Evaluation of scattering in a TEM cell by the FD-TD method

The TEM cell is a fundamental tool in electromagnetic compatibility in that it permits one to simulate the effects of a plane wave incident on equipment under test in a region large with respect to the wavelength where the field is strictly TEM. The main restriction to the high-frequency operation of the cell arises from the cutoff of the first higher order mode. The new GTEM cell permits one to overcome this restriction. In fact, the absence of edges on the external surface, its tapering, and the use of absorbing material on the end wall ensure operation up to frequencies of several GHz. The scattering of metallic object in a GTEM cell is analyzed and the results are compared with scattering with plane wave exitation. FD-TD proves to be effective for any shape of scattering body with both sinusoidal and pulse exitation even if it is computer time consuming. A 2D analysis that reduces the computing time is reported.