Wednesday, April 18, 2007

US Patents 7205021 and 7205940 - Carbon nanotube antennas - AMBIT CORP. patent - FUJI XEROX patent

One of the reasons I created this blog was to recognize the early potential commercialization of nanostructured materials for which patents, as opposed to scientific literature, can be a better judge. There have been several patents, such as the basic nanotube electron emitter patent by Till Keesmann, which have the potential to create entire industries (such as surface emitting displays) and from which hundreds of further patents have been filed.

Another group of fundamental nanotube patents with a lot of potentia,l but for which less of a patent thicket exists, are based on the optical reception and transmission properties of nanotubes. Robert Crowley of Ambit Corp. is arguably the first to patent the uses of carbon nanotubes in antenna elements and US Patent 7,205,021 is a continuation application based on earlier patents with priority going back to 1997. Claim 1 reads:

1. A method of manufacturing and using a device having an array of carbon nanotubes for the receipt and radiation of electromagnetic energy therefrom, comprising: providing a substrate; arranging a predetermined pattern of nanotube growth sites on said substrate; growing at least one electromagnetic energy receiving carbon nanotube from said growth sites on said substrate; receiving electromagnetic energy by said at least one carbon nanotube; and radiating said electromagnetic energy by a carbon nanotube.

Coincidentally another nanotube antenna patent issued this week from Fuji Xerox with priority going back only to 2003. Claim 1 reads:

1. An antenna characterized by comprising: a radiator formed of a carbon nanotube, an electrode that is connected with a part of the carbon nanotube and is for operating the antenna as a monopole antenna.

One of Crowley's earlier patents was cited by the Patent Examiner but the Examiner did not consider Crowley's design to fall under the category of "monopole" antennas since Crowley uses an array of nanotubes. The Examiner used an obviousness type rejection that was successfully refuted by the attorney. However, it seems to me that Crowley's design could be considered a monopole antenna in some sense. Fuji Xerox's patent specification defines a monopole antenna as follows

"That is, the present invention is directed to an antenna characterized by including a radiator made up of a carbon nanotube, and as a specific structure, for example, an antenna characterized by including an electrode that is connected with a part of the carbon nanotube and is for operating the antenna as a monopole antenna. The "monopole antenna" is directed to an antenna that has an electricity feeding portion (an antenna that is provided with an electrode) on an end portion of the radiator, whereas the "bipolar antenna" is directed to an antenna having an electricity feeding portion in the center of the radiator."

Figure 3 of Ambit's patent seemingly illustrates several examples of monopoles by this definition when the nanotube extends from only one side of substrate 11 (although the bipolar type are also included).

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