A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity Sensing
In this study, an ultra-compact humidity sensor based on a double-folded substrate integrated waveguide (SIW) re-entrant cavity was proposed and analyzed. By folding a circular re-entrant cavity twice along its two orthogonally symmetric planes, the designed structure achieved a remarkable size redu...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-07-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/19/15/3308 |
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| author | Zhihua Wei Jie Huang Jing Li Junshan Li Xuyang Liu Xingsheng Ni |
| author_facet | Zhihua Wei Jie Huang Jing Li Junshan Li Xuyang Liu Xingsheng Ni |
| author_sort | Zhihua Wei |
| collection | DOAJ |
| description | In this study, an ultra-compact humidity sensor based on a double-folded substrate integrated waveguide (SIW) re-entrant cavity was proposed and analyzed. By folding a circular re-entrant cavity twice along its two orthogonally symmetric planes, the designed structure achieved a remarkable size reduction (up to 85.9%) in comparison with a conventional TM<sub>010</sub>-mode circular SIW cavity. The operating principle of the humidity sensor is based on the resonant method, in other words, it utilizes the resonant properties of the sensor as signatures to detect the humidity condition of the ambient environment. To this end, a mathematical model quantitatively relating the resonant frequency of the sensor and the relative humidity (RH) level was established according to the cavity perturbation theory. The sensing performance of the sensor was experimentally validated in a RH range of 30%−80% by using a humidity chamber. The measured absolute sensitivity of the sensor was calculated to be 135.6 kHz/%RH, and the corresponding normalized sensitivity was 0.00627%/%RH. It was demonstrated that our proposed sensor not only has the merits of compact size and high sensitivity, but also benefits from a high Q-factor and ease of fabrication and integration. These advantages make it an excellent candidate for humidity sensing applications in various fields such as the agricultural, pharmaceutical, and food industries. |
| first_indexed | 2024-04-14T04:45:28Z |
| format | Article |
| id | doaj.art-501daff5d5cf45ec8c29b465b812c67d |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-04-14T04:45:28Z |
| publishDate | 2019-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-501daff5d5cf45ec8c29b465b812c67d2022-12-22T02:11:29ZengMDPI AGSensors1424-82202019-07-011915330810.3390/s19153308s19153308A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity SensingZhihua Wei0Jie Huang1Jing Li2Junshan Li3Xuyang Liu4Xingsheng Ni5College of Engineering and Technology, Southwest University, Chongqing 400715, ChinaCollege of Engineering and Technology, Southwest University, Chongqing 400715, ChinaCollege of Engineering and Technology, Southwest University, Chongqing 400715, ChinaCollege of Engineering and Technology, Southwest University, Chongqing 400715, ChinaCollege of Engineering and Technology, Southwest University, Chongqing 400715, ChinaCollege of Engineering and Technology, Southwest University, Chongqing 400715, ChinaIn this study, an ultra-compact humidity sensor based on a double-folded substrate integrated waveguide (SIW) re-entrant cavity was proposed and analyzed. By folding a circular re-entrant cavity twice along its two orthogonally symmetric planes, the designed structure achieved a remarkable size reduction (up to 85.9%) in comparison with a conventional TM<sub>010</sub>-mode circular SIW cavity. The operating principle of the humidity sensor is based on the resonant method, in other words, it utilizes the resonant properties of the sensor as signatures to detect the humidity condition of the ambient environment. To this end, a mathematical model quantitatively relating the resonant frequency of the sensor and the relative humidity (RH) level was established according to the cavity perturbation theory. The sensing performance of the sensor was experimentally validated in a RH range of 30%−80% by using a humidity chamber. The measured absolute sensitivity of the sensor was calculated to be 135.6 kHz/%RH, and the corresponding normalized sensitivity was 0.00627%/%RH. It was demonstrated that our proposed sensor not only has the merits of compact size and high sensitivity, but also benefits from a high Q-factor and ease of fabrication and integration. These advantages make it an excellent candidate for humidity sensing applications in various fields such as the agricultural, pharmaceutical, and food industries.https://www.mdpi.com/1424-8220/19/15/3308microwavehumidity sensorfolded SIWre-entrant cavity resonator |
| spellingShingle | Zhihua Wei Jie Huang Jing Li Junshan Li Xuyang Liu Xingsheng Ni A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity Sensing Sensors microwave humidity sensor folded SIW re-entrant cavity resonator |
| title | A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity Sensing |
| title_full | A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity Sensing |
| title_fullStr | A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity Sensing |
| title_full_unstemmed | A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity Sensing |
| title_short | A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity Sensing |
| title_sort | compact double folded substrate integrated waveguide re entrant cavity for highly sensitive humidity sensing |
| topic | microwave humidity sensor folded SIW re-entrant cavity resonator |
| url | https://www.mdpi.com/1424-8220/19/15/3308 |
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