Radar sensor system for blood pressure sensing, and associated method

A method comprising:

• transmitting a plurality of radar signals towards a surface of a skin using a millimeter-wave radar;
• receiving a plurality of reflected radar signals using the millimeter-wave radar;
• using the millimeter-wave radar, generating a displacement signal indicative of a distension of the surface of the skin based on the reflected radar signals, the skin covering a blood vessel;
• determining temperature values indicative of measured temperatures of the skin using a temperature sensor;
• during a calibration time interval,
• applying electromagnetic energy to the skin via the transmitted plurality of radar signals using the millimeter-wave radar to cause an increase in the temperature of the skin,
• collecting a plurality of distension values from the displacement signal, the plurality of distension values associated with a respective plurality of the temperature values determined using the temperature sensor, wherein the plurality of the temperature values are indicative of the increase in the temperature of the skin caused by the applied electromagnetic energy, and
• determining compensation coefficients associated with the plurality of the temperature values;
• and
• after the calibration time interval,
• collecting a first distension value from the displacement signal, the first distension value associated with a respective first temperature value of the temperature values, wherein the first distension value is separate from the plurality of distension values, and the first temperature value is separate from the plurality of the temperature values, and
• determining a blood pressure based on the first distension value, the first temperature value, and the determined compensation coefficients.

A wearable device comprising:

• a millimeter-wave radar configured to:
• transmit a plurality of a plurality of radar signals towards a surface of a skin,
• receive a plurality of reflected radar signals, and
• generate a displacement signal indicative of a distension of the surface of the skin based on the reflected radar signals;
• a temperature sensor configured to determine temperature values indicative of measured temperatures of the surface of the skin;
• and
• a controller configured to:
• during a calibration time interval,
• cause the millimeter-wave radar to apply electromagnetic energy to the skin to cause an increase in temperature of the skin,
• collect a plurality of distension values from the displacement signal, the plurality of distension values associated with a respective plurality of the temperature values determined using the temperature sensor, the plurality of the temperature values indicative of the temperature increase of the skin caused by the applied electromagnetic energy, and
• determine compensation coefficients associated with the plurality of the temperature values, and
• after the calibration time interval,
• collect a first distension value from the displacement signal, the first distension value associated with a respective first temperature value of the temperature values, wherein the first distension value is separate from the plurality of distension values, and the first temperature value is separate from the plurality of the temperature values,
• determine a blood pressure based on the first distension value, the first temperature value, and the determined compensation coefficients.