902–928MHz UHF RFID Tag Antenna Design, Fabrication and Test

Author

Chiweng Kam, California Polytechnic State University, San Luis ObispoFollow

DOI: https://doi.org/10.15368/theses.2011.158
Available at: https://digitalcommons.calpoly.edu/theses/598

Date of Award

8-2011

Degree Name

MS in Electrical Engineering

Department/Program

Electrical Engineering

Advisor

Dean Arakaki

Abstract

Radio Frequency Identification (RFID) uses RF radiation to identify physical objects. With decreasing integrated circuit (IC) cost and size, RFID applications are becoming economically feasible and gaining popularity. Researchers at MIT suggest that RFID tags operating in the 900 MHz band (ultrahigh frequency, UHF) represent the best compromise of cost, read range, and capabilities [1]. Passive RFID tags, which exclude radio transmitters and internal power sources, are popular due to their small size and low cost [1].

This project produced Cal Poly’s first ever on-campus printed, assembled, and operational UHF (902 to 928 MHz) passive RFID tag. Project goals include RFID tag antenna design and simulation using the EMPro electromagnetic (EM) simulation tool [47], establishing the tag fabrication process, and testing, operational verification, and comparisons to commercial tag performance. The tag antenna design goal is to meet or exceed the read range performance of the commercial Sirit tag [23] while minimizing the required tag conductive area.

This thesis provides an overview of the UHF passive RFID tag fabrication process. Cal Poly’s Graphic Communication Department Laboratory applied a screen‑printing process to print RFID tag antenna patterns onto plastic (PET) substrates. RFID IC-substrate packages were manually attached to tag antennas with conductive adhesives and functionally verified and compared to commercial tag performance.

RFID tag antennas were impedance matched (using EMPro) to the Monza 3 RFID IC to maximize IC to antenna power transfer and RFID tag read range.Tag antenna read range (maximum reader-tag communication distance) was characterized in Cal Poly’s Anechoic Chamber, while RFID tag matching characteristics were measured using the differential probe method [33-41] and compared to simulations. Read range results indicate that one of the designs developed in this thesis outperforms a commercial UHF RFID tag.