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Time‐domain magnetic field waveform measurement near printed circuit boards
Author(s) -
Harada Takashi,
Sasaki Hideki,
Hankui Eiji
Publication year - 1998
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/(sici)1520-6416(199812)125:4<9::aid-eej2>3.0.co;2-p
Subject(s) - waveform , magnetic field , microstrip , calibration , printed circuit board , time domain , materials science , field (mathematics) , electrical engineering , acoustics , physics , optoelectronics , nuclear magnetic resonance , optics , engineering , voltage , computer science , mathematics , quantum mechanics , pure mathematics , computer vision
This paper describes a time domain magnetic field measurement process for measuring magnetic fields near printed circuit boards (PCBs) with a loop probe. In carrying out these measurements, the loop probe needs to be calibrated in the frequency domain. In this process, a microstrip line with a teflon substrate serving as the standard magnetic field source is employed as a means of calibrating the probe. The standard magnetic field intensities of the line are calculated by using an approximate equation obtained from Ampère's law to simplify the calibration. The sensor‐factor of the probe obtained from this method agrees with that obtained through the use of a standard G‐TEM cell in 2 dB at frequencies below 1 GHz. The waveforms of magnetic fields near a PCB having a four‐layer construction are measured using a 10 mm diameter loop probe as the calibrated magnetic field sensor. The generation of magnetic field waveforms causing the radiated emission from the PCB is found to depend on the circuit operating conditions. Our results clarify the fact that the time domain magnetic field measurement process is an effective tool for analyzing the sources of emission radiated from PCBs and for investigating the radiation mechanism. © 1998 Scripta Technica, Electr Eng Jpn, 125(4): 9–18, 1998