I am hoping to contact someone about 125 kHz RFID readers. I am presently messing with the SeeedStudio RDM630, which works okay for what it is, but I would like options for a couple of things that this one doesn't do.
I need a larger antenna (170mm square) and I can find no guidelines about designing and optimizing a new antenna for the RDM630. This reader appears to be a bit-banging type implementation -- I do not see any commercial RFID parts on it, just an AVR, a counter/divider and an amplifier. Consequently it's not possible to look at the chip manufacturers specs.
Have folks designed new antennas for this or similar RFID readers? What's one gotta do to ballpark a design and tune it to optimum? Is there any way to judge if the antenna characteristics are ideal or sub-optimal?
Are there other 125 kHz RFID readers similar to the SeeedStudio one that I should look into? Maybe ones based on RFID chipsets and/or with documented designs?