Signal Reduction Due to Layer of Water at Low-THz Frequency for Automotive Radar Applications

Low-Terahertz (Low-THz) radar is the new research trend for automotive applications, as it can provide higher image resolution compared to traditional automotive radars. The knowledge of the performance of radars in harsh and uncontrolled outdoor environment is fundamentally important for the development of automotive sensors. The presence of water causes losses in the propagation channel, therefore in our study the transmissivity through uniform layer of pure water, salty water with different levels of salt and actual seawater is measured at 300 GHz and 670 GHz. The measured results show good agreement with the theoretical model based on Fresnel reflection and transmission theory. The importance of our results is the demonstration of the potential of Low-THz automotive sensors in harsh and uncontrollable outdoor environment.