Calibrating radar systems for movement detection

Abstract

Techniques for calibrating radar systems to remove undesirable effects of mutual coupling where radar receivers absorb energy emitted from nearby transmitters (e.g., leakage). Electronic devices may have radar systems that have multiple transmit antennas and multiple receive antennas, or Multiple-Input Multiple-Output (MIMO) radar systems. Electronic devices with MIMO radar systems may have closely spaced transmitter and receiver arrays with poor radio frequency (RF) isolation. Poor RF isolation may lead non-linearities in the receiver chain, which in turn leads to an increase in receiver noise floor that degrades the radar performance. The calibration process(es) described herein include identifying the receiver noise floor for the environment of the electronic device. The transmitter and/or receiver gain may then be fine-tuned to account for the noise floor such that the effects of poor RF isolation are substantially removed from the representations of objects in the environment created using the radar systems.