Studies on permittivity measurement of construction materials and techniques for living space design in full consideration of EMC

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For safe and effective use of electromagnetic, waves in a living space, methods for permittivity evaluation of construction materials and design techniques of construction materials are needed.A new standing wave method in which the model of the measuring system is used to estimate the true standing wave distribution has been developed to evaluate permittivity of those construction materials in the open air. The model is composed of the point wave source, reflected-wave source and the scattered-wave source. It is assumed that the standing wave is represented by the sum of those three wave components. Those model parameters are so determined as to minimize the least square errors between the calculated result of the model and measured value of the standing wave1 distribution. When the size of the material under test is larger than approximately 600 millimeters square, it has been verified that the accuracy is high enough to evaluate permittivity of construction materials in the frequency range from 850 to 2400 MHz.In order to solve the prolblems such as unnecessary absorption of electromagnetic waves, interference between communication devices, information leakage through electromagnetic waves radiated from a computer should be solved by selective use of electromagnetic waves in the living space. This will be realized by developing new construction materials that are able to transmit electromagnetic waves selectively. From ecoriomic point of View, suclv new functional materials should be made of traditional materials by. varying the constituents, cross selectional shape, and so on.As an example, the transmission characteristics of a new construction material that has a periodicity in the longitudinal direction have been analyzed by means of FD-TD analysis using a supercomputer. Based on the analysis, the algorithms for realizing the selective use of electromagnetic waves in a living space have been established.