Radio frequency automatic identification system
First Claim
1. A target for use in an automatic identification system comprising a plurality of independent solid bulk resonators, the resonators in said target resonating at a plurality of radio frequencies.
2 Assignments
0 Petitions
Accused Products
Abstract
A radio frequency automatic identification system detects targets which include solid resonators resonating at several frequencies, attributing information to the frequencies at which the target resonates. Preferred resonators are quartz crystals, which may be made by a process of heating quartz to soften it and cutting crystals to approximate size and resonant frequency. Resonators produced by such a process are measured to determine their actual resonant frequency, and preferably the crystals are sorted into predetermined frequency windows in accordance with their measured resonant frequency. A set of resonators having frequencies corresponding to predetermined data is selected from the sorted groups of resonators and incorporated into a target. The preferred target is an ink-like material having a plurality of resonators disposed in a matrix which is radio frequency transparent at the frequency of interest. Targets are preferably detected by repetitively sweeping the frequency of the interrogating signal through a range which includes the information-bearing range of the system.
87 Citations
17 Claims
- 1. A target for use in an automatic identification system comprising a plurality of independent solid bulk resonators, the resonators in said target resonating at a plurality of radio frequencies.
-
7. A method of making a target for use in a radio frequency automatic identification system comprising the steps of:
-
a. providing resonators, having differing resonant frequencies; b. measuring the resonant frequencies of the resonators provided in step a; c. selecting a set of said resonators measured in step b; and d. making a target comprising said selected set of measured resonators. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
-
- 16. A target for use in radio frequency automatic identification systems comprising a plurality of solid state resonators, having differing resonant frequencies, disposed in an adherent matrix of radio frequency transparent material to form an ink.
Specification