The design of a wearable antenna for UHF band at 900 MHz with an integrated front-end for a wireless sensor system targeting remote patient monitoring is presented. A wearable antenna for human body with -7.2 dB gain is demonstrated using five layer torso model. The antenna can deliver 25 mu W of power to the rectifier at 4.6 meters distance from the base station emitting P-EIRP=4 W. Local power management circuitry consumes a total power of 4 mu W while delivering 10 mu W of power for the sensors of the wireless sensor system. The system designed with 0.18 mu m CMOS process demonstrates the performance of the frontend together with 3D electromagnetic simulation results of the wearable antenna.