Simulating open area test site emission measurements based on data obtained in a novel broadband TEM cell

A type of electromagnetic compatibility (EMC) test chamber for both radiated emission and susceptibility measurements is discussed. The design is essentially a transverse electromagnetic cell (TEM-cell) anechoic-chamber hybrid. A steady input power generates an almost constant field (better than +/-4 dB) anywhere in the recommended test volume from DC to frequencies exceeding 1 GHz. Susceptibility testing is done as in a normal TEM cell. Emission testing models test object radiation as due to an equivalent set of multipoles (in essence electric and magnetic dipoles). The multipole components are determined through a sequence of measurements. Once found, the multipole model can be used to predict test object radiation both in an ideal free space and above a perfect ground screen. In this manner time-consuming emission measurements, such as those required by FCC Rules Part 15 Subpart J or VDE 0871, can be simulated numerically. Both experimental and theoretical measurement data are presented for a widely available personal computer.<
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