U.S. patent number 3,670,270 [Application Number 04/725,570] was granted by the patent office on 1972-06-13 for electrical component.
This patent grant is currently assigned to Technitrol, Inc.. Invention is credited to William T. Storey, II.
United States Patent |
3,670,270 |
Storey, II |
June 13, 1972 |
ELECTRICAL COMPONENT
Abstract
A distributed constant electrical component which may be
utilized as a transmission or a delay line is disclosed which
utilizes a length of non-conductive material such as a matrix of
polytetrafluoroethylene in which is dispersed particles of a
magnetic material such as powdered iron or powdered ferrite.
Alternatively, a length of ferrite material may be used. At least a
portion of a signal conductor extends through the length of
material to provide a path for electrical signals. Both balanced
and unbalanced lines are disclosed. There also is disclosed a
device which may be used as a variable delay line which includes
means for varying the spacing between portions of the length of
material.
Inventors: |
Storey, II; William T. (West
Chester, PA) |
Assignee: |
Technitrol, Inc. (Philadelphia,
PA)
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Family
ID: |
24915078 |
Appl.
No.: |
04/725,570 |
Filed: |
April 15, 1968 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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629139 |
Apr 7, 1967 |
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Current U.S.
Class: |
333/161 |
Current CPC
Class: |
H01P
9/00 (20130101) |
Current International
Class: |
H01P
9/00 (20060101); H03h 007/30 (); H03h 007/36 () |
Field of
Search: |
;333/84M,31,30,10,24.1,24.2,29,73 ;330/5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Saalbach; Herman Karl
Assistant Examiner: Baraff; C.
Parent Case Text
This application is a continuation-in-part of my copending
application, Ser. No. 629,139, filed Apr. 7, 1967, entitled "Delay
Line," now abandoned .
Claims
What is claimed is:
1. An electrical component including a planar single composite
section of nonconducting material having a dielectric constant
substantially independent of frequency, low dielectric and magnetic
loss, a magnetic permeability greater than unity and substantially
independent of frequency; an electrical signal conducting means in
contact with said material for providing a path for the
transmission of an electrical signal, said signal conducting means
comprising a first signal conductor adapted to be connected to a
first terminal, and a second signal conductor spacially displaced
from and electrically cooperable with said first signal conductor
and adapted to be connected to a second terminal, said first signal
conductor being formed by a plurality of serially connected
interdigit elements which are in adjacent and substantially
parallel relationship, said second signal conductor lying in the
same plane as said first signal conductor and comprising a
plurality of serially connected interdigit elements which are in
adjacent and substantially parallel relationship, said first and
second signal conductors being sized and positioned so that the
elements of said first signal conductor are spacially displaced
from and parallel to corresponding ones of said elements of said
second signal conductor.
2. An electrical component as in claim 1, and an electrically
conductive layer of material covering at least a surface of said
section of material.
3. An electrical component as in claim 1, wherein said
non-conductive material comprises a strip of
polytetrafluoroethylene having finely divided particles of magnetic
material dispersed therethrough.
4. An electrical component as in claim 1, in which said
non-conductive material is composed of a linear ferrite.
5. An electrical component comprising a length of composite
material having a permittivity substantially independent of
frequency, low dielectric and magnetic loss and a magnetic
permeability greater than unity; and signal conducting means for
conducting an electrical signal; at least a portion of said signal
conducting means extending through said material, said signal
conducting means including a first and a second signal conductor
each having serially connected interdigit elements which lie in the
same plane and are in adjacent and substantially parallel
relationship, said elements of said first conductor being spacially
displaced from and parallel to corresponding elements of said
second conductor.
6. An electrical component as in claim 5, and electrically
conductive layers of material on at least two opposed surfaces of
said length of material.
7. An electrical component comprising a length of composite
material having a permittivity substantially independent of
frequency, low dielectric and magnetic loss, and a magnetic
permeability greater than unity; and signal conducting means for
conducting an electric signal; at least a portion of said signal
conducting means extending through said material; said length of
material including a first section and a second section; said
signal conductor means including a first conductor disposed between
said first and second sections, and a second conductor comprising
ground plane elements of electrically conductive material on the
respective outer surfaces of said first and second sections, and
means for controllably varying the spacing between said sections to
vary the delay introduced in signals applied to said signal
conducting means.
8. An electrical component as in claim 5, in which said length of
material is a solid block of material, and said portion of said
signal conducting means is embedded therein.
Description
This invention pertains to electrical components and, more
particularly, to components which may be used as signal delay or
transmission lines.
While, as noted above, the electrical component of the present
invention may be utilized as a transmission line, it is
particularly advantageous to use the same as a signal delay line.
Hence, the component will be described below in the context of
being a delay line. However, this is by way of example only and is
not to be interpreted as being a limitation of the invention. That
is, it will readily be obvious to those skilled in the art that the
disclosure applies equally as well to transmission lines.
Signal delay lines have many applications in the fields of signal
processing such as radar and computers. Generally, the delay lines
are used to establish the time of arrival of signals at particular
points in the signal processing circuits.
As the signal processing art grew, delay lines, depending on the
overall delay required and the permissible signal distortion,
developed as lumped-constant transmission lines or as distributed
constant coaxial lines. Each type of line was relatively bulky. In
fact, it has been known to use many feet of coaxial line to obtain
fractions of millisecond delays. In the present era of
miniaturization heretofore available delay lines are becoming
impractical.
It is accordingly a general object of the invention to provide an
improved signal delay line.
It is another object of the invention to provide an improved delay
line of the distributed type which has a small volume to overall
delay ratio.
It is a further object of the invention to provide such a delay
line which is relatively inexpensive to manufacture and is at the
same time very reliable and rugged.
Accordingly, an electrical component constructed according to the
present invention includes a section of non-conductive material
having a dielectric constant substantially independent of
frequency, low dielectric loss and a magnetic permeability greater
than unity. In contact with the material is signal conducting means
for providing a path for the transmission of an electrical
signal.
Other objects, the features and advantages of the invention will be
apparent from the following detailed description, when read with
the accompanying drawings which show, by way of example and not
limitation, the now preferred embodiments of the invention.
In the drawings:
FIG. 1 is a perspective view, partially broken away, of an
electrical component according to the invention;
FIG. 2 is a perspective view of an electrical component similar to
that of FIG. 1 but which is controllably variable; and
FIG. 3 is a further modified embodiment of an electrical component
constructed according to the present invention.
Referring to FIG. 1, there is shown an electrical component in the
form of an unbalanced delay line 10 comprising a striplike element
12 and a signal conductor 14. Striplike element 12 comprises a
sheet 16 of conductive material such as copper (a ground plane
element) and a layer 18 of non-conductive material.
The non-conductive material should have a permeability-permittivity
product which is high and substantially frequency independent,
i.e., substantially less than a five per cent change in the range
of frequencies from 1 megahertz to 1 gigahertz. In addition, the
material should have a low dielectric and magnetic loss over the
cited range of frequencies. Such a material is a plastic matrix in
which is dispersed a magnetic material. Suitable plastics should be
those exhibiting substantially frequency independent dielectric
constants and low dielectric loss. The following plastics satisfy
these criteria: Polyethylene (which has a dielectric constant of
2.26 over the range under consideration), Polystyrene (which has a
dielectric constant of 2.56-2.55 over the range under
consideration). A plastic admirably suited for use and constituting
a preferred embodiment of the invention is polytetrafluoroethylene.
The magnetic material should exhibit a permeability much greater
than one in addition to having a permeability-permittivity constant
which is substantially independent of frequency over the range
under consideration. Such a material can be a ferromagnetic or a
ferrimagnetic material. In particular, powdered iron or powdered
ferrite is preferred.
Alternatively, the non-conductive material may comprise a linear
ferrite material because linear ferrites are found to possess the
above-noted characteristic at the frequencies of interest.
Although striplike element 12 has been described as two separate
portions it is preferably a laminated structure wherein the layer
18 of non-conductive material is bonded on the sheet 16 of
conductive material. The signal conductor 14 is of a conductive
material such as copper, silver or aluminum, preferably "printed"
on the exposed surface of layer 18. Printing is used in its generic
sense to include evaporating, sputtering, photoetching or other
techniques well known in the arts of printed circuitry and
microelectronic fabrication. This, in the application wherein the
layer 18 of non-conductive material comprises a linear ferrite,
both surfaces of the slab may be plated or coated with an
appropriate conductor. The bottom layer of the conductive coating
forms the sheet 16 and the signal conductor 14 is formed from the
upper layer, utilizing any of the conventional methods noted. The
signal conductor 14 traces out a meandering path and is formed by a
plurality of serially connected interdigit elements such as 14A and
14B which are adjacent and substantially parallel. It should be
noted that the lengths of the interdigit elements and their spacing
controls the coefficient of coupling between the elements and can
be used to vary the properties of the delay line.
The delay line 10 also may be fabricated by molding techniques.
Thus, the conductor 14 is traced on a conducting plate and removed
therefrom. A mold is filled with the dielectric material in
powdered form having the magnetic particles dispersed therethrough.
Alternatively, the mold may be filled with a powdered ferrite
material. The conductor 14 is placed on the dielectric material and
the mold is closed. Heat is applied to melt the material. The
resulting element is removed from the mold and the bottom surface
thereof is coated with a conducting material in any conventional
manner as by sputtering techniques or the like. In this respect, it
should be noted that it may be desirable to have the dielectric
material extend between and about the conductor 14.
The delay line 10 has an input terminal 20 and an output terminal
22. These terminals are connected to the ends of signal conductor
14. Signals applied between input terminal 20 and the grounded
sheet 16 travel along the signal conductor 14 and are transmitted
as signals across the output terminal 22 and ground.
The transmitted signals will be delayed a period of time related to
the mechanical length of the signal conductor 14 and the
electromagnetic properties such as the permeability and the
permittivity of the region surrounding the signal conductor 14.
Thus, it is seen that greater delays per unit length are obtained
from the meandering geometry of the signal conductor. In addition,
increasing the product of the average permeability and average
permittivity of the region surrounding the signal conductor 14
increases the delay per unit length.
Accordingly, another embodiment contemplates placing the striplike
element 24 over striplike element 12. Element 24 comprises sheet 26
of conductive material and layer 28 of non-conductive material.
Since sheet 26 is the same as sheet 16 and layer 28 is the same as
layer 18 they will not be discussed any further. It should be noted
that layers 18 and 28 are in opposed relation and sheets 16 and 26
are conductively connected together by a shorting wire 30. Such a
configuration, in addition to increasing the delay of the line by
surrounding signal conductor 14 with high-permeability and
high-dielectric constant material also provides signal shielding by
virtue of the ground planes established by sheets 16 and 26.
The embodiment including striplike elements 12 and 24 also may be
molded in a manner similar to that described above. For this latter
embodiment, both mold halves will be filled with dielectric
material and, after removal from the mold, the upper and the lower
surfaces of the resulting block of material are coated with an
electrically conducting material
It should be noted that by feeding signals between the signal
conductor 14 and the ground planes the delay line 10 is an
unbalanced line.
As has been stated above the delay per unit length of the delay
line is at least a function of the product of the average
permeability and average dielectric constant of the region
surrounding the signal conductor 14. Therefore, if an air gap
having a controllable thickness is introduced between elements 12
and 24 a delay line with a controllable delay is obtainable. Such a
delay line 10' is shown in FIG. 2. The delay line 10' is identical
in all respects to delay 10 of FIG. 1 except that sheets 16' and
26' are more rigid. In addition, leaf springs 32 of Nylon or the
like are interposed between elements 12' and 24' for biasing the
elements to separate. A screw C-clamp 34 engages the elements 12'
and 24' to move them together under the control of the rotation of
screw 36. Although leaf springs and a screw C-clamp have been shown
it should be apparent that other well known means are
available.
As noted above, the line shown in FIGS. 1 and 2 illustrates an
unbalanced line. However, in many applications it may be desirable
to provide a balanced delay or transmission line. Accordingly, FIG.
3 illustrates a balanced line which is designated generally by the
reference numeral 40. The line 40 includes a length of
non-conductive material 42 having the same properties as the layer
of material 18. Received on the material 42 are signal conducting
means such as signal conductors 44 and 46. The conductors 44 and 46
are identical in construction and include elements similarly to the
conductor 14. That is, the conductors 44 and 46 trace out
meandering paths and are respectively formed by a plurality of
serially connected interdigit elements such as 44A, 46A and 44B,
46B which are in adjacent and substantially parallel relationships.
Moreover, the elements of the conductor 44 are spacially displaced
from and substantially parallel to corresponding elements of the
conductor 46. Connected to one end of the conductors 44 and 46 are
respective input leads 48 and 50; connected to the other end of
conductors 44 and 46 are respective output leads 52 and 54. As
noted above, the line 40 may be constructed by lamination
techniques or by molding techniques, similarly to the line 10
disclosed above. Thus, the line 40 provides a means for conducting
a balanced signal with respect to an outside reference point such
as ground.
In many applications it may be desirable to shield the conductors
44 and 46 from external electric fields or to contain the electric
field produced by the signal carried by the conductors.
Accordingly, an electrically conducting layer 56 may be provided on
the outer surface of the material 42 to effect such shielding.
Moreover, another length of dielectric material (not shown) may be
placed over the conductors 44 and 46 to fully enclose the
conductors in a dielectric housing. If desired, both the upper and
the lower surfaces of this housing may be coated with a conductive
layer, or conductive layers may be laminated thereto, to effect
shielding of the conductors.
There has thus been shown an improved electrical component which by
using a material having a high permeability and high dielectric
constant in conjunction with a meandering signal conductor provides
an easily fabricated, very efficient and compact signal delay
device. In addition, by being able to control the separation
between the layers of the material it is possible to vary the
signal delay of the line.
Although only a single layered line has been shown, it should be
realized that such lines can be stacked to obtain greater delays
when used as a delay line. While only a limited number of
embodiments of the invention have been shown and described in
detail, there will now be obvious that numerous omissions, changes
and additions may be made in such embodiments without departing
from the spirit and scope of the present invention.
* * * * *