Transmission line delay-based radio frequency identification (RFID) tag

This paper presents the design, simulation, fabrication, and characterization of a transmission delay line-based RFID tag. The ID generating circuit is designed based on the transmission delay line concept. A compact, inset fed triangular patch antenna resonant at 915 MHz frequency is developed for integration with the tag application. The layout of the tag has been realized using conventional photolithography. Tags with alpha 5- and 10-ns delay ID generation circuits have been tested using input signals of 10-ns width. An OOK (On-Off Keying) modulation technique is employed for characterization of the tag. The received output consists of delayed signal from the tag added to the direct signal from the transmitter. Transmission delay line-based RFID technology can be exploited for low-end commercial applications that has a large market. (c) 2007 Wiley Periodicals, Inc.