Many attempts have been made in acoustic microscopy to both achieve nanomet
er lateral resolution and sub-A wave amplitude detection. Employing a scann
ing acoustic force microscopy technique, acoustic wave properties of arbitr
arily polarized modes can be measured with sub-wavelength resolution and hi
gh sensitivity. Surface acoustic wave fields of elementary model systems li
ke a single scatterer and a single wave source are analysed in detail. We a
re able to observe radiation patterns, revealing the influence of the aniso
tropy of the GaAs substrate and the angular distribution of the piezoelectr
ic coupling coefficient.