A Simple Method to Calculate Electric Field Distribution and Characteristic Impedance in ATEM Cell With Rectangular Metallic EUT

ATEM cell is widely used in electromagnetic compatibility (EMC) test. When loaded with equipment under test (EUT), the electric field in ATEM cell will be distorted , and the characteristic impedance changed. In this paper, the field distribution and characteristic impedance in ATEM cell loaded with rectangular metallic EUT is analyzed by a simple method--point matching method. The section of an asymmetric TEM was divided into five regions and potential function is expressed as a Fourier series in each region. The point-matching was used on the interface of these regions to determine coefficients of series. Thus, the characteristic impedance can be calculated and electric field obtained in terms of a potential function.