A generator of radio-frequency (rf) signals for wireless communication over some distance, which can vary from the short ranges within a building to intercontinental distances. Most applications utilize signals from very low frequencies (VLF) to extremely high frequencies (EHF); some applications require frequencies as low as 45 Hz or as high as 100 GHz. The radio-frequency output power varies from a fraction of a watt in emergency beacons and portable equipment to several megawatts in long-range, low-frequency transmitters.