Comparison of analysis of a WTEM cell with standard TEM cells for generating EM fields

The subject of this study is the analysis of a device for electromagnetic interference (EMI) measurements; the structure, called the wire TEM (WTEM) cell, is similar to a TEM cell but has an inner wire array rather than a conducting septum. The transmission line is terminated in a resistor array at low frequencies, and in anechoic material at higher frequencies. The device is designed specifically to provide a high field uniformity in the test region. The performance of the WTEM cell is compared with that of TEM striplines. An enlarged quasi-static frequency band is available with the WTEM cell; moreover the coupling of the device under test with the structure is lower. The performance of the device as a standard EM field generator has been predicted by a theoretical quasi-static analysis and estimated by measurements over a wide frequency band.