“…There is also another non-contact vital signs monitoring technique using radar sensors [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. The advantage of radar-based heart rate monitoring is that patients do not need to take off clothes and put on electrodes, which is convenient, and patients do not need to worry about privacy issues.…”