| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1992: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
The time domain technique is a powerful method for measuring the characteristic phenomena induced by impulse noise. In order to discuss the recent developments of the time domain and related techniques in connection with the electromagnetic compatibility (EMC), we visited the National Institute of Standards and Technology (NIST) in the USA and several research institutes in Japan.
The reflected electromagnetic wave from an absorber, which is placed at the front wall in an anechoic chamber, has been observed by the time domain method, at NIST. They evaluated the reflection coefficients in a frequency region between 30 MHz and 1 GHz. They successfully eliminated reflections from the floor, the left and right walls, the ceiling and the cart, and also the reflection within the antennas
Two types of antennas have been developed by NTT in Japan. One of them is a spherical dipole antenna with optical fiber which enables us to calculate the radiated electric field strength precisely. It can cover frequency range between 30 MHz and 1 GHz, and can radiate even an impulse. The second one is a receiving antenna with electric field sensor based on the integrated optical circuit technique with high sensitivity. An electromagnetic impulse of width wider than 5 ns and peak height larger than 10 V/m can be measured with this sensor.
Moreover, many studies have been done with special attentions on the electrical properties of materials, the random burst noise, the electric and electronic circuits, electrostatic discharge, the characteristic impedance of TEM cell, reproduces of electromagnetic environments in an anechoic chamber and so on.
In view of these developments, we are convinced that the time domain technique can be an effective method to characterize impulse noise associated with EMC problems, although there are many practical problems for future studies.
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