Method for forming radio frequency antenna

• US 7,639,184 B2
• Filed: 07/26/2005
• Issued: 12/29/2009
• Est. Priority Date: 03/13/2000
• Status: Expired due to Fees

• Current Assignee: RCD Technology Corporation
• Original Assignee: RCD Technology Corporation
• Inventors: Oberle, Robert R.
• Primary Examiner(s): DINH, TRINH VO
• Application Number:
  US11/189,503
• Publication Number:
  US 20050253772A1
• Time in Patent Office: 1,617 Days
• Field of Search: None
• US Class Current: 343/700.0MS
• 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 reinforcing the conductive pattern H05K3/24
• 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 in a pattern;

a conductive layer over portions of the seed layer, the antenna having a removed short region comprising a portion of the seed layer wherein the conductive layer is thinner than the remaining portions of the conductive layer;

wherein the removed short region is constructed by 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.

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 includes a single electroplated layer while the remaining portions of the conductive layer comprises two electroplated layers.

4. An antenna comprising:

a substrate layer;

a seed layer on top of the substrate layer, the seed layer being deposited in a pattern such that at least one portion of the substrate layer is not covered by the seed layer;

a conductive layer over portions of the seed layer, the antenna having a removed short region comprising a portion of the seed layer wherein the conductive layer is thinner than the remaining portions of the conductive layer;

wherein the removed short region is constructed by 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.

5. The antenna of claim 4 wherein the seed layer comprises a cured conductive ink layer.

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

7. 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;

wherein the seed layer has a coil pattern; and

wherein the electrical-short layer connects regions of the coil pattern of the seed layer.

8. The method of claim 7, wherein the element is an antenna.

9. The method of claim 7 wherein the seed layer comprises a conductive ink layer.

10. The method of claim 9 wherein the conductive ink layer is cured.

11. The method of claims 7 wherein a non-conductive layer is formed over top of the electrical-short layer before the electroplating step.

12. The method of claim 7 wherein the removing step comprises using a solvent to remove the electrical-short layer.

13. The method of claim 7 wherein the electrical-short layer is differentially removable from the seed layer.

14. The method of claim 7 wherein the substrate layer is flexible.