準マイクロ波による融雪用発熱モルタルブロックの基材層の厚さが電波吸収性能に与える影響

 It is expected that elderly people can't remove snow on their own, and have a trouble going out. There are some ways to remove snow which do not require physical effort, but each conventional way has problems.<br> Therefore, the authors have attempted to invent the “heating mortar block system” to remove snow. In this system, electromagnetic waves are generated by the oscillator, and then irradiated mortar blocks with. A heating mortar block is composed of 3 layers; 1. electromagnetic absorption material 2. base material (without electromagnetic absorption ability) 3. electromagnetic shielding material. Electromagnetic absorption material placed near the surface absorbs electromagnetic waves and converts it into heat. This system uses this heat to melt snow on the blocks. Electromagnetic absorption material is mortar mixed with electric arc furnace oxidizing slag as aggregate (hereinafter, called “the slag mortar”), and base material is a mortar mixed with sand as aggregate (hereinafter, called “the sand mortar”).<br> According to preceding research, there is a correlation between abilities of electromagnetic absorption and heating. But, the characteristics of electromagnetic absorption and heating about electromagnetic absorption material composed of the slag mortar and the sand mortar has not been studied enough.<br> So, the purpose of this study is to clarify these things and develop the base theory to design heating mortar blocks absorbing the electromagnetic waves and heating well. Ability of electromagnetic absorption is evaluated with return loss calculated by S-parameter method.<br> Within the measuring range, following things were clarified.<br> (1) When the sand mortar is superposed under the slag mortar, the thickness of which the sand mortar causes the prominent absorption of electromagnetic waves at specific frequency (hereinafter, called “peak”), has a period. And, it is possible to choose a thickness from some thickness by considering this period.<br> (2) When the sand mortar is superposed under the slag mortar, it is possible to determine the thickness, by specifying the thinnest thickness through the experiment and using the equation produced in this study.<br> (3) It is possible to adjust the temperature rises of the heating mortar block without changing the thickness of the slag mortar which is the electromagnetic absorption material, by just changing the thickness of the sand mortar.<br> (4) When the thickness of sand mortar superposed under the slag mortar is 30mm, 62mm or 93mm and it is irradiated with electromagnetic waves of frequency 2.45GHz, the temperature rises 20.6 °C, 17.3 °C or 19.2 °C each. In these thickness, return loss also rise as a peak.<br> (5) When the sand mortar is superposed under the slag mortar, it is possible to evaluate the heating ability by return loss.