Signal Transmission by Galvanic Coupling Through the Human Body

Galvanic coupling is a promising approach for wireless intrabody data transmission between sensors. Using the human body as a transmission medium for electrical signals becomes a novel data communication technique in biomedical monitoring systems. In this paper, special attention is given to the coupling of the current into the human body. Safety requirements have to be fulfilled, and optimal signal coupling is of essence. Therefore, different electrodes are compared. A test system offers up to 1 mA contact current modulated in the frequency range of 10 kHz to 1 MHz. The injected current is up to 20 times below the maximum allowed contact current. Such a low-current approach enables data communication that is more energy saving than other wireless technologies.