U.S. patent application number 14/872001 was filed with the patent office on 2017-03-30 for coaxial electrical interconnect.
This patent application is currently assigned to Raytheon Company. The applicant listed for this patent is Raytheon Company. Invention is credited to Michael M. Fitzgibbon, Ethan S. Heinrich, Chad Patterson, Duke Quach.
Application Number | 20170093092 14/872001 |
Document ID | / |
Family ID | 56411941 |
Filed Date | 2017-03-30 |
United States Patent
Application |
20170093092 |
Kind Code |
A1 |
Patterson; Chad ; et
al. |
March 30, 2017 |
COAXIAL ELECTRICAL INTERCONNECT
Abstract
A coaxial electrical interconnect is disclosed. The coaxial
electrical interconnect can include an inner conductor including an
electrically conductive spring probe. The coaxial electrical
interconnect can also include an outer conductor including a
plurality of electrically conductive spring probes disposed about
the inner conductor. Each spring probe can have a barrel and a
plunger biased out of the barrel. The plunger can have a first
plunger portion external to the barrel and a second plunger portion
disposed partially in the barrel. The first and second plunger
portions can have different diameters. A barrel of the spring probe
of the inner conductor can be located proximate a plunger of at
least one of the spring probes of the outer conductor.
Inventors: |
Patterson; Chad; (Marina Del
Rey, CA) ; Quach; Duke; (San Gabriel, CA) ;
Heinrich; Ethan S.; (San Pedro, CA) ; Fitzgibbon;
Michael M.; (Playa Del Rey, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Raytheon Company |
Waltham |
MA |
US |
|
|
Assignee: |
Raytheon Company
|
Family ID: |
56411941 |
Appl. No.: |
14/872001 |
Filed: |
September 30, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01R 13/2421 20130101;
H01R 13/2478 20130101; H01R 12/75 20130101; H01R 24/86 20130101;
H01R 24/44 20130101; H01R 13/405 20130101; H01R 31/06 20130101;
G01R 1/07328 20130101; H01R 12/91 20130101; H01R 12/714 20130101;
H01R 13/6473 20130101 |
International
Class: |
H01R 13/6473 20060101
H01R013/6473; H01R 12/75 20060101 H01R012/75 |
Claims
1. A coaxial electrical interconnect, comprising: an inner
conductor including an electrically conductive spring probe; and an
outer conductor including a plurality of electrically conductive
spring probes disposed about the inner conductor, each spring probe
having a barrel and a plunger biased out of the barrel, the plunger
having a first plunger portion external to the barrel and a second
plunger portion disposed partially in the barrel, the first and
second plunger portions having different diameters, wherein a
barrel of the spring probe of the inner conductor is located
proximate a plunger of at least one of the spring probes of the
outer conductor.
2. The coaxial electrical interconnect of claim 1, wherein the
spring probe of the inner conductor is inverted relative to the
spring probes of the outer conductor.
3. The coaxial electrical interconnect of claim 1, wherein the
spring probes of the inner and outer conductors are substantially
identical.
4. The coaxial electrical interconnect of claim 1, wherein the
spring probes of the outer conductor are disposed in a circular
configuration about the spring probe of the inner conductor.
5. The coaxial electrical interconnect of claim 1, further
comprising a spring probe support member configured to provide
mechanical support for the spring probes of the inner and outer
conductors.
6. The coaxial electrical interconnect of claim 5, wherein the
spring probe support member is constructed of a dielectric
material.
7. The coaxial electrical interconnect of claim 5, wherein the
spring probe support member is engaged with the first plunger
portion of the spring probe of the inner conductor and with the
barrels of the spring probes of the outer conductor.
8. The coaxial electrical interconnect of claim 7, further
comprising a second spring probe support member coupled to the
first spring probe support member, the second spring probe support
member configured to provide mechanical support for the barrel of
the spring probe of the inner conductor and the first plunger
portions of the spring probes of the outer conductor.
9. The coaxial electrical interconnect of claim 8, wherein the
barrels of the spring probes comprise capture features, and wherein
the first and second spring probe support members are configured to
provide mechanical interference with the capture features to
maintain the spring probes with the first and second support
members.
10. The coaxial electrical interconnect of claim 1, wherein each
spring probe comprises a spring to bias the plunger out of the
barrel.
11. The coaxial electrical interconnect of claim 1, wherein the
spring probe of the inner conductor comprises two barrels oriented
on opposite ends of the plunger.
12. The coaxial electrical interconnect of claim 1, wherein the
spring probes of the outer conductor comprise two plungers oriented
on opposite ends of the barrel.
13. The coaxial electrical interconnect of claim 1, wherein the
first plunger portion of the spring probe of the inner conductor
and the barrels of the spring probes of the outer conductor are
substantially equal in length to facilitate maintaining a
characteristic impedance of the electrical interconnect as the
plungers move relative to the barrels.
14. The coaxial electrical interconnect of claim 1, wherein the
spring probe of the inner conductor and the plurality of spring
probes of the outer conductor are sized and positioned relative to
one another to provide a given characteristic impedance.
15. The coaxial electrical interconnect of claim 1, wherein a first
region of the electrical interconnect comprises the first plunger
portion of the spring probe of the inner conductor and the barrels
of the spring probes of the outer conductor, a second region of the
electrical interconnect comprises the second plunger portions of
the spring probes of the inner and outer conductors, and a third
region of the electrical interconnect comprises the barrel of the
spring probe of the inner conductor and the first plunger portions
of the spring probes of the outer conductor, and wherein the spring
probes of the inner and outer conductors are sized and positioned
relative to one another to provide given characteristic impedances
for the first, second, and third regions.
16. The coaxial electrical interconnect of claim 15, wherein the
given characteristic impedances of the first, second, and third
regions are the same.
17. The coaxial electrical interconnect of claim 15, wherein the
first region further comprises a dielectric support member
configured to provide mechanical support for the spring probes of
the inner and outer conductors.
18. An electrically conductive spring probe for a coaxial
electrical interconnect, comprising: a barrel; and a plunger biased
out of the barrel, the plunger having a first plunger portion
external to the barrel and a second plunger portion disposed
partially in the barrel, the first and second plunger portions
having different diameters.
19. A method for facilitating a matched impedance electrical
connection, comprising: providing a coaxial electrical
interconnect, having an inner conductor including an electrically
conductive spring probe, and an outer conductor including a
plurality of electrically conductive spring probes disposed about
the inner conductor, each spring probe having a barrel and a
plunger biased out of the barrel, the plunger having a first
plunger portion external to the barrel and a second plunger portion
disposed partially in the barrel, the first and second plunger
portions having different diameters, wherein a barrel of the spring
probe of the inner conductor is located proximate a plunger of at
least one of the spring probes of the outer conductor; and
facilitating a constant characteristic impedance of the electrical
interconnect as the plungers move relative to the barrels.
20. The method of claim 19, wherein facilitating a constant
characteristic impedance comprises sizing the first plunger portion
of the spring probe of the inner conductor and the barrels of the
spring probes of the outer conductor with substantially equal
lengths.
Description
BACKGROUND
[0001] Some electrical circuits, particularly radio frequency (RF)
circuits, are impedance matched and therefore efforts are taken to
provide a given characteristic impedance through connecting cables
and electrical interconnects that couple various components of the
circuits. Often, electrical interconnects are utilized to
electrically couple adjacent circuit boards to one another.
However, the spacing between such circuit boards can vary.
Accordingly, spring probes, which can compress to vary in length,
are typically used to electrically connect such circuit boards.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] Features and advantages of the invention will be apparent
from the detailed description which follows, taken in conjunction
with the accompanying drawings, which together illustrate, by way
of example, features of the invention; and, wherein:
[0003] FIG. 1 is a coaxial electrical interconnect in accordance
with an example of the present disclosure.
[0004] FIG. 2 is a support member of the coaxial electrical
interconnect of FIG. 1.
[0005] FIG. 3 is a spring probe of the coaxial electrical
interconnect of FIG. 1.
[0006] FIG. 4A is a cross-sectional view of the coaxial electrical
interconnect of FIG. 1 in an uncompressed configuration.
[0007] FIG. 4B is a cross-sectional view of the coaxial electrical
interconnect of FIG. 1 in a compressed configuration.
[0008] FIG. 5A-5C illustrate cross-sections of different regions of
the coaxial electrical interconnect of FIG. 1, in accordance with
examples of the present disclosure.
[0009] FIG. 6 is a coaxial electrical interconnect in accordance
with another example of the present disclosure.
[0010] FIG. 7 is a support structure of the coaxial electrical
interconnect of FIG. 6.
[0011] FIG. 8 is a spring probe of the coaxial electrical
interconnect of FIG. 6.
[0012] FIG. 9 is a coaxial electrical interconnect in accordance
with yet another example of the present disclosure.
[0013] Reference will now be made to the exemplary embodiments
illustrated, and specific language will be used herein to describe
the same. It will nevertheless be understood that no limitation of
the scope of the invention is thereby intended.
DETAILED DESCRIPTION
[0014] As used herein, the term "substantially" refers to the
complete or nearly complete extent or degree of an action,
characteristic, property, state, structure, item, or result. For
example, an object that is "substantially" enclosed would mean that
the object is either completely enclosed or nearly completely
enclosed. The exact allowable degree of deviation from absolute
completeness may in some cases depend on the specific context.
However, generally speaking the nearness of completion will be so
as to have the same overall result as if absolute and total
completion were obtained. The use of "substantially" is equally
applicable when used in a negative connotation to refer to the
complete or near complete lack of an action, characteristic,
property, state, structure, item, or result.
[0015] As used herein, "adjacent" refers to the proximity of two
structures or elements. Particularly, elements that are identified
as being "adjacent" may be either abutting or connected. Such
elements may also be near or close to each other without
necessarily contacting each other. The exact degree of proximity
may in some cases depend on the specific context.
[0016] An initial overview of technology embodiments is provided
below and then specific technology embodiments are described in
further detail later. This initial summary is intended to aid
readers in understanding the technology more quickly but is not
intended to identify key features or essential features of the
technology nor is it intended to limit the scope of the claimed
subject matter.
[0017] Conventional coaxial interconnects, using spring probes,
have varying impedance mismatch dependent on the amount of
compression of the spring probes. When large compression
variability is required, very large impedance mismatch can occur.
In some cases, impedance mismatch due to the electrical
interconnect may require significant on-board matching. It is
therefore highly desirable to have a coaxial electrical
interconnect that can compress to vary in length while maintaining
a constant characteristic impedance independent of the amount of
compression of the electrical interconnect.
[0018] Accordingly, a coaxial electrical interconnect is disclosed
that can compress to vary in length and maintain a characteristic
impedance regardless of the amount of compression. The coaxial
electrical interconnect can include an inner conductor including an
electrically conductive spring probe. The coaxial electrical
interconnect can also include an outer conductor including a
plurality of electrically conductive spring probes disposed about
the inner conductor. Each spring probe can have a barrel and a
plunger biased out of the barrel. The plunger can have a first
plunger portion external to the barrel and a second plunger portion
disposed at least partially in the barrel. The first and second
plunger portions can have different diameters. A barrel of the
spring probe of the inner conductor can be located proximate a
plunger of at least one of the spring probes of the outer
conductor.
[0019] In addition, an electrically conductive spring probe for a
coaxial electrical interconnect is disclosed. The electrically
conductive spring probe can include a barrel and a plunger biased
out of the barrel. The plunger can have a first plunger portion
external to the barrel and a second plunger portion disposed
partially in the barrel. The first and second plunger portions can
have different diameters.
[0020] One example of a coaxial electrical interconnect 100 is
illustrated in FIG. 1. The coaxial electrical interconnect 100 can
be used as an RF interconnect to accommodate variations in distance
between adjacent electrically coupled components (e.g., circuit
boards) by being compressible in length. A characteristic impedance
of the coaxial electrical interconnect 100 can be maintained
substantially constant as the length of interconnect varies, as
described further below, which is highly desirable in impedance
matched circuits.
[0021] The coaxial electrical interconnect 100 can comprise an
inner conductor 101 and an outer conductor 102, which can be used
for signal and ground connections, respectively. The inner
conductor 101 can include at least one electrically conductive
spring probe 110a and the outer conductor 102 can include a
plurality of electrically conductive spring probes 110b-f disposed
about the inner conductor 101. As shown, the spring probes 110b-f
of the outer conductor 102 can be disposed in a circular
configuration about the spring probe 110a of the inner conductor
101. It should be recognized that the inner conductor 101 and the
outer conductor 102 can each include any suitable number of spring
probes. It should also be recognized that although the spring
probes 110b-f of the outer conductor 102 are shown disposed in a
circular configuration about the spring probe 110a of the inner
conductor 101, the spring probes 110b-f of the outer conductor 102
can be disposed in any suitable configuration (e.g., shape) about
the spring probe 110a of the inner conductor 101.
[0022] The coaxial electrical interconnect 100 can also comprise a
spring probe support member 120 configured to provide mechanical
support for the spring probes 110a-f of the inner and outer
conductors 101, 102. The spring probe support member 120 is shown
isolated in FIG. 2 and a representative spring probe 110 is shown
isolated in FIG. 3.
[0023] In general, as shown in FIG. 3, the spring probe 110 can
have a barrel 111 and a plunger 112 disposed at least partially in
an opening or cavity of the barrel and biased out of the barrel
111. The plunger 112 can have a first plunger portion 113 external
to the barrel 111 and a second plunger portion 114 disposed
partially in the barrel 111. The first and second plunger portions
113, 114 have different diameters 130, 131, respectively, which are
also different from a diameter 132 of the barrel 111. The first
plunger portion 113 can have a length 133 and the barrel 111 can
have a length 134. In one aspect, discussed in more detail below,
the length 133 of the first plunger portion 113 and the length 134
of the barrel 111 can be substantially the same, which when
combined with other similar spring probes in a coaxial electrical
interconnect can facilitate, at least in part, maintaining a
characteristic impedance of the electrical interconnect as the
plungers move relative to the barrels to accommodate variations in
distance between adjacent electrically coupled components.
[0024] The spring probe support member 120 can include openings to
receive portions of the spring probes. For example, as shown in
FIG. 2, the spring probe support member 120 can include an opening
121a to receive the first plunger portion 113a of the spring probe
110 and openings 121b-f to receive the barrels 111b-f of the spring
probes 110b-f. The spring probe support member 120 is shown as
having a cylindrical configuration but any suitable configuration
may be utilized.
[0025] As shown in FIG. 1, the spring probe 110a of the inner
conductor 101 can be inverted relative to the spring probes 110b-f
of the outer conductor 102. Thus, in one aspect, the barrel of the
spring probe 110a of the inner conductor 101 can be located
proximate one or more plungers of the spring probes 110b-f of the
outer conductor 102. Similarly, the plunger of the spring probe
110a of the inner conductor 101 can be located proximate one or
more barrels of the spring probes 110b-f of the outer conductor
102. In addition, the spring probe support member 120 can be
engaged with the first plunger portion of the spring probe 110a of
the inner conductor 101 and with the barrels of the spring probes
110b-f of the outer conductor 102. In one aspect, the spring probes
110a-f of the inner and outer conductors 101, 102 can be
substantially identical, although the springs probes of an
electrical interconnect as disclosed herein can include spring
probes that are different from one another.
[0026] The support member 120 can be constructed of any suitable
material or combination of materials, which may include a
dielectric material (e.g., a suitable polymer). In one aspect, the
support member 120 can be constructed entirely of a dielectric
material. In another aspect, illustrated in FIG. 2, the support
member 120 can be made of a dielectric material (indicated by
reference number 122) around the opening 121a for the inner spring
probe 110a. In addition, the support member 120 can have a
conductive material (indicated by reference number 123) on the
outside or periphery of the support member 120 that is at least
partially in communication with the openings 121b-f to electrically
connect the outer spring probes 110b-f to the same electrical
potential.
[0027] With continued reference to FIGS. 1-3, FIGS. 4A and 4B
illustrate schematic cross-sectional views of the coaxial
electrical interconnect 100 in an uncompressed configuration (FIG.
4A) and a compressed configuration (FIG. 4B), such when
establishing an electrical connection between two adjacent circuit
boards 103, 104. The spring probe of the inner conductor 101 is
referred to by reference no. 110a and the spring probes of the
outer conductor 102 are referred to collectively by reference nos.
110b-f. The spring probes 110a-f of the coaxial electrical
interconnect 100 can provide a certain range of motion or travel to
accommodate variations in distance or stack-up of the adjacent
circuit boards 103, 104. Thus, in one aspect, each spring probe
110a-f can include a spring to bias the plunger out of the barrel
and accommodate compression of the plunger into the barrel, as
illustrated by a spring 115 of the spring probe 110a. The
spring-loaded probes can provide a reliable electrical contact
between electrical components that may be located at a variable or
unknown distance from one another. The configuration of the spring
probes 110a-f can provide any suitable range of motion or travel to
accommodate a given maximum variation in distance between
electrical components. The ends of the spring probes 110a-f in
contact with the circuit boards 103, 104 can be electrically
coupled to the circuit boards in any suitable manner, such as by
spring force or by soldering if a fixed connection is desired. In
one aspect, no shrouds are needed for electrical purposes, but
shrouds can be used for mechanical reasons, such as to provide
protection and/or support.
[0028] In one aspect, the length 130a of the first plunger portion
113a of the spring probe 110a of the inner conductor 101 and the
lengths 134b-f of the barrels 111b-f of the spring probes 110b-f of
the outer conductor 102 can be equal or substantially equal in
length. Similarly, the length 133b-f of the first plunger portions
113b-f of the spring probes 110b-f of the outer conductor 102 and
the length 134a the barrel 111a of the spring probe 110a of the
inner conductor 101 can be equal or substantially equal in length.
As explained below, providing the first plunger portions 113a-f and
the barrels 111a-f with substantially equal lengths can facilitate
maintaining a characteristic impedance of the electrical
interconnect 100 as the plungers 112a-f move relative to the
barrels 111a-f.
[0029] The coaxial electrical interconnect 100 can also be divided
into several regions, as a first region 141, a second region 142,
and a third region 143, which can each have a nominal
characteristic impedance. Such nominal characteristic impedances
can be the same for all regions or they may vary from one another,
as desired. The first region 141 of the electrical interconnect 100
can include the first plunger portion 113a of the spring probe 110a
of the inner conductor 101 and the barrels 111b-f of the spring
probes 110b-f of the outer conductor 102. The second region 142 of
the electrical interconnect 100 can include the second plunger
portions 114a-f of the spring probes 110a-f of the inner and outer
conductors 101, 102 that are exposed or external to the barrels
111a-f. The third region 143 of the electrical interconnect 100 can
include the barrel 111a of the spring probe 110a of the inner
conductor 101 and the first plunger portions 113b-f of the spring
probes 110b-f of the outer conductor 102. Note that the length of
the second region 142 changes as the coaxial electrical
interconnect 100 is compressed (e.g., from length 135 in FIG. 4A to
a shorter length 135' in FIG. 4B). Because the second plunger
portions 114a-f are partially disposed in the barrels 111a-f and
move in and out of the barrels depending on the amount of
compression of the coaxial electrical interconnect 100, the second
region 142 is the only one of the three regions in FIGS. 4A and 4B
that undergoes a change in length as the interconnect 100 is
compressed. Thus, the lengths of the first and third regions 141,
143 are unaffected by compression of the interconnect 100, while
the second region 142 adjusts in length for the amount of
compression.
[0030] Viewed in cross-section in FIGS. 5A-5C, the first region
141, the second region 142, and the third region 143, respectively,
can each be configured to provide a given characteristic impedance.
Generally, characteristic impedance is determined by the geometry
and materials of the electrical interconnect. In this case,
characteristic impedance of each region 141-143 can be calculated
using the diameters of the inner conductor 101 and the outer
conductor 102, as well as accounting for a support structure (e.g.,
the spring probe support member 120) of the electrical interconnect
where applicable. In one aspect, the material of the spring probe
support member 120 can be used to tune the characteristic impedance
of the region in which it resides (i.e., the first region 141 in
this example). A support structure can interface with components of
the first, second, and/or third regions as desired. The spring
probe 110a of the inner conductor 101 is shown located at the
center of a circular arrangement of the spring probes 110b-f. The
centers or longitudinal axes of the spring probes 110b-f lie on a
circle 150, which remains the same diameter and at the same
location relative to the spring probe 110a for each region 141-143
because the spring probes 110b-f are parallel to one another,
although other configurations are possible. A circle 151, 151',
151'' of FIGS. 5A-5C, respectively, bounds the spring probes 110b-f
and defines a diameter of the outer conductor 102 for each region
141-143.
[0031] Due to the relationship of the diameter 130 for the first
plunger portions 113a-f, the diameter 131 for the second plunger
portions 114a-f and, the diameter 132 for the barrels 111a-f, the
diameters of the circles 151, 151', 151'' (i.e., the diameters of
the outer conductor 102) decrease from the first region 141 to the
third region 143 while the diameters of the inner conductor 101
increase from the first region 141 to the third region 143. This
inverse relationship in effective diameters of the inner and outer
conductors 101, 102 from the first region 141 to the third region
143 can be utilized to configure the characteristic impedances for
each region such that the characteristic impedances are equal
across the regions. Thus, for the first region 141, where there is
crowding in the outer conductor 102 due to the relatively large
diameter of the barrels 111b-f, the diameter of the inner conductor
101 is at its smallest (e.g., the diameter of the first plunger
portion 110a). This configuration of the first region 141, when
accounting for the presence of the support member 120 material,
which may be a dielectric material (e.g., a suitable polymer), can
provide a characteristic impedance that is equal to the
characteristic impedance of the second region 142 where the
crowding in the outer conductor is reduced as the diameter of the
inner conductor increases, and equal to the characteristic
impedance of the third region 143 where the crowding in the outer
conductor is reduced even further as the diameter 132 of the inner
conductor 101 increases even more. Thus, the coaxial electrical
interconnect inner and outer diameters 101, 102 can change with
each of the regions 141-143 while maintaining a consistent or
constant characteristic impedance across the regions. The spring
probes 110a-f of the inner and outer conductors 101, 102 can be
sized and positioned relative to one another to provide given
characteristic impedances for the first, second, and third regions
141-143 and/or the coaxial electrical interconnect 100 as a whole.
It should be recognized that identical spring probes can be
utilized throughout the interconnect 100 or interconnect 100 can
incorporate different spring probes, which may have different
diameters for the barrels, and plunger portions.
[0032] As mentioned with regard to FIGS. 4A and 4B, because the
lengths of the first and third regions 141, 143 are unaffected by
compression of the interconnect 100, these regions will maintain
the same characteristic impedance during compression of the
interconnect 100. Furthermore, because the second region 142 merely
changes in length (e.g., from length 135 to length 135') while the
cross-section illustrated in FIG. 5B remains the same, the
characteristic impedance of the second region will also be
maintained during compression of the interconnect 100. Thus, the
second region 142 can adjust in length for the amount of
compression of the interconnect 100 without altering the
characteristic impedance of the second region 142. In other words,
the characteristic impedance of the interconnect 100 can be
maintained substantially constant or stable throughout the range of
travel of the spring probes 110a-f. As a result, compression of the
interconnect 100 can have a minimal effect on impedance mismatch
over a wide frequency band. The interconnect 100 can therefore
provide for a high variability of compression without degrading
voltage standing wave ratio (VSWR) independent of the compression
of the interconnect 100.
[0033] The first plunger portion 110a and/or any of the barrels
111b-f of the spring probes 110a-f can be movable or fixed relative
to the support member 120. For example, the first plunger portion
110a and/or any of the barrels 111 b-f can be threadedly coupled,
adhesively coupled, or configured to have an interference fit with
the support member 120 to secure the first plunger portion 110a
and/or any of the barrels 111b-f to the support member 120.
[0034] The tips of the spring probes and the protrusion from the
support member near the circuit board 103 are examples of instances
where the characteristic impedance is not consistent with the
nominal characteristic impedance for a given region, as determined
based on the cross-sections of FIGS. 5A-5C. Similarly, although the
lengths 133a, 134b-f of the first plunger portion 113a and the
barrels 111b-f in the first region 141 are substantially equal, and
the lengths 134a, 133b-f of the barrel 111a and the first plunger
portions 113b-f in the first region 141 are substantially equal,
slight variations in these lengths due to manufacturing tolerances
may result in local instances where the characteristic impedance is
not consistent with the nominal characteristic impedance for a
given region. These variances from the nominal characteristic
impedance can be adjusted or controlled based on the application.
For example, a high frequency application may be less tolerant than
a lower frequency application and therefore may necessitate tighter
control on such local variations from the nominal characteristic
impedance than for a lower frequency application. Thus, terms such
as "substantially," "maintain," and "constant" when used in the
context of component dimensions or characteristic impedance will be
understood by one skilled in the art in light of the particular
application of the coaxial electrical interconnect.
[0035] FIG. 6 illustrates a schematic cross-sectional view of a
coaxial electrical interconnect 200 in accordance with another
example of the present disclosure. The coaxial electrical
interconnect 200 is similar to the coaxial electrical interconnect
100 discussed above in many respects. In this example, several
features are illustrated that can facilitate capture or retention
of spring probes and/or spring probe components as well as provide
mechanical support for the spring probes. In this case, an inner
conductor 201 can have a spring probe 211a and an outer conductor
202 can include six spring probes referred to collectively by
reference nos. 210b-g. First plunger portion 213a of the spring
probe 210a can be received in an opening 221a of a spring probe
support member 220, and barrels 211b-g of the spring probes 210b-g
can be received in openings 221b-g of the spring probe support
member 220. The first plunger portion 213a and the barrels 211b-g
and can be configured to move or slide relative to the spring probe
support member 220 in the openings 221a-g, respectively. An
additional spring probe support member 222 can be coupled to the
spring probe support member 220 to capture or retain the spring
probes 210a-g as well as to provide mechanical support for the
spring probes. The spring probe support members 220, 222 are shown
isolated in FIG. 7 and a representative spring probe 210 is shown
isolated in FIG. 8.
[0036] The spring probe 210 can include a detent 216 in a barrel
211 to interface with a capture feature 217 of a second plunger
portion 214 of a plunger 212 to maintain the plunger 212 at least
partially within the barrel 211. The second plunger portion 214 and
the detent 216 can be configured to provide a suitable range of
motion for the plunger 212 relative to the barrel 211. The spring
probe 210 can also include a capture feature 218, such as a flange
on the barrel 211, to capture or retain the spring probe with the
spring probe support members 220, 222. The spring probe support
member 220 can include one or more recesses 223, such as a counter
bore. The recess 223 can be configured to accommodate the capture
features 218b-g on the barrels 211b-g of the outer conductor 202
spring probes 210b-g, as shown in FIG. 6. The spring probe support
member 222 can have an inner diameter 224 configured to provide a
mechanical interference with the capture features 218b-g of the
barrels 211b-g in the recess 223, which can limit a range of motion
for the barrels relative to the support member 220 and capture or
retain the spring probes 210b-g of the outer conductor 202 with the
spring probe support members 220, 222. The spring probe support
member 222 can also have an end 225 with alignment openings 226a-g
configured to receive the first plunger portions 213b-g of the
spring probes 210b-g of the outer conductor 202 and the barrel 211a
of the spring probe 210a of the inner conductor 201. The openings
226a-g can be sized to allow movement of the first plunger portions
213b-g and the barrel 211a relative to the spring probe support
member 222 during compression of the interconnect 200, while
providing adequate mechanical support for lateral deflection of the
spring probes 210a-g. The opening 226a for the barrel 211a can also
be configured to provide a mechanical interference with the capture
feature 218a of the barrel 211a to capture or retain the spring
probe 210a of the inner conductor 201 with the spring probe support
members 220, 222. In one aspect, an outer portion or surface of the
spring probe support member 220 and/or the spring probe support
member 222 can comprise an overloading type of dielectric material
(e.g., metalized plastic) to create a ground shield around the
spring probes 210a-g.
[0037] The presence of the spring probe capture features 218a-g may
introduce a slight impedance mismatch. For example, the flanges on
the barrels 211a-g as well as the spring probe support member 222
can introduce material that can cause local variations in the
nominal impedance of a given region. As mentioned above, these
local variations in impedance can be reduced or minimized depending
on the application to acceptable levels. For example, the
interconnect 200 can be fine-tuned for higher frequency
applications by including local diameter expansions 219a and/or
contractions 219b in adjacent components to offset the presence or
absence of material in a neighboring component (e.g., detent 216a
and capture feature 218a). In one aspect, a material, such as a
dielectric material, can be included strategically to address local
impedance variations. As shown in FIGS. 6 and 7, the spring probe
support member 222 can be hollowed out with a minimal amount of
material at the end 225 to provide mechanical support for the
spring probes 210a-g. In one aspect, the spring probe support
member 222 can be configured with holes, suitable material type,
etc. to approximate the resistance of air so that impedance is
maintained within acceptable levels locally.
[0038] FIG. 9 illustrates a schematic cross-sectional view of a
coaxial electrical interconnect 300 in accordance with yet another
example of the present disclosure. The coaxial electrical
interconnect 300 includes many similarities to the coaxial
electrical interconnects 100 and 200 discussed above. In this
example, the electrical interconnect 300 is configured with spring
probes 310a-g that are double-ended, whereas the spring probes of
the electrical interconnects 100 and 200 are single-ended. Thus,
the spring probes 310a-g can compress independently on opposite
ends of the interconnect 300. In this case, the spring probe 310a
of an inner conductor 301 comprises two barrels 311a, 311a'
oriented on opposite ends of a plunger 312a, and the spring probes
310b-g of an outer conductor 302 comprise two plungers 312b-g,
312b'-g' oriented on opposite ends of a barrel 311b-g. The spring
probes 310a-g utilized in this example therefore are not all alike
or identical. The result of such a configuration is five different
regions 341-345, each of which can be configured to have a given
nominal characteristic impedance, as described herein. It should be
recognized that any suitable number of different regions can be
utilized.
[0039] In accordance with one embodiment of the present invention,
a method for facilitating a matched impedance electrical connection
is disclosed. The method can comprise providing a coaxial
electrical interconnect, having an inner conductor including an
electrically conductive spring probe, and an outer conductor
including a plurality of electrically conductive spring probes
disposed about the inner conductor, each spring probe having a
barrel and a plunger biased out of the barrel, the plunger having a
first plunger portion external to the barrel and a second plunger
portion disposed partially in the barrel, the first and second
plunger portions having different diameters, wherein a barrel of
the spring probe of the inner conductor is located proximate a
plunger of at least one of the spring probes of the outer
conductor. Additionally, the method can comprise facilitating a
constant characteristic impedance of the electrical interconnect as
the plungers move relative to the barrels. In one aspect of the
method, facilitating a constant characteristic impedance can
comprise sizing the first plunger portion of the spring probe of
the inner conductor and the barrels of the spring probes of the
outer conductor with substantially equal lengths. It is noted that
no specific order is required in this method, though generally in
one embodiment, these method steps can be carried out
sequentially.
[0040] It is to be understood that the embodiments of the invention
disclosed are not limited to the particular structures, process
steps, or materials disclosed herein, but are extended to
equivalents thereof as would be recognized by those ordinarily
skilled in the relevant arts. It should also be understood that
terminology employed herein is used for the purpose of describing
particular embodiments only and is not intended to be limiting.
[0041] Reference throughout this specification to "one embodiment"
or "an embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the present invention. Thus,
appearances of the phrases "in one embodiment" or "in an
embodiment" in various places throughout this specification are not
necessarily all referring to the same embodiment.
[0042] As used herein, a plurality of items, structural elements,
compositional elements, and/or materials may be presented in a
common list for convenience. However, these lists should be
construed as though each member of the list is individually
identified as a separate and unique member. Thus, no individual
member of such list should be construed as a de facto equivalent of
any other member of the same list solely based on their
presentation in a common group without indications to the contrary.
In addition, various embodiments and example of the present
invention may be referred to herein along with alternatives for the
various components thereof. It is understood that such embodiments,
examples, and alternatives are not to be construed as de facto
equivalents of one another, but are to be considered as separate
and autonomous representations of the present invention.
[0043] Furthermore, the described features, structures, or
characteristics may be combined in any suitable manner in one or
more embodiments. In the description, numerous specific details are
provided, such as examples of lengths, widths, shapes, etc., to
provide a thorough understanding of embodiments of the invention.
One skilled in the relevant art will recognize, however, that the
invention can be practiced without one or more of the specific
details, or with other methods, components, materials, etc. In
other instances, well-known structures, materials, or operations
are not shown or described in detail to avoid obscuring aspects of
the invention.
[0044] While the foregoing examples are illustrative of the
principles of the present invention in one or more particular
applications, it will be apparent to those of ordinary skill in the
art that numerous modifications in form, usage and details of
implementation can be made without the exercise of inventive
faculty, and without departing from the principles and concepts of
the invention. Accordingly, it is not intended that the invention
be limited, except as by the claims set forth below.
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