High-performance mobile power antennas
DC CAFCFirst Claim
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1. An RF tag system for collecting power from an electromagnetic field with a carrier frequency comprising:
- an antenna configuration that is substantially resonant at the carrier frequency and is excited by the electromagnetic field to cause an induced current to be present at antenna terminals of the antenna configuration, the induced current being at the carrier frequency;
one or more rectifiers that rectifies the induced current at the antenna terminals;
one or more capacitors that collects the rectified induced current to develop a voltage sufficient to power an electric circuit; and
attached RF tag circuitry comprising the electric circuit.
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Abstract
An RFID tag'"'"'s mobility can be increased and cost can be decreased by using high-performance mobile power antennas instead of battery powered tags. Disclosed are some power antennas that include a half wave rectifier, a full wave rectifier, and a voltage multiplier. These antennas can be cascaded to boost the power or voltage gain. Additionally, planar elements can be added to increase efficiency without decreasing mobility.
74 Citations
34 Claims
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1. An RF tag system for collecting power from an electromagnetic field with a carrier frequency comprising:
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an antenna configuration that is substantially resonant at the carrier frequency and is excited by the electromagnetic field to cause an induced current to be present at antenna terminals of the antenna configuration, the induced current being at the carrier frequency;
one or more rectifiers that rectifies the induced current at the antenna terminals;
one or more capacitors that collects the rectified induced current to develop a voltage sufficient to power an electric circuit; and
attached RF tag circuitry comprising the electric circuit.
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2. An antenna power collector system for collecting power from an electromagnetic field with a carrier frequency comprising:
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a dipole antenna that is substantially resonant with the carrier frequency and is excited by the electromagnetic field that causes an induced current to be present at two antenna terminals, the induced current being at the carrier frequency;
one or more rectifiers that rectifies the induced current at the antenna terminals;
a modulation circuit that shorts and opens the antenna terminals at a modulation frequency in order to change the antenna impedance;
one or more capacitors that collect the rectified induced current to develop a voltage sufficient to power an electric circuit, the voltage being developed within one period of the modulation frequency. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An antenna power collector system for collecting power from an electromagnetic field with a carrier frequency comprising:
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a dipole antenna that is resonant with the carrier frequency and is excited by the electromagnetic field that causes an induced current to be present at two antenna terminals, the induced current being at the carrier frequency;
one or more rectifiers that rectifies the induced current at the antenna terminals;
a modulation circuit that shorts and opens the antenna terminals at a modulation frequency in order to change the antenna impedance;
one or more capacitors that collect the rectified induced current to develop a voltage sufficient to power an electric circuit, the voltage being developed within one period of the modulation frequency, the capacitors combined with the rectifiers to form two or more rectifier circuits that are connected in series to increase the voltage that powers the electric circuit. - View Dependent Claims (20, 21, 22, 23)
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24. An antenna power collector system for collecting power from an electromagnetic field with a carrier frequency comprising:
- p1 an array of two or more dipole antennas that are resonant at the carrier frequency and are excited by the electromagnetic field to cause an induced current to be present at two antenna terminals on each of the antennas, the induced current being at the carrier frequency;
one or more rectifiers associated with each antenna that rectifies the induced current at the antenna terminals of each antenna respectively;
a modulation circuit that shorts and opens all the antenna terminals at a modulation frequency in order to change the antenna impedance of each antenna;
one more capacitors associated with each antenna that collects the rectified induced current and together with the rectifier associated with the respective antenna forms a rectifier circuit for each antenna;
whereby the rectifier circuit for each antenna is connected in series to develop a voltage sufficient to power an electric circuit, the voltage being developed within one period of the modulation frequency.- View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
- p1 an array of two or more dipole antennas that are resonant at the carrier frequency and are excited by the electromagnetic field to cause an induced current to be present at two antenna terminals on each of the antennas, the induced current being at the carrier frequency;
Specification