Switch mode capacitive pressure sensors
Abstract Switch mode capacitive pressure sensors are proposed as a new class of microfabricated devices that transform pressure into a mechanically switching capacitance to form an analog-to-digital signal with zero power, high sensitivity, and a high signal-to-noise ratio. A pressure-sensitive gold...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Publishing Group
2022-12-01
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| Series: | Microsystems & Nanoengineering |
| Online Access: | https://doi.org/10.1038/s41378-022-00469-w |
| _version_ | 1797977423086616576 |
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| author | Nabil Shalabi Kyle Searles Kenichi Takahata |
| author_facet | Nabil Shalabi Kyle Searles Kenichi Takahata |
| author_sort | Nabil Shalabi |
| collection | DOAJ |
| description | Abstract Switch mode capacitive pressure sensors are proposed as a new class of microfabricated devices that transform pressure into a mechanically switching capacitance to form an analog-to-digital signal with zero power, high sensitivity, and a high signal-to-noise ratio. A pressure-sensitive gold membrane suspended over a capacitive cavity makes ohmic contact with patterned gold leads on the substrate, closing circuits to fixed on-chip capacitors outside the cavity and leading to significant step responses. This function is achieved by allocating the switch leads on the part of the counter electrode area, while the remaining area is used for touch mode analog capacitive sensing. The sensor microchip is prototyped through a novel design approach to surface micromachining that integrates micro-Tesla valves for vacuum sealing the sensor cavity, showing an unprecedented response to applied pressure. For a gauge pressure range of 0–120 mmHg, the sensor exhibits an increase of 13.21 pF with resultant switch events, each of which ranges from 2.53–3.96 pF every 12–38 mmHg, in addition to the touch mode linear capacitive increase between switches. The equivalent sensitivity is 80–240 fF/mmHg, which is 11–600× more than commercial and reported touch mode sensors operating in similar pressure ranges. The sensor is further demonstrated for wireless pressure tracking by creating a resonant tank with the sensor, showing a 32.5–101.6 kHz/mmHg sensitivity with frequency jumps led by the switch events. The developed sensor, with its promising performance, offers new application opportunities in a variety of device areas, including health care, robotics, industrial control, and environmental monitoring. |
| first_indexed | 2024-04-11T05:06:40Z |
| format | Article |
| id | doaj.art-a237244ad95c4526b000c94c14cc6563 |
| institution | Directory Open Access Journal |
| issn | 2055-7434 |
| language | English |
| last_indexed | 2024-04-11T05:06:40Z |
| publishDate | 2022-12-01 |
| publisher | Nature Publishing Group |
| record_format | Article |
| series | Microsystems & Nanoengineering |
| spelling | doaj.art-a237244ad95c4526b000c94c14cc65632022-12-25T12:19:47ZengNature Publishing GroupMicrosystems & Nanoengineering2055-74342022-12-018111410.1038/s41378-022-00469-wSwitch mode capacitive pressure sensorsNabil Shalabi0Kyle Searles1Kenichi Takahata2Department of Electrical and Computer Engineering, University of British ColumbiaSchool of Biomedical Engineering, University of British ColumbiaDepartment of Electrical and Computer Engineering, University of British ColumbiaAbstract Switch mode capacitive pressure sensors are proposed as a new class of microfabricated devices that transform pressure into a mechanically switching capacitance to form an analog-to-digital signal with zero power, high sensitivity, and a high signal-to-noise ratio. A pressure-sensitive gold membrane suspended over a capacitive cavity makes ohmic contact with patterned gold leads on the substrate, closing circuits to fixed on-chip capacitors outside the cavity and leading to significant step responses. This function is achieved by allocating the switch leads on the part of the counter electrode area, while the remaining area is used for touch mode analog capacitive sensing. The sensor microchip is prototyped through a novel design approach to surface micromachining that integrates micro-Tesla valves for vacuum sealing the sensor cavity, showing an unprecedented response to applied pressure. For a gauge pressure range of 0–120 mmHg, the sensor exhibits an increase of 13.21 pF with resultant switch events, each of which ranges from 2.53–3.96 pF every 12–38 mmHg, in addition to the touch mode linear capacitive increase between switches. The equivalent sensitivity is 80–240 fF/mmHg, which is 11–600× more than commercial and reported touch mode sensors operating in similar pressure ranges. The sensor is further demonstrated for wireless pressure tracking by creating a resonant tank with the sensor, showing a 32.5–101.6 kHz/mmHg sensitivity with frequency jumps led by the switch events. The developed sensor, with its promising performance, offers new application opportunities in a variety of device areas, including health care, robotics, industrial control, and environmental monitoring.https://doi.org/10.1038/s41378-022-00469-w |
| spellingShingle | Nabil Shalabi Kyle Searles Kenichi Takahata Switch mode capacitive pressure sensors Microsystems & Nanoengineering |
| title | Switch mode capacitive pressure sensors |
| title_full | Switch mode capacitive pressure sensors |
| title_fullStr | Switch mode capacitive pressure sensors |
| title_full_unstemmed | Switch mode capacitive pressure sensors |
| title_short | Switch mode capacitive pressure sensors |
| title_sort | switch mode capacitive pressure sensors |
| url | https://doi.org/10.1038/s41378-022-00469-w |
| work_keys_str_mv | AT nabilshalabi switchmodecapacitivepressuresensors AT kylesearles switchmodecapacitivepressuresensors AT kenichitakahata switchmodecapacitivepressuresensors |