The disclosed radar system may include a radar mechanism comprising a transmitter and at least one receiver. The radar system may also include a signal generator that generates a frequency-modulated radar signal. In addition, the radar system may include at least one frequency multiplier that, after multiplying a frequency of the frequency-modulated radar signal by a certain factor, synchronously passes the frequency-modulated radar signal to (1) the transmitter to be transmitted to at least one transponder located on a wearable device and (2) a processing device communicatively coupled to the receiver. The processing device may (1) detect a signal returned to the receiver from the transponder in response to the frequency-modulated radar signal and (2) calculate a distance between the transponder and the receiver based at least in part on an analysis of the signal returned from the transponder and the frequency-modulated radar signal received from the frequency multiplier.