Mikroaallot

Mikroaallot, known in English as microwaves, are a form of electromagnetic radiation occupying roughly the frequency band from 1 gigahertz to 300 gigahertz, corresponding to wavelengths about 30 centimeters to 1 millimeter. They lie between radio waves and infrared light in the spectrum and interact particularly with polar molecules such as water, which makes them efficient for dielectric heating and sensing.

Propagation and characteristics vary by band. Mikroaallot primarily travel as line-of-sight signals and can be guided in waveguides or radiated by antennas. Some bands experience atmospheric absorption, notably around certain high-frequency ranges due to oxygen and water vapor, which can limit transmission distance.

Generation and transmission. Microwave energy is produced by devices such as magnetrons, klystrons, traveling-wave tubes, and solid-state amplifiers. Transmission paths use waveguides, coaxial or microstrip lines, and antennas such as horn antennas, parabolic dishes, or patch antennas to radiate and receive signals.

Applications. The technology is central to radar and satellite and terrestrial communications, including Wi‑Fi and cellular systems that operate in microwave bands. It is also used in microwave ovens for dielectric heating, as well as in industrial heating, spectroscopy, and various imaging systems.

Safety and regulation. Exposure to high-intensity microwaves can cause tissue heating; safety standards define exposure limits and measurement methods, such as specific absorption rate (SAR), under various national and international guidelines.

History. The practical use of microwaves grew from early 20th-century discoveries and culminated with radar development in the 1940s. The magnetron and other microwave sources enabled broad adoption in communications, sensing, and cooking, establishing mikroaallot as a mature technology.