RFID tags having improved read range
AssigneeEmerson & Cuming Microwave Products, Inc.
InventorsPaul Dixon, Michael Carpenter, Mary Osward, David Gibbs
Life of this patent
Estimating the term…
Abstract
The present invention provides a system and method for optimizing the performance of 13.56 MHz frequency RFID tags in conjunction with metal substrates. Briefly, a thickness exists for each type of RFID isolator material at which the performance of a 13.56 MHz RFID tag is optimal when used with metal. Varying from this optimal value, in either the positive or negative direction adversely affects read distance. A method of determining this optimal thickness is disclosed, as well as an RFID tag or a substrate being used in conjunction with a material of this thickness.
Claims29
An identification system, adapted to transmit identifying information about an article via radio frequency, comprising:
- an RFID tag, adapted to transmit said identifying information via radio frequency when energized;
- a layer having first and second opposite surfaces, wherein said first surface is adapted to be in contact with said article, said second surface is in contact with said RFID tag;
- said layer having a thickness of less than 0.1 inches.
An identification system, adapted to transmit identifying information about an article via radio frequency, comprising:
- an RFID tag, adapted to transmit said identifying information via radio frequency when energized;
- a layer having first and second opposite surfaces, wherein said first surface is adapted to be in contact with said article, said second surface is in contact with said RFID tag;
- said layer comprising ferromagnetic material having a permeability greater than 1 and a thickness, wherein said thickness, in mils, multiplied by said permeability is between about 170 and 450.
The method of determining the optimal thickness for a second ferromagnetic material for use with an RFID tag in close proximity to a metal substrate, where the optimal thickness and permeability of a first ferromagnetic material is previously known, said method comprising:
- a. determining the permeability of said second material;
- and
- b. calculating said optimal thickness by multiplying the optimal thickness of said first material by the ratio of the permeability of the first material to that of the second material.
An identification system, adapted to transmit identifying information about an article via radio frequency, comprising:
- a substrate comprising an antenna and a silicon chip mounted thereon, adapted to transmit said identifying information via radio frequency when energized;
- a layer having first and second opposite surfaces, wherein said first surface is adapted to be in contact with said article, said second surface is in contact with said substrate;
- said layer having a thickness of less than 0.1 inches.
An identification system, adapted to transmit identifying information about an article via radio frequency, comprising:
- a substrate comprising an antenna and a silicon chip mounted thereon, adapted to transmit said identifying information via radio frequency when energized;
- a layer having first and second opposite surfaces, wherein said first surface is adapted to be in contact with said article, said second surface is in contact with said substrate;
- said layer comprising ferromagnetic material having a permeability greater than 1 and a thickness, wherein said thickness, in mils, multiplied by said permeability is between about 170 and 450.
Dependencies are inferred from the claim text.