Study on Achievement of a High-performance Test Room for Measuring Electromagnetic Disturbance

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With the objective of achieving a high-performance test room for measuring electromagnetic disturbance, an electromagnetic anechoic chamber and a magnetic shield chamber are investigated.The results obtained are as follows :(1) Realization of High Performance Anechoic Chamber ; With the construction on an anechoic chamber which uses foamed ferrite as new absorbing material, it is confirmed that the absorber thickness can be decreased to lO cm, which is 1/10 that of the conventional absorber. This is the first in the world to realize a thickness of only lO cm in the frequency range of 30 MHz to 10 GHz.(2) Simulation of Electromagnetic Field for Anechoic Chamber ; We developed a calculation method of NSA (Normalized Site Attenuation) in the frequency range above 200 MHz by using ray tracing method and theoretically investigated methods of improving NSA of anechoic chamber using the same calculation method. For the frequency range below 200 MHz, we developed an NSA calculation method using FDTD (Finite Difference Time Domain) method.(3) Magnetic Material for Magnetic Shield Chamber ; We produced magnetic dielectric super lattices and- discovered that it is possible to control their electrical resistance while maintaining the magnetic properties. Furthermore, at extreme low temperatures, we discovered effects which are thought to be the result of a new phenomenon which increases permeability by more than a hundred times that of same-class conventional materials.