Based on work as part of the Children’s Hospital of Atlanta (CHoA) pediatric seed grants competition, a team of researchers put together this report in 2013 on the design of a battery-free moisture sensor for diapers and bed-wetting. The final design showed that diversity antennas feeding two RFID chips and a common moisture sensor could be placed on a low-cost, flexible inset and interrogated accurately in a room with a UHF RFID reader. Download the report here.
This article provides a derivation of the Rayleigh criterion for surface roughness. As a once-flat surface roughens, the specular reflected wave begins to degrade in power as some of it is scattered in different directions. The result is a predictable degradation that is a function of the rough surface statistics. The end result — the Rayleigh criterion — is used throughout science and engineering to describe everything from propagation off of building sides to the specifications for a satellite dish antenna. Download the article here here.
In this paper, the history of RFID energy-harvesting is tracked and compared against the theoretical thermodynamic limits of an RF-to-DC converter. Although RFID harvesting technology has reached a plateau, this is only due to it being “trapped” within the paradigm of Si-CMOS devices. There are tremendous gains to be had by looking at more specialized devices, particularly those that transform energy into non-electrical, intermediate forms. Thermal intermediary (TI) devices, are particularly promising. Browse What RFID Can Teach Us…
Note: This paper was a companion to an invented talk at the IEEE WPTC 2018 conference, which did not appear in the proceedings.
Table of Contents for the 2018 edition of the Extemporaneous Journal of Electronic Contributions and Topics (EJECT!)
12 December 2018: G.D. Durgin, Review of Geometrical Optics,
3 December 2018: G.D. Durgin, Scattering and Computer Graphics
5 September 2018: M.M. Morys and G.D. Durgin, High-Voltage Plasma Effects on Antennas
10 August 2018: G.D. Durgin, RF Band Chart
6 July 2018: G.D. Durgin, HF Isolators for RFID
2 July 2018: G.D. Durgin, UHF Isolators for RFID