A Paper-Based Screen Printed HF RFID Reader Antenna System

Screen printing is a stencil process where conductive inks are patterned onto substrates through a fine mesh of threads. Nowadays, screen printing can be used to print radio frequency identification (RFID) antenna structures onto flexible and ultra-low-cost substrates such as paper. In this paper, we present a high frequency RFID (HF RFID) reader antenna system, operating at 13.56 MHz, using screen printed Ag particle ink as conductor and using HP photo paper as substrate. The proposed antenna system comprises four loop antenna elements, matched to <inline-formula> <tex-math notation="LaTeX">$50~ \Omega $ </tex-math></inline-formula>, and one I²C addressed SP4T multiplexer circuitry, controlled through an exterior embedded system. The geometries, designs and characterizations of the antenna system are described in the manuscript in details. Measurement results show that the antenna system has low power reflections and a suitable <inline-formula> <tex-math notation="LaTeX">${Q}$ </tex-math></inline-formula> factor. It has a maximum 11.1 cm RFID tag read range at an antenna system input power of 33 dBm. 2-D RFID tag positioning can be enabled by utilizing the RFID tag interrogation zones formed by the four loop antenna elements. In addition, a parametrical study is carried out to investigate the effect of loop antenna element dc resistance on the antenna element performance. It can be concluded that the proposed method can be used to create low-cost and large-area HF RFID reader antenna systems.