Simulation of Antennae for Radio Frequency Identification (RFID)
BiotSavart was used to help design antennae for a radio tagging system. Various different shapes were simulated to find the most suitable to provide all-round coverage for different tag orientations. The final design used three orthogonal coils, each active at different times. Between the three coils, field in all directions is covered fairly uniformly around the antenna. BiotSavart also allowed measurement of the effect of misalignment of the coils through its flux-cutting measurement function. Simulation data was transferred into Excel to allow comparison with measurements made on an existing antenna, which had been modelled in BiotSavart. A search coil attached to an oscilloscope measured the field strength through induced EMF. This was compared with a calculation of field strength made from within BiotSavart.
RFID antennae system. On the left are the wireless clients (laptop and handheld), both accessing the website served by the PC with the antenna to the right.
(courtesy Ben Tuppen, Balliol College, Oxford, England)
