Wlodzimierz Kalita

Modelling and Design of HF RFID Passive Transponders with Additional Energy Harvester

The huge progress in electronics technology and RFID technique gives the opportunity to implement additional features in transponders. It should be noted that either passive or semipassive transponders are supplied with energy that is derived from the electromagnetic field generated by the read/write device and its antenna. This power source is used to conduct radio-communication process and excess energy could be used to power the extra electronic circuits, but the problem is to determine the additional power load impact on the RFID system proper operation and size of interrogation zone. The ability to power the supplementary electronic blocks applied in the HF passive transponders is discussed in detail this paper. The simulation model and test samples with a harvester that recovers energy from the electromagnetic field of read/write device and its antenna have been developed in order to conduct investigations. The harvested energy has been utilized to supply a microprocessor acquisition block for LTCC pressure sensor developed in research previously described by authors.

Modelling of Dynamic Temperature States in Layer Microelectronics Systems

The theoretical analysis (compared with experimental investigations) of dynamic temperature states in layer microcircuits (made in LTCC or HTCC technology) has been described in the paper. Two basic models and solution procedures of analytical equations system have been presented. Furthermore their basic advantages and disadvantages have been compared together with accuracy discussion. The solution of the analytical model (for the typical thick-film structure - active layer placed on alumina substrate) has been compared with the experimental results. The many factors which have influence on accuracy of obtained results have been taken into consideration and discussed. The results of analysis can be used in researches with reliability and tolerance aspect of microsystems (intensity of degradation processes) as well as in determination of thermal properties of the designed systems.

Simulation of transient thermal states in layered electronic microstructures

Abstract The analysis of dynamic temperature changes in microelectronic layered circuit (especially made in thick-film technology) has been presented in the paper. Such transient states are caused by electric pulse with high energy and short time of duration. It leads to short but the very violent temperature increase and – as result – defects or parameter changes of active layer. The mathematical function which describes the instantaneous temperature changes was presented in this paper in order to provide more accurate analysis of reliability and thermal properties measurement problems. The two-layer structures (with different thermo-physical properties) were the subject of conducted research, especially one of them, namely heat source excited by electric pulse. Such configuration is typical for microcircuits made in hybrid technology such as LTCC (low temperature co-fired ceramic), HTCC (high temperature co-fired ceramic) as well as thick – film technology in which polymer and photoimageable (photosensitive) materials are used.

Autonomous sensor-transponder RFID with supply energy conditioning for object navigation systems

The properties of energy conditioning electrical circuits that are developed for powering additional functional blocks of autonomous RFID transponders working in the HF band have been analyzed and presented in the paper. The concept of autonomy is realized by implementing extra functions in the typical transponder. First of all, the autonomous system should harvest energy, e.g. from the electromagnetic field of read/write devices but also the possibility of gathering information about environment should be available, e.g. by measuring different kind of physical quantities. In such an electrical device, the crucial problem consists in energy conditioning because the output voltage-current characteristic of an front-end (antenna with matching and harvesting circuit) as well as the total and instantaneous power load generated by internal circuits are strongly dependent on a realized function but also on energy and communication conditions in the RFID interface. The properly designed solution should improve harvesting efficiency, current leakage of supply storage, matching between antenna and input circuits, in order to save energy and increase operating time in such a battery-free system. The authors present methods how to increase the autonomous operation time even at advanced measuring algorithms. The measuring system with wide spectrum of sensors dedicated for different quantities (physical, chemical, etc.) has also been presented. The results of model calculations and experimental verifications have been also discussed on the basis of investigations conducted in the unique laboratory stand of object navigation systems.

Problem of interrogation zone synthesis in anticollision Radio Frequency Identification systems

The need for designing anticollision radio frequency identification (RFID) systems appears more often. The typical applications of such systems are concentrated on different economic and public activity in industry, commerce, science and medicine (Internet of things). Operation of passive RFID systems (low or high frequency inductive coupled, ultra high frequency) is characterized by the interrogation zone, which is estimated in any direction of 3D space for group of electronic tags. The comprehensive algorithm of identification of interrogation zone for inductive coupled anticollision RFID system taking into consideration the field, electrical and communication aspects of operation conditions has been partially presented in this paper. The mentioned aspects influence on RFID system reliability, which is characterized by the efficiency coefficient and the probability of identification of the objects in determined interrogation zone. Presented electromagnetic field and electric aspects of operation conditions of identification efficiency in anticollision RFID systems are the part of the algorithm of synthesis of RWD and tag antenna set for the system with inductive coupling. It defines the energy transfer and the conditions of passive tag supply, which expresses the elementary tag parameter defining the interrogation zone - the minimum value of magnetic induction.

Selected design aspects in CAN‐bus system connected with signal propagation in real transmission lines

Purpose – The paper focuses on CAN‐bus based systems: a determination of the configuration parameters by analysis of their characteristic structure, topology conditions and transmission properties.Design/methodology/approach – Voltage measurements were made in a test circuit of CAN‐bus together with calculations of adequate waveforms with the help of elaborated programs. The signal parameters transmitted in bus lines were logged and measured using digital oscilloscope.Findings – The results allow some conclusions to be drawn about the correctness of assumptions in realising the configurationOriginality/value – The results of the investigations have proved the possibilities of parameters calculation, required to choose relevant CAN controller configuration during the design.

Three Dimensional RC Model of Heat Transfer in Thick-Film Multilayer Structure

The complexity of heat exchange mechanisms in electronic circuits make the thermal analysis a complicated problem. In reality, only numerical calculations and specialized simulation programs can solve the systems of differential equations with very complicated boundary and initial conditions. The paper presents some aspects of describing of 3D thermal model of the thick-film multilayer structure with equivalent models (based on RC elements) which are used in temperature field simulation using PSPICE program.

TGS single crystals doped with lysine: new material for IR detectors

Ferroelectric single crystals of triglicine sulphate (TGS) doped with lysine (TGSL10) were grown from a water solution, below Curie point, with use of static method, by evaporation of the solvent. Morphology changes were observed in new grown single crystals, in comparison to pure TGS. Parameters of the crystal lattice were determined with use of powder X-ray diffraction method and compared with parameters of pure TGS. Temperature characteristics of spontaneous polarization Ps and coercive field Ec were measured as well as observations of domain structure of new material.

High Energy Pulse Generator in Reliability Researches of Thick-Film Structures

In modern electronic microcircuits the intended and unintentional dynamic changes of the temperature (for example caused be electrical signals) are very often observed. The good knowledge about these phenomena is the basis of lifetime and reliability determination in the real-world operating conditions. The presented pulse generator is very useful in researches connected with such problems especially with reliability researches. It allows generating the high-energy pulses with short time duration. The special solution of the discharge circuit has been applied in the generator - it causes the precise realization of voltage and current measurements of the discharge pulse. Using of the microprocessor control system allows to introduce the additional functions which are very useful for users. Additionally, it is equipped in many constructional solutions, which are useful for different kinds of laboratory investigations.

Temperature field simulation of thick-film microcircuits using finite element method

Temperature field calculation is a very big problem in the case of small objects heated to the high temperature. In reality, the solving of heat transfer problem using analytical methods is impossible. At the present time, the numerical procedures applied in specialized simulation programs can solve the systems of differential equations with good accuracy. The paper presents some aspects of describing of thermal model of the thick-film microcircuits using finite element method. The example results of simulation (using ANSYS program) the resistive heater systems have been also included.