I have been reading up on RFID design lately and came across some antenna design notes from TI. The two interesting concepts that they demonstrated are the ability to create a high performance, high-frequency (~13MHz) magnetic dipole antenna using copper tubing and the idea of using the coils from a tag in conjunction with a diode detector to measure transmission power. Why would this be interesting to anyone? The answer is two-fold: it is possible to create a simple detector for hidden RFID readers as well as detect some hidden tags. Current trend are such that tags are already incorporated in various security devices, however the security is either completely due to obscurity (see what happened to Kinkos recently) or is a very weak crypto-system (see TI troubles) so it is an interesting field for security research. There are also concerns that personal privacy might be invaded through tags, so detection of tags and readers can be useful.

( HFAntennaDesignNotes.pdf )

( HFAntennaCookbook.pdf )

 
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