Ing. Adam Bouřa, Ph.D.

The paper presents a USB measuring device, that can be used for characterization of the self-discharging properties of an electrolytical capacitor. It is basically a voltmeter with very high input impedance and very low input current, so just the leakage current of the capacitor affects its voltage. It is based on an instrumentation amplifier AD8422 with input impedance 200 GΩ and input bias current lower than 1 nA. Its functionality is demonstrated on measurement of electrolytical capacitors that were treated at different conditions (new/old capacitors, quick/slow charging, long-term treatment at the forming voltage). Main purpose of the device is to measure the leakage current of the storage capacitors when energy harvesting is applied. If weak energy sources are harvested, the storage capacitor’s leakage current is an important parameter to be considered in the design.The paper also presents method how the storage capacitor must be treated to minimize the leakage current.

The paper solves the model of the miniature Power supply based on the piezoelectric cantilever. The aim of the future is to further hybrid integration and use of nanotechnology. Contents of the article belongs to the category of renewable energy sources with environment energy conversion into electrical energy. The work is focused on the use in small temperature differences.

The work is focused on the analysis of the thermoelectric generator based on the thermoelectrical effect. The aim idea of the future is to further hybrid integration with semiconductor structures, event. used of nanotechnology. The work is focused on the use of heat of thermally stressed semiconductor structures with subsequent generation of electrical energy, such as GaN semiconductors designed for the automotive industry. The analysis is performed for 4 types of thermoelectric generators (TEG), obtaining energy and storing it in a supercapacitor. The aim was to verify the possibility of using thermoelectric effect, verifying properties using model, determine the essential characteristics, finding the optimum load, output voltage and output power achieved. The operation control of the thermoelectric generator was realized with the circuit LTC3108. We used thermoelectric batteries as a heat energy converter (TEC1- 12707, TEC1-071080, TEG-127020 a TEG-127009).

A nanocrystalline diamond (NCD) layer is used as an active (sensing) part of a conductivity gas sensor. The properties of the sensor with an NCD with H-termination (response and time characteristic of resistance change) are measured by the same equipment with a similar setup and compared with commercial sensors, a conductivity sensor with a metal oxide (MOX) active material (resistance change), and an infrared pyroelectric sensor (output voltage change) in this study. The deposited layer structure is characterized and analyzed by Scanning Electron Microscopy (SEM) and Raman spectroscopy. Electrical properties (resistance change for conductivity sensors and output voltage change for the IR pyroelectric sensor) are examined for two types of gases, oxidizing (NO2) and reducing (NH3). The parameters of the tested sensors are compared and critically evaluated. Subsequently, differences in the gas sensing principles of these conductivity sensors, namely H-terminated NCD and SnO2, are described.

The paper presents a circuit structure that can be used for powering an IoT (Internet of Things) sensor node and that can use just the energy from its surroundings. The main advantage of the presented solution is its very low cost that allows mass applicability e.g. in the IoT smart grids and ubiquitous sensors. It is intended for energy sources that can provide enough voltage but that can provide only low currents such as piezoelectric transducers or small photovoltaic panels (PV) under indoor light conditions. The circuit is able to accumulate energy into the capacitor until a certain level and then to pass it to the load. The presented circuit exhibits similar functionality to a commercially available energy harvester (EH) EH300. The paper compares electrical properties of the presented circuit and the EH300 device, their form factors and costs. The EH circuit’s performance is tested together with buck-boost DC/DC converter LTC3531 which can provide constant voltage for the following electronics. The paper provides guidelines for selecting an optimal value of the storage capacitor. The solution presented’s functionality is demonstrated on a sensor node that periodically transmits measured data to the base station using just the power from the PV panel or the piezoelectric generator. Presented harvester and powering circuit are compact part of the sensor node’s electronics but it can be also realized as an external powering module to be added to existing solutions.

A large number of IoT nodes creates a danger of extra expenditures when changing the battery. For this reason, the development of supply nodes tends to prefer systems capable of battery-less operation, obtaining energy from other sources. This article deals with an alternative method of electrical energy acquisition form the excessive heat appearing in LED lighting fixtures utilizing large-area LED chips. A Peltier cell was used for the conversion of heat energy to electrical energy, connected as thermo-electric generator into the thermal chain.

This paper demonstrates the concept of node consumption reduction for IoT applications. The main emphasis is placed on the autonomy of the whole device, which must be independent of external power supply. That is why energy harvesting based on temperature principle is used for power supply. One of the parameters monitored is the service uptime. The concept of intelligent control of the individual parts of the equipment leads to significant energy savings. This control requires the use of low power components, but only their appropriate connection and mutual monitoring of their operating modes leads to the desired savings. This algorithm can be adapted to the needs of IoT nodes focused on real-time performance applications or the process tracking slow low power applications. This concept will ultimately be adapted to a wireless node for monitoring position and temperature for use in medical applications to monitor the patient's position on the bed or position while moving.

The development of IoT instrumentation will always be strongly influenced by the properties of the power supply system. A large number of IoT nodes creates a danger of extra expenditures when changing the battery. For this reason, the development of supply nodes tends to prefer systems capable of battery-less operation, obtaining energy from other sources. This article deals with an alternative method of electrical energy acquisition form the excessive heat appearing in LED lighting fixtures utilizing large-area LED chips. A Peltier cell was used for the conversion of heat energy to electrical energy, connected as thermo-electric generator into the thermal chain.

This paper discusses the concept, design and testing monitoring system for the needs of farmers. The system consists of integrated autonomous BLE beacons, which are located on monitored objects (in our model case, cattle). These beacons transmit their identification data in specified periods together with other additional information, which is then used to perform the precise targeting of the monitored object in the monitored area (meadow, grazing, fence).

This paper discusses the concept, design and testing of a IoT based monitoring system for the needs of farmers. The system consists of integrated autonomous BLE beacons, which are located on the monitored objects (in our model case it is cattle). These beacons transmit their identification data in specified periods together with other additional information, which then serves to perform accurate targeting of the monitored object in the monitored area (meadow, fence). This data is periodically received by a central hub, which brings this information together, eliminates duplications and sends the final datagram containing information about active beacons via the GSM network (or LoRa) to a central server, where the data is subsequently processed. A pilot test experiment is taking place this summer on a private farm in Central Bohemia.

Článek se zabývá návrhem a testováním monitorovacího systému pro potřeby farmářů. Systém sestává z integrovaných autonomních BLE beacon, které jsou umístěny na sledovaných objektech (v našem modelovém případě se jedná o skot). Tyto beacony vysílají v určených periodách svoje identifikační údaje společně s dalšími doplňkovými informacemi, které následně slouží pro provedení přesného zaměření sledovaného objektu ve sledovaném prostoru (louka, pastva, ohradník). This paper discusses the concept, design and testing monitoring system for the needs of farmers. The system consists of integrated autonomous BLE beacons, which are located on monitored objects (in our model case, cattle). These beacons transmit their identification data in specified periods together with other additional information, which is then used to perform the precise targeting of the monitored object in the monitored area (meadow, grazing, fence).

The paper presents a universal Spice model that can be used for modelling the photovoltaic panels (PV) – namely the DC characteristics. The model was built on simplified schematic and fitting its parameters to the measured data. There were developed two types of the models – the simple model and the full model. The simple model is valid only for PVs with constant width of the PN junction strip (only the number and length are scalable). The full model allows user to set also the PN junction’s width. The simple model exhibits better accuracy, typically better than 5 %, while the full model’s accuracy is typically lower than 15 % (for illumination in the range from 20 lx to 2000 lx).

The core of the article solves the microsystem model of the electric generator based on the piezoelectric effect. The aim of the future is to further hybrid integration and use of nanotechnology. Contents of the article belongs to the category of renewable energy sources with environment energy conversion into electrical energy. The aim was to verify the possibility of using piezoelectric effect, verifying properties using model, determine the essential characteristics, finding the optimum load, output voltage and output power achieved. Attention is given to the basic principles of activities, electronic circuit connection as well as behaviour of the piezoelectric cantilever.

The paper presents a circuit structure that can be used as an energy harvester. It is intended for photovoltaic panels (PV) or other sources of energy that can provide enough voltage level but that can source only low currents. The circuit is able to accumulate the energy until certain level and then to pass it to the load. The presented circuit exhibits similar functionality as a commercially available energy harvester EH300. The paper compares their technical properties, form factors and costs. The circuit was tested with IoT (Internet of Things) node that can periodically transmit measured data to the base station using just the powering from the PV panel. Worse electrical properties of the circuit are repaid by its low cost that allows mass applicability in the IoT.

The work is about automated system that allows characterization of solar cells for low energy applications. The system is suited for small solar cells that can be used for indoor energy harvesting. These solar cells differ from standard solar cells in its ability to provide enough voltage level also at low levels of ambient light. This simplifies circuit for energy harvesting for wireless sensors application. Specialized solar cell of dimensions 2.5 × 2.5 cm2 was tested and the measured characteristics are compared with SPICE model that can be used for simulations. The solar cell was applied with energy harvester module EH300 at different light conditions. The testing proved that the developed system can provide enough energy for wireless and battery-less measurement even at light levels below 20 lx. The presented system thus can be used for various indoor IoT applications.

The paper deals with the single-coil metal detector. It presents measurement and test results that predict practical limitations of this detection concept. The studied principle is based on the coil’s inductivity change when a metal object is approached. This principle is very old and nowadays it is obsolete. Advantage of this principle is its simplicity. It can be easily implemented for several searching coils. As the result it can be constructed very cheaply device for effective and automated land screening. Six different oscillator types were tested with three different shapes of the searching coils. The sensitivity was tested on several metal objects. Maximal detection distance was tested in free air for axial distance.

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 paper deals with the single-coil metal detector. It presents measurement and test results that predict practical limitations of this detection concept. The studied principle is based on the coil’s inductivity change when a metal object is approached. This principle is very old and nowadays it is obsolete. Advantage of this principle is its simplicity. It can be easily implemented for several searching coils. As the result it can be constructed very cheaply device for effective and automated land screening. Six different oscillator types were tested with three different shapes of the searching coils. The sensitivity was tested on several metal objects. Maximal detection distance was tested in free air for axial distance.

The paper describes construction and applicability of the two dimensional sliding bench. It can be used for precise adjustment in the plane during the lithographical exposure of the substrate. It is applicable for exposure on the gel mask or direct exposure to the final substrate. It was developed mainly for preparing of the simple microelectromechanical structures for the gas sensors (SAW structures, application of active substances for conductivity sensors, micromechanical structures adjustment and trimming). Light exposure is provided via the lens and enlarged pattern for a given wavelength (these optical components are not a part of the bench). The bench allows replication of one structure over a larger area of the mask (substrate) and automated intensity setting and timing. The bench can also be used for direct writing of simple structures into the photo-resist.

The aim of the paper is to present results of design gas sensor with different form of polyaniline active layer for toxic gases detection. . Sensing of toxic gases is very important in many applications. Automotive, defence, aerospace, agriculture, chemical industry, medicine, environmental, food and drink are many important markets for chemical and biological sensors. The advantages of resistive sensors are easy fabrication, simple operation and low production cost. Using of polymer film causes that this sensor is not required heating of active layer. This leads to reduce power consumption. Active layer is operated at room temperature.

Presented work deals with crystal oscillators that can be used as a quartz crystal microbalance (QCM) gas sensor. There are presented two basic oscillators that are very common in literature. The oscillators were put into practice and tested in the gas chamber with different crystals of basic frequency 10 MHz. There were tested clean crystal resonators and resonators coated by a sensitive layer. Frequency response of the oscillators is usually very small and it is comparable with the effects such as temperature change or crosstalk in the evaluation circuit. The evaluation circuit thus must be designed carefully. Main goal of this paper is comparison of two basic designs of the oscillators and presentation of the precise evaluation circuit with minimal crosstalk and reverse transmission in signal ways.

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 work deals with crystal oscillators that can be used as a quartz crystal microbalance (QCM) gas sensor. There are presented two basic oscillators that are very common in literature. The oscillators were put into practice and tested in the gas chamber with different crystals of basic frequency 10 MHz. There were tested clean crystal resonators and resonators coated by a sensitive layer. Main goal of this paper is comparison of the crystal’s characteristics and comparison of two basic designs of the oscillators. The paper summarizes main pros and cons and suitability for the QCM gas detectors realization.

Článek popisuje konstrukci a vlastnosti obvodu, který lze použít jako náhradu běžného blesku ve fotografii. Obvod obsahuje měnič napětí z 2,4 V na cca 40V, časovač pro spouštěcí obvod a regulátor proudu do sériově-paralelní kombinace LED.

The paper presents solution for wireless and battery-less measurement in the enclosed areas. The principle is based on passive RFID; nevertheless this paper is focused on high power-demanding applications such as MEMS accelerometers, gas sensors, piezoresistive strain gauges, etc. Standard RFID communication scheme (sensing the input current change on the primary side) cannot be used in this case, because the communication channel is overloaded by the high power load. Paper presents possible solution which is based on the dual frequency scheme - one frequency for powering and other for the communication. This is ensuring capability for measurement up to several centimeters on the frequency bands 125 kHz and 375 kHz. It can be suitable for continual measurement in isolated systems such as the rotating objects, concrete walls, enclosed plastic barrels, high temperature chambers etc.

O artigo resume os problemas associados à compatibilidade de dimerização das modernas lâmpadas LED com a infraestrutura de dimerização atual. Em 2016, as lâmpadas incandescentes existentes passarão a ser proibidas no mercado europeu e precisarão, portanto, ser substituídas pela moderna iluminação de estado sólido baseada na eficiência energética, gerando problemas na compatibilidade de dimerização.

The paper summarizes basic problems of dimming compatibility of modern LED lamps with the legacy dimming infrastructure. In 2016 the legacy incandescent bulbs are going to be forbidden on the European market and thus it must be replaced by modern and energy efficient solid state lighting. The problems with dimming compatibility appeared. Standards phase-cutting dimmers are widely used in the households and consumers expect the modern lighting to have the same properties as the incandescent bulbs. The legacy dimmers are designed for some minimal load (usually 40 - 60 W) while the modern LED lamps replacements have only about 12 W keeping the 60 W incandescent bulb luminous flux (800 lm). Several different problems must be solved in order to keep the dimming ability, avoid the light flickering and keep the dimmer in the safe operation region. There are two basic dimmer types. The leading edge dimmers that are usually based on triac switch and trailing edge dimmers that use MOSFET switches and electronic control. Both types have its specific demands and need different approach for ensuring the dimming compatibility. New LED driver must be developed in order to be compatible with the legacy dimmers.

The paper summarizes basic problems of dimming compatibility of modern LED lamps with the legacy dimming infrastructure. In 2016 the legacy incandescent bulbs are going to be forbidden on the European market and thus it must be replaced by modern and energy efficient solid state lighting. The problems with dimming compatibility appeared. Standards phase-cutting dimmers are widely used in the households and consumers expect the modern lighting to have the same properties as the incandescent bulbs. The legacy dimmers are designed for some minimal load (usually 40 - 60 W) while the modern LED lamps replacements have only about 12 W keeping the 60 W incandescent bulb luminous flux (800 lm). Several different problems must be solved in order to keep the dimming ability, avoid the light flickering and keep the dimmer in the safe operation region. There are two basic dimmer types. The leading edge dimmers that are usually based on triac switch and trailing edge dimmers that use MOSFET switches and electronic control. Both types have its specific demands and need different approach for ensuring the dimming compatibility. New LED driver must be developed in order to be compatible with the legacy dimmers.

The paper summarizes basic problems with dimming compatibility of modern LED lamps using the legacy dimming infrastructure. Standards phase-cutting dimmers are widely used in the households and consumers expect the modern lightning to have the same properties as the incandescent bulbs. Presented work was made within the project CSSL (Consumerizing Solid State Lighting) which is aimed on development of a new affordable LED lightning to be equivalent to the 60 W incandescent bulbs.

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 solution for wireless and battery-less measurement in the enclosed areas. The principle is based on previous work, while this paper is focused on high power-demanding applications such as MEMS accelerometers, gas sensors, piezoresistive strain gauges [2], etc. Standard FRID communication scheme (sensing the input current change on the primary side) can not be used in this case, because the communication channel is overloaded by the high power load. Paper presents possible solution which is based on the dual frequency scheme - one frequency for powering and other for the communication. This is ensuring capability for measurement up to several centimeters on the frequency bands 125 kHz and 375 kHz. It can be suitable for continuous wireless and battery-less measurement in isolated systems such as the rotating objects, concrete walls, enclosed plastic barrels, high temperature chambers etc.

The paper presents solution for wireless and battery-less measurement in the enclosed areas. The principle is based on previous work, while this paper is focused on high power-demanding applications such as MEMS accelerometers, gas sensors, piezoresistive strain gauges, etc. It can be suitable for continuous wireless and battery-less measurement in isolated systems such as the rotating objects, concrete walls, enclosed barrels, high temperature chambers etc. It is based on near magnetic field coupling in radiofrequency band. The principle is similar to the RFID, while it is more powerful and the powering and signal transfer is separated by the different frequencies. The antennas are designed for surface mounting. The system is desired to be used in long-term monitoring of the environment.

The article solves the design and implementation of a simple intelligent sensor network for physical quantities measurement. The system uses wireless data transmission. Sensor network is designed as a basic element of the ZigBee network. Each unit has a sensor attached to a microcontroller. The system is controlled by PC, the variable arrangement can be used. The different type of the sensor can be used. The system can be extended to other types of sensors for measuring the chemical variables. The data transfer from PC can be transmitted by internet.

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.

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.

There is described a MOS structure in the use of flow sensor system in the paper. MOS structure as a temperature sensor allows measurement of temperature gradient. One allows computation of direction of air flow over the structure chip. Four MOS structure of temperature sensors has been used for the design of sensitivity flow sensor. Different arrangements of MOS structure have been designed. Software standard tools have been used for simulation and modeling of structure properties. Maximum values of structure sensitivity in dependence on operating temperature have been computed. The parameters have been used for the design. Suitable structure temperature was found during simulations. Circuit connection of sensor temperature matrix was designed. New results of sensitivity and resolution of MOS sensor systems were obtained. The working efforts were focused on the sensitivity, angle resolution and small power consumption.

Paper presents wireless powering and signal transfer solution using the inductive coupling. It can be suitable for enclosed systems that are isolated from the surroundings and where the batteries cannot be used. It can be used for biomedical probes, probes bricked in to the wall for long-term monitoring, extreme temperature environment measurement etc. The powering is provided by the near magnetic field. The serial and parallel resonances are considered in the design in order to increase the voltage transfer. Voltage levels, power transfer efficiency and signal modulation effects are studied up to distance of 30 cm. Presented principle of powering and communication is similar to the RFID systems (Radio Frequency Identification). The main contribution of this paper is powering potentialities and distance limits prediction of this powering strategy. The simple coils are considered. Special converter is presented for this purpose.

Paper presents possible solution and practical examples for wireless powering and signal transfer using the inductive coupling. It can be suitable for long term monitoring in enclosed areas and systems that are isolated form the surroundings. This solution allows avoiding the batteries. It can be used for probes bricked in to the wall, extreme temperature environment measurement, the barrels internal shells health monitoring etc. Main advantage of this kind of powering is nearly unlimited lifetime, no toxic pollutions (such as Cd, Li, H2SO4,… contained in the batteries) and universal applicability. The main contribution of this paper is prediction of the powering potentialities and distance limits of this strategy. Voltage levels, power transfer efficiency and signal modulation effects are studied up to distance of 30 cm. Special converter principle is presented for this purpose.

Following text describes a universal test bench that can be used for characterization of the sensors. It offers sufficient distance and force ability to characterize a wide sort of the sensors. It is suitable for precise distance setting. It is able to set the distance in the range of 10 cm with the resolution up to 10 μm. The mechanical tolerance is negligible. It is less than five micrometers for unloaded viper. Possible relevant tolerance can be caused only by the structure frame bending when the high mechanical stress is applied. The test bench was developed as a research instrument for characterization of new sensor structures and it is also used as a teaching facilitation in the sensor systems tutorial. The test bench functionality is illustrated on five types of the sensors - the capacitive sensor, the optic sensor GP2D120, the Hall sensor A1301, the magneto resistive sensor HMC1501 and for the compression measurement was used the cantilever beam LC501-100.

The paper describes a universal test bench that can be used for distance characterization of the sensors. It is suitable for precise distance setting - it is able to set the distance in the range of 10 cm with the resolution up to 10 μm. The mechanical hysteresis is negligible - it is less than five micrometers. The test bench was developed as a teaching facilitation for sensor systems lecturers and also as the tool for the scientific characterization. The test bench functionality is performed on four types of the sensors - the capacitive sensor, the optic sensor GP2D120, the Hall sensor A1301 and the magneto resistive sensor HMC1501.

The core of the paper is the control system with a few electronic blocks (control, actuator, software, and RF wireless communication). The control block drives operations in the system, the wireless block ensures communication, and data transfer, the actuator part is drived by control block. The software drives all operations in the system. Sensors ensure basic information about environment. The number of sensor can be variable. The control block cooperates with wireless sensors, and wireless actuators. The heart of the system is the control microprocessor. The system communicates with PC, mobile phone etc. There was used a new architecture of a multisensor system for physical measurement using wireless data transfer in the paper. Different control software was designed for wireless parts.

The system contains units: wireless, control, actuator, software equipment. RF wireless unit ensures wireless communication between control unit and sensors as well as wireless switch unit. The control unit controls system operation, i.e. communication transfer, sensor data processing as well as switching of actuator unit. Actuator switch unit is wireless controlled by control unit. There were hardware and software realized and tested in the designed system. The system was designed to operate with different type of physical sensors. The system can used PC, PDA or mobile phone to communication as well as signal processing. The control unit communicates with wireless temperature sensors and wireless switch units. The wireless temperature sensors measure temperature periodically and convey the measured data to the control unit. The actuator units communicate with the control unit. The main part is the control microprocessor. The run of the system is supported by the control programs.

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.

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 paper describes an analog circuit system which processes an analog current mode signals. This circuit serves as a preamplifier and also it is able to correct a transfer characteristic of some input device or sensor. The circuit is based on the sub-threshold CMOS multiplying cells. The cells are interconnected in order to form powering stages and thus the output signal from the circuit is not linear dependent but there is some multinomial dependency on the input signal. It can be used directly or it can be encircled by a negative feedback in order to realize the inverse function. The transfer characteristic is tunable aid four ten-bit digital to analog converters. The program CADENCE and the CMOS 180 nm technology were used for simulations.

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.

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.

Vertical Velocity Measurement - Processing of Sensor Data Using Altitude Corrections

Paper describes the circuit structure, which is able to evaluate the temperature difference. It can be used for sensing temperature difference on the surface of the chip. Output signal from this sensor can drive the temperature compensation of the whole chip or it can be used for evaluating internal and external condition around and inside the chip. Circuit structure is based on CMOS technology which guarantees compatibility with other circuits on the chip. Paper describes the sensing circuit structure and also the circuit for compensation of the channel length modulation effect of the transistors in the sensing current mirrors. The programs Cadence and WinSpice were used for simulations.

The paper describes a circuit system which is able to process an analog current mode signals. It is intended to use it as a preamplifier and corrector of the transfer characteristic of some kind of sensor.

Paper presents the basic principles and problems which must be considered in the design of the wind sensor. First it is described the basic principle of the wind flow sensor which is based on the heating CMOS chip. Paper presents possibilities of the chip layout and crucial parameters of the CMOS sensing elements. Sensor is intended to be used for wireless applications, so the power consumption of the sensor is one of the most important parameter. Programs CovenorWare, Cadence and 180 nm CMOS technology were used for simulations.

The paper describes a circuit system which is able to process an analog current mode signals. It is intended to use it as a preamplifier and corrector of the transfer characteristic of some kind of sensor. The circuit is based on the sub-threshold CMOS multiplying cells. Those cells are interconnected by the current mirrors to form a circuit with desired transfer characteristic. There are two ways how to use this circuit. It can be used for direct linearization (pre-distortion) of the signal from the sensor or it can be encircled by a negative feedback in order to realize the inverse function. The circuit is dedicated for slow signals and for extremely low power applications. The transfer characteristic is tunable aid four ten-bit digital to analog converters. The program CADENCE and the CMOS 180 nm technology were used for simulations.

In the paper there is presented temperature transducer with PLL signal processing of sensor data. The principle of temperature sensor is based on the MOS structure behaviour in the temperature range. The strong and weak inversion modes are used. There is used matrix of temperature sensors in the design of air flow sensor. Various arrangements of temperature structure are designed. The new circuits design is used.

The work describes a design of the biquad section using log-domain CMOS technology. Low-pass, band-pass and high-pass filter can be realized using this biquad section. The transfer function of the filter is determined by the feedback around the input and output of the biquad. My design is based on demand to have a universal building block which is able to filter the frequency band from DC to radio frequencies. The frequency band and the transfer function of the filter is determined only aid few devices connected to this building block. It is intended to use these current-mode filters in the design of the wireless sensor systems. In these applications the low-pass filters are usually used as an anti-aliasing filter before the signal is sampled. Also the radio frequency part of the circuit uses the filters.

Work describes a circuit system which is able to process analog current mode signals. The circuit is based on the sub-threshold CMOS multiplication cells. Those cells are interconnected by current mirrors to form the circuit with desired transfer characteristic. There are two ways how to use this circuit. It can be used for direct linearization (pre-distortion) of the signal or it can be encircled by a negative feedback in order to realize the inversion function. The circuit is dedicated for slow signals and for extremely low power applications. The program CADENCE and the MOSFET 180nm technology were used for simulations.

In the article there is presented a new arrangement of a temperature sensor system for air velocity and direction measurement. The system utilizes temperature dependence of the current through the channel of MOS structure. The geometric arrangement of temperature sensors allows measurement of temperature gradient. Temperature gradient allows to compute direction of air flow over the chip. Optimal operating modes of weak and strong inversion of MOS structure operation have been selected for the design of integrated temperature matrix. The matrix has been used for the design of a probe for measurement. Various arrangements of MOS sensor structures have been designed. CoventorWare and CADENCE software tools have been used for simulation and modeling of sensor properties.

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.

The work describes a design of the filter using log-domain CMOS technology. Filter only consists of capacitances and CMOS transistors in the week inversion mode and they are treated in the subthreshold conduction region. Low-pass, band-pass and high-pass filter is considered in the design. The transfer function of the filter is determined by the feedback around its input and output. My design is based on demand to have a universal building block which is able to filter the frequency band from DC to radio frequencies. This building block is represented by the log-domain differentiator. The frequency band and the transfer function of the filter is determined only aid few devices connected to this building block. It is intended to use these current-mode filters in the design of the wireless sensor systems. In these applications the low-pass filters are usually used as an anti-aliasing filter before the signal is sampled. Also the radio frequency part of the circuit uses the filters.

Článek pojednává o prvotních zkušenostech, problémech a postřezích, se kterými jsem se, co by nový asistent, setkal při výuce na cvičeních z předmětů Elektronické součástky, Elektronika a Senzorové systémy v lékařství. Jedná se o předměty vesměs povinné, a proto lze za zásadní problém označit nezájem většiny studentů o samotný předmět a o snahu získat za něj pouze potřebné kredity. Dále to může být též ne zcela vhodná náplň cvičení a rovněž nesystémová skladba celého studia. To ve výsledku vede k zahlcení studenta množstvím nesourodých informací, které není schopen plně postihnout a uchyluje se proto k "otrockému" memorování vzorečků na místo pochopení logiky věci. V závěru se snažím naznačit možná řešení a přístupy k tomuto problému

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.

Work describes a simple circuit structure which is designed to cooperate with the intelligent pressure sensor. In fact this circuit is an analog to digital converter based on the principle of the Voltage to Frequency Converter (V/F Converter).

Článek se zabývá charakterizací MEMS mikrovlnných přepínačů a porovnáním jejich vlastností s PIN diodovými a FET přepínači.Dále je proveden výběr vhodného MEMS přepínače pro přepínání mikrovlnného signálu, do kmitočtu 1600 MHz, mezi čtyřmi větvemi.

Článek se zabývá optimalizací účinnosti výkonového stupně zesilovače v pásmu rádiových vln. Výkonový stupeň, pracující ve třídě A, je pomocí metody řízeného biasu výkonového tranzistoru nastavován pro optimální energetickou účinnost. Důraz je dán především na maximální zachování čistoty spektra výstupního signálu, tedy na nalezení optima mezi energetickou účinností a přijatelným harmonickým zkreslením.

Sensor System with Differential Arrangement of Temperature MOS Sensor

In this article, an arrangement of a temperature sensor system is presented. The system utilizes temperature dependence of the current through the channel of MOS structure. Differential arrangement of the temperature sensor is designed. The arrangement allows measurement of temperature gradient. Using suitable geometric arrangement it is possible to compute direction from the temperature gradient, i.e. for example angle of air flow over the chip. Integrated structure of temperature sensors on the chip has orthogonal arrangement. Optimal operating modes have been selected for the design. There have been performed simulations of dependence of temperature sensitivity of the transistors as temperature sensor on changes of its basic parameters. Modes of weak and strong inversion of MOS structure operation have been simulated in the design. Optimal setup of operating mode has been selected for the design of integrated temperature matrix. The matrix has been used for the design of a probe for measurement of velocity and direction of the gas (air) flow over the chip. Various arrangements of MOS sensor structures have been designed. CoventorWare and CADENCE software tools have been used for simulation and modeling of sensor properties

Článek popisuje základní principy výroby polymerních součástek.

Work describes a simple circuit structure which is designed to cooperate with the intelligent pressure sensor and RF transmitter.

Základní principy a struktury MEMS systémů