In one example, a system includes one or more waveguides configured to guide radio frequency (RF) signals, a controller comprising a transmitter configured to output RF signals representing a control signal via the one or more waveguides, and a power module. In this example, the power module includes a receiver configured to receive the RF signals representing the control signal from the controller via the one or more waveguides, and a driver configured to output a power signal to a load based on the control signal.