Dielectric structure for antennas in RF applications

• US 9,496,596 B2
• Filed: 01/06/2011
• Issued: 11/15/2016
• Est. Priority Date: 01/06/2010
• Status: Active Grant

• Current Assignee: Psion PLC (Motorola Solutions, Inc.)
• Original Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Inventors: Chirila, Laurian Petru
• Primary Examiner(s): Simone, Catherine A
• Application Number:
  US13/520,739
• Publication Number:
  US 20120276311A1
• Time in Patent Office: 2,140 Days
• Field of Search: 428/166, 428/323, 428/325, 428/421, 343/700.MS, 343/846
• US Class Current: 1/1
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 1/526 Electromagnetic shields
• CPC Class Codes: H01Q 5/364 Creating multiple current paths
• 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: Y10T 428/13 Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/249923 Including interlaminar mechanical fastener
• CPC Class Codes: Y10T 428/31544 Addition polymer is perhalogenated

Abstract

A dielectric structure for positioning adjacent to an active element of an antenna for radio frequency (RF) applications, the dielectric structure comprising: a plurality of individual dielectric material layers in a stacked layer arrangement including a first layer including a first dielectric material and a second layer including a second dielectric material.

Claims

1. A dielectric structure positioned adjacent to an active element of an antenna for a radio frequency (RF) application, the dielectric structure comprising:

a plurality of individual layers in a stacked layer arrangement including a first layer having a top surface and an opposing bottom surface and including a first RF dielectric material, a second layer adjacent to and in contact with the first layer, the second layer having a top surface and an opposing bottom surface and including a second RF dielectric material, a third layer adjacent to and spaced apart from the second layer by a predetermined distance to form a gap layer between the second layer and the third layer;

a passage in the third layer configured to route a grounding line to a ground element of the antenna, the ground element disposed below the third layer; and

at least one non-conductive mechanical fastening mechanism configured to couple the plurality of individual layers to one another and to inhibit short-circuiting the active element with the ground element of the antenna.

2. The dielectric structure of claim 1, wherein the first RF dielectric material and the second RF dielectric material have substantially similar dielectric constants D_k.

3. The dielectric structure of claim 1, wherein a resonance frequency of the RF application is between about 300 MHz and about 14 GHz.

4. The dielectric structure of claim 1 wherein the predetermined distance is substantially less than a layer thickness of each of the plurality of individual layers.

5. The dielectric structure of claim 4 further comprising a gap material positioned in the gap layer, the gap material being RF unsuitable material for resonating at a resonance frequency of the RF application.

6. The dielectric structure of claim 5, wherein the gap material is an adhesive for adhering the third layer to the second layer.

7. The dielectric structure of claim 5, wherein the gap material has a dielectric constant value from about D_k=1.0 to about D_k=4.0.

8. The dielectric structure of claim 4 wherein the plurality of individual layers in the stacked layer arrangement further include a fourth layer adjacent to the third layer, the fourth layer including a fourth RF dielectric material.

9. The dielectric structure of claim 8 wherein the fourth layer is spaced apart from the third layer to form a second gap layer between the third layer and the fourth layer.

10. The dielectric structure of claim 9 further comprising a second gap material positioned in the second gap layer, the second gap material being RF unsuitable material for resonating at a resonance frequency of the RF application.

11. The dielectric structure of claim 10, wherein the second gap material is an adhesive that adheres the third layer to the fourth layer.

12. The dielectric structure of claim 1, wherein at least one of the plurality of individual layers is composed of a composite polymer resin system having a resin carrier.

13. The dielectric structure of claim 12, wherein the resin carrier is polytetrafluoroethylene (PTFE).

14. The dielectric structure of claim 13, wherein the composite polymer resin system includes a filler inserted into the resin carrier.

15. The dielectric structure of claim 14, wherein filler is ceramic particles.

16. The dielectric structure of claim 1, wherein the first RF dielectric material has a dielectric constant value between D_k=2.0 and D_k=100.0 and the second RF dielectric material has a dielectric constant value between D_k=2.0 and D_k=100.0.

17. The dielectric structure of claim 4 further comprising a cavity positioned in the second layer.

18. The dielectric structure of claim 17, wherein the cavity is positioned in the second layer and the first layer is adapted for positioning adjacent to the active element.

19. The dielectric structure of claim 17 further comprising at least one additional layer positioned between the second layer and the third layer, wherein each additional layer includes an additional RF dielectric material.

20. The dielectric structure of claim 17 wherein the second layer includes a plurality of pieces, each piece being made of the second RF dielectric material, and wherein the plurality of pieces are arranged in the second layer to form the cavity.

21. The dielectric structure of claim 17, wherein walls of the cavity are positioned away from exterior lateral surfaces of the first, second, and third layers.

22. The dielectric structure of claim 19, wherein the cavity is positioned in a center of the second layer.

23. The dielectric structure of claim 2, wherein the first dielectric material and the second dielectric material are the same material type.

24. A dielectric structure positioned adjacent to an active element of an antenna for a radio frequency (RF) application, the dielectric structure comprising:

a plurality of individual layers in a stacked layer arrangement including a first layer having a top surface and an opposing bottom surface and including a first RF dielectric material, a second layer adjacent to and in contact with the first layer, the second layer having a top surface and an opposing bottom surface and including a second RF dielectric material, a third layer adjacent to and spaced apart from the second layer by a predetermined distance to form a gap layer between the second layer and the third layer; and

a passage in the third layer configured to route a grounding line to a ground element of the antenna, the ground element disposed below the third layer,

wherein,

the predetermined distance is substantially less than a layer thickness of each of the plurality of individual layers,

the plurality of individual layers in the stacked layer arrangement further include a fourth layer adjacent to the third layer, the fourth layer including a fourth RF dielectric material, and

the fourth layer is spaced apart from the third layer to form a second gap layer between the third layer and the fourth layer.

25. A dielectric structure positioned adjacent to an active element of an antenna for a radio frequency (RF) application, the dielectric structure comprising:

a plurality of individual layers in a stacked layer arrangement including a first layer having a top surface and an opposing bottom surface and including a first RF dielectric material, a second layer adjacent to and in contact with the first layer, the second layer having a top surface and an opposing bottom surface and including a second RF dielectric material, a third layer adjacent to and spaced apart from the second layer by a predetermined distance to form a gap layer between the second layer and the third layer;

a passage in the third layer configured to route a grounding line to a ground element of the antenna, the ground element disposed below the third layer;

a cavity positioned in a center of the second layer; and

at least one additional layer positioned between the second layer and the third layer, wherein the at least one additional layer includes an additional RF dielectric material.