Microwave readable dielectric barcode

Abstract

Presented is a system and method for reading a microwave readable barcode formed from a pattern of dielectric material. The dielectric pattern creates a strong microwave contrast with the surrounding media selectively resonating with or scattering an interrogating microwave signal. Dielectric bars can be fabricated by inkjet printing, injection, spraying, drawing or any other technique. Barcode information is encoded using different lengths, angles, or positions of dielectric bars. A microwave readable dielectric barcode system includes a barcode fabricated from a dielectric material, a transmitter with an antenna, and a sensor that senses the effect produced by the dielectric barcode on the microwave signal. The dielectric barcode system can use multiple microwave signals that differ in one or more respects, such as polarization or frequency.

1 . A barcode detectable by remote interrogation comprising:
 a plurality of dielectric bars arranged on or within a substrate, wherein the dielectric bars are arranged in a spatial manner to encode information.   
     
     
         2 . The barcode of  claim 1 , wherein the dielectric bars are formed from a dielectric material having a suspension of a metallic material in a density insufficient to provide conductivity at an operating frequency of a remote interrogator. 
     
     
         3 . The barcode of  claim 2 , wherein the metallic material is formed from heavy metals and their salts. 
     
     
         4 . The barcode of  claim 2 , wherein the metallic material is selected from the group consisting of BaTiO 3 , NaKNbO 3 , PbZrTiO 3 , and Na x K 1−x NbO 3 . 
     
     
         5 . The barcode of  claim 1 , wherein the spatial manner arrangement of the plurality of dielectric bars includes at least one of a variation in length, a variation in width, a variation in relative positioning angle, and a variation of interstitial gaps. 
     
     
         6 . The barcode of  claim 1 , wherein the plurality of dielectric bars are formed from dielectric inks. 
     
     
         7 . A barcode interrogation system comprising:
 a dielectric barcode formed from a plurality of dielectric bars arranged on or within a substrate, wherein the dielectric bars are arranged in a spatial manner to encode information;   a signal transmitter connected to a first antenna so as to radiate an interrogation signal on the dielectric barcode;   a signal receiver connected to an antenna so as to receive a return signal from the dielectric barcode; and   a processor connected to the receive signal and operable to extract the encoded information.   
     
     
         8 . The interrogation system of  claim 7 , wherein the interrogation signal is scanned through a volume of space by one of rotation of the first antenna, frequency shifting, phase shifting. 
     
     
         9 . The interrogation system of  claim 7 , wherein the first antenna comprises an antenna array and the interrogation signal is scanned by adjusting an inter-element phasing of the antenna array. 
     
     
         10 . The interrogation system of  claim 7 , wherein the dielectric bars are formed from a dielectric material having a suspension of a metallic material in a density insufficient to provide conductivity at a frequency of the interrogation signal. 
     
     
         11 . The interrogation system of  claim 10 , wherein the metallic material is formed from heavy metals and their salts. 
     
     
         12 . The interrogation system of  claim 10 , wherein the metallic material is selected from the group consisting of BaTiO 3 , NaKNbO 3 , PbZrTiO 3 , and Na x K 1−x NbO 3 . 
     
     
         13 . The interrogation system of  claim 7 , wherein the spatial manner arrangement of the plurality of dielectric bars includes at least one of a variation in length, a variation in width, a variation in relative positioning angle, and a variation of interstitial gaps. 
     
     
         14 . The interrogation system of  claim 7 , wherein the plurality of dielectric bars are formed from dielectric inks. 
     
     
         15 . The interrogation system of  claim 7 , wherein the receiver is connected to a second antenna. 
     
     
         16 . A method of interrogating a barcode comprising the steps of:
 providing a dielectric barcode formed from a plurality of dielectric bars arranged in a spatial manner so as to encode information;   providing a signal generation and reception system capable of transmitting an interrogation signal and receiving a return signal;   transmitting an interrogation signal;   receiving a return signal from the dielectric barcode; and   processing the return signal to extract the encoded information.   
     
     
         17 . The method of  claim 16  further including the step of scanning the interrogation signal through a volume of space. 
     
     
         18 . The method of  claim 16 , wherein the dielectric barcode is provided by one of printing, spraying, and injecting. 
     
     
         19 . The method of  claim 16 , further including the step of creating the dielectric bars from a dielectric material having a suspension of metallic material in a density insufficient to provide conductivity at a frequency of the interrogation signal. 
     
     
         20 . The method of  claim 16 , wherein the transmitting step transmits a signal in the range of about 90 GHz to about 30 THz.