Design and characterisation of GTEM cell

The Gigahertz Transverse Electromagnetic (GTEM) cell has been experimental and certified as a suitable test environment for radiated emission and susceptibility testing. In this paper the numerical technique applied for the fabrication of a typical GTEM cell has been explained. A method of moments based technique is applied to evaluate the charge distribution on the two conductors and the capacitance per unit length of the cell. The conductors are divided into large number of subsections. The charge density is assumed to be constant throughout a particular sub-section and concentrated at the center of a particular sub-section. This theory is further applied to design a GTEM cell with a characteristic impedance of 50 ohms. According to the size of the equipment under test (here the EUT is taken as a personal computer) the size of the cell is chosen. The cell is designed with appropriate low and high frequency terminations. The testing of the GTEM cell has been completed and the results are satisfactory.