Novel Manufacturing Methods and Materials for UHF RFID Tags in Identification and Sensing Applications

The continuously increasing amount of radio frequency identification tags needed in our daily lives, not forgetting the broadly widening concept of the Internet of Things, sets high demands on the tag materials selection and manufacturing processes. The huge amount of needed tags requires environmentally sustainable material selection together with the requirement of very low cost. In addition, the manufacturing capacity needs to be very high, hence high-volume capable production methods are needed. In addition to identification applications, also sensing applications established with radio frequency identification tags are of great interest in many application fields.

This thesis reports the possibilities of radio frequency identification tags manufactured on eco-friendly substrate materials using conductive inks and photonic sintering. The used manufacturing methods use raw materials efficiently. Especially brush-painting together with photonic sintering is capable for low-cost high-volume manufacturing. In addition, the possibilities of radio frequency identification tags for humidity sensing applications are studied.

The results of this thesis confirmed that the materials and processes studied in this thesis are suitable for environmentally friendly low-cost radio frequency identification tag manufacturing. Especially brush-painting of regular screen printing conductive inks, both silver and copper oxide ink, on wood and cardboard substrates combined with photonic sintering confirmed to be a very good choice for the application area focused in this thesis. Furthermore, especially the use of screen printable copper oxide ink for identification applications is a very low-cost possibility. The results showed that humidity sensing with passive ultra-high frequency radio frequency identification tags, which were manufactured with regular screen printing silver ink on wood substrate without any coating on the tag, is a very promising approach.