10-Mbps Short-Range Baseband Wireless Communications via Quasi-Static Electric Fields

Ai-ichiro SASAKI  Akinori FURUYA  Mitsuru SHINAGAWA  

IEICE TRANSACTIONS on Communications   Vol.E93-B   No.1   pp.144-153
Publication Date: 2010/01/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E93.B.144
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Terrestrial Radio Communications
short-range wireless communications,  quasi-static electric field,  electro-optic sensor,  electromagnetic radiation,  baseband,  earth ground,  

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We propose a novel short-range wireless communications technology that uses quasi-static electric fields; it enables data communication between devices separated by up to 10 cm via dielectric media at a speed of 10 Mbps. It is considered to be a secure wireless technology since communication area is restricted to below about 10 cm. To suppress electromagnetic radiation, we adopted a baseband transmission scheme in which the quasi-static electric field is directly modulated by 10 BASE-T data signals. Since the spectra of the data signals are concentrated to below 20 MHz, the amplitude of the electric field rapidly decreases outside the communication area. This contributes to enhancing security of the communications system. In this paper, we explain a basic principle of the short-range wireless communications technology. Since baseband data signals are carried by the quasi-static electric field, the quality of the communication is easily degraded by the existence of the earth ground. To isolate the communications system from the earth ground, we introduce a novel electro-optic sensor to receive the quasi-static electric field. With the electro-optic sensor, stable data communication is possible at 10 Mbps via dielectric materials, such as a wooden table.