Extended Noise Analysis Model of CW-type Radar Sensors with IQ Down-Conversion

Abstract

CW-type structures belong to the most frequently employed radars, especially in a form of small sensors used, for example, in security applications or automotive industry. Range and reliability of operation of these sensors strongly depend upon their noise parameters. This paper extends previously published works by considering all potential inner noise sources and creating complex noise model of the concerned radar family including often used IQ signal processing. The noise sources cover local oscillator amplitude-noise and phase-noise, noise of a RF signal path and noise of a low-frequency signal path. The resulting noise model was verified by practical measurements which included different local oscillator types, different low-frequency bandwidths and different time-delays of the cross-talked signals. In all cases, the agreement between theory and measurement was within estimated limits. The developed model is applicable for noise analysis and design of all common CW-type radars.