UHF RFID wristband transponder
The present invention provides for an RFID transponder, suitable for use in a wristband, which has a non-uniform loop that provides a staple RF environment between the wrist and the transponder; a tuning capacitor for minimizing the overall transponder link; a single transmission line for fine tunings; and an asymmetric location of the RFID IC and capacitor for accommodating needs for specified “keep out” areas for packaging.
1. A radio frequency identification (RFID) apparatus comprising:
a dielectric separator;
a RFID loop antenna with a RFID chip connection region that connects a RFID chip to the dielectric separator, the RFID loop antenna having a width on a first side of the dielectric separator greater than a width on a second side of the dielectric separator;
a gap defined within the conductive portion of the RFID loop antenna; a shunt capacitor for tuning the RFID device, the shunt capacitor positioned within the gaps and forms a single transmission line positioned along a portion of a circumference of the antenna loop, the shunt capacitor further connected to a terminal of the RFID chip.
2. The RFID apparatus according to claim 1 wherein the single transmission line defines a gap along a length of the transmission line, a position of the gap affecting a frequency at which the RFID apparatus operates.
3. The RFID apparatus according to claim 1 wherein the capacitor has a 2.2 pF value.
4. A radio frequency identification (RFID) apparatus consisting of:
a dielectric separator;
a RFID loop antenna with a RFID chip connection region that connects a RFID chip to the dielectric separator, the RFID loop antenna having a width on a first side of the dielectric separator greater than a width on a second side of the dielectric separator;
a gap defined within the conductive portion of the RFID loop antenna, a capacitor for tuning the RFID device the capacitor positioned within the gap; and,
a shunt capacitor in the form of a single transmission line positioned along a portion of a circumference of the antenna loop.
5. The RFID apparatus according to claim 4 , wherein the single transmission line defines a gap along a length of the transmission line.
6. The RFID apparatus according to claim 3 wherein the capacitor has a pF value of between about 0.5 to about 3.0.
7. The RFID apparatus according to claim 4 wherein the capacitor has a 2.2 pF value.
8. The RFID apparatus according to claim 4 wherein the capacitor has a pF value of between about 0.5 to about 3.0.
9. The apparatus according to claim 1 wherein the RFID apparatus radiates in the same plane as the loop antenna.
10. The apparatus according to claim 4 wherein the RFID apparatus radiates in the same plane as the loop antenna.