Long-Distance Heart Sound Detection using 122 GHz CW Radar with 3D Printed High-Gain Antennas

This contribution presents a 122 GHz continuous wave (CW) radar system capable of detecting human heart sounds over a distance of at least five meters. A bidirectional long short-term memory (LSTM) neural network is used to extract precise inter-beat-intervals (IBIs) from the radar data. A small-scale human trial with two persons is carried out, and the resulting accuracy of the system is compared to a gold-standard electrocardiogram (ECG). The proposed system shows a mean absolute error of 5 ms and a standard deviation (SD) of 63 ms compared to the ECG IBIs.