Here is a unique overview of Geometrical Optics that presents a first-principles treatment for students. The practical development of this topic has been used in several courses at Georgia Tech, although some of the text was developed over 20 years ago.
Archives for December 2018
2008: Josh Griffin built a custom 5.8 GHz down-converter and demonstrated tag gains at 5.8 GHz when small, multiple tags are modulated jointly. Thus, Griffin modulation was born!
Josh Griffin demonstrates how the modulation of two antennas beside one another with identical signals significantly improves the backscatter data link (contrary to conventional radio links). Not only does the extra antenna scatter more power (rather than simply re-arrange the gain pattern), but the additional scattered impart peculiar and improved fading behavior to a multipath channel.
Theory and Design of a Retrodirective Rat-Race-Based RFID Tag
Mohammad Alhassoun, Michael A. Varner, Gregory D. Durgin
IEEE Journal of Radio Frequency Identification
The full-length journal paper on Mohammad Alhassoun’s rat-race design for retro directive RFID tags is now available on IEEExplore. The work presents a new design for a microwave antenna and feed topology that allows a single IC to control retro directive behavior and modulate information back to a reader. This invited paper was an extension of the award-winning conference paper by Mr. Alhassoun.
Low-power and Compact Microwave RFID Reader for Sensing Applications in Space
Cheng Qi, Joshua D. Griffin, Gregory D. Durgin
IEEE International Conference on RFID Technology & Application (RFID-TA)
Macau SER, Sep 2018, 6 pages
Paper from the IEEE RFID-TA 2018 conference presenting the latest generation microwave backscatter reader developed by the lab. Winner of the best student paper award.