A prototype fibre-optic-based Fizeau medical pressure and temperature sensor system using coherence reading

This paper presents an optical fibre pressure and temperature sensor (OFPTS) system, which is adapted for use as a urodynamic pressure measurement system (UPS) for differential pressure measurement with temperature compensation. The OFTPS is based on a Fabry Perot interferometer (FPI), which acts as a pressure sensor and includes an embedded fibre Bragg grating (FBG) for temperature measurement. The sensor system is evaluated in a lower urinary tract (LUT) simulator, which simulates the bladder, rectum and detrusor muscle. The system was benchmarked against a commercially available urodynamic system, at the University Hospital Limerick (UHL) Urology Clinic. Both systems demonstrate a high correlation with a relative pressure variation of less than ±2.8cmH₂O for abdominal and ±4cmH₂O for vesical pressure. The repetitive measurement of the OFPTS system in the LUT simulator against the commercial system demonstrated the high repeatability. Furthermore, the low fabrication cost makes the OFPTS a potentially interesting instrument for urodynamic and other medical applications.

A single-chip pressure and temperature sensor system with on chip electronics for measuring blood pressure and temperature in human arteries is presented. The pressure sensor is fabricated by surface micromachining techniques using a CMOS process. For the signal processing switched capacitor circuits are used. The sensor signals are converted to a pulse width modulated output signal.

IT HAS been found that the design of a good pressure or temperature sensing system requires more than choosing a sensing probe which has good internal performance and reproducibility. The external effects of the probe on its environment and the effects of the environment on the performance of the probe must always be considered. In fact, a good job usually requires complete knowledge of the flow pattern, flow boundaries, boundary layer thickness, Mach number range, pressure range, and temperature range. The design, development, and manufacture of individual probes, rakes, and complete integrated sensing systems have been the specialty of the Aero Research Instrument Company, Inc., for the past three years. ARi has also performed wind tunnel tests and calibrations on a contract basis and has developed instrument wind tunnels for other agencies. A typical example of the latter is a wind tunnel now under construction designed to operate at total temperatures to 4800 R and up to Mach 1.0 at static pressures from y 5 to 2 atmospheres. This is probably the highest temperature, continuous flow wind tunnel in existence.

Biomedical researchers and clinicians have long sought the development of small, low cost and disposable sensors for in-vivo measurements of pressure and temperature. These sensors typically measure static or quasi-static pressure and temperature and are required for direct and accurate measurements over a wide range of operational, enviromental and (especially) handling conditions.

We report on an application of a pulsed distributed feedback quantum cascade laser (QCL) for long open path readout system of multiple passive temperature, pressure, humidity or other sensors. Unlike the usually used active sensors, containing radio or optical data transmitters, the presented system does not contains any active transmitters at the sensors side. The QCL and the receiver are displaced on one side of the path. On the opposite path side, a modified Michelson interferometer, based on corner cube retroreflectors, is placed. One retroreflector is fixed and another one is attached to the appropriate sensor, which moves it when the measured parameter is changed. The useful travel range of the movable retroreflector is less than lambda/2 (4.8 mum) to obtain a monotonic transfer function between the measured parameters and the received signals. This system measures distances in the micrometer and sub-micrometer range but displaced up to a few kilometers from the transmitter/receiver station. A relatively long laser pulse of 150-200 ns is used to scan the interferometers and to read out the information. During the pulse, the QCL frequency is swept within a 40 GHz range. This frequency sweeping allows decreasing significantly the influence of the atmospheric turbulence over the accuracy of the data transfer. When the swept radiation illuminates the interferometer, oscillations in the received signal occur due to the interference between the different parts of the beam. The period of the oscillations and the oscillation phase depend on the distance between retroreflectors and the changes in this distance, respectively. The main advantage of the system proposed is that a single transmitter-receiver pair allows reading out multiple sets of completely passive sensors offering high level of data protection due to the low beam divergency

Nowadays, three-dimensional (3D) integration has been widely applied in semiconductor and electronics industry. When 3D integration applied in MEMS (micro electromechanical system) packaging, it is possible to stack host MEMS chip/wafer with other chips/wafers (such as ASIC) to lower package profile and realize area array sensor system. In this paper, a miniaturized piezoresistive pressure sensor system with TSV structure has been designed to demonstrate the application of TSV in MEMS packaging. TSV in pressure sensor chip is designed to provide communication paths for electrical signals. Cu/Sn bump is electroplated after exposing TSV from backside and backside metallurgy. Signal read-out chip contains redistribution circuits and Au studs. The pressure sensor chip and signal read-out chip are flip chip bonded using Au-Sn eutectic bonding. To realize this pressure sensor system, a systematic process flow including piezoresistors fabrication and circuits patterning, TSV process, flip chip bonding, polymer hermetic sealing is designed and implemented experimentally.

This paper describes initial development and testing of a novel high temperature capacitive pressure sensor system. The pressure sensor system consists of two 4H-SiC 11-stage ring oscillators and a SiCN capacitive pressure sensor. One oscillator has the capacitive pressure sensor fixed at one node in its feedback loop and varies as a function of pressure and temperature while the other provides a pressure-independent reference frequency which can be used to temperature compensate the output of the first oscillator. A two-day repeatability test was performed up to 500C on the oscillators and the oscillator fundamental frequency changed by only 1. The SiCN capacitive pressure sensor was characterized at room temperature from 0 to 300 psi. The sensor had an initial capacitance of 3.76 pF at 0 psi and 1.75 pF at 300 psi corresponding to a 54 change in capacitance. The integrated pressure sensor system was characterized from 0 to 300 psi in steps of 50 psi over a temperature range of 25 to 500C. The pressure sensor system sensitivity was 0.113 kHzpsi at 25C and 0.026 kHzpsi at 500C.

Preface. About the Authors. 1 Smart Sensor Systems: Why? Where? How? ( Johan H. Huijsing ). 1.1 Third Industrial Revolution. 1.2 Definitions for Several Kinds of Sensors. 1.3 Automated Production Machines. 1.4 Automated Consumer Products. 1.5 Conclusion. References. 2 Interface Electronics and Measurement Techniques for Smart Sensor Systems ( Gerard C.M. Meijer ). 2.1 Introduction. 2.2 Object-oriented Design of Sensor Systems. 2.3 Sensing Elements and Their Parasitic Effects. 2.4 Analog-to-digital Conversion. 2.5 High Accuracy Over a Wide Dynamic Range. 2.6 A Universal Transducer Interface. 2.7 Summary and Future Trends. Problems. References. 3 Silicon Sensors: An Introduction ( Paddy J. French ). 3.1 Introduction. 3.2 Measurement and Control Systems. 3.3 Transducers. 3.4 Transducer Technologies. 3.5 Examples of Silicon Sensors. 3.6 Summary and Future Trends. References. 4 Optical Sensors Based on Photon Detection ( Reinoud F. Wolffenbuttel ). 4.1 Introduction. 4.2 Photon Absorption in Silicon. 4.3 The Interface: Photon Transmission Into Silicon. 4.4 Photon Detection in Silicon Photoconductors. 4.5 Photon Detection in Silicon pn Junctions. 4.6 Detection Limit. 4.7 Photon Detectors with Gain. 4.8 Application Examples. 4.9 Summary and Future Trends. Problems. References. 5 Physical Chemosensors ( Michael J. Vellekoop ). 5.1 Introduction. 5.2 Physical Chemosensing. 5.3 Energy Domains. 5.4 Examples and Applications. 5.5 Examples of in situ Applications. 5.6 Microfluidics Devices. 5.7 Conclusions. Problems. References. 6 Thermal Sensors ( Sander (A.W.) van Herwaarden ). 6.1 The Functional Principle of Thermal Sensors. 6.2 Heat Transfer Mechanisms. 6.3 Thermal Structures. 6.4 Temperature-Difference Sensing Elements. 6.5 Sensors Based on Thermal Measurements. 6.6 Summary and Future Trends. Problems. References. 7 Smart Temperature Sensors and Temperature-Sensor Systems ( Gerard C.M. Meijer ). 7.1 Introduction. 7.2 Application-related Requirements and Problems of Temperature Sensors. 7.3 Resistive Temperature-sensing Elements. 7.4 Temperature-sensor Features of Transistors. 7.5 Smart Temperature Sensors and Systems. 7.6 Case Studies of Smart-sensor Applications. 7.7 Summary and Future Trends. Problems. References. 8 Capacitive Sensors ( Xiujun Li and Gerard C.M. Meijer ). 8.1 Introduction. 8.2 Basics of Capacitive Sensors. 8.3 Examples of Capacitive Sensors. 8.4 The Design of Electrode Configurations. 8.5 Reduction of Field-bending Effects: Segmentation. 8.6 Selectivity for Electrical Signals and Electrical Parameters. 8.7 Summary and Future Trends. Problems. References. 9 Integrated Hall Magnetic Sensors ( Radivoje S. Popovi'c and Pavel Kejik ). 9.1 Introduction. 9.2 Hall Effect and Hall Elements. 9.3 Integrated Hall Sensor Systems. 9.4 Examples of Integrated Hall Magnetic Sensors. Problems. References. 10 Universal Asynchronous Sensor Interfaces ( Gerard C.M. Meijer and Xiujun Li ). 10.1 Introduction. 10.2 Universal Sensor Interfaces. 10.3 Asynchronous Converters. 10.4 Dealing with Problems of Low-cost Design of Universal Interface ICs. 10.5 Front-end Circuits. 10.6 Case Studies. 10.7 Summary and Future Trends. Problems. References. 11 Data Acquisition for Frequency- and Time-domain Sensors ( Sergey Y. Yurish ). 11.1 Introduction. 11.2 DAQ Boards: State of the Art. 11.3 DAQ Board Design for Quasi-digital Sensors. 11.4 Universal Frequency-to-digital Converters (UFDC). 11.5 Applications and Examples. 11.6 Summary and Future Trends. Problems. References. 12 Microcontrollers and Digital Signal Processors for Smart Sensor Systems ( Ratcho M. Ivanov ). 12.1 Introduction. 12.2 MCU and DSP Architectures, Organization, Structures, and Peripherals. 12.3 Choosing a Low-Power MCU or DSP. 12.4 Timer Modules. 12.5 Analog Comparators, ADCs, and DACs as Modules of Microcontrollers. 12.6 Embedded Networks and LCD Interfacing. 12.7 Development Tools and Support. 12.8 Conclusions. References Sites. Appendix A Material Data. Appendix B Conversion for non-SI Units. Index.

Monolithic integrated pressure sensor systems are realized by the combination of two different technologies: CMOS-technology for the electrical part and MEMS-technology for the pressure sensor part. The paper describes the modification of such pressure sensor systems to extend their original nominal pressure range from 600 mbar to the low pressure range of 40 mbar by keeping a sufficient signal to noise ratio and without changing the original mask set. The general methodology is described, and a comparison between theoretical signal evaluation and measurement is given. The study concentrates on the aspect of the different piezocoefficients for various Boron doping concentrations of the piezoresistors

A pressure and shear sensor system for stress measurement at lower limb residuum/socket interface

The integration of the Internet of Things (IoT) into smart medical devices and health equipment represents a significant advancement in the healthcare sector. These smart devices, equipped with sensors and connectivity features, enable continuous monitoring, data collection, and analysis, enhancing patient care and operational efficiency. This chapter explores the landscape of IoT-enabled smart medical devices, highlighting their potential to revolutionize patient monitoring, diagnostics, and treatment. Key applications include various patient health monitoring such as temperature sensor, ECG sensor, smart contact lens, pressure sensor, pulse oximeter and many more patient monitoring systems. The benefits of these technologies encompass improved patient outcomes, real-time health tracking, and Additionally, personalized the chapter medicine. addresses challenges such as data security, privacy concerns, and the need for standardization in the deployment of IoT in healthcare. The current trends and future direction states that the transformative impact of IoT on medical devices and health equipment paves a way for a more connected, efficient and a patient centric healthcare ecosystem.

This paper presents recent results on a NASA program to build a low-loss, multi-sensor, SAW temperature sensor system. Multi-track CDMA tags have been previously studied, which helps to balance the tag reflectivity from chip-to-chip. Normally the IDT's beam extends over all tracks and the bandwidth is the same for all tracks, and there is no significant advantage over a single-track using this approach. Wideband tags using orthogonal frequency coding (OFC) can use multi-frequency chips subdivided into multi-tracks with low loss operation. Each track has one or more chips, with each chip having a different chip frequency. The track-transducer is then designed to operate only over the required frequency bands; making each non-interacting track low loss. The overall transducer embodiment is now tailored for optimum performance for loss, coding and chip reflectivity. If all tracks are electrically in parallel, the overall transducer Q remains the same as a short wideband IDT, but the electrical reflection coefficient is chosen for minimum loss or matching. Measured parallel track OFC Sn response was measured where the reflection coefficient is nearly optimized for minimum unmatched loss. In comparison, for a short wideband transducer of equivalent bandwidth, the reflection coefficient is close to unity with large unmatched loss. An analytic, synthesis model and the coupling-of-modes model (COM) were developed for predictions. Experimental devices were fabricated on YZ LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> at 250, 500 and 915 MHz for evaluation. Several frequency, track number and chip configurations were designed and fabricated having various beam widths. The Sn response illustrates the rotation on the Smith chart around the constant Q arc. Current designs indicate that an unmatched sensor loss is approaching 10 dB, which is 20-40 dB less loss than typical CDMA performance. This paper will present the approaches, analysis, design, layout, and results of several multi-track OFC devices, having several differing operating frequencies and embodiments. The experimental results agree remarkably well with analysis and predictions and confirm the advantageous of the multi-track approaches. The results of this work will ultimately produce lowloss SAW sensor platforms, which lead to greater sensor system range and performance.

This study presents the environmental sensing hub with vertical integration of humidity, pressure, and temperature sensors on a single chip (Fig. 1). The presented device is fabricated through TSMC 0.18 <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">µ</inf> m 1P6M CMOS platform, and in-house post-CMOS processes. The proposed environmental sensing hub has following features: (1) monolithic integration of humidity (H), pressure (P), and temperature (T) sensors to form the sensing hub, (2) vertical integration of H/P/T sensors to reduce the footprint of chip (as compare with the existing side by side designs). Measurement results of presented environmental sensing hub are: humidity sensor with sensitivity of 2.025fF/%RH, pressure sensor with sensitivity of 0.38fF/kPa, and diode temperature detector with sensitivity of 1.6mV/ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sup> C.

We have proposed “Smart Artificial Heart (SAH)” through which doctor can observe the real-time condition of the patients and artificial heard whenever doctor wants to and wherever the patient is, and doctor can treat the patients properly using SAH in case of emergency. The purpose of this study is to develop the small size, good accuracy, bloodless and noninvasiv sensor system for SAH. The sensor system consists of the temperature sensor, flow meter and pressure sensor, which measures blood temperature pump flow, pump-inlet-pressure and pump-outlet-pressure respectively. In the test of the mock experiment and animal experiment, the following results were obtained: (1) The temperature sensor using semiconductor sensor which have good accuracy than thermocouple thermometer was built into the pump, and the reproducibility was ±0.3% and the linearity was ±0.1% in the moc experiment. (2) The doppler flow meter was built into the pump. And the measurement of the doppler flow meter built in the pump was compared with the measurement of the ready-made flow meter on the tube. The coefficient of correlation was 0.815 in the mock experiment and 0.758 in the animal experiment. (3) The pressure sensor using the strain gauge was fixed on the inlet and outlet point of the pump, and in the animal experiment, the coefficient of correlation was over 0.75 in the pump-inlet-pressure and pump out-outlet-pressure compared with LVP and AoP respectively. We could unify the sensor system including the circuits and me probe for the artificial heart. The effectiveness is confirmed through the sensor system applied to the long-term animal experiment.

On-line monitoring technology for internal corrosion of CO2-EOR oil field