RFID antenna gain and range enhancement

• US 20080217309A1
• Filed: 03/01/2007
• Published: 09/11/2008
• Est. Priority Date: 03/01/2007
• Status: Active Grant

• Current Assignee: James Neil Rodgers
• Original Assignee: James Neil Rodgers
• Inventors: Rodgers, James Neil
• Granted Patent: US 7,893,385 B2
• Time in Patent Office: Days
• US Class Current: 219/121.68
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: B23K 26/361 for deburring or mechanical trimming B23K26/351 takes precedence
• 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 1/2208 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 15/0086 said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials

Abstract

This is an invention which addresses the need of the RFID industry to produce antennas which do not detune due to the proximity of other antennas. This invention also addresses the problem of reading RFID transponders which are not in a perpendicular orientation to the interrogator. This invention also addresses the need of the RFID industry to increase the read range of RFID antennas. Although this invention focuses primarily on the interrogator side of antenna gain and range enhancement it is equally applicable to the antenna portion of the base metal material which comprises the antenna structure of a transponder. The useful, non-obvious and novel steps of this invention include a laser ablation process applied to the base metal material, whether copper or aluminum, for the purpose of creating three dimensional nano structures on the surface of the base metal material. Pursuant to this process the absorption rate of the base metal material is enhanced thereby increasing the gain and range of the manufactured and implanted antennas.

Claims

1. A system of using femtosecond laser ablation of the metal base material which comprises the elements of a radio frequency identification antenna;

a system of using a generic laser pulse device to treat commercially produced bulk sheets of the metal base material with a pulse of sharply focused laser energy;

a system of using the bulk commercially produced sheets of base metal material so that they are manufactured into radio frequency identification antennas after the femtosecond laser ablation technique has been applied;

all for the purpose of creating three dimensional nano structures on the metal base material.

2. A system of claim 1 whereby the femtosecond laser ablation is limited to the metal base material which comprises the elements of a radio frequency identification antenna for the purpose of increasing the radiation sensitivity of the metal base material used in the construction of the RFID antenna to increase the gain and range of same;

3. A system of claim 1 whereby the generic laser pulse device used to treat commercially produced bulk sheets of the metal base material is of the Ti:

Sapphire Femto-Second laser type used for machining metal surfaces for the purpose of increasing the radiation sensitivity of the metal base material used in the construction of the RFID antenna to increase the gain and range of same;

4. The system of claim 1 whereby the laser ablation process blackens the surface of the metal base material creating surface roughness and formation of micro and nano sized structures for the purpose of increasing the electro magnetic absorption rate of the metal base material used in the construction of the RFID antenna to increase the gain and range of same;

5. The system of claim 1 whereby reflectance measurements are made of the metal base material subsequent to the laser ablation process through the use of ellipsometry and integrating sphere as well as the EDX, XPS, and AES techniques which are used to analyze the surface properties of the metal base material to determine the parameters of the reflectance values of the laser machined metal base material for the purpose of verifying the presence of sufficient three dimensional nano structures to adequately increase the sensitivity of the antenna;

6. The system of claim 1 whereby the femtosecond laser pulses of high intensity light are less than a picosecond but long enough duration in femotoseconds to reach the ablation threshold yet short enough to confine collateral damage on the base metal material to less than 10 nano meters;

7. The system of claim 1 whereby the femtosecond laser pulses emanate from technologies of the nonlinear multi photon laser matter interaction processes thereby allowing the ablation process to overcome the diffraction limit for the purpose of fabricating three dimensional nano structures on the base metal materials;

8. The system of claim 1 whereby the femtosecond laser pulse is unleashed at a frequency which equals the frequency of surface charge oscillations on the base metal material thereby increasing absorption of the laser pulse;

9. The system of claim 1 whereby the femtosecond laser ablation can be applied at a sufficiently high fluence and with a multitude of applied pulses for the purpose of raising the absorption rate to 100% on the base metal materials;

10. The system of claim 1 whereby the three dimensional nano structures are developed from a process of a nano scale melt which relocates the base metal material from the center of the melted site to peripheral areas resulting in nano cavities, nano rims, and nano protrusions for the purpose of raising the absorption rate on the base metal materials.