Noncontact Vital Sign Detection using 24GHz Two-Dimensional Frequency Scanning Metamaterial Leaky Wave Antenna Array

This paper presents a noncontact vital sign detection scheme using a two-dimensional (2-D) frequency scanning metamaterial leaky wave antenna (L W A) array at 24 GHz band. To avoid the self-resonance issue of interdigital capacitors and the parasitic inductance of shorted stubs, gap capacitors and vialess open stub-loaded resonators are applied to design a one-dimensional (1-D) frequency scanning metamaterial L W A which has a wide scanning angle from -62° to +71° as the frequency increased from 23.4 to 25.4 GHz, in which the broadside is at 24.1 GHz. Four 1-D frequency scanning meta material LWAs and a series feeding network are combined to realize 2-D beam scanning. Noncontact vital sign detections using the proposed 2-D frequency scanning metamaterial L W A array can detect multiple persons with different heights. For demonstration, the respiration rate and heartbeat rate of two persons with standing and sitting postures are measured.