RFID antenna with asymmetrical structure and method of making same
First Claim
1. A multiband antenna comprised of three structures:
- a first arm,a load element, anda second arm which are positioned along a defined major axis;
wherein the first arm and the second arm are located at the extremities of the major axis and are each separately connected through a first and second port to respective ends of the load element;
wherein the load element is positioned off-center along the major axis and the antenna does not have symmetry when folded about the midpoint of the major axis;
wherein the load element contains one or more load circuits;
wherein the load element is comprised of a network matching the complex impedance presented by physical connections from the ports to the corresponding complex conjugate impedance of the load circuits;
wherein the load element does not present a purely resistive impedance into either the first or second port or combinations thereof at any of the operational frequencies of the antenna;
wherein one or both arms each are comprised of one or more Faraday coils operating at one or more low and high frequency bands with signal connections into the load circuit or load circuits; and
wherein a coupling of RF currents and electromagnetic fields within and near the surface of the three structures provides an antenna function for a first UHF frequency band.
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Accused Products
Abstract
An RFID antenna comprised of a first arm, load element, and second arm together providing a complex impedance match to one or more load circuits contained within the load element for operation at one or more frequency bands. The load element is comprised of one or more load circuits. Load circuits are further comprised of one or more RFID transponders, energy scavengers, microcontrollers, and associated sensor circuits. The first and second arms are different in length and shape resulting in an asymmetrical antenna structure along the major axis. The first arm, the load element, and the second arm all comprise radiative electromagnetic structures for ultra high frequency and higher bands of operation. Embodiments provide an antenna with Faraday coils located within the arms operating in one or more of low frequency and, high frequency bands.
41 Citations
12 Claims
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1. A multiband antenna comprised of three structures:
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a first arm, a load element, and a second arm which are positioned along a defined major axis; wherein the first arm and the second arm are located at the extremities of the major axis and are each separately connected through a first and second port to respective ends of the load element; wherein the load element is positioned off-center along the major axis and the antenna does not have symmetry when folded about the midpoint of the major axis; wherein the load element contains one or more load circuits; wherein the load element is comprised of a network matching the complex impedance presented by physical connections from the ports to the corresponding complex conjugate impedance of the load circuits; wherein the load element does not present a purely resistive impedance into either the first or second port or combinations thereof at any of the operational frequencies of the antenna; wherein one or both arms each are comprised of one or more Faraday coils operating at one or more low and high frequency bands with signal connections into the load circuit or load circuits; and wherein a coupling of RF currents and electromagnetic fields within and near the surface of the three structures provides an antenna function for a first UHF frequency band. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification