Method for forming radio frequency antenna

• US 20050253772A1
• Filed: 07/26/2005
• Published: 11/17/2005
• Est. Priority Date: 03/13/2000
• Status: Active Grant

• Current Assignee: RCD Technology Corporation
• Original Assignee: RCD Technology Corporation
• Inventors: Oberle, Robert R.
• Granted Patent: US 7,639,184 B2
• Time in Patent Office: Days
• US Class Current: 343/895
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• 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 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• 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 9/27 Spiral antennas
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 2201/0347 Overplating, e.g. for reinforcing conductors or bumps; Plating over filled vias
• CPC Class Codes: H05K 2203/0191 Using tape or non-metallic foil in a process, e.g. during filling of a hole with conductive paste
• CPC Class Codes: H05K 2203/0769 Dissolving insulating materials, e.g. coatings, not used for developing resist after exposure
• CPC Class Codes: H05K 3/242 characterised by using temporary conductors on the printed circuit for electrically connecting areas which are to be electroplated
• CPC Class Codes: H05K 3/246 Reinforcing conductive paste, ink or powder patterns by other methods, e.g. by plating
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making

Abstract

A metalized circuit suitable for application as a radio frequency antenna is produced by forming an antenna coil pattern on a flexible substrate. The antenna coil pattern is formed using a conductive ink which is patterned on the substrate. The conductive ink is cured and an electrical-short layer is formed across the coils of the conductive ink pattern. An insulating layer is formed over top of the electrical-short layer, a metal layer electroplated on top of the conductive layer, and then the electrical-short layer is removed. The use of the electrical-short layer during the electroplating allows for the voltage at the different points on the conductive ink layer to be relatively similar, so that a uniform electroplate layer is formed on top of the conductive ink layer. This results in a better quality radio frequency antenna at a reduced cost.

Claims

1. An antenna comprising:

a substrate layer;

a seed layer on top of the substrate; and

a conductive layer over portions of the seed layer, the antenna having a removed short region comprising a portion of the seed layer not covered by the conductive material or comprising a portion of the seed layer wherein the conductive layer is thinner than the remaining portions of the conductive layer.

2. The antenna of claim 1 wherein the seed layer comprises a cured conductive ink layer.

3. The antenna of claim 1 wherein the removed short region comprises a portion of the seed layer not covered by conductive material.

4. The antenna of claim 1 wherein the removed short region comprises a portion of the seed layer wherein the conductive layer is thinner than the remaining portions of the electroplated conductive layer.

5. The antenna of claim 4 wherein the removed short region includes a single electroplated layer while the remaining portions of the conductive layer comprises two electroplated layers.

6. An element comprising:

a substrate layer;

a seed layer on top of the substrate; and

a conductive layer over portions of the seed layer, the element having a removed short region comprising a portion of the seed layer not covered by the conductive material or comprising a portion of the seed layer wherein the conductive layer is thinner than the remaining portions of the conductive layer.

7. The element of claim 6 wherein the element is an antenna.

8. The element of claim 6 wherein the seed layer comprises a cured conductive ink layer.

9. The element of claim 6 wherein the removed short region comprises a portion of the seed layer not covered by conductive material.

10. The element of claim 6 wherein the removed short region comprises a portion of the seed layer wherein the conductive layer is thinner than the remaining portions of the electroplated conductive layer.

11. The element of claim 10 wherein the removed short region includes a single electroplated layer while the remaining portions of the conductive layer comprises two electroplated layers.

12. A method of an element, comprising:

providing a substrate layer;

forming a seed layer on top of the substrate;

forming an electrical-short layer;

using the electrical-short layer to electroplate a conductive layer over at least portions of the seed layer; and

removing the electrical-short layer.

13. The method of claim 12, wherein the element is an antenna.

14. The method of claim 12, wherein the seed layer has a coil pattern.

15. The method of claim 14, wherein the electrical-short layer formed to connects regions of the coil pattern of the seed layer

16. The method of claim 12 wherein the seed layer comprises a conductive ink layer.

17. The method of claim 16 wherein the conductive ink layer is cured.

18. The method of claims 12 wherein a non-conductive layer is formed over top of the electrical-short layer before the electroplating step.

19. The method of claim 12 wherein the removing step comprises using a solvent to remove the electrical-short layer.

20. The method of claim 12 wherein the electrical-short layer is differentially removable from the seed layer.

21. The method of claim 12 wherein the substrate layer is flexible.