U.S. patent application number 12/369155 was filed with the patent office on 2010-08-12 for method of incorporating microwave structures within reinforced composites by overstitching patterns of conductive fibers onto reinforcement fabric.
Invention is credited to Michael A. Deaett, Willam H. Weedon, III.
Application Number | 20100199903 12/369155 |
Document ID | / |
Family ID | 42539302 |
Filed Date | 2010-08-12 |
United States Patent
Application |
20100199903 |
Kind Code |
A1 |
Deaett; Michael A. ; et
al. |
August 12, 2010 |
Method of Incorporating Microwave Structures within Reinforced
Composites by Overstitching Patterns of Conductive Fibers onto
Reinforcement Fabric
Abstract
A method of attaching conductive fiber to composite laminate
reinforcement fabric and to other fabrics utilizing stitching which
comprises: a means of precisely arranging said conductive fiber on
the surface of said reinforcement fabric to minimize radio
frequency losses; an overstitching means wherein said conductive
fiber is attached to said reinforcement fabric by a non-conductive
retention thread.
Inventors: |
Deaett; Michael A.; (North
Kingstown, RI) ; Weedon, III; Willam H.; (Warwick,
RI) |
Correspondence
Address: |
MAURICE M. LYNCH
429 CHURCH AVENUE
WARWICK
RI
02885
US
|
Family ID: |
42539302 |
Appl. No.: |
12/369155 |
Filed: |
February 11, 2009 |
Current U.S.
Class: |
112/475.19 |
Current CPC
Class: |
D05D 2209/12 20130101;
D05C 7/08 20130101; H01Q 1/273 20130101; D05D 2303/08 20130101 |
Class at
Publication: |
112/475.19 |
International
Class: |
D05C 5/02 20060101
D05C005/02 |
Claims
1. A method of attaching conductive fiber to composite laminate
reinforcement fabric and to other fabrics utilizing stitching which
comprises: a means of precisely arranging said conductive fiber on
the surface of said reinforcement fabric to minimize radio
frequency losses; an overstitching means wherein said conductive
fiber is attached to said reinforcement fabric by a non-conductive
retention thread.
2. The method of claim 1 wherein the arranging means and stitching
means are accomplished by a person skilled in the art of
embroidery.
3. The method of claim 1 wherein the arranging means and the
stitching means are accomplished by a person skilled in the art of
operating a stitching or embroidery machine.
4. The method of claim 3 wherein the operation of the stitching or
embroidery machine is controlled by a computer or other electronic
control device
Description
FIELD OF INVENTION
[0001] This invention relates to methods of constructing radio
frequency antennas, transmission lines and other structures such as
filters.
BACKGROUND OF INVENTION
[0002] In many radar and communications systems, it is desirable to
employ an antenna or transmission line that is lightweight and
flexible. For example, an antenna may be incorporated into a fabric
structure such as a garment or a tent. In other applications, an
antenna may be incorporated into a composite laminate. This
laminate is first comprised of a reinforcement fabric which is then
impregnated with a resin. This prepreg structure is often merged
with other prepreg structures and then cured to produce a final
assembly. Prior to merging and curing, it is desirable to
incorporate said antenna structures into the laminate reinforcement
fabric and thereby obtain a durable, low cost, integrated antenna
structure.
[0003] In the past, several methods of constructing radio frequency
structures from textile materials have been proposed. See "Method
for constructing microwave antennas from textile fabrics and
components", Provisional Patent Application, U.S. application Ser.
No. 60/557,431, Mar. 29, 2004 and "The Characterization of
Conductive Textile Materials Intended for Radio Frequency
Applications", Robert K. Shaw, et. al., IEEE Antennas and
Propagation Magazine, Vol. 49, No. 3, June 2007, pp. 28-40.
Structures have been built using conductive foil or fabric attached
to a laminate or conductive ink printed onto a laminate. However,
under fatigue stress, such embedded radio frequency (RF) structures
can cause delamination.
[0004] Also in the past, methods of incorporating conductive fibers
into reinforcement fabric by direct stitching of said fiber have
resulted in undesirable radio frequency losses due to propagation
disturbances. The inventors have tried that method and the data for
that method is included in FIG. 3.
SUMMARY OF INVENTION
[0005] It is therefore the object of this invention to provide
methods of constructing RF structures by attaching conductive fiber
to the reinforcement fabrics of composite laminates.
[0006] It is a further object of this invention to provide a means
of constructing RF structures by attaching conductive fiber to the
surface of fabric structures so that propagation losses are
reduced.
[0007] It is another object of this invention to provide a means of
construction of microwave antennas on a reinforcing fabric for
later incorporation into laminated structures.
[0008] It is another object of this invention to provide a means of
constructing RF structures and to incorporate said structures into
clothing in a way that allows said RF structures to look like
fashion designs or appliques.
[0009] It is the realization of these-objects that an RF structure
can be incorporated into ordinary fabrics, non-woven fabrics and
even clothing so that said RF structures are flexible, not subject
to delamination and the basic structure can also be incorporated in
to laminate prepeg structures for other applications.
[0010] This invention features conductive fiber such as copper
wire, stainless steel wire or other conductive fibers that is
attached to fabric such as composite laminate reinforcement fabric
by means of zigzag overstitching. This overstitching is
accomplished by use of cording embroidery and can be implemented
with, for example, Schiffley or Cornelly Embroidery machine or with
cording attachments to lock-stitch embroidery machines or by other
similar means. It is important that the fibers be attached onto the
reinforcing fabric as opposed to being stitched through said fabric
as stitching through the fabric diminishes the microwave properties
of the antenna.
BRIEF DESCRIPTION OF THE INVENTION
[0011] FIG. 1 is a depiction of the working parts of an embroidery
or overstitching sewing machine used to manufacture a microwave
structure such as an antenna, feed or filter.
[0012] FIG. 2 shows a transmission line constructed by said
methods.
[0013] FIG. 3 shows performance data for an antenna produced by a
stitched through method of incorporating conductive fabric within
non-conductive fabric.
[0014] FIG. 4 is a graph of performance data for the overstitched
method of constructing a microwave fabric antenna.
DISCLOSURE OF PREFERRED EMBODIMENT
[0015] Other objects, features and advantages will occur to those
skilled in the art from the following description of a preferred
embodiment and the accompanying drawings in which:
[0016] There is shown in FIG. 1 an overstitching sewing machine
incorporating a foot and platen 4 lock stitch overstitching needle
7 and a wire feed. Said overstitching feature feeds the fabric
along the sewing machine base 5 though the stitching mechanism in a
regular zigzag pattern 6 onto the reinforced fabric 8.
Simultaneously, the conductive fiber 9 is precisely fed in front of
the stitching mechanism coming off a spool 2 and wire feed 3. Not
shown is a means of computer control, so that a precisely planned
pattern of conductive fiber 9 can be attached to the reinforced
fabric 8.
[0017] FIG. 2 is a rendition of the completed antenna with the
zigzag pattern 6 holding the conductive fabric 9 in place. The
reinforced fabric 8 provides the backing for the antenna.
[0018] FIG. 3 shows the data for the cross-stitched antenna with
curve 12 representing the S.sub.12 and the S.sub.21 overlapping
data for insertion loss. Curve 11 represents the S.sub.11 data for
power from the input port and represents the reflected energy Curve
22 represents the S.sub.22 data for power. This data is can easily
be compared to that of the overstitched antenna in FIG. 4. Here the
insertion loss data is less as represented by curve 12 and the
energy output is greater as shown by curves 11 and 22.
* * * * *