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.

Factors Affecting the Synthesis of Autonomous Sensors with RFID Interface

“…In this context, problems encountered when manufacturing flexible RFID tags dedicated to work in the UHF and HF bands are presented in [35,72]. If designers are aware of technology difficulties that they may face in the fabrication process, they can significantly accelerate the synthesis of the devices.…”

“…It should be emphasized that in order to develop a robust RF system, it is necessary to precisely identify not only the influence of the processes’ accuracy but also the parameters of new materials used [29] and to skillfully apply this knowledge at the design stage [32,34,35]. The worked out procedural knowledge was applied to the project of antenna dedicated to the UHF AMS SL900A chip (Figure 9a) [72]. The correctness of obtained design can be confirmed by convergence of measured and calculated impedance values of inductive circuit (Table 2).…”

“…A very good convergence between the measured and simulated results is obtained (Table 4) in the case of the PCB antennas, as this technology is well known and easy to use on the prototype stage. The discrepancies obtained for subsequent test versions of flexible antennas (Table 3) result mainly from corrections introduced in the technological process settings aimed at increasing the accuracy of mapping developed project [35,72]. Both versions of antennas were tested in the RFID sensors (Figure 5) that were designed on the basis of microprocessor data acquisition system (with the C8051F988 microcontroller) which enabled to measure various physical quantities including those from the LTCC thick-film pressure sensor developed as a part of earlier research described in [92].…”

Investigation of inkjet printed path resistance in the context of manufacture and flexible application

“…The main goal of this study was to obtain an answer to the question as to what the repeatability of inkjet printed paths in the manufacturing process is and how the properties of paths will change under the influence of environmental and mechanical exposures that may occur under typical application conditions. The basic assumption of this research is that the path as a simple element can be used to build a more complex structure like a radio-frequency identification antenna and results from the authors’ previous work (Tomaszewski et al , 2016a, 2016b; Jankowski - Mihułowicz et al , 2015). In those studies, the antennas were built from the paths with a width of about 1 mm.…”

“…The preliminary conditions for the sintering were set on the basis of the ink manufacturer datasheet (Amepox Microelectronics, 2012) at 220°C and 1 h. According to the note, this condition allows one to obtain relatively low electrical resistivity. The choice of a lower recommended temperature was conditioned by the results of the authors’ previous studies with a different type of nanoparticle ink (Lukacs et al , 2017; Tomaszewski et al , 2016a, 2016b). The sintering conditions were changed after the first unsatisfactory result for the path resistance had been obtained.…”