Electrical and electromagnetic apparatuses using laminated structures having thermoplastic elastomeric and conductive layers

• US 5,844,523 A
• Filed: 02/29/1996
• Issued: 12/01/1998
• Est. Priority Date: 02/29/1996
• Status: Expired due to Term

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Brennan, Joan V., Ginkel, Scott T., Skogland, Timothy S.
• Primary Examiner(s): Le, Hoanganh T.
• Application Number:
  US08/609,092
• Time in Patent Office: 1,006 Days
• Field of Search: 343/700 MS, 343/846, 343/767, 343/770, 174/138 A, 174/149 R, 174/148, 174/153 A, 174/152 A
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H05K 1/024 Dielectric details, e.g. changing the dielectric material around a transmission line
• CPC Class Codes: H05K 1/032 consisting of one material
• CPC Class Codes: H05K 1/0373 containing additives, e.g. fillers H05K1/036 takes precedence
• CPC Class Codes: H05K 1/162 incorporating printed capacitors
• CPC Class Codes: H05K 2201/0129 Thermoplastic polymer, e.g. auto-adhesive layer; Shaping of thermoplastic polymer
• CPC Class Codes: H05K 2201/0133 Elastomeric or compliant polymer
• CPC Class Codes: H05K 2201/0158 Polyalkene or polyolefin, e.g. polyethylene [PE], polypropylene [PP]
• CPC Class Codes: H05K 2201/0209 Inorganic, non-metallic particles

Abstract

Electromagnetic and electrical apparatuses use a laminate structure having a thermoplastic elastomer with variable dielectric loss as a dielectric layer. A conductive layer laminated to the thermoplastic elastomer allow use for applications such as printed circuit boards and slot antennas. Additional conductive and dielectric layers still allow use as a printed circuit board as well as other antenna structures. Some embodiments of the apparatuses disclosed exhibit many desired properties, such as flexibility, conformability and weatherability.

Claims

1. An electromagnetic structure comprising:

a first conductive substrate having a first side and a second side;

a first dielectric layer having a first side and a second side, said second side of said first conductive substrate adjacent said first side of said first dielectric layer, said first dielectric layer consisting essentially of a thermoplastic elastomer with a loss tangent (tan □

) of less than about 0.2 and a sufficient, non-zero amount of a dielectric filler selected from the group, consisting of undoped ceramics, doped ceramics and mixtures thereof to provide a dielectric constant of about 1 to about 50 in the first dielectric layer;

a second conductive layer having a first side and a second side, said second side of said first dielectric layer adjacent said first side of said second conductive layer; and

feeding means for feeding said first conductive substrate.

2. The electromagnetic structure according to claim 1, wherein said first conductive substrate comprises a first microstrip patch.

3. The electromagnetic structure according to claim 2, wherein said feeding means comprises a microstrip transmission line connected to said microstrip patch.

4. The electromagnetic structure according to claim 1, wherein said feeding means comprises:

a second dielectric substrate having first and second faces, said first face of said second dielectric substrate adjacent said second face of said second conductive layer; and

a microstrip transmission line having first and second faces, said first face of said transmission line adjacent said second face of said second dielectric substrate and aligned with said first conductive substrate;

said second conductive substrate having an aperture therethrough, said aperture aligned with said first conductive substrate.

5. The electromagnetic structure according to claim 4, wherein said second dielectric substrate comprises a thermoplastic elastomer with a loss tangent (tan δ

) of less than about 0.2.

6. The electromagnetic structure according to claim 5, wherein said second dielectric layer further comprises a sufficient, non-zero amount of a filler to provide a predetermined dielectric constant from about 1 to about 50 in the second dielectric layer, said dielectric constant of the second dielectric layer having a lower value than the dielectric constant of said first dielectric layer.

7. The electromagnetic structure according to claim 1, wherein said first dielectric layer further comprises a polymeric filler.

8. The electromagnetic structure according to claim 1, wherein the thermoplastic elastomer comprises:

a thermoplastic polymeric component selected from the group consisting of polypropylene, polyethylene, and copolymers of ethylene and propylene; and

an elastomeric component selected from the group consisting of butyl rubber, natural rubber, ethylene-propylene rubber (EPR), ethylene-propylene diene rubber (EPDM) and silicone rubber.

9. The electromagnetic structure according to claim 8, wherein the thermoplastic component is polypropylene and the elastomeric component is crosslinked or uncrosslinked EPDM.

10. The electromagnetic structure according to claim 1, wherein said first conductive substrate is patterned in an array of microstrip patches and wherein said second conductive layer has a plurality of apertures therethrough, each of said apertures aligned with a corresponding microstrip patch from said array of microstrip patches.

11. An electromagnetic structure according to claim 1, wherein the loss tangent (tan δ

) of the thermoplastic elastomer is less than about 0.005.

12. An electromagnetic structure comprising:

a first conductive substrate having a first side and a second side;

a first dielectric substrate having a first side and a second side, said second side of said first conductive substrate adjacent said first side of said first dielectric substrate, said first dielectric substrate consisting essentially of a thermoplastic elastomer with a loss tangent (tan □

) of less than about 0.2 and about 5% to about 60% by volume of thermoplastic elastomer of a dielectric filler selected from the group consisting of undoped ceramics, doped ceramics and mixtures thereof to provide a dielectric constant of about 1 to about 50 in the dielectric substrate; and

feeding means for feeding said first conductive layer.

13. The electromagnetic structure according to claim 12, wherein said first conductive substrate has a slot therethrough.

14. The electromagnetic structure according to claim 13, wherein said feeding means comprises:

a second dielectric substrate having first and second faces, said first face of said second dielectric substrate adjacent said first side of said first conductive substrate; and

a microstrip transmission line having first and second faces, said first face of said transmission line adjacent said second face of said second dielectric substrate and perpendicularly aligned with said slot.

15. The electromagnetic structure according to claim 14, wherein said second dielectric substrate comprises a thermoplastic elastomer with a loss tangent (tan δ

) of less than about 0.2.

16. The electromagnetic structure according to claim 15, wherein said second dielectric substrate fuirther comprises a sufficient non-zero amount of a filler to provide a predeterniined dielectric constant from about 1 to about 50, said dielectric constant having a lower value than the dielectric constant of said first dielectric substrate.

17. The electromagnetic structure according to claim 12, wherein said dielectric substrate further comprises a polymeric filler.

18. An electromagnetic structure according to claim 12, wherein the loss tangent (tan δ

) of the thermoplastic elastomer is less than about 0.005.

19. An electronic display system for both visual and electromagnetic data communication, said system comprising:

display means having visual information thereon;

antenna means for electromagnetic communication, said antenna means comprising at least one dielectric substrate, said dielectric substrate consisting essentially of a thermoplastic elastomer with a loss tangent (tan □

) of less than about 0.2 and a sufficient, non-zero amount of a dielectric filler selected from the group consisting of undoped ceramics, doped ceramics and mixtures thereof to provide a dielectric constant of about 1 to about 50 in the dielectric substrate; and

coupling means for allowing coupling to said antenna means.

20. The electronic display system for both visual and electromagnetic data communication according to claim 19, wherein said display means further comprises retrorefiective sheeting having first and second faces, wherein said dielectric substrate has first and second faces, said first face of said dielectric substrate adjacent said second face of said retrorefiective sheeting and wherein said antenna means further comprises:

radiating means disposed between said second face of said retroreflective sheeting and said first face of said dielectric substrate for radiating electromagnetic energy; and

a generally planar electrically conductive member having a first face and a second face for acting as a ground plane for said radiating means, said first face of said electrically conductive member being adjacent said second face of said dielectric substrate.

21. The electronic displaay system for both visual and electromagnetic data communication according to claim 19, wherein said antenna means comprises a first conductive substrate with a first side and a second side, and a first side of the dielectric substrate is adjacent the second side of the first conductive substrate, and a second side of the dielectric substrate is adjacent a first side of a second conductive layer, and wherein said coupling means comprises:

a second dielectric substrate having first and second faces, said first face of said second dielectric substrate adjacent a second side of said second conductive layer; and

a microstrip transmission line having first and second faces, said first face of said transmission line adjacent said second face of said second dielectric substrate and aligned with said first conductive substrate;

said second conductive substrate having an aperture therethrough, said aperture aligned with said first conductive substrate.

22. The electronic display system according to claim 19, wherein the thermoplastic elastomer comprises:

a thermoplastic polymeric component selected from the group consisting of polypropylene, polyethylene, and copolymers of ethylene and propylene; and

an elastomeric component selected from the group consisting of butyl rubber, natural rubber, ethylene-propylene rubber (EPR), ethylene-propylene diene rubber (EPDM) and silicone rubber.

23. The electronic display system according to claim 22, wherein the thermoplastic component is polypropylene and the elastomeric component is crosslinked or uncrosslinked EPDM.

24. An electronic display system according to claim 19, wherein the loss tangent (tan δ

) of the thermoplastic elastomer is less than about 0.005.