An antenna system may include an antenna operable in a selected frequency band of a plurality of frequency bands. In some examples, the antenna system may include an antenna circuit having an RF (radio frequency) communication path and one or more configurable elements in the RF communication path. The antenna system may include a transmission line coupled to the antenna circuit. The antenna system may include a control unit configured to modulate a control signal onto an RF signal to generate a transmit signal for communication over the transmission line to the antenna circuit. The antenna circuit may be configured to demodulate the control signal from the transmit signal. The antenna circuit may be operable to adjust the one or more configurable elements in the RF communication path based at least in part on the control signal to configure the RF communication path to operate in the selected frequency band.