New Wideband Passive and Active Wearable Energy Harvesting Systems for Wearable Sensors

Abstract

Demand for green energy is in continuous growth. Wide band efficient wearable systems and antennas are crucial for energy harvesting wearable systems for medical and sport wearable sensors. Small harvesting antennas suffer from low efficiency. The efficiency of energy harvesting wearable systems may be improved by using active wearable harvesting systems with low power consumption. Amplifiers may be connected to the wearable antenna feed line to increase the system dynamic range. Novel active wearable harvesting systems are presented in this paper. Notch and Slot antennas are low profile and low cost and may be employed in energy harvesting wearable systems. The wearable harvesting system components are assembled on the same PCB. The notch and slot antennas bandwidth is up to 100% for VSWR better than 3:1. The slot antenna gain is around 3 dBi with efficiency higher than 90%. The antennas electrical parameters were computed in vicinity of the human body. The active antenna gain is 24 ± 2.5 dB for frequencies from 200 MHz to 900 MHz. The active antenna gain is 12.5 ± 2.5 dB for frequencies from 1 GHz to 3 GHz. The active slot antenna Noise Figure is 0.5 ± 0.3 dB for frequencies from 200 MHz to 3.3 GHz.