An RTE-based Compact Model for Light Propagation Simulation in fNIRS Systems.

As an emerging category of brain-computer interface technology, functional near-infrared spectroscopy (fNIRS) has garnered significant attention due to its non-invasiveness, portability, and energy efficiency. However, the efficient design and optimization of circuits for complex fNIRS systems remain unresolved challenges in the field. In this study, we propose an RTE-based compact model for simulating light propagation in biological tissues, serving as an effective tool to aid in the design of the signal chain for fNIRS systems. The paper begins by providing a comprehensive theoretical derivation of the model construction. Subsequently, the model is implemented using MATLAB and Verilog-A, and simulations are performed in SIMULINK and Cadence Virtuoso respectively. Compared with the widely used FEM technique, the simulation speed of the model is improved by 300×, while the simulation error of the model stays below 5%.