Temperature Compensation Research Papers - Academia.edu (original) (raw)

2025, 2012 Solid-State, Actuators, and Microsystems Workshop Technical Digest

For the first time, lateral-extensional micromachined resonators fabricated on highly n-type doped silicon substrates and aligned to the [100] crystalline orientation are shown to exhibit an adjustable turnover temperature. This behavior commonly observed in quartz resonators is a key to achieving exceptional temperature stability in oven-controlled crystal oscillators. To demonstrate the effect of doping concentration and resonator alignment to different crystalline orientations, the thinfilm piezoelectric-on-silicon (TPoS) platform is utilized. It is shown through combined theoretical analysis and finite element simulation that the turnover temperature is a sensitive function of doping concentration and also can be adjusted by changing the thickness of the resonant structure. In order to experimentally validate these results, similar resonators are fabricated on three silicon-on-insulator (SOI) substrates and the temperature variation of frequency for several devices are measured and the trends are shown to agree with theory. The minimum temperature variation of frequency is measured for a ~25MHz TPoS resonator aligned to the [100] crystalline orientation showing a maximum frequency variation of 148ppm over the -40°C to 85°C temperature range. This is more than 20x reduction compared to the earlier results from similar uncompensated devices.

2025, 2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS)

This work demonstrates electronically controllable frequency trimming and temperature compensation of individual single crystalline silicon thermal-piezoresistive resonators via localized self-induced thermal oxidation. Frequency trimming as high as ~3.7% has been demonstrated using this technique for a 53MHz resonator. At the same time, the formed oxide layer using this technique can significantly suppress the temperature coefficient of frequency (TCF) for such resonators. TCF values as low as 0.2 ppm/ºC have been demonstrated for resonators with initial TCF of -37ppm/ºC.

2025, Procedia Engineering

2025, Journal of Theoretical Biology

From the viewpoint that reaction rates will change with temperature, we present a general method to build circadian clock models that generate circadian oscillations with almost constant period under different constant ambient temperature, and propose an algorithm estimating the parameter condition for compensated period against the change of temperature based on the PER single-feedback loop model of A model for circadian oscillations in the Drosophila period protein (PER). Proc. R. Soc. London Ser. B 261, 319-324] for Drosophila. We show that the model with derived parameters can realize the temperature compensation over a wide range of temperature, and simultaneously can realize the entrainment to temperature cycles.

2025, Journal of Microelectromechanical Systems

2025, Journal of Alloys and Compounds

The flow curve is constructed by flow stress data obtained from compression test conducted at different temperature and strain rate. Accurate flow stress model is crucial for investigating magnesium alloys deformation behaviour at the elevated temperatures. An analytical method, which reflects temperature, strain and strain rate effect by introducing temperature-compensated strain rate (Zener-Hollomon Parameter), is proposed in this study. This model has been applied on the experimental data and predicted flow stress curve match well with those measurements.

2025, Desalination

Appropriate devices for obtaining either interstitial water or grain particle samples or for measuring dissolved oxygen (DO) at depth within the interior of large-scale, industrial granular bed filters are currently lacking. We developed two innovative samplers for studying a Rapid Sand Filter (RSF) at an operational SWRO plant: the first for water and granular material, the second for DO measurements. 1. The particle and interstitial water sampler is based on a corer that retains grain particles inside a chamber using water suction created by an external peristaltic pump. 2. The DO sampler incorporates a temperature compensated oxygen measuring optode over which laminar water flow is maintained by an external peristaltic pump. To test these samplers, an operational, full-scale RSF at a SWRO plant was monitored at various depths within the filter bed over several months. Additionally, DO profiles within the filter bed were followed during and after a backwash cycle. These samplers enable efficient and precise collection of DO data, interstitial water, and granular material from previously inaccessible depth layers within the filter bed without interruption of the filter operation, providing information on microbiological processes such as biofilm development, microbial community structure and organic matter cycling.

2025, 2010 IEEE International Ultrasonics Symposium

In this work, we propose a compensated temperature pressure sensor fabricated on compound LiNbO 3 /Quartz/Quartz substrates obtained by Au/Au bonding at room temperature and double face lapping/polishing of LiNbO 3 /Quartz stack and a final gold bonding with a structured Quartz wafer. This paper shows the possibility to obtain device which is intrinsically low sensitive to thermal effects, and even allowing a second order compensation thanks to the Quartz thermal stability Sensitivity of the final sensor to bending moments then is tested and results show pressure sensitivity of such devices.

2025, 2011 Faible Tension Faible Consommation (FTFC)

A low power voltage reference generator operating with a supply voltage ranging from 1.6V to 3.6V has been implemented in a 90-nm standard CMOS process. The reference is based on MOSFETs biased in the weak inversion region to consume nanowatts of power and uses no resistors. The maximum supply current at 3.6V and at 125 • C is 173nA. It provides an 771mV voltage reference. A temperature coefficient of 7.5ppm/ • C is achieved at best and 39.5ppm/ • C on average, in a range from -40 to 125 • C, as the combined effect of a suppression of the temperature dependence of mobility and the compensation of the threshold voltage temperature variation. The total block area is 0.03mm 2 .

2025, IEEE Photonics Technology Letters

2025

We propose and demonstrate a simple dual port tunable from the C-to the L-band multi-wavelength fiber laser based on a SOA designed for C-band operation and fiber loop mirrors. The laser incorporates a polarization maintaining fiber in one of the fiber loop mirrors and delivers multi-wavelength operation at 9 laser lines with a wavelength separation of ~2.8 nm at room temperature. We show that the number of lasing wavelengths increases with the increase of the bias current of the SOA. Wavelength tunability from the C to L-band is achieved by exploiting the gain compression of a SOA. Stable multi-wavelength operation is achieved at room temperature without temperature compensation techniques, with measured power and the wavelength stability within < ±0.5 dB and ±0.1 nm, respectively.

2025, Journal of Alloys and Compounds

The microstructure, sintering and microwave dielectric properties of (1Àx)LiZnPO 4 þxLiMnPO 4 (x ¼ 0.0 e1.0) composite ceramics were discussed specifically through density functional theory calculation and solid-state reaction experiment. The (1Àx)LiZnPO 4 þxLiMnPO 4 (x ¼ 0.0e1.0) composite ceramics were characterised using network analyser, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and differentialethermal and thermo-mechanical analyser. The solid solution of Mn 2þ -ion-doped LiZnPO 4 ceramic and Zn 2þ -ion-doped LiMnPO 4 ceramic formed when the LiMnPO 4 ceramic was added into the LiZnPO 4 ceramic. The modification of the bond length, bond population and electron density could be observed in the ZnO 4 tetrahedron and MnO 8 octahedron. Moreover, the densification window of the LiZnPO 4 ceramic decreased slightly. Experimental results were specifically explicated by the calculation result. Peak dielectric properties were obtained when x ¼ 0.3 sintered at 800 C, ε r ¼ 5.83, Q Â f ¼ 71,007 GHz, t f ¼ À82.84 ppm/ C and relative density ¼ 97.33%. The addition of the LiMnPO 4 ceramic is an effective method for improving the sintering and microwave dielectric properties of the LiZnPO 4 ceramic.

2025, IEEE MTT-S International Microwave Symposium Digest, 2003

synthetic thinned array radiometer (STAR) is described. The total power architecture of a radiometer receiver requires special considerations to control gain fluctuations due to small temperature drifts. The STAR application requires consistent passband and stable phase between receivers. The design presented incorporates direct detection to eliminate distributed local oscillators for phase stability, distributed ceramic interference reject filters for passband consistency and temperature compensating attenuators for gain stability. The receiver is packaged in a unique "winged-hex" shape to enable close packaging with the STAR antennas and to facilitate thermal management. The resulting low cost, compact receiver is made from COTS components.

2025, IEEE solid-state circuits letters

This paper presents the most accurate shunt-based high-side current sensor ever reported. It achieves a 25V input common-mode range from a single 1.8V supply by using a beyond-the-rails ADC. A hybrid analog/digital temperature compensation scheme is proposed to simplify the circuit implementation while maintaining the state-of-the-art accuracy. Over a ±12A current range, the sensor exhibits 0.35% gain error from -40°C to 85°C with 3x better power efficiency.

2025, Journal of the Taiwan Institute of Chemical Engineers

Since organophosphorous compounds (OPCs) and carbamate compounds (CBCs) result in much lower bioaccumulation and higher biodegradability, they have replaced organochlorine to become the most popular pesticides. Presently, approximately 70% of the insecticides used worldwide fall into these two categories. However, overuse still leaves OPC and CBC residues in the soil, crops and surface water, which exert a great threat to the environment and the health of human beings. Once OPCs and CBCs enter organisms, they inhibit the activity of acetyl cholinesterase (AChE) by irreversibly binding to the active site of this enzyme. They retard the hydrolysis of acetyl choline (ACh), and therefore, interfere with the transmission of nerve impulses. The induced symptoms including tiredness, nausea, blurred vision, drowsiness, and ultimately death, are closely related to the toxicity, quantity, and exposure time of the pesticide itself. Many countries, therefore, pay serious attention to pesticides and have enacted strict regulations to prevent their contamination of wastewater, drinking water, soil, and food, among other things. Conventionally, the chemical analysis methods, such as HRGC (high resolution gas chromatography), GC-MS (gas chromatography mass spectrum), and HPLC (high-performance liquid chromatography), are adopted to determine concentrations of the pesticides in real samples. Even though these approaches provide precise and detailed analysis information, the cost and time of using them are too high to be generally useful. In addition, a long and complicated pretreatment procedure and well-trained personnel are required for chemical analysis methods, which make them unsuitable for on-line monitoring. For agricultural products facing immediate sales, these chemical analysis methods cannot help much with pesticide residue monitoring, especially when a mass screening is needed. Accordingly, a sensor possessing advanced characteristics, such as

2024, Current Biology

• Neural activity is generically highly temperature sensitive • Neurons achieve temperature robustness with highly variable conductance densities • Feedback regulation shapes variability to permit temperature robust neural activity • Robustness to global perturbations constrains cellular regulation mechanisms eTOC summary All biochemical processes, including neuronal activity, are temperature sensitive. Yet many animal species experience large temperature fluctuations. O'Leary and Marder show how a simple regulatory control mechanism can ensure temperature robust neural activity by balancing expression of multiple, temperature dependent ion channel types.

2024, 10th IEEE International Conference of Advanced Thermal Processing of Semiconductors

Vortek's new 300mm flash-assist RTP™ tool uses a pair of arc lamps to heat wafers at >200ºC/s to an intermediate temperature of between 700°C and 1200ºC. A high power, millisecond duration flash is then applied to the device side of the wafer, raising it to a higher peak temperature. Water-cooled windows and the cooling walls of the arcs attenuate incident radiation at the diagnostic wavelength of 1450nm. This facilitates measuring the temperature of both wafer surfaces during the entire thermal process. A fast radiometer, which samples the back surface of the wafer at 25kHz, provides feedback to a 1kHz arc control system. An emissometer measures the back-surface emissivity, while one of its components, a near-infrared camera, provides a two-dimensional map of wafer temperature. An ultra-fast radiometer, which samples at up to 1MHz, measures the device side of the wafer and estimates the peak temperature of the wafer during the flash. This radiometer has dynamic re-calibration and temperature-compensated electronics. All detectors are InGaAs. The fast radiometer, the ultra-fast radiometer, and the camera have effective resolutions of 16, 14, and 11 bits respectively. The individual components of the temperature measurement system are described. The methodologies used to achieve intermediate temperature control of better than ±2ºC and emissometer stability of ±0.2% are discussed.

2024, IEEE Sensors Journal

The thermal drift of the characteristic wavelength of fiber Bragg gratings (FBGs) photowritten in the core of microstructured fibers (MOFs) is significantly reduced by inserting a liquid of suitable refractive index into their holes. For instance, the spectral range of variations is divided by a factor of 4 over a temperature range larger than 20°C in a 6-hole MOF, and the maximum sensitivity is reduced. Such passive FBG temperature compensation technique is of great interest for applications involving accurate sensing free of thermal effects.

2024

A scheme utilizing a temperature probe iemera.d in the work ing fluid to compensate for the dependence of hot-wire velocity calibration on ambient temperature variations was analyzed. One need. only to know the properties of the anemometer bridge and the velocity and temperature probes to achieve the compensation. Hence the scheme provides means for incorporating the tempera .ure compensation a priori to conducting the ezperi.ents without any need for temperature calibration. Estimates of the errors introduc•d through th. non-ideal

2024

This Phase I SBIR report documents the establishment of feasibility of a electromagnetic diaphragm compressor which is designed to drive cryocoolers. Two prototype compressors were built and tested as part of this feasibility establishment program. The first prototype used permanent magnet bias while the second prototype used electromagnet bias. Testing the first prototype indicated that the diaphragm used in it is too stiff for satisfactory operation. As a result, electromagnet was used as biasing device in the second prototype and the stiff diaphragm is replaced by a more flexible one. In addition to this prototype building activity, a computer code to analyze and size this type of compressor has been developed in this phase I effort. Testing the prototype has indicated that it can develop pressure ratios of up to 1.7 at frequencies of up to 60 diaphragms Hz. Since the prototype demonstrated performance parameters that are within the realm of cryocoolers, we conclude that it is feasible to engineer an electromagnetic diaphragm compressor that can meet the design requirements of cryocoolers. As a result, it is recommended to move the project to Phase 11.

2024, SID Symposium Digest of Technical Papers

The driving techniques used for bistable reflective cholesteric displays are typically a function of application, temperature, and other material constraints. As such, new and unique driving techniques are employed continuously in order to optimize the updating methods of cholesteric displays. This paper focuses on several such techniques and related issues with these methods.

2024, IEEE Particle Accelerator Conference

3. Particle Tracking with ORBIT Since this accumulator has relatively short bending magnets, the fringe-field effecrs are large, and special attention had to be paid to the tracking of particles through the magnet as well as to its representation in the machine lattice. Here we describe the procedures, making use of measured field tables in computer programs to determine the properties of the machine, and compare predicted machine parameters with measured ones.

2024, IEEE MTT-S International Microwave Symposium Digest, 2003

2024

In this paper the preliminary work of laboratory practices developed for didactic purposes for undergraduate courses at the Engineering Faculty of Polytechnic of Bari is presented. The educational purposes of these experiments can be summarized as follow: to grant students the opportunity to verify theoretical arguments introduced in theoretical lessons; to give technical skills; to integrate research work and educational programs promoting the insertion of student in the scientific community. In this paper a technical solution useful to measure temperature by means of thermocouples is described; the main goal of the proposed technique is that it employs only one programmable multimeter and devices commonly available in university laboratories.

2024, IEEE Journal of Solid-state Circuits

This paper presents a fully integrated shunt-based current sensor that supports a 25-V input common-mode range while operating from a single 1.5-V supply. It uses a highvoltage beyond-the-rails ADC to directly digitize the voltage across an on-chip shunt resistor. To compensate for the shunt's large temperature coefficient of resistance (∼0.335%/°C), the ADC employs a proportional-to-absolute-temperature voltage reference. This analog compensation scheme obviates the need for the explicit temperature sensor and calibration logic required by digital compensation schemes. The sensor achieves 1.5-μV rms noise over a 2-ms conversion time while drawing only 10.9 μA from a 1.5-V supply. Over a ±4-A range, and after a one-point trim, the sensor exhibits a 0.9% (maximum) gain error from -40 °C to 85 °C and a 0.05% gain error at room temperature.

2024, 2011 IEEE International Conference on Microwaves, Communications, Antennas and Electronic Systems (COMCAS 2011)

This paper presents a fully integrated 81-86GHz power amplifier (PA) fabricated in a 0.12 μm SiGe BiCMOS technology. Three cascode stages, followed by two common-emitter stages were utilized to achieve power gain of 30dB with 12dBm output power at 1dB compression and saturated power of 14dBm. Small signal characteristics show peak gain achieved at 86GHz with both input and output matching is better than-15dB from 77GHz to 87GHz. A 40dB image rejection is accomplished by a selective notch filter also integrated on chip. The PA's bias is applied by digitally adjustable bias circuits to provide process and temperature compensation and was measured in room temperature, 50 0 C and 85 0 C. It consumes quiescent currents of 120mA and 85mA from a 2V and 2.7V supplies respectively at 1dB compression and occupies area of 1.6mm 2 .

2024, 16th Symposium on Integrated Circuits and Systems Design, 2003. SBCCI 2003. Proceedings.

The design of an IC on-chip oscillator including a temperature compensation circuitry, a robust spread reduction technique and digital trimming is described. The IC oscillator provides a 12.8MHz clock signal with a frequency spread of ±25% before the 8-bits digital trimming. After centering the oscillator at the target frequency, a temperature compensated voltage and current reference circuit allows for less than ±5% frequency variation when operating from 3 to 5V of power supply and from-40 to 125°C of temperature range. The oscillator is implemented in a 0.5µm CMOS technology, occupies an area of 420x440µm 2 and dissipates less than 400µW at 3V of supply without requiring any external reference or components.

2024, Sensors and Actuators A: Physical

A sensitive micro-Pirani vacuum sensor has been fabricated. With effective schemes of ambient-temperature compensation and stabilization, it is capable of measuring vacuum pressure linearly from 1 torr down to 10-7 torr, a three orders-of-magnitude improvement in resolution over conventional gauges. A special electrothermal SPICE model, complementary to the conventional analog representation of thermal parameters, is also proposed. It allows a high-level sensor-circuit integrated simulation based on the most fundamental principle and thermal variables. Good agreement between the measured data obtained from a constant-temperature readout circuit and the simulation result is demonstrated.

2024

Micro-electric discharge machining (micro-EDM) is the most considerable micro-manufacturing process used to engineer miniaturized features on any high temperature resistive hard material. The machining parameters of micro-EDM are very stochastic in nature. The spark gap measure acts as a vital parameter that correlates with other process parameters for enhancement of the material removal rate (MRR) in micro-EDM. The real-time actual measurement of the spark gap between the electrodes is highly challenging and is limited due to the small gap measure. This article is about the development of a novel sensing technique for spark gap measurement, based on a fiber Bragg grating (FBG) sensor. The sensing system is developed on a cantilever structure bonded with the FBG sensor, for performing accurate spark gap measurements with the displacement measurement of the tool electrode. The deflection on the cantilever during spark gap generation is translated into strain variations, as monitored by the FBG bonded over it. Experimental trials are conducted on the micro-EDM setup with the cantilever beam-based displacement sensing with a sensitivity of 10 µm/pm. Real-time spark gap data obtained by FBG are in the range of 1.1-18.6 µm and are validated against a precision measuring instrument. This sensing technology employed for micro-EDM spark gap measurement establishes a novel technique in the micro-machining field and formulates a smart system.

2024, IEEE Transactions on Microwave Theory and Techniques

High dielectric-constant materials are increasingly needed in microwave circuit miniaturization for outdoor and indoor wireless applications. In this paper, we introduce temperature-stable high dielectric-constant thermoplastic polymer compositions and copper-laminated sheets made out of them for microwave circuits. The compositions are made by mixing suitable ceramics and polymers. The design, fabrication, and properties of these compositions are discussed. The effect of temperature on the resonance frequency of a patch antenna made out of the copper-laminated high dielectric-constant composite sheets is also discussed. Index Terms-Copper laminates, high Dk material, microwave materials, patch antennas, polymers. I. INTRODUCTION M ICROWAVE laminates based on high dielectricconstant (or Dk) materials are needed in highfrequency applications [1]-[3] for component miniaturization. The miniaturization of high-frequency components can be affected in two ways: 1) by increasing the frequency of operation, which will decrease the size of printed RF components since the size is proportional to the wavelength and/or 2) by using high dielectric-constant materials that enable miniaturization since the effective wavelength in the substrate is inversely proportional to the square root of the dielectric constant. High dielectric-constant materials and particularly high Dk polymer composite formulations and copper laminates made out of these compositions are already in use in the rapidly expanding wireless segment of the electronic industry and their use continues to increase. The high dielectric-constant compositions include: ceramic-filled polymers such as epoxy, poly(tetrafluorethylene) (PTFE), and various types of thermoset hydrocarbons [4], [5]. Temperature stability of the dielectric constant is important in many outdoor wireless applications for reduction or control

2024, IEEE Transactions on Instrumentation and Measurement

In conventional constant temperature hot-wire anemometers, the compensation for the fluid temperature is done by using two sensors. In this paper, the analysis of an anemometer circuit using only one sensor, operating alternately at two different temperatures is presented. The effect of the amplifier input offset voltage is taken into account, and its influence on the measurement of fluid velocity is quantified. Preliminary experimental results are also presented.

2024, Plant Direct

Casein kinase 1 (CK1) is an evolutionarily conserved protein kinase family among eukaryotes. Studies in non‐plants have shown CK1‐dependent divergent biological processes, but the collective knowledge regarding the biological roles of plant CK1 lags far behind other members of the Eukarya. One reason for this is that plants have many more genes encoding CK1 than do animals. To accelerate our understanding of the plant CK1 family, a strong CK1 inhibitor that efficiently inhibits multiple members of the CK1 protein family in vivo (i.e., in planta) is required. Here, we report a novel, specific, and effective CK1 inhibitor in Arabidopsis. Using circadian period‐lengthening activity as an estimation of the CK1 inhibitor effect in vivo, we performed a structure–activity relationship study of analogues of the CK1 inhibitor PHA767491 (1,5,6,7‐tetrahydro‐2‐(4‐pyridinyl)‐4H‐pyrrolo[3,2‐c]pyridin‐4‐one hydrochloride). A propargyl group at the pyrrole nitrogen atom (AMI‐212) or a bromine atom ...

2024, IEEE Transactions on Microwave Theory and Techniques

Oscillators based on AlN thin-film bulk acoustic resonators are designed, fabricated and measured. The circuits are realised as silicon-on-silicon multichip modules where SiGe transistors are flip-chip mounted on a novel carrier substrate which includes monolithically integrated resonators and passive components. The paper describes the development and processing of the carrier substrate and resonators, as well as the development of the oscillator circuits. The oscillators operate at 2 GHz. Measurements of the oscillators reveal a lowest phase-noise of 125 dBc Hz at 100 kHz offset.

2024

Dispersion of Lamb waves propagating in AlN plates with a periodic Al grating on the top surface and an Al electrode on the bottom surface is investigated using the numerical technique SDA-FEM-SDA. The structures of typical Lamb waves are examined via visualization of the instantaneous displacement fields in the AlN plate. The mechanism of building hybrid modes, which arise from intermode coupling between the counter-propagating Lamb waves of different symmetry and order, is illustrated by the mode propagating with wavelength λ=3p, where p is the pitch of the grating.

2024, Applied sciences

The intrinsic advantages of optical sensor technology are very appealing for high voltage applications and can become a valuable asset in a new generation of smart grids. In this paper the authors present a review of optical sensors technologies for electrical current metering in high voltage applications. A brief historical overview is given together with a more detailed focus on recent developments. Technologies addressed include all fiber sensors, bulk magneto-optical sensors, piezoelectric transducers, magnetic force sensors and hybrid sensors. The physical principles and main advantages and disadvantages are discussed. Configurations and strategies to overcome common problems, such as interference from external currents and magnetic fields induced linear birefringence and others are discussed. The state-of-the-art is presented including commercial available systems.

2024, Optics Communications

In this paper, two hybrid multimode/single mode fiber Fabry-Pérot (FP) cavities were compared. The cavities fabricated by chemical etching are presented as high temperature and strain sensors. In order to produce this FP cavity a single mode fiber was spliced to a graded index multimode fiber with 62.5 μm core diameter. The Fabry-Pérot cavities were tested as a high temperature sensor in the range between room temperature and 700°C and as strain sensors. A reversible shift of the interferometric peaks with temperature allowed to estimate a sensitivity of 0.75 ± 0.03 pm/°C and 0.98 ± 0.04 pm/°C for the sensor A and B respectively. For strain measurement sensor A demonstrated a sensitivity of 1.85 ± 0.07 pm/μ and sensor B showed a sensitivity of 3.14 ± 0.05 pm/μ. The sensors demonstrated the feasibility of low cost fiber optic sensors for high temperature and strain.

2024, Optics Communications

2024

2024, Applied Sciences

2024, Sensors and Actuators B: Chemical

A microfluidic based optical biosensor is introduced to detect concentrations of biochemical substances in solution using refractive index measurement with high sensitivity and accuracy. The sensor consists of a liquid channel forming a Fabry-Perot cavity between two semitransparent Ag/SiO 2 reflective surfaces. Light is transmitted through the cavity to construct interference peaks in the transmission spectra which depend on the refractive index of the test samples in the channel. The refractive index of glucose, potassium chloride, and sodium chloride solutions is measured in different concentrations. Continuous change in refractive index is resolved by observing the peak wavelength shift in the transmitted spectrum. The sensor is characterized using the contact angle measurer, surface profilometer, and spectrophotometer. The proposed Fabry-Perot etalon biosensor shows real time linear responses as well as high accuracy and sensitivity of 10 −3 refractive index per percent of glucose, 1.4 × 10 −3 and 1.8 × 10-3 refractive index per percent of KCl and NaCl solution, respectively.

2024, Electronics Letters

Proposed is an ISFET readout scheme with minimum analogue components to minimise parasitic and noise effects in large-scale chemical sensing arrays. For each array pixel, a pair of complementary ISFETs shares the same floating gate in an inverter configuration. An additional electrical input is capacitively coupled to the same floating gate with a periodic reference signal input. In this way, the conventional ISFET analogue output is replaced by a chemically controlled pulse width modulated signal. Theoretical analysis and experimental results show a pulse width pH sensitivity of around 6%, of the input reference signal period, per pH. This is achieved along with +1 V offset suppressing capability.

2024, Proceedings of the IEEE

REFERENCES [l] W. R. &nnaf "New results in the caldation of modulation products," Brll Sysf. Tech. J., voi. 12, Apt. 1933, pp. 228-243. [2] J. G. Gardiner, 'The rdationship betureen crOssmodulation and intermodulation distortions in the... more

2024, Microelectronics Journal

An integrated and new interface circuit with temperature compensation has been developed to enhance the ISFET readout circuit stability. The bridge-type floating source circuit suitable for sensor array processing has been proposed to maintain reliable constant drain-source voltage and constant drain current (CVCC) conditions for measuring the threshold voltage variation of ISFET due to the corresponding hydrogen ion concentration in the buffer solution. The proposed circuitry applied to Si 3 N 4 and Al 2 O 3-gate ISFETs demonstrate a variation of the drain current less than 0.1 mA and drain-source voltage less than 1 mV for the buffer solutions with the pH value changed from 2 to 12. In addition, the scaling circuitry with the V T temperature correction unit (extractor) and LABVIEW software are used to compensate the ISFET thermal characteristics. Experimental results show that the temperature dependence of the Si 3 N 4-gate ISFET sensor improved from 8 mV/1C to less than 0.8 mV/1C.

2024, Microelectronics Journal

With the advantages of small size, reliability, rapid response, compatibility to standard CMOS technology and on-chip signal processing, Ion-Sensitive Field Effect Transistor (ISFET)-based transducers are increasingly being applied in physiological data acquisition and environment monitoring. This paper presents a signal processing Application Specific Integrated Circuit (ASIC) and a discrete temperature compensation chip design of a potentiometric ISFET-based chemical sensor. To assure the measurement of a correct pH value, the two-point calibration circuitry based on the response of standard pH 4 and 7 buffer solution has been implemented by using Algorithmic State Machine hardware algorithms. For battery power consideration, the proposed signal processing ASIC consisting of low voltage (3 V) mixed signal modules has been developed and fabricated in a 0.5 mm CMOS technology. The results demonstrate small differences of pH response of ISFET's operating with and without ASIC device, i.e. only the order of 0.1 mV/pH with respect to sensitivity. Furthermore, using the temperature compensating circuitry reduces the ISFET temperature coefficient to þ0.15 mV/8C, and hence results in a lower pH value variation of 20.0023 pH/8C. It was shown that more accurate pH measurement can be concluded with the proposed ASIC and V T extractor circuitry.

2024, Sensors, 21, 7863

Lately, wearable applications featuring photonic on-chip sensors are on the rise. Among many ways of controlling and/or modulating, the acousto-optic technique is seen to be a popular technique. This paper undertakes the study of different multilayer structures that can be fabricated
for realizing an acousto-optic device, the objective being to obtain a high acousto-optic figure of merit (AOFM). By varying the thicknesses of the layers of these materials, several properties are discussed. The study shows that the multilayer thin film structure-based devices can give a high
value of electromechanical coupling coefficient (k2) and a high AOFM as compared to the bulk piezoelectric/optical materials. The study is conducted to find the optimal normalised thickness of the multilayer structures with a material possessing the best optical and piezoelectric properties for fabricating acousto-optic devices. Based on simulations and studies of SAW propagation characteristics such as the electromechanical coupling coefficient (k2) and phase velocity (v), the acousto-optic
figure of merit is calculated. The maximum value of the acousto-optic figure of merit achieved is higher than the AOFM of all the individual materials used in these layer structures. The suggested SAW device has potential application in wearable and small footprint acousto-optic devices and gives better results than those made with bulk piezoelectric materials.

2024, IEEE Transactions on Electron Devices

2024, Sensors and Actuators B: Chemical

An exposed Bragg grating incorporated into a planar waveguide forms an optical device that acts as a refractive index sensor. The exposed evanescent field causes the Bragg peak to be sensitive to the refractive index of its surroundings and can be used to detect changes in this environment. The method reported is able to provide accurate temperature compensation by applying a scaling factor derived from measurement of the birefringence of the transverse electric (TE) and transverse magnetic (TM) modes of the Bragg reflection. For a fluid sensor, fluctuations in ambient temperature can be both accounted for and compensated to produce a temperature-insensitive sensor.

2024, Zenodo (CERN European Organization for Nuclear Research)

In this paper we present a design approach based on a reassessment of design priorities in order to obtain robust circuits with respect to process variability. We show that if we address variability as one of the main issues in circuit design, and make it inform our very first design choices, we are able to significantly reduce dispersion of circuit characteristics without degrading of the other performance figures. We apply this variability-aware approach to the design of a nanopower reference voltage generator in 0.18 μm CMOS technology. The result is a BJT-based topology, which provides a reference voltage of about 241 mV from a 1 V supply voltage. Measurements on 20 samples from a single batch show that the reference voltage exhibits a relative standard deviation of 0.18%, while consuming only 68.3 nW. This is comparable with the performance of references that are either trimmed or consume much more power. This reduced process sensitivity comes at the cost of a significant increase of die area (0.28 mm 2).