Low Frequency Reader Design Approach for Metallic Environments

Low frequency transponder systems are the method of choice in metallic and hydrous environments. To achieve high energy efficiency in mobile reader devices the antenna circuit is designed for a high quality factor. Metal in e.g. industrial and medical environments has a significant influence on such systems. An analysis of the influences of metal on the reader circuit impedance and the energy transfer function is presented. A smart approach to compensate the detuning of resonant circuits in mobile devices due to metallic environment is given. Finally applications in metallic environments from the current research are presented.