Noninvasive measurement of subcutaneous temperature using active antenna and high gain low noise microwave radiometer

ABSTRACT

This paper presents a radiometric thermometer for non-invasive measurement of the internal body temperature. The proposed radiometric thermometer designed in 1.575 GHz band consists of a near-field probe and a high gain Dick radiometer. A phantom based on Agar material was developed to emulate the real tissue of skin and muscle for experiments. The measured results show that the active probe antenna provides additional 12.5 dB gain with noise figure less than 1dB, and the radiometer has a system gain of 50 dB and total noise figure of 1.738 dB at 1.575 GHz. The output voltage measured by the proposed 1.575 GHz microwave radiometer is 2.994 V when the water temperature is set to 25 °C, while it is 3.129 V when the water temperature is set to 80 °C. The study demonstrates that using the active probe connected to the radiometer can identify temperature difference of the body.

KEYWORDS:

• Radiometry
• active antenna
• low noise amplifier
• thermometer
• near-field probe antenna

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Ministry of Science and Technology, Taiwan [grant number MOST 108-2221-E-197-007-] .

Notes on contributors

Yu-Jen Chi

Yu-Jen Chi was born in Taipei, Taiwan, Republic of China (R.O.C.), in 1985. He received his B.S. and M.S. degrees in Electronic Engineering from National Ilan University, I-Lan, Taiwan, R.O.C., in 2007 and 2009, respectively, and the Ph.D. degree in Electrical Engineering from National Chiao Tung University, Hsinchu, Taiwan, R.O.C., in 2014. After graduation, he joined as faculty at Tamkang University, New Taipei City, Taiwan, in 2014, where he is currently an Associate Professor of Electrical and Computer Engineering. His main research interests are in RF circuits, multiband antennas for mobile devices, reconfigurable antennas, millimeter-wave antennas, metamaterials, and antennas for biomedical applications. Dr. Chi was the recipient of the Best Poster Award in the 2009 IEEE International Workshop on Antenna Technology (iWAT 2009). In 2019, he received the Best Paper Award in the International Technical Conference on Circuits/Systems, Computers and Communications (ITC-CSCC 2019). He also won the gold medal award at the 2022 Taiwan Innotech Expo Invention Competition.

Bing-Chao Huang

Bing-Chao Huang was born in New Taipei City, Taiwan, R.O.C., in 1997. He received his M.S. degree in electronic engineering from National Ilan University, Ilan, Taiwan, R.O.C., in 2021. He is currently an RF hardware engineer in Compal Electronics Inc., Taiwan. His research interests include RF circuit and antenna design.

Chien-Wen Chiu

Chien-Wen Chiu was born in Maoli, Taiwan, R.O.C., in 1962. He received his B. S. degree from National Taiwan Normal University, Taipei, Taiwan in 1984, and his M.S. and Ph. D. degrees in electrical engineering from National Taiwan University, Taipei, Taiwan, R.O.C., in 1990 and 1996, respectively. He is currently a Professor of the Electronic Engineering Department, National Ilan University in Ilan City, Taiwan. Prof. Chiu's research recently focuses on AIoT applications, ultra-wideband antenna design, and microwave radiometer design.