Estimation of the waveform of voltage exciting a monopole antenna to confirm magnetic field measurement

Electromagnetic fields radiated by electrostatic discharges (ESD) are major sources of electromagnetic interference. Such fast transient fields may cause severe malfunction in equipment even though the average power is low. Therefore, measurement of the waveforms of the electromagnetic disturbances is important when designing digital equipment. To observe such transient radiation fields, the authors have developed a technique for reconstructing an electromagnetic waveform using the complex antenna factor (CAF) (see Ishgami, S. et al., IEE Trans EMC, vol.38 p.424-32, 1996; IEICE Trans. Commun., vol.E-79B, no.4, p.715, 1996). However, CAF is defined only in the presence of plane wave incidence, while the waveforms are usually measured in the vicinity of the radiating source. In order to examine the reconstruction technique using CAF in the near-field measurements, the voltage waveforms exciting a monopole antenna are estimated through reconstructing the magnetic fields and compared with directly measured results.