无线电波是频率介于3赫兹和约300吉赫之间的电磁波，也作射频电波，或简称射频、射电。

无线电技术将声音信号或其他信号经过转换，利用无线电波传播。

射频技术也用在核磁共振及磁振造影上；射频线圈是其研究课题之一。

无线电波的来源也可能是自然的，比如射电天文学就是研究来自外空的无线电波的一门科学。

The radio spectrum is the part of the electromagnetic spectrum from 3 Hz to 3000 GHz (3 THz) allocated to some 40 Radiocommunication services in line to the Radio Regulations (RR) of the International Telecommunication Union (ITU). The transmission, emission and/or reception of radio waves for specific telecommunication purposes of radio waves is strictly regulated by the national administration.