rf

Radio frequency (RF) denotes the range of electromagnetic radiation used for wireless communication. In common technical usage RF covers roughly 3 kilohertz (kHz) to 300 gigahertz (GHz), a portion of the spectrum above audio and below infrared. RF signals are carried by oscillating electric and magnetic fields and can be radiated from antennas or guided in transmission media.

In communication systems, information is encoded onto a carrier wave by modulation. RF signals are transmitted through free space or guided media such as coaxial cables or waveguides and received by antennas. Performance depends on frequency, bandwidth, power, modulation, and impedance matching. Antennas convert electrical signals to radio waves and back; propagation is influenced by reflection, diffraction, and atmospheric conditions.

Applications span broadcasting, mobile networks, Wi‑Fi and Bluetooth, satellite links, radar, RFID, and medical and industrial uses. Standards bodies such as the ITU allocate frequency bands and regulate usage, often requiring licensing. RF design aims for efficiency, spectral purity, and coexistence with other services.

Safety and measurement: exposure limits aim to prevent harmful heating. RF equipment is analyzed with spectrum analyzers, network analyzers, and other instruments. Engineering practices include shielding, filtering, and careful antenna placement to manage emissions and interference.