In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. Types of EMR include radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays, all of which are part of the electromagnetic spectrum.
A nuclear electromagnetic pulse is a burst of electromagnetic radiation created by a nuclear explosion. The resulting rapidly varying electric and magnetic fields may couple with electrical and electronic systems to produce damaging current and voltage surges. The specific characteristics of a particular nuclear EMP event vary according to a number of factors, the most important of which is the altitude of the detonation.
Electromagnetic radiation can be classified into two types: ionizing radiation and non-ionizing radiation, based on the capability of a single photon with more than 10 eV energy to ionize atoms or break chemical bonds. Extreme ultraviolet and higher frequencies, such as X-rays or gamma rays are ionizing, and these pose their own special hazards: see radiation poisoning.
The microwave auditory effect, also known as the microwave hearing effect or the Frey effect, consists of the human perception of audible clicks, buzzing, hissing or knocking induced by pulsed or modulated radio frequencies. The perceived sounds are generated directly inside the human head without the need of any receiving electronic device. The effect was first reported by persons working in the vicinity of radar transponders during World War II. In 1961, the American neuroscientist Allan H. Frey studied this phenomenon and was the first to publish information on the nature of the microwave auditory effect. The cause is thought to be thermoelastic expansion of portions of the auditory apparatus, although competing theories explain the results of holographic interferometry tests differently.
A microwave oven is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce thermal energy in a process known as dielectric heating. Microwave ovens heat foods quickly and efficiently because excitation is fairly uniform in the outer 25–38 mm(1–1.5 inches) of a homogeneous, high-water-content food item.
A directed-energy weapon (DEW) is a ranged weapon that damages its target with highly focused energy without a solid projectile, including lasers, microwaves, particle beams, and sound beams. Potential applications of this technology include weapons that target personnel, missiles, vehicles, and optical devices. In the United States, the Pentagon, DARPA, the Air Force Research Laboratory, United States Army Armament Research Development and Engineering Center, and the Naval Research Laboratory are researching directed-energy weapons to counter ballistic missiles, hypersonic cruise missiles, and hypersonic glide vehicles. These systems of missile defense are expected to come online no sooner than the mid to late-2020s.
Wireless power transfer (WPT), wireless power transmission, wireless energy transmission (WET), or electromagnetic power transfer is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system, an electrically powered transmitter device generates a time-varying electromagnetic field that transmits power across space to a receiver device; the receiver device extracts power from the field and supplies it to an electrical load. The technology of wireless power transmission can eliminate the use of the wires and batteries, thereby increasing the mobility, convenience, and safety of an electronic device for all users. Wireless power transfer is useful to power electrical devices where interconnecting wires are inconvenient, hazardous, or are not possible.
The antennas contained in mobile phones, including smartphones, emit radiofrequency (RF) radiation ; the parts of the head or body nearest to the antenna can absorb this energy and convert it to heat. Since at least the 1990s, scientists have researched whether the now-ubiquitous radiation associated with mobile phone antennas or cell phone towers is affecting human health. Mobile phone networks use various bands of RF radiation, some of which overlap with the microwave range. Other digital wireless systems, such as data communication networks, produce similar radiation.
A gyrotron is a class of high-power linear-beam vacuum tubes that generates millimeter-wave electromagnetic waves by the cyclotron resonance of electrons in a strong magnetic field. Output frequencies range from about 20 to 527 GHz, covering wavelengths from microwave to the edge of the terahertz gap. Typical output powers range from tens of kilowatts to 1–2 megawatts. Gyrotrons can be designed for pulsed or continuous operation. The gyrotron was invented by Soviet scientists at NIRFI, based in Nizhny Novgorod, Russia.
Dielectric heating, also known as electronic heating, radio frequency heating, and high-frequency heating, is the process in which a radio frequency (RF) alternating electric field, or radio wave or microwave electromagnetic radiation heats a dielectric material. At higher frequencies, this heating is caused by molecular dipole rotation within the dielectric.
Bioelectromagnetics, also known as bioelectromagnetism, is the study of the interaction between electromagnetic fields and biological entities. Areas of study include electromagnetic fields produced by living cells, tissues or organisms, the effects of man-made sources of electromagnetic fields like mobile phones, and the application of electromagnetic radiation toward therapies for the treatment of various conditions.
The International Microwave Power Institute (IMPI) is an organization devoted to microwave energy and its usage. The organization has conducted surveys as well as educated the public to dispel microwave myths.
IEEE Transactions on Microwave Theory and Techniques (T-MTT) is a monthly peer-reviewed scientific journal with a focus on that part of engineering and theory associated with microwave/millimeter-wave technology and components, electronic devices, guided wave structures and theory, electromagnetic theory, and Radio Frequency Hybrid and Monolithic Integrated Circuits, including mixed-signal circuits, from a few MHz to THz.
IEEE Microwave and Wireless Components Letters is a monthly peer-reviewed scientific journal published by the IEEE Microwave Theory and Techniques Society. The editor-in-chief is Roberto Gómez García. The journal covers research on electromagnetic radiation and the relevant, physical components to achieve such radiations. It focuses on devices, intermediate parts of systems, and completed systems of the interested wavelengths, but also includes papers which emphasize theory, experiment, and applications of the subjects covered.
Microwave burns are burn injuries caused by thermal effects of microwave radiation absorbed in a living organism.
Non-ionizingradiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum to ionize atoms or molecules—that is, to completely remove an electron from an atom or molecule. Instead of producing charged ions when passing through matter, non-ionizing electromagnetic radiation has sufficient energy only for excitation. Non-ionizing radiation is not a significant health risk. In contrast, ionizing radiation has a higher frequency and shorter wavelength than non-ionizing radiation, and can be a serious health hazard: exposure to it can cause burns, radiation sickness, many kinds of cancer, and genetic damage. Using ionizing radiation requires elaborate radiological protection measures, which in general are not required with non-ionizing radiation.
Electromagnetics is a peer-reviewed scientific journal that is published by Taylor & Francis. It covers all aspects of electromagnetics and electromagnetic materials. The editor-in-chief is H. Y. David Yang.
An electromagnetic pulse (EMP), also referred to as a transient electromagnetic disturbance (TED), is a brief burst of electromagnetic energy. The origin of an EMP can be natural or artificial, and can occur as an electromagnetic field, as an electric field, as a magnetic field, or as a conducted electric current. The electromagnetic interference caused by an EMP can disrupt communications and damage electronic equipment. An EMP such as a lightning strike can physically damage objects such as buildings and aircraft. The management of EMP effects is a branch of electromagnetic compatibility (EMC) engineering.
Stepan Lucyszyn FIEEE is a British engineer, inventor and technologist, and has been a Professor of Millimetre-wave Systems at Imperial College London, England, since 2016. He was named a Fellow of the Institute of Electrical and Electronics Engineers (IEEE) in 2014. Lucyszyn's research has mainly focused on monolithic microwave integrated circuits (MMICs), radio frequency microelectromechnical systems, wireless power transfer (WPT), thermal infrared technologies and additive manufacturing.
The Journal of Electromagnetic Waves and Applications is a peer-reviewed scientific journal published by Taylor & Francis in 18 issues per year. It covers electromagnetic wave theory and its applications, including but not limited to wave propagation, antenna theory, photonics, and electromagnetic compatibility. The editors-in-chief are Pankaj Kumar Choudhury and Mohamad Abou El-Nasr. The founding editor-in-chief of the journal was Jin Au Kong.
