The Construction And Research Of Three Polarizations TEM Transmission (Triple-TEM) Cell

The fundamental principle, history and category of the TEM Cells(transversal electromagnetic transmission cell) is introduced in this paper. It is described emphatically about the theory, design and construction of the Triple-TEM Cell (three polarizations transversal electromagnetic transmission cell). Its performance of time-domain and frequency-domain is evaluated. Finally, its application including emission measurements and susceptibility measurements is discussed.Triple-TEM Cell has one more perpendicular inner electric septum than the traditional Cells. It is repeatable and low-cost because the EUT(equipment under testing) can be irradiated in three polarization directions without overturning. Finite element method (FEM) is adopted to analysis the impedance and the electromagnetic field of the Triple-TEM Cell. Using 2-D quasi-static method(ANSYS), the characteristic impedance is calculated; and using 2-D modal analysis method (ANSYS), the polarization of individual modes in the Triple-TEM Cell is researched; with 3-D full wave method (HFSS ), the electromagnetic field in the Triple-TEM Cell is simulated. Furthermore,the necessity of the grounded septum is discussed. Finally, the characteristic and the performance of the absorber is presented.After a 2.5-meter-long Triple-TEM Cell is completed, its performance of time-domain and frequency-domain is evaluated. The characteristic impedance of its main body is ～ and the VSWR(voltage station wave ratio) is less than 1.4 from 300kHz to 1GHz.The radiated emission testing is investigated theoretically. At 30MHz, 150MHz and 600MHz, the radiated susceptibility testing has been carried out according to IEC61000-4-20. At 30MHz and 150MHz, the one third area achieves the uniformity requirement; And at 600MHz, the uniform area is reduced. Moreover, from 200MHz to 1GHz, the constant forward power method is carried out for the field uniformity in the Triple-TEM Cell.