A 3-D Ray Tracing Model for Short-Range Radar Sensing of Hand Gestures

In this paper, a three-dimensional (3-D) ray tracing model is presented for touchless sensing of hand gestures using a microwave or millimeter-wave radar. The model was built up based on radar range equation by analyzing the electromagnetic waves transmitted to the target hand and reflected from the numerous scattering points on the hand. The detailed mathematical approach for building up the 3-D ray tracing model was discussed, including both nonlinear phase modulation and linear phase demodulation of the gesture motions. Simulation results show that the proposed 3-D model can be used to accurately predict the complex motions of the action gestures.