Systems and methods for stirring electromagnetic fields and interrogating stationary RFID tags
First Claim
1. A method for interrogating one or more stationary RFID tags in a static interrogation environment, the method comprising:
- providing a stationary antenna for transmitting and receiving RF signals to and from the one or more stationary RFID tags;
generating, by the stationary antenna, an electromagnetic interrogation field of a predetermined frequency in the interrogation environment; and
moving a first conductor positioned inside the electromagnetic interrogation field while both the stationary antenna and the one or more stationary RFID tags are stationary, wherein moving the first conductor varies a position of at least one low energy region present within the electromagnetic interrogation field.
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Accused Products
Abstract
RFID tags are used for many purpose including tracking RFID interrogators are used to retrieve information from tags. In many applications, RFID interrogators and RFID tags remain stationary during interrogation. Regions of low energy due to interference from either additional antenna or reflections from RFID tags and objects can impede or prohibit the reading of RFID tags residing in such regions. Stirring of the generated electromagnetic field is a method of moving around the regions of low energy, where tags can not be read, during the interrogation process. Mechanical stirring is accomplished by introducing a conductor into the electromagnetic field and moving it about in the field. Solid state stirring is accomplished by introducing a variable conductor into the field and varying the conductivity of the variable conductor. Mathematical stirring is accomplished by use of a plurality of antenna and controlling the phase difference between the antenna in a configuration known as phased antenna arrays.
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Citations
14 Claims
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1. A method for interrogating one or more stationary RFID tags in a static interrogation environment, the method comprising:
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providing a stationary antenna for transmitting and receiving RF signals to and from the one or more stationary RFID tags; generating, by the stationary antenna, an electromagnetic interrogation field of a predetermined frequency in the interrogation environment; and moving a first conductor positioned inside the electromagnetic interrogation field while both the stationary antenna and the one or more stationary RFID tags are stationary, wherein moving the first conductor varies a position of at least one low energy region present within the electromagnetic interrogation field. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification