Radio Frequency (RF) refers to the portion of the electromagnetic spectrum, roughly 3 kHz to 300 GHz, used to transmit information wirelessly by modulating alternating current onto an antenna. It is the physical-layer medium underlying cellular networks, Wi-Fi, Bluetooth, and low-power wide-area networks such as LoRa. RF characteristics, including frequency band, transmit power, and propagation behaviour, determine a wireless technology’s range, bandwidth, and power consumption trade-offs.