U.S. patent application number 11/529251 was filed with the patent office on 2007-04-19 for meter antenna.
Invention is credited to Robert Hugo De Angelis.
Application Number | 20070085750 11/529251 |
Document ID | / |
Family ID | 34226304 |
Filed Date | 2007-04-19 |
United States Patent
Application |
20070085750 |
Kind Code |
A1 |
De Angelis; Robert Hugo |
April 19, 2007 |
Meter antenna
Abstract
The antenna configuration presented is an integral component of
a retrofit module designed to incorporate a data telemetry
transceiver within the confines of a utility meter.
Inventors: |
De Angelis; Robert Hugo;
(Burnaby, CA) |
Correspondence
Address: |
Patent Dept. / Tantalus Systems Corp.
100-2955 Virtual Way
Vancouver
BC
V5M 4X6
CA
|
Family ID: |
34226304 |
Appl. No.: |
11/529251 |
Filed: |
September 29, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10656279 |
Sep 8, 2003 |
7129900 |
|
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11529251 |
Sep 29, 2006 |
|
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Current U.S.
Class: |
343/767 ;
343/702 |
Current CPC
Class: |
H01Q 21/29 20130101;
H01Q 13/10 20130101; H01Q 1/2233 20130101; H01Q 1/42 20130101 |
Class at
Publication: |
343/767 ;
343/702 |
International
Class: |
H01Q 13/10 20060101
H01Q013/10 |
Claims
1. A method for use with differing metallic infrastructures of
resource-measuring meters, to minimize the effects on the
performance of a first RF radiating/receiving element located
within one such infrastructure due to its interactions with said
such one infrastructure, comprising the step of placing a first
metallic structure physically closer to said first RF
radiating/receiving element than said such one infrastructure
is.
2. The method of claim 1, comprising the additional steps of (i)
placing a second RF radiating/receiving element within said one
such infrastructure and (ii) placing a second metallic structure
physically closer to said second RF radiating/receiving element
than said such one infrastructure is
3. The method of claim 1, wherein said placing of first and second
metallic structures is performed to effect cooperative RF
performance of said first and second antennas.
4. The method of claim 2, wherein said placing of first and second
metallic structures is performed to effect cooperative RF
performance of said first and second antennas.
5. The method of claim 1, wherein the cooperative performance is
achieved by locating said first and second metallic structures so
that the dominant null of the first RF radiating/receiving element
is mitigated by the second RF radiating/receiving element.
6. The method of claim 2, wherein the cooperative performance is
achieved by locating said first and second metallic structures so
that the dominant null of the first RF radiating/receiving element
is mitigated by the second RF radiating/receiving element.
7. The method of claim 3, wherein the cooperative performance is
achieved by locating said first and second metallic structures so
that the dominant null of the first RF radiating/receiving element
is mitigated by the second RF radiating/receiving element.
8. The method of claim 4, wherein the cooperative performance is
achieved by locating said first and second metallic structures so
that the dominant null of the first RF radiating/receiving element
is mitigated by the second RF radiating/receiving element.
9. The method of claim 1, wherein said placing of first metallic
structure includes (a) the supporting of said first metallic
structure with a supporter having dielectric properties that do not
adversely affect the performance of said first RF
radiating/receiving element and (b) the shaping of said supporter
to maximize the amount of surface space for supporting said first
metallic structure.
10. The method of claim 2, wherein said placing of first metallic
structure includes (a) the supporting of said first metallic
structure with a supporter having dielectric properties that do not
adversely affect the performance of said first RF
radiating/receiving element and (b) the shaping of said supporter
to maximize the amount of surface space for supporting said first
metallic structure.
11. The method of claim 3, wherein said placing of first metallic
structure includes (a) the supporting of said first metallic
structure with a supporter having dielectric properties that do not
adversely affect the performance of said first RF
radiating/receiving element and (b) the shaping of said supporter
to maximize the amount of surface space for supporting said first
metallic structure.
12. The method of claim 4, wherein said placing of first metallic
structure includes (a) the supporting of said first metallic
structure with a supporter having dielectric properties that do not
adversely affect the performance of said first RF
radiating/receiving element and (b) the shaping of said supporter
to maximize the amount of surface space for supporting said first
metallic structure.
13. The method of claim 5, wherein said placing of first metallic
structure includes (a) the supporting of said first metallic
structure with a supporter having dielectric properties that do not
adversely affect the performance of said first RF
radiating/receiving element and (b) the shaping of said supporter
to maximize the amount of surface space for supporting said first
metallic structure.
14. The method of claim 6, wherein said placing of first metallic
structure includes (a) the supporting of said first metallic
structure with a supporter having dielectric properties that do not
adversely affect the performance of said first RF
radiating/receiving element and (b) the shaping of said supporter
to maximize the amount of surface space for supporting said first
metallic structure.
15. The method of claim 7, wherein said placing of first metallic
structure includes (a) the supporting of said first metallic
structure with a supporter having dielectric properties that do not
adversely affect the performance of said first RF
radiating/receiving element and (b) the shaping of said supporter
to maximize the amount of surface space for supporting said first
metallic structure.
16. The method of claim 8, wherein said placing of first metallic
structure includes (a) the supporting of said first metallic
structure with a supporter having dielectric properties that do not
adversely affect the performance of said first RF
radiating/receiving element and (b) the shaping of said supporter
to maximize the amount of surface space for supporting said first
metallic structure.
17. An RF telemetry unit for use with resource-measuring meters
having differing metallic infrastructures, comprising: (a) a first
RF radiating/receiving element locatable within one such
infrastructure; and (b) a first metallic structure located
physically closer to said first RF radiating/receiving element than
any said one such infrastructure is when said first RF
radiating/receiving element is located within said one such
infrastructure.
18. The unit of claim 17, further comprising: (d) a second RF
radiating/receiving element locatable within one such
infrastructure; (e) a second metallic structure placed physically
closer to said second RF radiating/receiving element than said one
such infrastructure is when said second RF radiating/receiving
element is located within said one such infrastructure.
19. The unit of claim 17, wherein said first and second metallic
structures are located to effect cooperative RF performance of said
first and second radiating/receiving elements.
20. The unit of claim 19, wherein the cooperative RF performance is
achieved by locating said first and second radiating/receiving
elements so that the dominant null of said first
radiating/receiving element is mitigated by said second
radiating/receiving element.
Description
NOTICE REGARDING COPYRIGHTED MATERIAL
[0001] A portion of the disclosure of this patent document contains
material which is subject to copyright protection. The copyright
owner has no objection to the facsimile reproduction by anyone of
the patent document or the patent disclosure as it appears in the
Patent and Trademark Office file or records, but otherwise reserves
all copyright rights whatsoever.
FIELD OF THE INVENTION
[0002] This invention relates to antennas for use with utility
meters.
BACKGROUND OF THE INVENTION
[0003] Antenna performance parameters such as efficiency,
radiation/reception pattern, and resonant frequency are affected
when the antenna is placed in the vicinity of metallic
infrastructures. The incumbent or resident metallic infrastructures
in conventional electromechanical utility meters (such as GE
Watthour Meter 1-70-S and ABB AB-1) greatly affect the performance
parameters of conventional half-wave dipole or quarter-wave whip
antennas when such antennas are incorporated within the confines of
a conventional meter. The interactions between the metallic
infrastructure in a conventional meter and such conventional
antennas are highly sensitive in the sense that the difference in
the metallic infrastructures themselves between different meter
models is sufficient to cause inconsistent antenna performance. The
goal of the invention is to increase the stability and efficiency
of antenna performance over many meter types.
SUMMARY OF THE INVENTION
[0004] There is provided an antenna arrangement for a conventional
utility meter having a cover and metallic infrastructure plus RF
communications capability, comprising a slot antenna formed to fit
under the cover and cooperating with said RF communications
capability.
[0005] There is also provided a method of managing the varying
effects of differing incumbent metallic infrastructures on the
performance of a radiating/receiving element of an antenna,
comprising the steps of inserting a metallic structure closer to
the radiating/receiving element than the incumbent metallic
infrastructure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] A better understanding of the present invention can be
obtained when the following detailed description of the preferred
embodiment is considered in conjunction with the following
drawings, in which:
[0007] FIG. 1 shows an exploded view of a RF retrofit module with
the slot antenna of the present invention.
[0008] FIG. 2 shows the slot antenna of the present invention,
formed to the contour of the RF retrofit module.
[0009] FIG. 3 shows the actual dimensions of the slot antenna of
the preferred embodiment.
[0010] FIG. 4 shows a view complementary to that of FIG. 1.
[0011] FIG. 5 shows a front perspective, partially broken away view
of a meter with the RF retrofit module that includes the antenna
invention installed.
[0012] FIG. 6 shows a view complementary to that of FIG. 5.
[0013] All drawings are drawn for ease of explanation of the basic
teachings of the present invention only; the extensions of the
drawings with respect to number, position, relationship, and
dimensions of the parts to form the preferred embodiment will be
explained or will be within the skill of the art after the
following teachings of the present invention have been read and
understood. Further, the exact dimensions and dimensional
proportions to conform to specific force, weight, strength, RF
performance and similar requirements will likewise be within the
skill of the art after the following teachings of the present
invention have been read and understood.
[0014] Where used in the various drawings, the same numerals
designate the same or similar parts. Furthermore, when the terms
"top", "bottom", "first", "second", "inside", "outside", "edge",
"side", "front", "back", "length", "width", "inner", "outer", and
similar terms are used herein, it should be understood that these
terms have reference only to the structure shown in the drawings as
it would appear to a person viewing the drawings and are utilized
only to facilitate describing the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] With reference to FIGS. 1 and 2, a conventional meter 100
houses electro-mechanical (incumbent or resident) metallic
infrastructures (consisting of gears, brackets, prongs, tumblers,
disks, rivets and the like, identified generally as 140) enclosed
by a transparent (typically glass or plastic) cover 90. Herein, the
term "metallic infrastructure" is meant to describe the (resident
or incumbent) metallic infrastructure 140 whereas the term
"metallic structure" is meant to describe the contribution of the
present invention.
[0016] As seen in FIGS. 1 and 2, the present invention teaches the
use of a slot antenna 10 and 20 with a RF retrofit module 40 that
is placed within meter 100 under the cover 90. RF retrofit module
40 has transceiver assembly 70 and is shaped to be attached to the
resident metallic infrastructure 140 of meter 100. Details of
quarter-wave slot 125 in antennas 10 and 20 are explained below.
The fully assembled version of the exploded view of FIGS. 1-2, is
shown in FIGS. 5-6.
[0017] Those skilled in the art realize that an efficient antenna
that is insensitive to meter incumbent metallic infrastructures
placed in its vicinity, faces conflicting requirements. In the
present invention, the quarter-wave radiating/receiving RF slot 125
is inherently adjacent to the metallic structure of brass sheet 115
it is cut out of. Thus the metallic infrastructure 140 of the
conventional meter 100 is (compared to the metallic structure of
brass sheet 115) relatively "far" away from the slot 125, resulting
in an antenna that is less sensitive to de-tuning when compared to
the aforementioned conventional antennas.
[0018] Cover 90 is typically frusto-conical (as the result of
conventional manufacturing processes). RF retrofit module 40 is
pre-formed and shaped accordingly as a smaller frusto-cone to fit
under cover 90. The brass sheet 115 of antennas 10 and 20 is
required to fit snugly over the frusto-cononical outer surface of
RF retrofit module 40 and under cover 90, as seen in FIGS. 1,4-6
and so is correspondingly frusto-conical itself and is dimensioned
to fit over as much of the outer surface RF retrofit module 40 as
physically allowed thereby under cover 90.
[0019] Mounting holes 110 and 120 in antennas 10 and 20 are
elongated to allow for thermal expansion and contraction over the
expected operating temperature range of the antennas 10 and 20.
Antenna 10 is attached to the RF retrofit module 40 with four
plastic rivets 30 inserted through the mounting holes 110 and 120
in FIG. 3 and through the corresponding mounting holes 80 in the RF
retrofit module 40. The plastic rivets 30 are heat-staked to
complete the fastening.
[0020] Antenna 10 is pre-formed to snugly fit the contour of part
of the outer surface of the RF retrofit module 40 as shown in FIG.
2. In the same fashion the complementary, pre-formed antenna 20 is
attached to another part of the outer surface of the RF retrofit
module 40. Antenna 10 is coupled to the transceiver assembly 70 via
coaxial cable 50. Coaxial cable 50 is soldered to the transceiver
assembly 70 at a transceiver coupling point. The other end of
coaxial cable 50 is soldered to antenna 10 as per the detail A in
FIG. 3 at points 130. In the same fashion antenna 20 is coupled to
the transceiver assembly 70 via coaxial cable 60. The fully
assembled RF retrofit module 40 is fastened to meter 100 (by
conventional means like screws or snap/friction fit) and enclosed
by the cover 90.
[0021] The RF radiation/reception pattern of antenna 10 is
perturbed to some degree when incorporated into the meter 100.
Accordingly, in the preferred embodiment, two slot antennas 10 and
20 are used and are placed offset from the center of the outer
surface of the retrofit module 40 as explained above. The resultant
dominant null in the RF radiation/reception pattern for each of
antennas 10 and 20 occurs at different azimuths such that one
antenna mitigates the null of the other. The selection of antenna
10 and 20 is conventionally performed by the transceiver assembly
70 where the selection is made by assessing the quality of the
received signal for each antenna in the actual operating
environment. As such, a switched-diversity antenna is implemented.
Alternatively, as a function of the capabilities of transceiver
assembly 70, both antennas 10 and 20 may be active to perform
transceive functions.
[0022] Antenna 10 and 20 are made of hard brass material of about 8
mil thickness. The brass material is selected for its oxidation and
solderability properties that are favourable for the environment
which the antennas are intended to operate in (e.g. hot and humid
climates which would result in considerable heat and humidity under
cover 90). In other environments, copper and stainless steel would
suffice, as a matter of routine design choice.
[0023] FIG. 3 shows the dimensions of antenna 10 (including those
of slot 125) in millimeters for a resonant frequency of 915 MHz in
the preferred embodiment, with details on the coupling points that
gives the best return loss in a 50 ohm system. Those skilled in the
art could scale the dimensions to operate at other frequencies for
maximum effectiveness.
[0024] RF retrofit module 40 has a housing or frame made of
polycarbonate plastic or other like material with dielectric
properties that may be advantageous (e.g. fibreglass). RF Retrofit
module 40 has transceiver assembly 70 placed as far away as
possible relative to the slot antenna 10 and 20.
[0025] An alternative embodiment of the invention (not shown) uses
one single slot antenna. The dimensions of this alternative antenna
would remain about the same as for antenna 10 or 20 but its
location on the surface of the RF retrofit module 40 would change
so that the (longitudinal) center of its slot 125 would align with
the top or twelve o'clock position of the RF retrofit module 40 and
accordingly that of the meter 100.
[0026] An alternative embodiment of the invention (not shown) uses
three slot antennas, appropriately sized, to cover the available
surface area of the RF retrofit module 40. Depending on the
intended application and environment, three antennas are identical
in size and shape and are equi-spaced and uniformly orientated on
the surface area of RF retrofit module 40, or they may be of
differing sizes, shapes and orientations. The variations can be
accomplished easily by the empirical means (e.g. experimentation
for the intended application and environment with consequent design
(of shape, size, orientation)).
[0027] For these alternative (single or more than two slot
antennas) embodiments, the transceiver assembly 70 of the preferred
embodiment (for two antennas 10 and 20), and any upstream
application, would be adapted and programmed conventionally to
accommodate the single path or the switching of the multiple
antenna paths, as the case may be.
[0028] Although the preferred and alternative embodiments have been
given in the context of a conventional utility meter, the present
invention is not limited to such contexts. The present invention
teaches that incumbent or resident metallic infrastructures which
are problematic because they vary from (conventional meter) model
to model, can be substantially "tamed" by inserting a metallic
structure that becomes more "dominant" than the incumbent or
resident "adjacent" metallic infrastructure because of its closer
proximity to the RF radiating/receiving element of the subject
antenna. This more "dominant" metallic structure is more manageable
than the varying incumbent or resident metallic infrastructures
because its effects are more uniform and thus predictable.
[0029] Although the method and apparatus of the present invention
has been described in connection with the preferred embodiment, it
is not intended to be limited to the specific form set forth
herein, but on the contrary, it is intended to cover such
alternatives, modifications, and equivalents, as can be reasonably
included within the spirit and scope of the invention as defined by
the appended claims.
* * * * *