I'm starting a project to create an RFID writband. I'm planning on putting tags on common objects so that I can use the wristband to detect when I'm holding something. I've googled a bunch but haven't found this implementation using Arduino.
So far I've chosen the 13.56 MHZ frequency because it's low power, has good penetration through metal and water (i.e. flesh). I've bought the SM130 module from Sparkfun and I have an Arduino Uno for prototyping (eventually I will switch to a smaller arduino). I'm hoping to get a range of about 10-15 cm from the bracelet.
My question is all about the building of the antenna. Should I use a PCB antenna or make a wire loop antenna that would fit around the wrist? What's the optimal length and the optimal amount of loops for my purpose? Basically any information about how to select an antenna design and how to build it would be very helpful...