rfid for help!!

recently i got my project: design a transponder IC for redio frequency identification systems. i've search this topic for several days. but mostly i only got some articles about rfid transponder IC work on 13Mhz or something below this frequency, but mine is 868-915Mhz. is there anyone can offer me some relative sources on it. or just give me some advises. thanks a lot!

WJ Communications is one of the companies that are doing RFID components and modules for this band.
http://www.wjcommunications.com/pdf/...duct_Flyer.pdf