Novel Electromagnetic Field Confinement Device Based on SIW Technology for RFID Near-Field Applications

In this paper, a slotted waveguide structure based on SIW technology is presented as a near-field RFID reader antenna. The structure enables the control of electromagnetic field decay with distance. A prototype that operates within the EPC Gen2 protocol was implemented. The imposed decay factor was achieved as 1 dB/cm at 867 MHz and 2 dB/cm at 915 MHz. The structure was fabricated using a Rogers RO3010 substrate, with silver ink applied to the edges of the SIW. A comparison between theoretical predictions and experimental electric field decay in the broadside direction is presented, demonstrating a high degree of agreement between them. Additionally, S-parameters are provided, illustrating excellent impedance matching across the entire bandwidth. The system's functionality was verified by connecting the device to a Motorola FX7500 RFID reader and testing the read range with a commercial tag oriented and placed in various positions along the structure.