Time-Division Multiple Tags Based Multitarget Respiration Monitoring Radar With a Single Beam

A novel multitarget respiration monitoring radar scheme based on time-division multiple tags (TDMTs) is proposed. The key innovation in this letter is the introduction of the TDMT, which leverages the frequency-division characteristic of multiple frequency-tunable tags attached on different human bodies to implement the time division of the reflected beat signals in frequency modulated continuous wave (FMCW) system, which is used to separate respiration signals from two closely spaced human targets. To validate the proposed scheme, a radar prototype and two tunable tags have been developed. The experimental results verify the effectiveness of the proposed method by monitoring two closely spaced targets in indoor environment.