On the Impact of System Nonlinearities in Continuous-Wave Radar Systems for Vital Parameter Sensing

This paper investigates the influence of nonlinearities on relative distance measurements by continuous-wave radar systems. For the case of a six-port receiver architecture, a mathematical relationship between detector nonlinearity and measurement error is derived. Moreover, a generalized sinusoidal error model, which fits both six-port and mixer-based radar systems, is used to study the effect of nonlinear mixing when one or more displacement movements with different amplitudes are to be detected.