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US 10,089,570 B2Granted
Card with metal layer and an antenna
AssigneeCompoSecure, LLC
InventorsJohn Herslow, Michele Logan, David Finn
Life of this patent
Estimating the term…
Abstract
In a smart card having an antenna structure and a metal layer, an insulator layer is formed between the antenna structure and the metal layer to compensate for the attenuation due to the metal layer. The thickness of the insulator layer affects the capacitive coupling between the antenna structure and the metal layer and is selected to have a value which optimizes the transmission/reception of signals between the card and a card reader.
Claims20
A card comprising:
- a singular metal layer;
- an antenna structure;
- an insulator layer formed between the metal layer and the antenna structure, said insulator layer having first and second surfaces and a thickness, said first surface in direct contact with said antenna structure and said second surface in direct contact with said metal layer, said insulator layer exhibiting a coupling capacitance between said antenna structure and said metal layer, said coupling capacitance having a value that is a function of the thickness of the insulator layer, said metal layer tending to attenuate the amplitude of a radio frequency (RF) signal of a predetermined frequency received at the antenna structure;
- wherein the insulator layer thickness is selected to provide a maximum amplitude of the RF signal within a limited range of permissible insulator thicknesses.
1 more element
A card comprising:
- an antenna structure configured to receive a predetermined radio frequency (RF) signal;
- an RFID chip coupled to the antenna structure;
- a singular metal layer that has a tendency to attenuate amplitude of the RF signal received at the antenna structure;
- and
- an insulator layer in direct contact between the antenna structure and the metal layer, said insulator layer functional to provide capacitance coupling between the antenna structure and the metal layer and having a thickness that affects the value of capacitance between said antenna structure and said metal layer, said insulator layer thickness selected to provide a resonant or quasi-resonant response to the predetermined RF frequency.
2 more elements
Dependencies are inferred from the claim text.