Total Power Radiometer for Medical Sensor Applications Using Matched and Mismatched Noise Sources
This paper presents a simple total power radiometer to noninvasively measure the temperature of the human body. The proposed 3-GHz radiometer consists of an antenna collecting the noise power generated by a target, a low-noise and high-gain receiver amplifying the noise power, and a detector convert...
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| Format: | Article |
| Language: | English |
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MDPI AG
2017-09-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/17/9/2105 |
| _version_ | 1811279054023688192 |
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| author | Woojin Park Jinho Jeong |
| author_facet | Woojin Park Jinho Jeong |
| author_sort | Woojin Park |
| collection | DOAJ |
| description | This paper presents a simple total power radiometer to noninvasively measure the temperature of the human body. The proposed 3-GHz radiometer consists of an antenna collecting the noise power generated by a target, a low-noise and high-gain receiver amplifying the noise power, and a detector converting the noise power to voltage. A single-pole-triple-throw (SP3T) switch is placed between the antenna and the receiver, while a personal computer is used to control the SP3T switch, collect and process the data such as detector output voltages and physical temperatures of the reference noise sources and the target. The fabricated radiometer shows a good performance agreement with a thermometer in the temperature measurement of water from 25.0 to 43.1 °C. For the accurate prediction of the target temperature, the radiometer is calibrated adaptively to the environment and radiometer variations. For this purpose, two reference noise sources (hot and cold) are proposed using matched and mismatched resistors at room temperature. These resistor-based noise sources offer a reliable performance without complex temperature control systems. Furthermore, they can be easily calibrated in real time by periodically measuring the physical temperatures of the resistors. In addition, the logarithmic detector with wide dynamic range is adopted and logarithmically-fitted based on the measurement results instead of linear approximation, which reduces the error caused by the limited dynamic range of resistor-based noise sources. In order to further increase the accuracy, the performance imbalances between ports in the SP3T switch are also taken into account by employing offsets in the radiometer output voltages. |
| first_indexed | 2024-04-13T00:47:55Z |
| format | Article |
| id | doaj.art-80d8938271d84880b1492a342cb18a19 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-04-13T00:47:55Z |
| publishDate | 2017-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-80d8938271d84880b1492a342cb18a192022-12-22T03:09:57ZengMDPI AGSensors1424-82202017-09-01179210510.3390/s17092105s17092105Total Power Radiometer for Medical Sensor Applications Using Matched and Mismatched Noise SourcesWoojin Park0Jinho Jeong1Department of Electronic Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, KoreaDepartment of Electronic Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, KoreaThis paper presents a simple total power radiometer to noninvasively measure the temperature of the human body. The proposed 3-GHz radiometer consists of an antenna collecting the noise power generated by a target, a low-noise and high-gain receiver amplifying the noise power, and a detector converting the noise power to voltage. A single-pole-triple-throw (SP3T) switch is placed between the antenna and the receiver, while a personal computer is used to control the SP3T switch, collect and process the data such as detector output voltages and physical temperatures of the reference noise sources and the target. The fabricated radiometer shows a good performance agreement with a thermometer in the temperature measurement of water from 25.0 to 43.1 °C. For the accurate prediction of the target temperature, the radiometer is calibrated adaptively to the environment and radiometer variations. For this purpose, two reference noise sources (hot and cold) are proposed using matched and mismatched resistors at room temperature. These resistor-based noise sources offer a reliable performance without complex temperature control systems. Furthermore, they can be easily calibrated in real time by periodically measuring the physical temperatures of the resistors. In addition, the logarithmic detector with wide dynamic range is adopted and logarithmically-fitted based on the measurement results instead of linear approximation, which reduces the error caused by the limited dynamic range of resistor-based noise sources. In order to further increase the accuracy, the performance imbalances between ports in the SP3T switch are also taken into account by employing offsets in the radiometer output voltages.https://www.mdpi.com/1424-8220/17/9/2105detectormicrowave radiometernoisetemperatureremote sensing |
| spellingShingle | Woojin Park Jinho Jeong Total Power Radiometer for Medical Sensor Applications Using Matched and Mismatched Noise Sources Sensors detector microwave radiometer noise temperature remote sensing |
| title | Total Power Radiometer for Medical Sensor Applications Using Matched and Mismatched Noise Sources |
| title_full | Total Power Radiometer for Medical Sensor Applications Using Matched and Mismatched Noise Sources |
| title_fullStr | Total Power Radiometer for Medical Sensor Applications Using Matched and Mismatched Noise Sources |
| title_full_unstemmed | Total Power Radiometer for Medical Sensor Applications Using Matched and Mismatched Noise Sources |
| title_short | Total Power Radiometer for Medical Sensor Applications Using Matched and Mismatched Noise Sources |
| title_sort | total power radiometer for medical sensor applications using matched and mismatched noise sources |
| topic | detector microwave radiometer noise temperature remote sensing |
| url | https://www.mdpi.com/1424-8220/17/9/2105 |
| work_keys_str_mv | AT woojinpark totalpowerradiometerformedicalsensorapplicationsusingmatchedandmismatchednoisesources AT jinhojeong totalpowerradiometerformedicalsensorapplicationsusingmatchedandmismatchednoisesources |