Advanced sensors technology survey

This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed

Control Circuitry for Self-Repairable MEMS Accelerometers

A BISR (Built-in Self-Repairable) MEMS comb accelerometer with modularized design has been previously reported. In this paper, the differential capacitance sensing circuitry for MEMS comb accelerometer is discussed. The BISR control circuitry based on CMOS transmission gates (TGs) is proposed. Each BISR module is connected to the capacitance sensing circuitry through a transmission gate. By turning on or off a transmission gate, the corresponding module can be either connected to or isolated from the capacitance sensing circuitry. In this way, the faulty module can be easily replaced with a good redundant module for self-repair. The parasitic model for the BISR control circuitry is also analyzed. The analysis results show that the parasitic capacitance will not affect the proper operation of the BISR control circuitry. Furthermore, the signal strength will not be degraded due to the insertion of analog multiplexers. The control circuitry can effectively isolate the faulty module of the BISR MEMS comb accelerometer. Both BISR and non-BISR MEMS accelerometer designs are suggested and their performances are also extracted for comparison

Integrated Electronics for Wireless Imaging Microsystems with CMUT Arrays

Integration of transducer arrays with interface electronics in the form of single-chip CMUT-on-CMOS has emerged into the field of medical ultrasound imaging and is transforming this field. It has already been used in several commercial products such as handheld full-body imagers and it is being implemented by commercial and academic groups for Intravascular Ultrasound and Intracardiac Echocardiography. However, large attenuation of ultrasonic waves transmitted through the skull has prevented ultrasound imaging of the brain. This research is a prime step toward implantable wireless microsystems that use ultrasound to image the brain by bypassing the skull. These microsystems offer autonomous scanning (beam steering and focusing) of the brain and transferring data out of the brain for further processing and image reconstruction. The objective of the presented research is to develop building blocks of an integrated electronics architecture for CMUT based wireless ultrasound imaging systems while providing a fundamental study on interfacing CMUT arrays with their associated integrated electronics in terms of electrical power transfer and acoustic reflection which would potentially lead to more efficient and high-performance systems. A fully wireless architecture for ultrasound imaging is demonstrated for the first time. An on-chip programmable transmit (TX) beamformer enables phased array focusing and steering of ultrasound waves in the transmit mode while its on-chip bandpass noise shaping digitizer followed by an ultra-wideband (UWB) uplink transmitter minimizes the effect of path loss on the transmitted image data out of the brain. A single-chip application-specific integrated circuit (ASIC) is de- signed to realize the wireless architecture and interface with array elements, each of which includes a transceiver (TRX) front-end with a high-voltage (HV) pulser, a high-voltage T/R switch, and a low-noise amplifier (LNA). Novel design techniques are implemented in the system to enhance the performance of its building blocks. Apart from imaging capability, the implantable wireless microsystems can include a pressure sensing readout to measure intracranial pressure. To do so, a power-efficient readout for pressure sensing is presented. It uses pseudo-pseudo differential readout topology to cut down the static power consumption of the sensor for further power savings in wireless microsystems. In addition, the effect of matching and electrical termination on CMUT array elements is explored leading to new interface structures to improve bandwidth and sensitivity of CMUT arrays in different operation regions. Comprehensive analysis, modeling, and simulation methodologies are presented for further investigation.Ph.D

Design of sensor electronics for electrical capacitance tomography

The design of the sensor electronics for a tomographic imaging system based on electrical capacitance sensors is described. The performance of the sensor electronics is crucial to the performance of the imaging system. The problems associated with such a measurement process are discussed and solutions to these are described. Test results show that the present design has a resolution of 0.3 femtofarad. (For a 12-electrode system imaging an oil/gas flow, this represents a 2% gas void fraction change at the centre of the pipe) with a low noise level of 0.08 fF (RMS value), a large dynamic range of 76 dB and a data acquisition speed of 6600 measurements per second. This enables sensors with up to 12 electrodes to be used in a system with a maximum imaging rate of 100 frames per second, and thus provides an improved image resolution over the earlier 8-electrode system and an adequate electrode area to give sufficient measurement sensitivit

SPRZĘT I OPROGRAMOWANIE DO BADAŃ ELEMENTÓW ELEKTRONICZNYCH I CZUJNIKÓW

The main results of RETwix development are presented in the paper. RETwix is an universal hardware and software means for laboratory research, which can be used for investigation both electronic components and arbitrary electrical, thermal, chemical or biochemical processes. Sensors, actuators and signal transducers of the Analog Front-End are used for this purpose. The RETwix means includes two CV-LAB devices (Capacitance & Voltage LABoratory) and UA-LAB (Universal Analog LABoratory). The peculiarities of construction and examples of RETwix using are described.Główne wyniki opracowania RETwix zostały przedstawione w artykule. RETwix jest uniwersalnym sprzętem i oprogramowaniem do badań laboratoryjnych, które można wykorzystać do badania zarówno komponentów elektronicznych, jak i dowolnych procesów elektrycznych, termicznych, chemicznych lub biochemicznych. W tym celu zostały wykorzystane czujniki, aktuatory i przetworniki sygnału Analog Front-End. RETwix zawiera dwa urządzenia CV-LAB (Capacitance & Voltage LABoratory) oraz UA-LAB (Universal Analog LABoratory). Zostały opisane osobliwości budowy oraz przykłady zastosowania RETwix

Development of a Capacitance Sensor System to Measure Ultra-Low Water Content in Crude Oil

The capacitance sensor system had been applied in various applications including measurement of water content in crude oil. The purity of crude oil is graded based on the water content found in it. The lesser the amount of water detected, the higher the purity of crude oil. The determination of water content is crucial as it directly reflects the quality of crude oil. However, the capacitance sensor system is limited to a high water concentration measurement. In this project, a higher resolution measurement is introduced which utilizes the capacitance sensor system based on phase angle conversion. The presence of water inside the crude oil is indicated by the change in capacitance value and results in a phase shift. The sensor system is capable of detecting a very small change of capacitance, meaning it is able to measure ultra-low water content inside the crude oil