A novel multi-slot antenna with a conducting backplane reflector (MSA-BP) designed for Wireless Body Area Networks (WBANs) applications is presented. The effect of the metallic backplane on the antenna impedance characteristics was studied. The desensitization of the antenna is studied through measuring its impedance characteristics when the antenna closes to a human body. Measured path gains under three radio links (hip to chest, hip to wrist, and hip to toe) on a human body phantom are presented.