Ping-pong sample times on a linear array halve the Nyquist rate [antenna array signal processing]

Staggering the sample times for alternate elements of a linear antenna array is shown to halve the usual Nyquist sample-rate bound of twice the one-sided signal bandwidth while preserving alias-free mapping between spectral components and plane waves in the far field. This approach can be used on transmit or receive and with lowpass or bandpass sampling, and it can involve analog up- or down-conversion between data conversion and the array. The usual element-spacing bound of half a wavelength at the upper RF band edge is replaced with a quarter-wavelength bound at the center of the Nyquist sampling band referred to RF, a reduction only for bandpass sampling.