UHF Rectenna for Implanted and Free Space Communications

The design of a UHF rectenna that is able to communicate with an RFID reader at a distance of 50 cm when it is implanted in human muscle phantom, and at a distance of 6 m when in free space, is described. The antenna has a size of 38 mm by 12.7 mm. An experimental prototype of the rectenna was fabricated on a Rogers R3010 substrate that is optimized to operate with a commercial RFID tag IC. The optimal rectenna was tested in a liquid phantom mimicking the properties of muscle. Experiments showed successful detection when the designed tag was submerged by 5 cm of liquid phantom at a detection distance of 50 cm.