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US 7,612,676 B2Granted
RFID tag and antenna
AssigneeThe Hong Kong University of Science and Technology
InventorsMatthew Ming Fai Yuen, Bo Gao, Ross David Murch, Chi Ho Cheng
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AssigneeThe Hong Kong University of Science and Technology
InventorsMatthew Ming Fai Yuen, Bo Gao, Ross David Murch, Chi Ho Cheng
Estimating the term…
The present invention relates to an RFID Tag and Antenna for use with an RFID tag and a method of radio frequency identification (RFID). The RFID Tag comprises a RFID chip 5 for storing data, an antenna 6 and an electromagnetic band gap substrate 12. The RFID chip 5 and the antenna 6 are mounted above the electromagnetic band gap substrate 12. The electromagnetic band gap substrate has a reflection phase which is different from 180° at the operation frequency of the antenna. The electromagnetic band gap substrate enables the RFID to operate even if it is mounted on a conductive object, as the reflection phase is not 180° so it does not destructively interfere with the radiation from the antenna at the operating frequency. Preferably the reflection phase is between 340° and 115° or −95° and 145°. The preferred embodiment uses a band gap substrate having two mushroom-like conductive layers 3, 7 with a dielectric in between.
An RFID tag comprising:
An antenna system for use with an RFID tag, the system comprising an electromagnetic band gap substrate comprising a first conductive layer, a second conductive layer, a common conductive ground plate electrically connected to said first and second conductive layers and a dielectric between said first and second conductive layers and said second conductive layer and said ground plate;
Dependencies are inferred from the claim text.