RFID reader design: Diminutive dependency of antenna orientation exploiting revolving field

Automated-reading process of an RFID reader can be interrupted due to the relative orientation of the transponder (tag) antenna with respect to the reader antenna. This article proposed a modified revolving magnetic field based RFID reader, which is capable to produce a rotating near field in space. When a magnetically coupled RFID tag placed in the near field zone or read range, the tag can easily harvest energy for its circuit operation from the reader-rotating magnetic field. Due to presence of a rotating magnetic field in the reader antenna coil, the induced voltage in the tag antenna coil is always constant. Therefore, this phenomenon reflects less significance of the relative orientation of the tag antenna coil with respect to the reader antenna coil. The design was simulated and verified by different types of mathematical and VLSI design software (Mat lab 7.4, Mentor Graphics ADK-3, Microwind 3.1) tools. The system was designed using foundry CMOS 0.18 μm rules and Level-3 transistor model for VLSI circuit design.