Design and manufacture of electromagnetic absorber composed of boric acid-incorporated waste paper composites

Abstract

With the effect of technological advances, the use of electrical and electronic devices has increased dramatically in recent years. Wireless technologies and related applications are mostly preferred for the communication of these devices with each other. Thus, people are easily exposed to electromagnetic waves in daily life. The extensive global use of these devices raises the question of their possible biological effects on human health. Also, electromagnetic waves influence the functioning of a nearby device. In this study, an electromagnetic absorber based on boric acid (5, 10, 20 and 30 wt%) added waste paper was developed. Copper (Cu) and aluminum (Al) were also used as mineral additives for comparison. Three different kinds of waste paper namely, office paper, newsprint and cardboard paper were selected for the experimental study. The effect of varying boric acid contents on the electromagnetic absorption of the boards manufactured was evaluated and compared to Cu (30 wt%) and Al (30 wt%) added boards. The results show that newsprint has better absorption effectiveness than office and cardboard paper and an absorption up to 40 dB was achieved. The absorption effectiveness of Al, Cu and boric acid added boards was achieved approximately 40, 30 and 20 dB, respectively. As a result, electromagnetic absorption effectiveness of boric acid added board is acceptable levels. Also, apart from the use of boric acid as a powder, it has been determined that the application of the surface as a layer is effective in absorption.