Piotr Jankowski-Mihułowicz

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).

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.

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.

Ink-jet printed conductive films — Geometrical and electrical characterization

This paper presents the results of electrical and geometrical characterization of conductive films ink-jet printed on flexible substrates. Two commercially available single component nanoinks from Amepox, AX JP-6n and AX JP-60n, based on silver grains with 3-7 nm or 50-80 nm diameters were deposited onto Kapton or Mylar substrates and properly cured (sintered). Test structures, composed of a number of different patterns, allow optical inspection as well as measurement of geometrical (planar size, cross-section) and electrical (resistivity, sheet resistance) properties. Presented results show that the control of geometry of ink-jet printed films is more difficult to control than standard screen-printed ones. The cross-section of such paths has two lateral peaks (sometimes very strong) and very thin layer between them. This is related with viscosity and surface tension of the applied ink. There are also large differences in sheet resistance of layers - both kind of inks as well as substrate affects this parameter. The smallest received value, about 8 mΩ/sq (recalculated for 25 μm thick film) is larger than for high-temperature silver cermet pastes (approx. 2-3 mΩ/sq), but smaller than for polymer thick-film conductive inks (approx. 10-30 mΩ/sq).