Modeling An RFID Tag Antenna With MicroStripes

RFID (Radio-Frequency Identification) is one of the fastest growing sectors of today's radio technology industry. The number of companies involved in the development and sale of RFID systems is constantly increasing. In 2000, global sales of these systems were approximately $900 million (US). Predictions for 2005 are in the region of $2.65 billion (US) [RFID Hand Book, 2nd Edition, Klaus Finkenzeller, Wiley & Sons, 2003].

An important element of the RFID system is the tag or antenna. Initially, tagging will be done only at container and carton level. Item tagging will occur in the next 5 to 10 years.

The most common bands allocated to RFID systems are 13.56 MHz, 860-930 MHz and 2.45 GHz. For this application note, we chose a tag in the 860-930 MHz bandwidth.

Based on the ACIS solid modeling kernel, MicroStripes' build tool allows arbitrary shaped antenna structures to be easily created. Then, the return loss and radiation pattern can be accurately predicted. In this example we modeled a UHF RFID tag. The scope of the analysis is to see the influence on the return, of the material on which the tag is mounted.