Design and implementation of a hybrid piezoelectric, radio frequency, solar, and thermal energy‐harvesting system for portable medical devices

Abstract Today, energy harvesting has developed into a technique from which various aspects are still hidden. By extracting energies from the environment and even the human body, and converting them into electrical energy, we can supply power to low‐consumption electronic devices. Energy harvesting works by inhibiting small amounts of ambient energies; otherwise, it is wasted in other forms such as heat, vibration, and light. In this paper, we aim to eliminate or minimize the dependence of portable electronic devices to the batteries, which have limited life times, service costs, handling, and environmental problems. This is accomplished via incorporating the hybrid energy‐harvesting techniques and designed to power (bio)medical devices in order to measure vital signs. In this circuit, by simultaneously harvesting RF, light, thermal, and solar (natural and artificial) energies, we were able to increase the reliability of continuous supply of electrical energy in energy‐harvesting systems by generating and storing maximum power from the environment. Supercapacitors are used as the energy storage elements so that there is no energy waste, and each system is constantly storing the electrical energy with the aid of a diode block. In addition, with the help of supercapacitors, this device is able to transmit a maximum of 420 mW to the load and the total efficiency is equal to 74%.