A 1.4-GHz radiometer for internal body temperature measurements

This paper presents a 1.4-GHz microwave radiometer for noninvasive measurements of internal (core) body temperature. The 1.4GHz frequency of operation is chosen for deep cm-range penetration into tissues, as well as low radio-frequency interference (RFI). The radiometer is implemented with off-the-shelf components with several near-field probes. System measurements and temperature estimation are compared for a dipole and circular patch probe, with about 0.5K temperature sensitivity on a single-layer water phantom. These results show a path to a wearable thermometer for sub-surface body temperature measurements.