A novel quasi-static channel enhancing technique for body channel communication

Body channel communication (BCC) is a most power efficient way for communications among sensors in a wireless body-area network (WBAN). In BCC, the forward signal of the quasi-static field is conducted by the body surface, whereas the backward path is formed by the electrostatic coupling between the GND electrodes (GEs) of transmitter and receiver. As a result, the transmission loss is dominated by the backward path, which has high impedance due to small air capacitance between two compact GEs. Conventional backward path enhancement techniques make use of a large inductor to resonate with the air capacitance in order to reduce the impedance. Such approach is not suitable for integrated solution and not reconfigurable for varying communication distances. In this paper, we propose a novel active channel enhancer to compensate the loss in backward path, which is integratable and reconfigurable for variable distances and frequencies. Designed with 0.13 μm CMOS process, the proposed active enhancer improves the quasi-static coupling by more than 15 dB for a wide frequency band of 40 MHz-120 MHz compared to the 4 dB enhancement of conventional method; and the power consumption is only 0.6 mW.