Ing. Pavel Kulha, Ph.D.

This study presents a sensor based on quartz crystal microbalance (QCM) coated with nanocrystalline diamond (NCD) thin film, functionalization method and novel application of such sensor. Diamond-coated QCMs (DQCMs) were superficially terminated by hydrogen and oxygen (H-NCD and O-NCD) to control its surface dipole/potential. Two protein solutions were tested: bovine serum albumin (BSA) and fibronectin (FN). We performed reference measurements of serial resonant frequency (SRF) of clean QCMs loaded with protein and compared them with SRF shifts DQCMs loaded with proteins. In order to investigate the influence of the deposited NCD thin film on QCM measuring capabilities, additional FEM analysis was performed. The simulation results showed that QCM sensors maintain the sensing capabilities with a rigid thin film of NCD on its surface. The shift of SRF was demonstrably caused by the weight of protein adhered to the diamond film's surface. We compared masses estimated from the Sauerbrey equation to characterize the adhesive properties of the studied proteins. Comparing bare QCM and DQCM, we discovered diamonds enhance the sensing performance for proteins. At the same time, it saturates quickly with phosphate buffer saline used as a diluent solution for proteins. Results showed a significant increase in protein adhesion confirmed by the increase of the mass for both oxygen and hydrogen-terminated DQCMs. Moreover, a different time-dependent behaviour (i.e. different adsorption rate, degrees of physisorption and/or preference of the diamond surface functionalization) of the O-NCD and H-NCD QCMs was observed for BSA and FN proteins. In this meaning, we propose a schematic model which describes the detection principle of BSA and FN proteins on H- and O-terminated DQCM sensors. Finally, a simple proof of concept for using the functionalized diamond-coated sensors with current stimulation and EQCM (Electrochemical Quartz Crystal Microbalance) is also proposed.

We report on polymer optical waveguides fabricated by roll-to-plate technology (R2P) nanoimprinting. Our measurement proved that the presented waveguides will allow the realization of optical waveguides with low optical losses at the key optical communication wavelengths at 850 and 1300 nm. We also show low optical losses of these waveguides in the visible spectrum at 530 nm (green light) and 650 nm (red light). The paper has also demonstrated that the R2P fabrication procedure allows the easy fabrication of optical waveguide devices and has great potential for the implementation of optical polymer waveguides for optical interconnection applications.

The paper reports on the properties of UV-curable inorganic-organic hybrid polymer multimode optical channel waveguides fabricated by roll-to-plate (R2P) nanoimprinting. We measured transmission spectra, refractive indices of the applied polymer materials, and optimized the R2P fabrication process. Optical losses of the waveguides were measured by the cut-back method at wavelengths of 532, 650, 850, 1310, and 1550 nm. The lowest optical losses were measured at 850 nm and the lowest average value was 0.19 dB/cm, and optical losses at 1310 nm were 0.42 dB/cm and 0.25 dB/cm at 650 nm respectively. The study has demonstrated that nanoimprinting has great potential for the implementation of optical polymer waveguides not only for optical interconnection applications.

In this work we demonstrate the realization of a simple and low cost NO 2 gas sensor on a flexible polymer substrate. The sensor was fabricated using inkjet printing and hydrothermal growth and consists of a printed interdigital structure on which a sensitive zinc oxide layer was grown. The chosen growing process does not require an additional seed layer, which allows to directly grow the zinc oxide layer on the substrate. Furthermore, the operating temperature was intrinsically achieved with an inkjet printed heater, which is located at the backside of the sensor.

The aim of this paper is to present the design of a sensor array based on a single substrate with various composite polymer films as active layers for gas detection. A low power, four element flexible sensor platform with heater and temperature sensor was designed. The advantages of resistive sensors are easy fabrication, simple operation and low production cost. Composite polymer films exhibit good sensitivity to low gas concentrations at room temperatures. The principle of the designed sensor array is a change of electrical resistance in dependence of gas concentration. PANI, PANI/CNT, PANI/SnO2 and PANI/TiO2 composites were used as active layers. Gas sensing properties of active layers for NH3, CO2, NO2, O2, acetone, toluene and relative humidity were studied. PANI composites, unlike pristine PANI, exhibit good reversibility and lower temperature dependence.

In this work, we present a method for the realization of printed strain gauges on pre-coated sheet steel substrates. The state of the art is to glue strain gauges on foil onto a substrate. This, however, has inherent disadvantages in terms of force coupling between the bent substrate and the glued strain gauge sensors. The fact that the glue and the substrate have in general different moduli of elasticity affects the achievable gauge factor of the final sensor stack. The method presented in this work circumvents these problems completely by eliminating the gluing process and integrating the sensor into a cover layer on the substrate. In the considered case, the substrate is a steel sheet with an organic coating. We integrate the sensor in this coating by screen-printing it on a pre-coated layer. The results in terms of the various determined gauge factors including the influence of a top coating layer, as well as temperature dependences of the strain sensors fabricated with carbon black and silver ink are presented in this work.

We provide an overview on our recent work on embedded printed transducers. This includes the description of appropriate technologies as well as technological considerations for the integration of sensors and actuators into polymer coatings, e.g., of sheet metal. In particular, the integration of capacitive large area sensors, piezo- and pyroelectric layers, and strain gauges is discussed. The devised concept has the potential to introduce additional functionality to a variety of products without the need of significant changes to associated production processes.

The fabrication procedure and characterization of low-cost electrodes for capacitive level sensors realized on a flexible substrate are presented in this paper. The aim was to prepare conductive electrodes by printing of silver and PEDOT:PSS pastes on coated PET foil. Individual interdigital capacitors and a system with embedded microcontroller readout were designed for a comparative study. Individual capacitors in the form of interdigital electrodes (IDT) were designed with different finger width/spacing dimensions from 300/300 mu m to 800/800 mu m, a finger length 10 mm and 15 mm and an overall length of 100 mm. A demonstrator device featuring an integrated microcontroller, sensing and reference capacitive sensors and a resistive temperature sensor was realized to proof a practical utilization. The microcontroller is used to calculate capacitances of IDT electrodes in terms of charging time proportional to the fluid level. The design with reference capacitor can be directly applied to different fluids with a wide range of conductivities and dielectric constants without recalibration. The printed structures were thermally laminated with covering PET foil. The sensitivity of the fabricated devices was characterized in liquids with different relative permittivity and conductivity (water and oil). The highest measured sensitivity was 0.7 pF/mm and 0.08 pF/mm for water and oil respectively, with resolution down to 0.1 mm.

Diamond thin films provide unique features as substrates for cell cultures and as bio-electronic sensors. Here we employ solution-gated field effect transistors (SGFET) based on nanocrystalline diamond thin films with H-terminated surface which exhibits the sub-surface p-type conductive channel. We study an influence of yeast cells (Saccharomyces cerevisiae) on electrical characteristics of the diamond SGFETs. Two different cell culture solutions (sucrose and yeast peptone dextrose–YPD) are used, with and without the cells. We have found that transfer characteristics of the SGFETs exhibit a negative shift of the gate voltage by −26 mV and −42 mV for sucrose and YPD with cells in comparison to blank solutions without the cells. This effect is attributed to a local pH change in close vicinity of the H-terminated diamond surface due to metabolic processes of the yeast cells. The pH sensitivity of the diamond-based SGFETs, the role of cell and protein adhesion on the gate surface and the role of negative surface charge of yeast cells on the SGFETs electrical characteristics are discussed as well.

We report on the design, fabrication and optical properties of large core multimode optical polymer splitter fabricated using fill up core polymer in substrate that was made by 3D printing technology. The splitter was designed by the beam propagation method intended for assembling large core waveguide fibers with 735 μmμm diameter. Waveguide core layers were made of optically clear liquid adhesive, and Veroclear polymer was used as substrate and cover layers. Measurement of optical losses proved that the insertion optical loss was lower than 6.8 dB in the visible spectrum.

The article describes the principles of analysis of pollutants in water by molecular absorption spectrometry. The spectrometer is used for analysis. Design and implementation of software for the evaluation of water analysis is part of the work. The software is designed with ease of use and retrieval of data. Analysis of water is mainly focused on nitrates. The detection is focused on determining levels of particular components, suitable algorithm recognizes the substance.

In this work we present a method for the fabrication of all-printed strain gauges on pre-coated sheet steel substrates. The state of the art is to glue strain gauges on foil onto a substrate. This, however, has inherent disadvantages in terms of force coupling from the surface strain within the bent substrate to the glued strain gauge sensors. The fact that the glue and the strain gauge substrate have in general different moduli of elasticity affects the maximum achievable gauge factor of the final sensor stack. The method presented in this work circumvents these problems completely by removing the glue and the substrate layer from the stack and by printing the sensor layer directly on top of the pre-applied organic coating. We present comparative measurements of carbon black based sensors, as well as two different polymeric silver ink based sensors.

The paper presents fabrication and characteri-zation of a Quartz Crystal Microbalance based gas sensor with a diamond powder sensitive layer deposited using the ink-jet printing technique. The sensor was exposed to a low concentration of ammonia, acetone vapors and different levels of humidity. Impedance characteristics close to the natural resonant frequency of 10 MHz were examined. The sensor exhibits significant shifts in serial resonant frequency under different gas environments.

A high-temperature piezo-resistive nano-crystalline diamond strain sensor and wireless powering are presented in this paper. High-temperature sensors and electronic devices are required in harsh environments where the use of conventional electronic circuits is impractical or impossible. Piezo-resistive sensors based on nano-crystalline diamond layers were successfully designed, fabricated and tested. The fabricated sensors are able to operate at temperatures of up to 250°C with a reasonable sensitivity. The basic principles and applicability of wireless powering using the near magnetic field are also presented. The system is intended mainly for circuits demanding energy consumption, such as resistive sensors or devices that consist of discrete components. The paper is focused on the practical aspect and implementation of the wireless powering. The presented equations enable to fit the frequency to the optimal range and to maximize the energy and voltage transfer with respect to the coils’ properties, expected load and given geometry. The developed system uses both high-temperature active devices based on CMOS-SOI technology and strain sensors which can be wirelessly powered from a distance of up to several centimetres with the power consumption reaching hundreds of milliwatts at 200°C. The theoretical calculations are based on the general circuit theory and were performed in the software package Maple. The results were simulated in the Spice software and verified on a real sample of the measuring probe.

The aim of this paper is to present design of sensor array with composite polymer films as active layers for gas detection. Low power, four element flexible sensor platform with heater and temperature sensor was designed. The advantages of resistive sensors are easy fabrication, simple operation and low production cost. Composite polymer films exhibits good sensitivity to low concentrations of ammonia at room temperatures. Sensing of toxic gases is very important in many applications as automotive, defense, aerospace, agriculture, chemical industry, medicine, environmental, food and drink.

Nanocrystalline diamond (NCD) films were grown on the commercially available sensor product consisted of a bulit-in microheater, a platinum temperature sensor, and a pair of Pt interdigitated electrodes using microwave plasma enhanced chemical vapor deposition process. We investigated the effect of fluorine- and hydrogen-terminated diamond surface on the gas sensing properties at room temperature. The gas sensing properties diamond-based sensor were measured by the changes of electrical resistance to various volatile organic compounds(C6H6, C3H6O, isopropylalcohol) and relative humidity. The comparative sensing performance of hydrogenated diamond surface shows improvement in sensitivity toward benzene, acetone, isopropylalcohol and humid air in contrast to fluorinated diamond surface, where the surface conductivity was suppressed. The sensor functionality was explained by the surface transfer doping effect.

This paper presents design and fabrication process details of a piezoelectric generator with a thin film Zinc Oxide (ZnO) layer. Structure of the piezoelectrical cantilever beam harvester consists of ZnO layer in between two insulating Al2O3 layers and outer aluminium contacts deposited on a silicon substrate. This multilayer system was prepared by the combination of radio - frequency and direct - current magnetron sputtering. Geometrical arrangement of the substrate holder and deposition target was optimized in order to reduce the disruptive effect of the high energy ions bombardment on the ZnO film microstructure. We present ZnO microstructure characterizati on by means of X-ray diffraction and scanning electron microscopy related to the estimation of internal micro-strains, crystallite sizes and deposition rates. Maximum generated open-circuit voltage achieved close to the cantilever resonant frequency of 595 Hz was 0.975 V.

The paper presents fabrication and characterization of Quartz Crystal Microbalance based gas sensor with diamond powder sensitive layer deposited using ink-jet printing technique. The sensor was exposed to a low concentration of ammonia, acetone vapors and different levels of humidity. Impedance characteristic close to the natural resonant frequency of 10MHz was examined. The sensor exhibit significant shifts in serial resonant frequency under different gas environments.

Gas sensors based on a quartz crystal microbalance (QCM) coated with nanocrystalline diamond (NCD) were developed and tested on NH3, CO2, and humidity detection at room temperature and compared with the bare (uncoated) QCM. NCD films were directly grown on the QCM by a large-area pulsed linear-antenna microwave plasma CVD process from the CH4/CO2/H2 gas mixture at temperatures below 400 °C. The as-grown NCD films on QCM and reference Si substrates were characterized by scanning electron and atomic force microscopies as well as Raman and optical spectroscopies. The NCD-coated QCM gas sensors showed a reasonable performance with a stable repeatability to the tested gases. The response time of the tested diamond-coated sensor was fast (~5s). Moreover, we also observed higher sensitivity and better stability for NCD-coated QCM than for the bare QCM.

Synthetic diamond has remarkable properties comparable with natural diamond and hence is a very promising material for many various applications (sensors, heat sink, optical mirrors, cold cathode, tissue engineering, etc.). Nowadays, deposition of diamond films is normally employed in chemical vapor deposition (CVD) usually at high temperatures (800-900 °C), what limit its application to high melting substrates. Gravimetric (mass) sensors belong to the major categories of chemical sensors and the most common type of mass sensor is the bulk acoustic quartz crystal microbalance (QCM). This contribution deals with a nanocrystalline diamond (NCD) growth from the H2/CH4/CO2 gas mixture at low temperature (400 °C) by pulsed linear antenna microwave plasma system on 10 MHz circular AT-cut quartz resonators substrate. Gas sensor based on the NCD-coated QCM was developed for detection of ammonia (NH3) at room temperature. Measurements not only confirmed the functionality of this first published NCD-coated QCM sensor.

The paper presents the simulation of beam structures for piezoelectric microgenerators. Beam structures have various applications in MEMS, including bi-stable switch design and also residual stress measurement. Such structure has two stable states switchable by appropriate level of force or acceleration. The main advantage of using the bi-stable structures for constructing the piezoelectric power microgenerator lies in broad band frequency operation (the structure can switch to the other stable state at arbitrary frequency when appropriate level of actuating force or acceleration is applied) and generated voltage is higher due to higher stresses in the beam during switching. The paper is aimed to make precise models of multifrequency and bi-stable microstructures. Piezoelectric energy harvesters exploiting strong mechanical nonlinearities exhibit intrinsic suitability for one of several modern challenges in vibratory energy harvesting: consistent kinetic performance in the presence of broadband environmental excitation. Design of such structures in terms of potential well shaping, dimensions and optimal electromechanical coupling is very complex and highly non-linear problem with lack of analytical solutions. Utilizing the software packages of CoventorWare enable creation of precise 3D models and help with simulation of non-linear behavior of resonant multifrequency and bi-stable structures.

The objective of this paper is to present simulation results of the Thickness Shear Mode (TSM) resonator based on quartz using finite element simulation method. 3D model of quartz resonator and simulations were completed using finite element method in CoventorWare software suite for design and simulation of MEMS devices. Different techniques for simulation of adsorption effect on selective layer were studied: influence of change in mass of the sensitive layer and influence of change in density of the sensitive layer. Analyses of resonant modes were performed for both cases and displacement profiles in selected modes were determined for the resonator under study. Impedance and phase characteristics were calculated and measured for clean sample and sample with selective layer coated. The adsorption model calculates the frequency shift in basic resonant frequency with adsorbed amount of sensed gas. The simulation results were used in design of gas sensors for dangerous substances detection.

This study describes an integrated NH3 sensor based on a hydrogenated nanocrystalline diamond (NCD)-sensitive layer coated on an interdigitated electrode structure. The gas sensing properties of the sensor structure were examined using a reducing gas (NH3) at room temperature and were found to be dependent on the electrode arrangement. A pronounced response of the sensor, which was comprised of dense electrode arrays (of 50 µm separation distance), was observed. The sensor functionality was explained by the surface transfer doping effect. Moreover, the three-dimensional model of the current density distribution of the hydrogenated NCD describes the transient flow of electrons between interdigitated electrodes and the hydrogenated NCD surface, that is, the formation of a closed current loop.

In the paper, strain-gauge sensor design and low voltage precision digital conditioning circuit are presented. The strain sensor was designed using FEM (Finite Element Modeling) and uses piezoresistive strain sensitive boron doped nanocrystalline layers. Nanocrystalline Diamond (NCD) is a very promising material for fabrication of harsh-environment devices (especially high-temperatures due to wide band gap) because of its unique mechanical and electrical properties. The prospective of using diamond is not only in sensors (e.g. MEMS) but in RF and power electronic as well. Since the piezoresistive effect in boron doped diamond layer is lower compared to the silicon, the goal was to develop a very small system with high resolution and low power consumption suitable for wireless powering and data acquisition. The resulting circuit described here uses a single 3.3 V power supply, highly integrated, precision, low noise, 24-bit sigma-delta analog-to-digital converter and ARM Cortex-M3 processor for controlling and acquiring data from analog-to-digital converter (ADC).

The core of the article deals with the principles of analysis of pollutants in water by molecular absorption spectrometry. The spectrometer is used for analysis. Design and implementation of software for the evaluation of water analysis is part of the work. The software is designed with ease of use and retrieval of data. Analysis of water is mainly focused on nitrates. The detection is focused on determining levels of particular components, suitable algorithm recognizes the substance. The method with the exchange of energy between radiation and the material under investigation (the spectrometric method) is used in the work. The energy exchange is the absorption or emission of radiation.

In the paper, strain-gauge sensor design and high temperature signal conditioner designed with HTCMOS operational amplifiers are presented. Amplifiers are based on SOI technology (Honeywell) to ensure high-temperature operation up to 225°C. The circuit is consist of three operational amplifiers (HT1104) to form precision instrumental amplifier and oscillator which is modulated by amplified signal from sensor. The output is square wave signal with variable duty cycle. The strain sensor was designed using FEM (Finite Element Modeling) and uses piezoresistive SOI strain gauges or strain sensitive boron doped nanocrystalline layers (NCD).

The paper presents design methodology and fabrication process of piezoelectric generator with thin-film Zinc Oxide (ZnO) layer. The design methodology utilizing FEM simulations is presented. Modeling and simulation of mechanical stresses, resonant frequencies, vibration modes and magnitude of generated voltage is virtually essential for any design of MEMS energy harvesting structures. CoventorWare software package was used as a very strong tool in the structure design. Simulation results opens the possibility for optimization of shape and position of the piezoelectric elements on the deformation transducer to achieve the maximum sensitivity and performance.

The paper reports on design, fabrication and characterization of piezoresistive sensors based on boron doped nanocrystalline diamond (NCD) layers. The shape and position of the piezoresistive element was optimized using finite element 3D modeling. Mechanical and piezoresistive simulations were performed. The piezoresistive sensing boron doped diamond thin films were realized on SiO2/Si3N4/Si substrates by microwave plasma enhanced chemical vapor deposition (CVD) and the piezoresistive structures were formed by reactive ion etching. The extensive study of sensor parameters e.g. deformation sensitivity, edge and contact resistances, temperature dependences gauge factor, temperature coefficient of resistance and bridge output voltage was performed.

The paper presents modeling and simulation of thermal distribution, heat transfer, and mechanical stress are virtually essential for any design of structures and devices in electronic industry simulation tools make the design easier and enable optimization of many different parameters before fabrication of new structure. This paper presents simulation validation of 3D model of solid state lighting LED bulb for energy efficient and durable light sources. The modeling of structures was performed by CoventorWare tools utilizing finite the element method (FEM). The calculated thermal distribution has been validated with thermal measurement on a commercial LED lamp. Materials parametric study has been carried out to discover problematic parts for heat transfer from power LEDs to ambient.

The paper presents modeling and simulation of thermal distribution, heat transfer, and mechanical stress are virtually essential for any design of structures and devices in electronic industry simulation tools make the design easier and enable optimization of many different parameters before fabrication of new structure. This paper presents simulation validation of 3D model of solid state lighting LED bulb for energy efficient and durable light sources. The modeling of structures was performed by CoventorWare tools utilizing finite the element method (FEM). The calculated thermal distribution has been validated with thermal measurement on a commercial LED lamp. Materials parametric study has been carried out to discover problematic parts for heat transfer from power LEDs to ambient.

Článek popisuje způsob korekce převodní charakteristiky senzoru. Korekce je založena na předřazení analogového obvodu v proudovém módu, který má převodní charakteristiku inverzní k charakteristice senzoru. Tím lze docílit linearizace či zvýraznění některých částí charakteristiky. Popisovaný způsob uvažuje obvod složený z CMOS tranzistorů v režimu podprahové vodivosti.

The paper presents the design and realization of a tactile sensor, which can detect x and y position of action force in an area of 7 cm x 7 cm and also measure amount of the force. Membrane structure with piezoresistive thin-film metal layer was used in first version of tactile sensor. The second version utilized force microsensors FSS1500 in order to sensitivity and resolution enhancement. Sensitivity of membrane sensor and FSS1500 was 0.022 mV/g and 0.12 mV/g respectively. Particular forces are measured using multichannel data acquisition unit and position is calculated and displayed by Labview virtual instrument.

Modelování a simulace mechanických namáhání a deformaci je prakticky nezbytné při jakémkoli návrhu nových MEMS struktur. Moderní simulační prostředky tento návrh velmi usnadňují a umožňují optimalizaci nejrůznějších parametrů ještě před vlastní výrobou nové struktury. Tento článek ukazuje příklad optimalizace polohy piezorezistivních prvků na substrátu pro různé typy deformačních převodníků (jednostranně vetknutý nosník a membrána). Modelování struktur bylo provedeno simulátorem využívajícím metodu konečných prvků (FEM). Navržené struktury byly následně vyrobeny a testovány.

In this paper, novel strain-gauge sensor design and its application for wireless measurement of blade deformations and strains are presented. The strain sensor was designed using FEM (Finite Element Modelling) and uses piezoresistive strain sensitive boron doped nanocrystalline layers. Nanocrystalline Diamond (NCD) is a very promising material for fabrication of harsh-environment devices because of its unique mechanical and electrical properties. The prospective of using diamond is not only in sensors (MEMS) but in RF and power electronic as well. Selection of method for data transfer is the key problem in rotating mechanisms. Telemetry can be related to transfer a data over any media, but is typically applied on wireless communications. A basic telemetry system consists of a measuring element or sensor, a device for sending the transmission, a receiver, and an output controller that records and displays data.

Carbon nanotubes (CNTs) are molecular-scale tubes of graphitic carbon with outstanding properties. They are among the stiffest and strongest fibers known, and have remarkable electronic properties and many other unique characteristics. In our experiment, CNTs were synthesized using plasma enhanced chemical vapor deposition on the silicon wafer with patterned iron catalytic layer. If the catalyst is only located in certain areas (patterned), then nanotubes grow only in those areas. The arrays with freestanding carbon nanotubes were created. It is possible to apply this method of CNTs preparation in many areas, such as sensor-based applications.

This work deals with thermal simulation and characterization of solid state lightening (SSL) LED Lamp in order to get precise 3D thermal models for further lamp thermal optimization. Simulations are performed with ANSYS-CFX and CoventorWare software tools. The simulated thermal distribution has been validated with thermal measurement on a commercial 8W LED lamp. Materials parametric study has been carried out to discover problematic parts for heat transfer from power LEDs to ambient. The objectives are to predict the thermal management by simulation of LED lamp and environment and to get more insight in the effect of lamp shape and materials used in order to design more effective LED lamps

This paper describes thermal simulation and validation of solid state lighting (SSL) LED Lamp with a view to get accurate 3D thermal models for supplementary lamp thermal optimization. Simulations are made by ANSYS-CFX and CoventorWare software tools. The calculated thermal distribution has been validated with thermal measurement on a commercial 8W LED lamp. Materials parametric study has been carried out to discover problematic parts for heat transfer from power LEDs to ambient. Main goal of the work is to predict the thermal management by simulation of LED lamp to get more insight in the effect of lamp shape and materials used in order to design more effective and more power LED lamps

Maximum operating temperature is usually one of the limiting factors for using of conventional sensors and other electronic devices. High-temperature sensors and electronics are required in some special applications e.g. measurement of deformations, stresses and pressures inside power generators. The design methodology of the some piezoresistive sensors utilizing FEM simulations is presented. Piezoresistive sensors based on thin-film metal sputtered layers, silicon-on-insulator (SOI) and nanocrystalline diamond layers (NCD) were successfully designed, fabricated and measured. The fabricated sensors are able to operate at temperatures up to 250 °C. Extensive study of sensor parameters e.g. deformation sensitivity, edge and contact resistances, temperature dependences gauge factor, bridge output voltage was performed. The measured values and investigated findings can be used for calibration of simulation software and in prospective design of more complex sensor structures.

Models and simulation results presented in the following sections were created in MEMS simulator CoventorWare. The simulator enables drawing of layout of designed structures, creation of 3d models and mesh generation for FEM and analyzing in different domains, such as mechanical, piezoresistive, electrostatic, piezoelectric, thermal etc. The mechanical solver, in CoventorWare called MemMech, computes the displacement and stresses in the structure. The user applies the boundary conditions, e.g. one of the beam end is fixed, while the opposite is loaded by uniaxial force and others.

Paper presents theory and practical examples of inductive coupling for the powering and communication with devices in isolated systems. It can be suitable for biomedical probes, encased systems such as tubes or sensors in the cement concrete, extreme temperature environments etc. The powering is realized using the near magnetic field.

Článek se zabývá možnostmi využití indukční vazby k napájení bezdrátových systémů. Je zde uvedeno stručné odvození základních vztahů pro nedokonale vázané induktory s důrazem na optimální volbu pracovní frekvence, napětí a maximalizaci výkonu. Pro tři konkrétní případy jsou tu pak uvedeny výsledky z měření, které jsou dále srovnány se simulacemi v programu SPICE.

Nanocrystalline Diamond (NCD) is a very promising material for fabrication of high-temperature devices because of its unique mechanical and electrical properties. The prospective of using diamond is not only in sensors (MEMS) but in RF and power electronic as well. The strain gauges based on nanocrystalline diamond layers have been successfully designed and fabricated using mainly domestic technological background.

Strain gauges are broadly used in sensors that detect and measure force and force-related quantities, such as deflection, torque, acceleration, pressure, and vibration. The piezoresistor is a basic building block for strain sensors that often use multiple strain gauges (piezoresistors) in their construction. A strain gauge is usually exposed to a small mechanical deformation which results in a small change in gauge resistance proportional to the applied strain (force, or other strain related quantity). Nanocrystalline Diamond (NCD) is a very promising material for fabrication of high-temperature devices because of its unique mechanical and electrical properties.

The paper presents improved method for estimation of the total ionizing dose (TID). Radiation environment can significantly affect the electronic devices performance. In order to avoid the problems the electronics must be designed with respect to the radiation environment. This is essential especially in situations where the radiation environments can be expected - nuclear power stations, satellites, medical devices, etc. The paper is based on analysis that was made for satellite operating at near polar orbit between 530 km (BOL) and 300 km (EOL) altitudes for at least four years.

High-temperature sensors and electronics are required for harsh environments where the application of conventional electronics is impossible or impractical, such as in industrial, automotive, aircraft and aerospace applications [1]. The design methodology utilizing FEM simulations is presented. Piezoresistive sensors based on thin-film metal sputtered layers, silicon-on-insulator and nanocrystalline diamond layers were successfully designed, fabricated and measured. The fabricated sensors are able to operate at temperatures up to 250 °C. Extensive study of sensor parameters e.g. deformation sensitivity, edge and contact resistances, temperature dependences gauge factor, bridge output voltage was performed. The measured values and investigated findings can be used for calibration of simulation software and in prospective design of more complex sensor structures.

The design, fabrication and test of piezoresistive sensors based on nanocrystalline diamond (NCD) films are reported. The CoventorWare FEM calculations of the mechanical stress and geometrical deformations of a 3-D structure are used for a proper localization of the piezoresistor on the carrying substrate. The boron-doped piezoresistive sensing element was realized using a directed patterned growth of NCD film on SiO2/Si by microwave plasma-enhanced chemical vapour deposition (CVD).

Motivation for this paper is to present possible solution for measuring analog values in isolated systems with out batteries. It can be suitable for biomedical probes, enclosed systems such as tubes, extreme temperature environments etc. The system is considering no batteries because of their finite lifetime, toxicity or an extreme temperatures environment that is improper for the batteries. System thus must be powered wirelessly and also the information must be transmitted without any wires. It is not necessary a long distance for this powering. Usually it is enough to transfer up to 20 cm. Paper presents basic theory needed for a design of the powering, communication and also the analog to digital converter. The converter is presented consisting of discrete devices and also it is presented scheme for chip realization using the 500 nm CMOS technology.

V současné době se kladou stále větší nároky na elektroniku pro přístrojové a řídící systémy, kdy jedním z požadavků je také provozuschopnost při vyšších teplotách. Elektronické prvky schopné pracovat při teplotách vyšších než 200 °C jsou potřeba zejména v průmyslových aplikacích, např. v řízení a diagnostice turbínových generátorů v elektrárnách. Technologie SOI (Silicon-on-Insulator) je vhodná pro realizaci elektronických prvků a senzorů nejen pro vysokoteplotní, ale i RF (Radio Frequency) aplikace. Tento článek představuje proces výroby a charakterizace piezorezistivních senzorů deformace (tenzometrů) v SOI technologii pro průmyslové aplikace.

The following paper introduces the CoventorWare design environment for SOI based piezoresistive sensor design. Fabrication process and characterization of designed sensors is also presented. The software package CoventorWare has been used for design of mechanical and electrical characteristics of the structure. The tools enable design, modelling and successive modification of designed MEMS structures.

Electronics for instrumentation and control systems are required to operate at ever increasing temperatures. Device operation at temperatures greater than 200 °C is required for a variety of present and next-generation control applications including e.g. turbine engine control and other industrial applications. SOI technology is suitable technology for fabrication of hi-temperature devices as well as devices for RF applications. The following paper introduces the CoventorWare design environment for SOI based piezoresistive sensor design. It uses a hybrid approach that is a unique combination of diaphragm FEM analysis using Analyzer and piezoresistive sensor modelling using Architect's circuit simulation environment.

The paper decribes design methodology of a presure sensor using software package Coventorware.

This paper introduces the fabrication process of the sensors and other passive elements based on SOI technology. Simple passive elements (strain sensitive resistors - piezoresistors) were fabricated on SIMOX SOI substrates. Planar inductors and capacitors were fabricated on standard Si/SiO2 substrates with sputtered AlCuSi metallization. Basic parameter extraction and their temperature dependence were performed.

The paper presents possible solutions for wireless powering of the electronic systems. The goal of this paper is to describe methods for simple implementation of such powering using the inductance coupling. This kind of powering is usually used for RFID or for the system that can not be powered using the wires (biomedical probes, encased monitoring systems, etc.). The powering system should provide the energy for the electronics across the distance of several centimeters and the powered electronics is desired to not being enclosed by the magnetic loop.

Paper describes NMOS and PMOS translinear cell which multiplies the current signals and which can be used for the current-mode signal processing. The translinear cell consists of NMOS or PMOS transistors that are treated in the sub-threshold conduction region. In this region the transistors exhibit an exponential dependency of the drain current versus the gate voltage and thus the translinear principle can be used for description of the functionality. Operation region of the cell is limited by the validity of the exponential dependency and also by the transistors leakage currents. Significant error is also induced by the auxiliary current mirrors which are biasing the cells. Channel length modulation effect causes error of the input signals and thus the output signal is affected by the multiplicative error. Paper presents basic idea of the multiplying cell, presents results of simulations in CADENCE and also presents results of measurements on real structure composed using dis. tran.

The following paper introduces the CoventorWare design environment for piezoresistive sensor design. It uses a hybrid approach that is a unique combination of diaphragm FEM analysis using Analyzer and piezoresistive sensor modeling using Architect's circuit simulation environment.

Electronics for instrumentation and control systems are required to operate at ever increasing temperatures. Device operation at temperatures greater than 200 °C is required for a variety of present and next-generation control applications including e.g. turbine engine control and other industrial applications. SOI technology is suitable technology for fabrication of hi-temperature devices as well as devices for RF applications.

Design and technology of some types of micromechanical sensors based on tensometric layers sputtered on silicon substrates is described. The aim is to prepare sensors suitable for higher operational temperatures utilizing both available high-quality insulating layers and local reduction of substrate thickness by anisotropic etching. To achieve long-term temperature stability the layers of NiCr, Ta2N and CrSi have been studied. Several variants of active layers combined with multilayer electrical contacts were evaluated to prepare successfully the samples Sensors of both one-dimensional type (cantilevers for deformation sensing) and two-dimensional one (membranes) have been studied. Simulations using Coventor-Ware software were performed for modelling of properties of the microstructures under study.

The paper describes design of a temperature sensor with a CMOS temperature transducer and a circuit with phase lock determined for signal processing with PWM output. Two types of the CMOS temperature sensor operating in the weak and strong inversion region were designed.

The paper describes design of a temperature sensor with a CMOS temperature transducer and a circuit with phase lock determined for signal processing with PWM output. Two types of the CMOS temperature sensor operating in the weak and strong inversion region were designed.

Approach to Microsystem Design

Design of Temperature Matrix with Direction Sensitivity

Design of Temperature Matrix with Direction Sensitivity

Design of Temperature Matrix with Direction Sensitivity

Work summarize the principles of the measuring the pressure with the special accent on the possibility of representing the measured pressure by the electric signal. Main purpose of my work is the design of an analog to digital converter, suitable for the cooperation with the pressure sensor MPX4115A and with some kind of a transmitter.

Integrated Pressure Sensor - Use of Microsystems Model Flow

Intelligent Sensor Structure for Tilt Measure

Macromodel of Intelligent Sensor Structure with Accelerometer

Macromodel of Intelligent Sensor Structure with Accelerometer

Microsystem Models in Integrated Pressure Sensor Design

Microsystem Models in Integrated Pressure Sensor Design

This paper describes the Design of Anemometric Sensor System for Measurement of Wind Velocity and Direction with Integrated Measure Probe

The Design of Anemometric Sensor System for Measurement of Wind Velocity and Direction with Integrated Measure Probe

In the paper there is characterized physical model of implanted strain gauges; various girder topologies are designed and basic technological steps during realization of cantilever are described. Simulation using CoventorWare (MEMCAD) program is used for verification of mechanical properties and temperature distribution in cantilever structures. At realized structures of cantilever with strain gauges, there have been measured basic parameters, as dependence of electric parameters of strain gauges on mechanical deformation, temperature dependence at different mechanical load, temperature stability of output parameters, temperature dependence of pn junctions in the structure. From measured data there have been calculated piezoresistive coefficients, coefficients of deformation sensitivity, linearity, hysteresis, temperature coefficients of resistance, etc. Based on measured data, there has been designed connection of a simple electric equivalent model of the structure.