Electromagnetic Radiation Harvesting
Electromagnetic radiation harvesting captures ambient radio frequency, microwave, and other electromagnetic energy from the environment and converts it into usable electrical power. With the proliferation of wireless communications, broadcast signals, and intentional power transmission systems, electromagnetic energy has become an increasingly available resource for powering low-power electronic devices. This technology enables battery-free operation of sensors, RFID tags, and IoT nodes by scavenging energy from sources including WiFi routers, cellular base stations, television broadcasts, and dedicated wireless power transmitters.
The core of electromagnetic harvesting systems consists of an antenna or rectenna (rectifying antenna) that captures incident electromagnetic waves and converts them to direct current through specialized rectifier circuits. Maximizing harvested power requires careful optimization of antenna design, impedance matching, rectifier efficiency, and power management circuits across the frequency bands and power densities encountered in real-world environments. Advances in antenna miniaturization, wide-band rectifier design, and ultra-low-power electronics continue to expand the practical applications of electromagnetic energy harvesting.
Subcategories
RF Energy Harvesting
Capture and convert radio frequency signals into electrical power. Topics include antenna design for RF harvesting, rectifier topologies, impedance matching networks, multi-band and broadband harvesters, ambient RF power density mapping, and system integration for powering wireless sensor nodes from WiFi, cellular, and broadcast signals.
Wireless Power Transfer
Transmit electrical power wirelessly over short and long distances. Coverage encompasses inductive coupling, magnetic resonance coupling, microwave power transmission, laser power beaming, near-field and far-field techniques, safety standards, efficiency optimization, and applications from smartphone charging to powering remote sensors and drones.
Rectenna Design
Design and optimize rectifying antennas for electromagnetic energy conversion. Topics include antenna element selection, Schottky diode rectifiers, voltage multiplier circuits, DC combining networks, array configurations, harmonic rejection, circular polarization handling, and performance characterization across frequency and power levels.
Ambient Electromagnetic Harvesting
Scavenge energy from unintentional electromagnetic sources in the environment. Coverage includes multi-source harvesting strategies, spectrum sensing and adaptive tuning, urban RF environment characterization, interference mitigation, hybrid harvesting combining RF with other energy sources, and regulatory considerations for ambient harvesting systems.
Microwave Power Transfer
Transmit power via microwave beams using magnetron-based systems, klystron power sources, phased array transmitters, and rectenna arrays. Coverage includes beam steering techniques, safety interlocking systems, atmospheric propagation effects, power beaming efficiency, space solar power satellites, unmanned aerial vehicle charging, industrial microwave power, microwave-powered transportation, retrodirective arrays, and adaptive beamforming systems.
Optical Wireless Power
Transfer energy using light beams including lasers and LEDs. Topics cover laser power beaming, LED-based power transfer, photovoltaic receivers, optical beam shaping, atmospheric compensation, safety systems for laser power, infrared and visible light power transfer, underwater optical power, fiber-coupled power delivery, optical resonators, distributed photodiode arrays, satellite optical power, and indoor optical wireless power systems.
Radio Frequency Energy Harvesting
Capture ambient RF energy from wireless signals. Topics include rectenna design, impedance matching networks, voltage multiplier circuits, RF-DC conversion efficiency, multiband energy harvesting, WiFi energy harvesting, cellular signal harvesting, TV broadcast harvesting, dedicated RF power transfer, near-field and far-field harvesting, metamaterial-enhanced harvesting, and RF-powered sensor networks.
About This Category
Electromagnetic radiation harvesting represents a growing frontier in energy harvesting technology, driven by the ever-increasing density of wireless signals in modern environments. From powering passive RFID systems and wireless sensors to enabling new paradigms in the Internet of Things, this technology leverages the electromagnetic spectrum as a power source rather than just a communication medium. This category explores the principles, circuits, and systems that enable practical electromagnetic energy harvesting, providing essential knowledge for designing truly wireless electronic systems.