MEMS-Enabled Wireless Ureteral Stent with Integrated Antenna for Local Pressure Monitoring

Darestani, Mohammad Reza Yousefi; Shalabi, Nabil; Lange, Dirk; Chew, Ben H.; Takahata, Kenichi

doi:10.1109/transducers50396.2021.9495464

Cited by 1 publication

(3 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These capabilities could uniquely advance a broad range of application areas that need pressure tracking and management, including medical devices, robotics, human interface devices, environmental and industrial pressure alarms, as well as applications that go beyond analog sensing with pressure switching into other circuit elements such as a wake-up circuit in zero power electronics and the Internet of Things. The capacitive principle of the device allows for the implementation of resonant wireless sensing through simple passive circuitry without needing a dedicated power source, which greatly aids the miniaturization of the wireless sensors [28][29][30][31][32][33] .…”

Section: Introductionmentioning

confidence: 99%

“…Stents, or tubular scaffolds implanted to open diseased or narrowed ducts inside the body, are an exemplary device area for this technology. Smart vascular and ureteral stents have been reported for RF sensing of blood and kidney pressures using integrated MEMS capacitive sensors for wireless diagnosis of their target diseases (known as restenosis and hydronephrosis, respectively) 28,[31][32][33] . The proposed switch mode sensor allows smart implants to automatically issue an alert when the local pressure reaches a dangerous threshold level, thereby enabling immediate necessary treatments.…”

Section: Introductionmentioning

confidence: 99%

“…The proposed switch mode sensor allows smart implants to automatically issue an alert when the local pressure reaches a dangerous threshold level, thereby enabling immediate necessary treatments. Signal damping and noise in RF communication with a device inside the body remains a challenge, particularly in resolving small pressure/capacitance changes when using conventional analog sensors 28,[31][32][33] . This can be effectively addressed by a switch mode sensor that provides distinct step increases of capacitance at designed pressure levels, which, in turn, vastly raises the sensitivity and reliability of sensing through the implant.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Switch mode capacitive pressure sensors

2022

Self Cite

View full text Add to dashboard Cite

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.

show abstract