Table 1.
Comparison of different systems.
| References | P/S 1 | NSST 2 | NV 3 | ST 4 | SR 5 (Meter) | Technology | Frequency |
|---|---|---|---|---|---|---|---|
| [10] | Lying | 1 | 10 | HB 6 | on Body | CW 8 Radar | 1 GHz |
| [7] | Vertical: Standing/facing Antenna | 1 | 1 | RR 7 | No Contact | CW 8 Doppler Radar | 2.45 GHz |
| [4] | Standing/walking | 1 and 2 | 1 | HB 6 | Wearable Sensor | UWB 9 Wireless Communication | 3.5–4.5 GHz |
| [14] | Standing | 1 | 1 | RR 7 | 1 to 5 | UWB 9 Radar | - |
| [2,15] | Sitting/Supine | 1 | 3 | HB 6 | 1 | Quadrature Doppler Radar | 2.4 GHz |
| [8] | Standing | 1 | 1 | HB 6/RR 7 | Doppler Radar | 2.4 GHz | |
| [1] | Standing | 1 | 1 | HB 6/RR 7 | 1 | CW 8 Radar | 12 GHz/24 GHz |
| [9] | Standing | 1 | 1 | HB 6/RR 7 | 0.55 | UWB 9 Radar/Stepped Frequency CW 8 | 3 GHz |
| [16] | Sitting | 1 | 1 | HB 6/RR 7 | 1 | Doppler Radar | 5.8 GHz |
| [11] | Lying | 1 | 1 | HB 6 | 0.5 | Radar | 10, 15/18 GHz |
| [3] | Simulation | HB 6 | Direct Conversion Doppler Radar | 2.4 GHz | |||
| [17] | Sitting | 1 | 1 | HB 6 | Doppler Radar | 5.8 GHz/20 GHz | |
| [18] | Simulation | HB 6/RR 7 | 0.5, 1 & 2 | Millimetre-Wave Doppler Radar | 60 GHz | ||
| [19] | Walking | 1 | 2 | Target Position | 5 × 5 | UWB 9 Radar | 2.45 GHz |
| [20,21] | Walking | Multi | HB 6/RR 7 | 8 × 8 | Injection Locked I/Q Receivers | 2.4 GHz | |
| This Work | Standing/walking | 1 and 2 | 8 | RR 6 | 0.3–1.5 | CW 8 Radar | 4 GHz |
1 Positioning/Situation; 2 Number of subjects in same test; 3 Number of volunteers; 4 Signal type; 5 Sensing range; 6 Heartbeat; 7 Respiration rate; 8 Continuous wave; 9 Ultra-wideband.