Design and implementation of a 2.45 GHz RF sensor for non-contacting monitoring vital signs

The design and implementation of a non-contact RF (radio frequency) sensor that can monitor vital signsrespiration rate and heat rate is proposed. The designed low-cost system operates at 2.45 GHz by using one single Yagi antenna system to transmit and receive RF signals, realizes a miniaturized design of PCB that integrates both microwave transceivers and receivers. The gain of the sensor is 8.96 dB. The return loss is −22.87 dB at 2.45 GHz and the directionality of the antenna is satisfactory for monitoring vital signs. In comparison with pulse sensor and respiration sensor, it has been validated that the sensor could detect the respiration and heartbeat with mean error for the respiration rate within 0.5 beat/min and the heart rate within 1.9 beat/min.