Demonstration of a Coherent RF Repeater for Distributed Communications

In this letter, we demonstrate a coherent radio frequency repeater. The repeater adds the appropriate phase shift to amplify or null a signal generated by another platform and directed to a target point. It leverages a high-accuracy microwave ranging system to estimate the range between platforms and maintain phase coherence when the platforms are moved without additional feedback from the receiver. A continuous beamforming gain operation is achieved without phase or frequency locking the repeater to the transmitter. We include measurements of the stability of the ranging system and discuss potential sources of the variations that limit system performance. Results from outdoor experiments demonstrating successful amplification and nulling of an existing communications link with the repeater are provided.