Method for forming radio frequency antenna

• US 6,933,892 B2
• Filed: 09/11/2002
• Issued: 08/23/2005
• 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:
  US10/238,598
• Publication Number:
  US 20030011523A1
• Time in Patent Office: 1,077 Days
• Field of Search: H01/Q00.1/38, H01/Q00.1/36, 343/700.MS, 343/895, 343/873, 343/866, 343/867, 296/00, 257/679, 257/782, 257/777, 257/778, 438/667, 438/668
• 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. A method of forming an RF antenna, comprising:

providing a substrate layer;

forming at least one hole in the substrate layer on a first side of the substrate layer, attaching a conductive foil material such that the conductive foil material covers one side of the at least one hole;

on a second side of the substrate layer, forming a conductive ink layer on top of the substrate in at least part of an antenna coil pattern, the conductive ink filling the at least one hole to form an electrical contact with the conductive foil material.

2. The method on claim 1 wherein the conductive foil material is attached to the substrate layer using a conductive adhesive.

3. The method of claim 1 further comprising step of electroplating an electroplated conductive layer on top of the antenna coil pattern.

4. The method of claim 1 wherein the antenna coil pattern is such that there are two adjacent conductive pads not separated by loops of the antenna coil pattern.

5. The method of claim 4 wherein the conductive pads are adapted for connection to an integrated circuit device.

6. The method of claim 1 wherein the conductive ink layer is cured.

7. The method of claim 1, wherein the at least one hole comprises at least two holes.

8. The method of claims 1, further comprising forming a conductive layer of the first side of the substrate layer.