A novel and inexpensive short range FM-CW radar design

A low-cost FM-CW radar sensor with a novel design concept is presented. The sensor is ideally suited for industrial applications, e.g. for process engineering to accurately measure the filling heights of fluids in tanks. The new ideas and features are: nonlinear VCO, based on a frequency doubling concept; DRO, based on a frequency doubling concept; no circulator, isolator or isolating hybrid to separate transmit-receive path; multiple signal mixer (VCO-transmit×receive signal×DRO); and single input IF-channel mixer. These features improve the specifications and additionally cut costs to 1/3 compared to conventional designs