Transparent radio frequency antenna and EMI shield
This disclosure includes, and results in the creation of, a printed carbon nanotube and/or graphene hybrid antenna and/or EMI shield, comprised of a conductive layer that comprises a metal mesh (MM) layer or a nanowire layer on a substrate, with a printed Signal Enhancement Layer (SEL) on the conductive layer. The SEL includes an ink that includes one or both of carbon nanotube (CNT) and graphene. The circuit pattern results after the “exposed” conductive layer (i.e., the regions where the CNT/graphene ink is not printed) is removed via chemical etching or mechanical cutting. The structure (the antenna/EMI shield) is preferably but not necessarily transparent.
1. A carbon nanoparticle hybrid antenna, comprising:
a substrate;
a conductive layer on a surface of the substrate and comprising either a metal mesh (MM) layer that comprises a metallic grid composed of ultranarrow interconnected spaced linear metal structures or a nanowire layer that comprises nanowires with diameters that are less than their lengths randomly distributed on the surface; and
wherein the conductive layer is overlain by a signal enhancement layer that comprises a dried ink that comprises conductive nanoparticles that comprise one or both of carbon nanotubes (CNTs) and graphene, wherein the areal coverage of conductive nanoparticles of the signal enhancement layer is from 0.75 to 5 mg/m2.
2. The antenna of claim 1 that has a visible light transmission (VLT) (without the substrate) of at least 90%.
3. The antenna of claim 1 wherein the substrate comprises one of polyethylene terephthalate (PET), cyclo-olefin (COP), clear polyimide (CPI), and polycarbonate (PC).
4. The antenna of claim 1 wherein the metal mesh metal linear structures are made from at least one of copper, silver, aluminum and tin.
5. The antenna of claim 1 wherein the metal mesh metal linear structures have a spacing of 50, 100, 200, 250, 300, 400, or 500 microns, have a line width of 3, 5, 7, 10, 15, or 20 microns, have a line height of 0.25, 0.5, 0.75, 1, 2, or 3 microns, and are in a square, hexagonal, random or fractal pattern.
6. The antenna of claim 1 wherein the nanowires comprise silver and have diameters between 15 and 35 nm, lengths between 20 and 50 microns, and an areal coverage of from 15 mg/m2 to 150 mg/m2.
7. The antenna of claim 1 wherein the signal enhancement layer is made from an ink that comprises between 0.05 and 0.5 grams of the conductive nanoparticles per liter of ink.
8. The antenna of claim 1 wherein the signal enhancement layer further comprises a binder.
9. The antenna of claim 8 wherein the ratio of binder to conductive nanoparticles is 1:1, 20:1, 100:1, 200:1, 240:1, 300:1 or 400:1.
10. The antenna of claim 8 wherein the ratio of binder to conductive nanoparticles is from 1:1 to 400:1.
11. The antenna of claim 1 wherein the metal mesh metal linear structures have a spacing of 500 microns in a hexagonal pattern, a line width of 30 microns, and a line height of 0.5-1.5 microns.
12. The antenna of claim 1 wherein the metal mesh metal linear structures have a spacing of 300 microns in a square pattern, a line width of 5 microns, and a line height of 2 microns.
13. The antenna of claim 1 wherein the metal mesh metal linear structures have a spacing of 100 microns in a square pattern, a line width of 5 microns, and a line height of 2 microns.
14. A carbon nanoparticle hybrid antenna, comprising:
a substrate;
a conductive layer on a surface of the substrate and comprising either a metal mesh (MM) layer that comprises a metallic grid composed of ultranarrow interconnected spaced linear metal structures or a nanowire layer that comprises nanowires with diameters that are less than their lengths randomly distributed on the surface; and
wherein the conductive layer is overlain by a signal enhancement layer that comprises a dried ink that comprises conductive nanoparticles that comprise one or both of carbon nanotubes (CNTs) and graphene, wherein the signal enhancement layer is made from an ink that comprises between 0.05 and 0.5 grams of the conductive nanoparticles per liter of ink.
15. A carbon nanoparticle hybrid antenna, comprising:
a substrate;
a conductive layer on a surface of the substrate and comprising either a metal mesh (MM) layer that comprises a metallic grid composed of ultranarrow interconnected spaced linear metal structures or a nanowire layer that comprises nanowires with diameters that are less than their lengths randomly distributed on the surface; and
wherein the conductive layer is overlain by a signal enhancement layer that comprises a dried ink that comprises conductive nanoparticles that comprise one or both of carbon nanotubes (CNTs) and graphene, wherein the signal enhancement layer further comprises a binder, wherein the ratio of binder to conductive nanoparticles is 1:1, 20:1, 100:1, 200:1, 240:1, 300:1 or 400:1.