Articles
RFID Transponder Operating At 13.56 MHz
August 6, 2007
By CST of America®, Inc. Radio frequency identification (RFID) systems are widely used and allow advanced solutions for a variety of applications in the area of authentication, ticketing, access control, supply management, etc. The example presented here is operating at 13.56 MHz with dimensions given by an Internet data sheet. After rebuilding the 3-D geometrical model the frequency domain solver of CST MICROWAVE STUDIO has been used to accurately compute the input impedance versus a limited frequency band. In another step the impedance data has been used as a reference to develop a simple equivalent circuit consisting of lumped elements.
Figure 1. shows a typical example of an RFID. Dimensions are publically available, e.g. on the Internet. The 2D-layout was modeled in CST MWS. Applying appropriate extrusion operations to create metal thicknesses and by adding the substrate (with an assumed epsilon-rel=3) the model was converted into a 3D model shown in Figure 2.
•Application Note: RFID Transponder Operating At 13.56 MHz
