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The effect of antenna design modification, paper substrates and relative electrical permittivity of background materials on the reflection coefficient of UHF RFID antennas was studied. Simulation software was used to modify the design and calculate the reflection coefficient of the antennas. By modifying the coupling of the dipole with the induction loop of the antennas, areduction of the simulated reflection coefficient was achieved compared to thecommercial antenna. The positive effect of antenna modification was also confirmed by measuring thereflection coefficient of antennas printed on paper by thermal transfer printing, placed on extruded polystyrene and particle board. The reflection coefficient of the modified antennas was lower when placed on extruded polystyrene, whose relative electrical permittivity was lower than particle board. After installing the memory chip to the antennas printed on paper and paperboard, the identification, reading and recording range of passive UHF RFID tags were measured after they were placed on thicker paperboard, extruded polystyrene and particle board. The positive effect of antenna modification on improving the communication quality of passive UHF RFID tags placed on background materials with a relative electrical permittivity of 2.4 to 6.7 wasconfirmed.

The effect of surface roughness and water contact angle of commercial paperboard before and after surface modification by calendering, coating and calendering and plasma treatment on the functionality of UHF RFID antennas printed with thermal transfer aluminum ribbon was evaluated. A hydrophilic surface was created by coating or plasma treatment, which improved the wettability of the paperboard surface, the spreading of the thermoplastic tie layer and theadhesion of the conductive aluminum layer. Anew paper product was created with permanent surface wettability by coating, without theneed for plasmatreatment before printing. Theplasma treatment provided time-limited wettability, needed only during printing, and made it possible to restore the original hydrophobic surface of thepaperboard. In addition to themeaning of these surface modifications, the importance and need to reduce the surface roughness was confirmed, as the higher surface roughness of the paperboard limited the effect of the plasma treatment in terms of its printability and the functionality of the printed aluminum antenna. The printability of the paperboard and the functionality of the printed antennas were evaluated using electrical conductivity. The electrical conductivities of the dipole and inductor loop of the UHF RFID antennas printed on modified paperboards varied depending on theantenna design.

The methods of coatedpaperboards smoothing witha hot stamping machine using asmooth metal die and a conventional calender were compared. The printing roughness required for printing electrical and electronic components was achieved by both smoothing methods. The printing roughness of the coated paperboards decreased after hot stamping by18to 42% and after calendering by 22 to 41% depending on the grade of coated paperboard. Thestiffness of coated paperboards decreased after hot stamping by only 4 to 21%, while by up to 38to 51% after calendering. The ratio of specific stiffness and printing roughness of coated paperboards after hot stamping ranged from 2.5 to 8.1 mN.μm-2and after calendering from 2.0to 6.7 mN.μm-2. The stiffness of the coated paperboards decreased less after hot stamping, and that only in the printed electronics area, while after calendering the stiffness decreased significantly more in the whole profile. It can be assumed that packaging made from coated paperboards smoothed by hot stamping will have a lower weight and thus lower costs than packaging from calendered coated paperboards.

The influence of addition of deinked pulps with low and high brightness to bleached eucalyptus and pine kraft pulps on functional tissue paper properties was studied. Deinked pulps with low and high brightness had some different functional properties. Deinked pulp with high brightness has higher bulk, porosity, water absorption after immersion, initial water absorption, bulk softness as well as brightness. On the contrary, the difference in relative bonded area and porosity e between deinked pulps with low and high brightness was moderate. The mixed pulps laboratory pulp sheets from bleached eucalyptus kraft pulp or bleached pine kraft pulp with addition of 20, 40 and 80% of deinked pulp with low brightness or deinked pulp with high brightness were prepared. The addition of the deinked pulp with high or low brightness to bleached kraft pulp leads to increasing of bulk, bulk softness as well as high water absorption after immersion and initial water absorption. The tensile index rapidly decreased by the addition of deinked pulps with high brightness to bleached eucalyptus and pine kraft pulps. Similarly, the addition of deinked pulp with low brightness to bleached pine kraft pulp led to rapid decreasing of tensile index. On contrary, with the addition of deinked pulp with low brightness to eucalyptus kraft pulp, the decreasing of tensile index was less pronounced. Mixed pulp from bleached eucalyptus kraft pulp with a small content of deinked pulp with low brightness with functional properties suitable for production of tissue papers was found as optimal.

Papers for the thermal transfer printing of UHF RFID antennas were prepared by coating and calendering. Real and imaginary components of the impedance of the UHF RFID antennas depended on their design, coating composition and conditions of paper calendering. Passive UHF RFID tags were constructed from antennas and chips whose real and imaginary components of impedance in the 860–960 MHz frequency band were at approximately the same level. The communication quality of passive UHF RFID tags was evaluated by measuring the reading range using the designed UHF RFID reading unit. The reading range of experimental UHF RFID tags with printed antennas on paper and commercial UHF RFID tags with chemically etched antennas on a PET film were identical in the 860 MHz frequency.

The influence of surface-applied original and enzymatically-modified sugar beet pectin on strength properties of fluting, coating base paper, and core board was investigated. The effect was compared with the application of commercial strength-increasing agents. With increasing the polymer uptake, measured strength of paper increased. Original sugar beet pectin increased the strength properties of papers, at the same uptake of polymer, to a higher extent than oxidised potato starch or modified grain flour, while the effect of enzymatically-modified sugar beet pectin was the lowest. For the same increase of paper strength, a several times higher uptake of enzymatically-modified sugar beet pectin was required when compared with the original pectin, oxidised potato starch, or modified grain flour.