Modeling and Suppressing Substrate Coupling of RF CMOS FMCW Sensor Incorporating Synthetic Quasi-TEM Transmission Lines

An electromagnetic (EM) model for investigating the substrate coupling of the CMOS FMCW sensor is presented. Such EM model, which invokes the large-scale field analyses, can make a quantitative assessment of the EM coupling and can be applied into the system simulations for designing the CMOS FMCW sensor. A practical example is reported to demonstrate the feasibility of the proposed model. Furthermore, the model is applied to validate the effectiveness of the chip-scale leakage suppression by incorporating the complementary conducting strips transmission line (CCS-TL). The system simulations, which are performed with the proposed EM model, compared with those of the experimental results, showing a slight difference of 2.6 dB on the prediction of the isolation improvement.