Time-harmonic echo generation

We propose an approach to the design of array-based, 2D echo generators. The radiating elements are located on non-uniform grids and the quiet zone (QZ) design specifications are enforced at non-uniformly spaced sampling locations. The approach, based on a singular values optimization process, allows dimensioning the size of the echo generator to meet the QZ specifications, defining the number and locations of the QZ sampling points and of the radiators to control the ill-conditioning when searching for the excitation coefficients, dramatically reducing the number of radiating elements, and finding the excitations by a Singular Value Decomposition approach. The performance of the method in terms of QZ field behavior and robustness against realization errors is numerically assessed. An experimental validation of the technique is also presented.