This category includes RF (射频) modules and components specifically designed for radio frequency applications, such as synthesizers, switches, and integrated circuits. It excludes antennas, attenuators, filters, transceivers, mixers, modulators, receivers, and transmitters. Examples include dual-band RF synthesizers, RF switches, and advanced base station ICs. Excludes items like diodes, remote controls, and development kits that do not primarily function at RF frequencies.