Patent ID: 7727143

Claim:
A gastric band system adapted for locating an access port, comprising: a gastric band with a fill line having an access port for receiving a needle, wherein the access port comprises a radio frequency identification (RFID) tag; and a locator comprising: a radio frequency transmitter generating an interrogation signal, wherein the RFID tag operates in response to the transmitted interrogation signal to generate a tag response signal; an antenna array with an array face having a minimum of two pairs of antennae positioned an equal distance apart from each other, each of the antennae being spaced an equal distance from a central axis of the antenna array, the array operable by the radio frequency transmitter for transmitting the interrogation signal and receiving the tag response signal; and a location processing module processing the tag response signal to determine location information for the access port, wherein the location processing module processes a difference signal for each pair of antennae to determine the location information for the access port, the difference signals being generated based on the tag response signal received by each of the antennae.