Broad bandwidth, high impedance transponder for electronic identification system
First Claim
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1. A transponder for an electronic radio frequency identification system, comprising:
- an antenna having an antenna impedance at a feedpoint thereof; and
an electronic circuit having an input impedance at an input thereof, the input being connected to the feedpoint, wherein the antenna impedance has impedance characteristics for developing first and second voltage maxima across the input at first and second frequencies respectively, thereby providing a continuous operative frequency band for the transponder including the first and second frequencies.
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Abstract
A transponder 14.1 for an electronic radio frequency identification system comprises an antenna 18 having an antenna impedance at a feedpoint thereof. The transponder further comprises an electronic circuit 19 having an input connected to the antenna. The antenna impedance having impedance characteristics for developing first and second voltage maxima (36, 38) across the input at first and second frequencies (fL and fH) respectively, thereby to provide a continuous operative frequency band for the transponder including the first and second frequencies.
23 Citations
11 Claims
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1. A transponder for an electronic radio frequency identification system, comprising:
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an antenna having an antenna impedance at a feedpoint thereof; and
an electronic circuit having an input impedance at an input thereof, the input being connected to the feedpoint, wherein the antenna impedance has impedance characteristics for developing first and second voltage maxima across the input at first and second frequencies respectively, thereby providing a continuous operative frequency band for the transponder including the first and second frequencies. - View Dependent Claims (2, 3, 4, 5, 6, 7, 11)
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- 8. An antenna for a transponder of an electronic identification system, the transponder having an impedance, and the antenna having a feedpoint and an antenna impedance at the feedpoint, the antenna impedance having impedance characteristics for developing first and second voltage maxima at first and second frequencies, respectively, across the input impedance of the transponder.
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10. An antenna as claimed in 8, wherein the antenna comprises a combination of a first loop and an appendage to the first loop, and wherein the appendage comprises a second loop linked to the first loop.
Specification