Mariusz Węglarski

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.

Flexible antenna design for semi-passive HF RFID transponder in ink-jet technology

The synthesis process of flexible antenna dedicated to semi-passive transponders of HF RFID system with inductive coupling is presented in the paper. The problem of antenna matching to a chip is considered in details. The emphasis is put on the possibility of manufacturing the antenna in the ink-jet technology. The impact of technology on antenna parameters is also discussed as it is important for transponder operation in a target application. The validation study of the synthesis method and samples behaviour in inhomogeneous magnetic field has been carried out. Streszczenie. W artykule omowiono proces syntezy elastycznej anteny dedykowanej do pracy w polpasywnych, indukcyjnie sprzezonych systemach RFID pasma HF. Szczegolowej analizie poddano problem dopasowania anteny i chipu. Przeanalizowano takze mozliwośc wykonania zaprojektowanej anteny w procesie druku strumieniowego, zwracając szczegolną uwage na wplyw parametrow technologicznych na dzialanie identyfikatora w docelowej aplikacji systemu RFID. W artykule omowiono rowniez proces syntezy ukladow testowych oraz ich prace w niejednorodnym polu magnetycznym. (Projekt elastycznej anteny polpasywnego identyfikatora RFID pasma HF realizowanej w procesie druku strumieniowego).

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.

Inkjet-printed flexible RFID antenna for UHF RFID transponders

Abstract The results of technological investigations in the scope of inkjet-printed flexible RFID antennas dedicated to UHF transponders and also problems with the application of nanomaterials are reported in this paper. The design of the antenna electrical circuit and the parameters of the inkjet printing process were elaborated on the basis of the numerical model prepared in the Mentor Graphics HyperLynx 3D EM software. The project evaluation was performed by measuring electrical parameters of the structures printed with silver-based conductive inks. The obtained results confirm coincidence between the model and its implementation in the inkjet printing technology. Finally, the prepared antenna has been applied in an RFID transponder of UHF band and the functional tests are also reported in this paper.

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.

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.

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.

Mechanical properties of SMD interconnections on flexible and rigid substrates

Purpose – The paper aims to investigate on the mechanical properties of surface-mount device (SMD) interconnections made on flexible and rigid substrates. Design/methodology/approach – The durability of joints to shear strength was measured with tensile machine. Investigations were carried out for 0402- and 0603-sized ceramic passives and integrated circuits in SOIC-8, TSSOP-8, XSON3 and XSON6 packages. Three types of flexible substrates (Kapton, Mylar and Pyralux) and two types of rigid substrates (LTCC and alumina) were used. SMD components were mounted with SAC solder or electrically conductive adhesive. Contact pads were made of Ag-based polymer paste on flexible substrates and PdAg-based cermet paste on ceramics. The shear strength was measured for as-made and long-term thermally aged test structures. The average durability and standard deviation were compared for different combination of materials. Moreover, mechanical properties of interconnections made of polymer thick-film pastes or electrically/...