Radio waves are electromagnetic waves used for wireless communication. They span from about 3 kHz to 300 GHz. They travel at the speed of light. They can pass through walls and travel long distances. They carry radio, television, mobile, Wi-Fi, and satellite signals. They are invisible and everywhere.

Radio waves are generated by oscillating electric currents in an antenna. They propagate through space. A receiving antenna captures them and converts them back to electrical signals. The frequency determines the properties. Low frequencies travel far. High frequencies carry more data.

Radio wave bands

• ELF: submarine communication
• AM: medium wave broadcast
• FM: VHF broadcast
• Microwave: satellite and radar
• Millimeter wave: 5G and WiGig

Radio waves are regulated. Governments allocate spectrum. Unlicensed bands are shared. Licensed bands are auctioned. Interference is managed. The airwaves are a public resource. They are used by broadcasters, carriers, and consumers. The radio wave is the medium of wireless communication.