Software Defined Radars for Low-Cost Healthcare Monitoring and Imaging Systems: A Comprehensive Review

Technological advancements have enabled the implementation of software-defined radars (SDRadar) as low-cost, reconfigurable radar systems using software processing. The adaptability and reusability of SDRadar have expanded their application in many healthcare applications. An SDRadar is usually designed with a basic architecture that includes a transmitter, receiver, and a digital signal processor. The transmitter sends out radio waves, which are reflected, or penetrated and scattered, from the targeted object. Those reflected or scattered signals are captured by the received and processed using a digital signal processor to extract useful information. This flexibility allows SDRadar to be easily reprogrammed for different tasks without changing the hardware. To support and motivate researchers and practitioners of various scientific and engineering expertise, a state-of-the-art review of SDRadar, focusing on the healthcare applications of continuous waves, frequency-modulated continuous waves, and stepped-frequency continuous-wave modes, is presented. The review focuses on heart rate and respiration monitoring, as well as medical radar imaging, over a broad frequency range from 0.2 GHz to 20 GHz. Future research trends and potential advancements are also discussed.