Antenna Design for Long Range 13.56MHz RFID Reader

Antenna is the most important device to extend the working range of long range 13.56MHz radio frequency identification (RFID) system. Methodology of field strength calculation, bandwidth decision and common mode noise compensation is proposed to obtain better antenna performance. A new antenna driving method is proposed to remove blind area caused by in-phase and out-of-phase complementary antennas and realize all vertical orientation recognition of tags. Both the formulation and simulation results are given to explain the advantage of this method.