Monitoring antenna system
First Claim
1. In a monitoring system for detecting the presence of a tag the improvement comprising:
- a digital signal source for generating digital signals representing selected frequencies;
an antenna tap connected to said signal source for receiving said digital signals and generating an analog signal having a signal frequency of one of said selected frequencies; and
a planar antenna loop connected to said antenna tap for transmitting signals at the signal frequency of said analog signal;
wherein said antenna is responsive to signals from said tap for generating a magnetic field surrounding said loop at said analog signal frequency.
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Accused Products
Abstract
A monitoring system incorporates antennas that transmit signals at predetermined frequencies; the transmitted signals are received by tags located in the active monitoring area of the antenna which then transmit signals back to the antenna. The antennas are tuned to each desired frequency prior to driving the antennas to transmit at the desired frequency. The system transmits a range of frequencies in a sequence that uses overlapping frequency steps. The monitoring system is also constructed having a variable configuration resulting in the ability to be reconfigured under program control to conform to varying system requirements. The integrated monitoring system employs programmable formats for reconfiguration such that upon program input from a host computer the system can assume predetermined configurations to conform to the particular tasks for the specific application. The monitoring system incorporates an antenna system that employs digitally controlled, differentially driven, scanning transceivers, and walk through magnetic induction antennas positionable in various configurations to maximize detection of tags being transported through the antenna system.
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Citations
21 Claims
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1. In a monitoring system for detecting the presence of a tag the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies;
an antenna tap connected to said signal source for receiving said digital signals and generating an analog signal having a signal frequency of one of said selected frequencies; and
a planar antenna loop connected to said antenna tap for transmitting signals at the signal frequency of said analog signal;
whereinsaid antenna is responsive to signals from said tap for generating a magnetic field surrounding said loop at said analog signal frequency.
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2. In a monitoring system for detecting the presence of a tag, the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies;
an antenna tap connected to said signal source for receiving said digital signals and generating an analog signal having a signal frequency of one of said selected frequencies, said tap including differential antenna drivers; and
a differentially drive planar antenna loop connected to said antenna drivers for transmitting signals at the signal frequency of said analog signal. - View Dependent Claims (3)
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4. In a monitoring system for detecting the presence of a tag, the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies;
an antenna tap connected to said signal source for receiving said digital signals and generating an analog signal having a signal frequency of one of said selected frequencies; and
a portal planar loop antenna connected to said antenna tap for transmitting signals at the signal frequency of said analog signal;
whereinsaid antenna is responsive to the signals from said tap for generating a magnetic field surrounding said loop at said analog signal frequency; and
said portal antenna has a magnetic field coupling to the tag in said magnetic field being transported through said loop. - View Dependent Claims (5)
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6. In a monitoring system for detecting the presence of a tag, the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies;
an antenna tap connected to said signal source for receiving said digital signals and generating an analog signal having a signal frequency of one of said selected frequencies; and
a transversal planar loop antenna connected to said antenna tap for transmitting signals at the signal frequency of said analog signal;
whereinsaid antenna is responsive to signals from said tap for generating a magnetic field surrounding said loop at said analog signal frequency; and
said transversal antenna has a magnetic field coupling to the tag in said magnetic field being transported adjacent said loop. - View Dependent Claims (7)
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8. In a monitoring system for detecting the presence of a tag the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies;
a plurality of antenna taps connected to said signal source for receiving said digital signals and generating respective first and second analog signals each having a frequency corresponding to one of said selected frequencies;
a first planar antenna loop connected to one of said antenna taps for transmitting signals at the signal frequency of the first analog signal; and
a second planar antenna loop connected to another of said antenna taps for transmitting signals at the signal frequency of the second analog signal;
whereinsaid first and second planar antenna loops are positioned in planes at an angle with respect to each other. - View Dependent Claims (9, 10, 11)
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12. In a monitoring system for detecting the presence of a tag the improvement comprising;
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a digital signal source for generating digital signals representing selected frequencies;
a plurality of antenna taps connected to said signal source for receiving said digital signals and generating respective first and second analog signals each having a frequency corresponding to one of said selected frequencies;
a first portal planar antenna loop connected to one of said antenna taps for transmitting signals at the signal frequency of the first analog signal; and
a second portal planar antenna loop connected to another of said antenna taps for transmitting signals at the signal frequency of the second analog signal;
whereinsaid first and second portal planar antenna loops are positioned in parallel planes spaced along a path of the tag to be detected; and
each of said antenna loops is driven differentially with respect to each other to cancel noise existing along said path.
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13. In a monitoring system for detecting the presence of a tag, the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies;
a first antenna tap and a second antenna tap each connected to said signal source for receiving said digital signals and generating analog signals each having a frequency correspondence to one of said selected frequencies; and
a first planar antenna loop connected to said first antenna tap for transmitting signals at the signal frequency of the first analog signal;
a second planar antenna loop connected to said second antenna tap for transmitting signals at the signal frequency of the second analog signal;
whereinsaid first and second antenna taps drive said first and second planar antenna loops respectively with respective signals that are phase shifted with respect to each other. - View Dependent Claims (14)
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15. In a monitoring system for detecting the presence of a tag the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies and for generating transmit mode signals and receive mode signals;
an antenna tap connected to said signal source for receiving said digital signals and said mode signals and generating an analog signal having a signal frequency of one of said selected frequencies; and
a planar transceiver antenna loop connected to said antenna tap for transmitting signals at the signal frequencies of said analog signal and for receiving signals transmitted by the tag;
whereinsaid antenna tap is connected to said planar transceiver antenna loop for receiving and amplifying tag signals detected by said antenna. - View Dependent Claims (16, 17)
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18. In a monitoring system for detecting the presence of a tag, the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies and for generating transmit mode signals and receive mode signals;
an antenna tap connected to said signal source for receiving said digital signals and mode signals and generating an analog signal having a signal frequency of one of said selected frequencies; and
a planar portal transceiver loop antenna connected to said antenna tap for transmitting signals at the signal frequency of said analog signal and for receiving signals transmitted by the tag;
whereinsaid portal planar transceiver loop antenna is responsive to signals from said tap for generating a magnetic field surrounding said loop at said analog signal frequency and is responsive to signals received from a tag; and
said antenna tap is connected to said antenna for receiving and amplifying tag signals detected by said antenna.
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19. In a monitoring system for detecting the presence of a tag, the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies and for generating transmit mode signals and receive mode signals;
an antenna tap connected to said signal source for receiving said digital signals and said mode signals and generating an analog signal having a signal frequency of one of said selected frequencies; and
a planar transceiver antenna loop connected to said antenna tap for transmitting signals at the signal frequency of said analog signal and for receiving signals transmitted by the tag;
whereinsaid antenna tap responsive to said mode signals for selecting the reactance of a resonant circuit including said antenna; and
said planar transceiver antenna loop has a higher Q during said transmit mode signal than during said receive mode signal.
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20. In a monitoring system for detecting the presence of a tag, the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies and for generating transmit mode signals, receive mode, signals, and squelch mode signals;
an antenna tap connected to said signal source for receiving said digital signals and mode signals and generating an analog signal having a signal frequency of one of said selected frequencies; and
a planar transceiver loop antenna connected to said antenna tap for transmitting signals at the signal frequency of said analog signal and for receiving signals transmitted by the tag;
whereinsaid antenna tap is responsive to said mode signals for selecting the reactance of a resonant circuit including said antenna and for squelching all transmissions in response to said squelch mode signal; and
said planar transceiver antenna loop has a higher Q during said transmit mode signal than during said receive mode signal and being squelched during said squelch signal.
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21. In a monitoring system for detecting the presence of a tag the improvement comprising:
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a digital signal source for generating digital signals representing selected frequencies;
an antenna tap connected to said signal source for receiving said digital signals and generating an analog signal having a signal frequency of one of said selected frequencies;
a planar transceiver antenna loop connected to said antenna tap for transmitting signals at the signal frequency of said analog signal and for receiving signals transmitted by the tag; and
a resonant circuit including said antenna;
whereinsaid resonant circuit has a higher Q when said antenna is transmitting than when said antenna is receiving.
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Specification