In this paper numerical calculation concerning homogeneity of electric fiel
ds in restricted areas inside Crawford- and GTEM-cells are presented. The c
alculations were carried out with the method of moments and based an a harm
onic signal with low frequency in order to excite TEM-mode only. The calcul
ation takes into account the derivation of field strength of the desired co
mponent of the electric field in symmetry avens as well as the influence of
undesired components of the electric field perpendicular to the desired on
e.