CA2862457A1 - Device and method for transforming a manhole cover as a bidirectional antenna without making any modification at the manhole cover - Google Patents
Device and method for transforming a manhole cover as a bidirectional antenna without making any modification at the manhole cover Download PDFInfo
- Publication number
- CA2862457A1 CA2862457A1 CA2862457A CA2862457A CA2862457A1 CA 2862457 A1 CA2862457 A1 CA 2862457A1 CA 2862457 A CA2862457 A CA 2862457A CA 2862457 A CA2862457 A CA 2862457A CA 2862457 A1 CA2862457 A1 CA 2862457A1
- Authority
- CA
- Canada
- Prior art keywords
- antenna
- manhole cover
- manhole
- coupling element
- cover
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D29/00—Independent underground or underwater structures; Retaining walls
- E02D29/12—Manhole shafts; Other inspection or access chambers; Accessories therefor
- E02D29/14—Covers for manholes or the like; Frames for covers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/44—Details of, or arrangements associated with, antennas using equipment having another main function to serve additionally as an antenna, e.g. means for giving an antenna an aesthetic aspect
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
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- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Details Of Aerials (AREA)
- Underground Structures, Protecting, Testing And Restoring Foundations (AREA)
Abstract
An antenna coupling device for transforming a manhole metallic cover use in municipality sewer system as a bidirectional radio frequency antenna without making any physical modification to the said manhole metallic cover. More specifically, an antenna coupling device located within one of the ventilation hole of the manhole cover that capacitively and inductively couple within the near-field to the ventilation hole surrounding metal that further couple to the entire manhole metallic upper and lower metal surface. Such coupling method resulting in an overall antenna radiation pattern and gain that is much less sensitive to the manhole metallic cover upper surface accumulation of snow, salty water and debris conditions.
Description
DEVICE AND METHOD FOR TRANSFORMING A MANHOLE COVER
AS A BIDIRECTIONAL ANTENNA
WITHOUT MAKING ANY MODIFICATION AT THE MANHOLE COVER
FIELD OF THE INVENTION
This invention relates to a device and method for transforming a sewer metallic manhole cover as a bidirectional communication antenna, independent of the geometry of the manhole, allowing electronic devices positioned inside the sewer to communicate externally bringing sewer sensing data into the Internet cloud.
BACKGROUND OF THE INVENTION
With the recent changes in global weather, aged municipality sewer systems are often stressed beyond designed capacities, causing increases in waste water overflow. Such waste water overflow needs to be monitored in a number of events, volume per event, etc.
Such a monitoring system, must relay the monitored sensors data to a database allowing remote data processing.
Current monitoring systems either require a human to physically access the sewer sensors to retrieve the recorded data or to transmit the data using hardwire or by wireless means.
Wireless mean presents ease of installation but suffers from strong radio frequency (RF) absorption by from the medium surrounding the manhole. Current techniques to surpass such strong RF absorption use external antenna positioned nearby the manhole exit.
Current antenna technologies are often embedded in the pavement surrounding the manhole exit or they are simply mounted on the surface of manhole cover or surrounding pavement. The use of such antenna is restricted to none Nordic environment, where the passage of snowplows restrict mounting any antenna, even low-profile antenna, on any surface. In addition the buildup of ice or the use of ice melting salt degrades the efficiency of any embedded antenna.
, This allows the development of an antenna that takes advantage of the manhole cover.
Current techniques replace the entire metallic manhole cover by a RF
transparent composite material. Similar techniques partially replace a section of a metallic cover with RF transparent material, making an RF window. Other more complex techniques require physical modification of the manhole cover to engrave an antenna.
Every one of the current techniques either calls for physical modifications of the manhole cover or the installation of low-profiled or embedded antenna.
PRIOR ART
There is two different kind of antenna described in the literature. They are either surface mount low profile antenna mounted on the street side of the manhole cover or a physical modification of the metal manhole cover structure to either insert a RF
transparent section or to machine a slot into the metal structure.
US patent application 20120206270 Al entitled "Manhole cover type sensor node apparatus" present the most complex solution grouping two antennas, one on either side of the manhole cover.
One example of manhole cover fabricated in hole or in part with RF transparent material: Elan Technologies Inc., New Lenox, IL, USA, claims the introduction of a unique solution for monitoring sewers using a composite cover that functions as a bi-polar antenna for manholes to communicate with below grade instrumentation.
Two example of machined manhole cover: 1) The recent, 2013, IEEE Antenna and Propagation Society publication, entitled "A Cavity-backed Slot Antenna with High Upper Hemisphere Efficiency for Sewer Sensor Network" , by Dr Seongheon Jeong, et al, Purdue University, presents an exhausted reference. 2) J. F. Mastarone and W.
J. Chappell presented "Urban sensor networking using thick slots in manhole covers," IEEE Antennas and Propagation Society International Symposium, Page:
779-782, 2006. This is a conventional cast-iron manhole cover studied and converted to a thick slot antenna. The slot is implemented by milling the thick cast-
AS A BIDIRECTIONAL ANTENNA
WITHOUT MAKING ANY MODIFICATION AT THE MANHOLE COVER
FIELD OF THE INVENTION
This invention relates to a device and method for transforming a sewer metallic manhole cover as a bidirectional communication antenna, independent of the geometry of the manhole, allowing electronic devices positioned inside the sewer to communicate externally bringing sewer sensing data into the Internet cloud.
BACKGROUND OF THE INVENTION
With the recent changes in global weather, aged municipality sewer systems are often stressed beyond designed capacities, causing increases in waste water overflow. Such waste water overflow needs to be monitored in a number of events, volume per event, etc.
Such a monitoring system, must relay the monitored sensors data to a database allowing remote data processing.
Current monitoring systems either require a human to physically access the sewer sensors to retrieve the recorded data or to transmit the data using hardwire or by wireless means.
Wireless mean presents ease of installation but suffers from strong radio frequency (RF) absorption by from the medium surrounding the manhole. Current techniques to surpass such strong RF absorption use external antenna positioned nearby the manhole exit.
Current antenna technologies are often embedded in the pavement surrounding the manhole exit or they are simply mounted on the surface of manhole cover or surrounding pavement. The use of such antenna is restricted to none Nordic environment, where the passage of snowplows restrict mounting any antenna, even low-profile antenna, on any surface. In addition the buildup of ice or the use of ice melting salt degrades the efficiency of any embedded antenna.
, This allows the development of an antenna that takes advantage of the manhole cover.
Current techniques replace the entire metallic manhole cover by a RF
transparent composite material. Similar techniques partially replace a section of a metallic cover with RF transparent material, making an RF window. Other more complex techniques require physical modification of the manhole cover to engrave an antenna.
Every one of the current techniques either calls for physical modifications of the manhole cover or the installation of low-profiled or embedded antenna.
PRIOR ART
There is two different kind of antenna described in the literature. They are either surface mount low profile antenna mounted on the street side of the manhole cover or a physical modification of the metal manhole cover structure to either insert a RF
transparent section or to machine a slot into the metal structure.
US patent application 20120206270 Al entitled "Manhole cover type sensor node apparatus" present the most complex solution grouping two antennas, one on either side of the manhole cover.
One example of manhole cover fabricated in hole or in part with RF transparent material: Elan Technologies Inc., New Lenox, IL, USA, claims the introduction of a unique solution for monitoring sewers using a composite cover that functions as a bi-polar antenna for manholes to communicate with below grade instrumentation.
Two example of machined manhole cover: 1) The recent, 2013, IEEE Antenna and Propagation Society publication, entitled "A Cavity-backed Slot Antenna with High Upper Hemisphere Efficiency for Sewer Sensor Network" , by Dr Seongheon Jeong, et al, Purdue University, presents an exhausted reference. 2) J. F. Mastarone and W.
J. Chappell presented "Urban sensor networking using thick slots in manhole covers," IEEE Antennas and Propagation Society International Symposium, Page:
779-782, 2006. This is a conventional cast-iron manhole cover studied and converted to a thick slot antenna. The slot is implemented by milling the thick cast-
2 iron manhole cover. The antenna is not fully protected from the loads and harsh environment of the road bed.
Three examples of commercially available manhole antenna are: 1) Teledyne Technologies Incorporated, Lincoln, NE, USA, 2103Gi module, in-street antenna model 68-2000-086 and manhole cover antenna model 68-2000-088. 2) Hach Company, Loveland, CO, USA, Traffic rated manhole lid GSM quad, 5255400 and Traffic rated in-road/burial antenna GSM dual 6683000. 3) Optimum Instruments Inc., Edmonton Alberta, Canada, Digital Cellular (ANT-ML-8619), ISM Spread Spectrum (ANT-ML-902), and Bluetooth, Wifi, ZigBee (ANT-ML-2400).
The closest one to this invention will be the one that machine a slot into the cover using the cover as the ground plane. In addition to the disadvantage of having to modify the cover, this slotted type antenna will only operate at one frequency, whereas GSM must function at 4 bands.
Therefore, the main advantages of this invention are: no modification of the cover, easy to install, works on any type of cover (as long as there is 1 inch, approximately, diameter hole) and bi-directional radiation pattern.
SUMMARY OF THE INVENTION
According to the present invention there is provided a method of transforming the metallic manhole cover into a wireless RE antenna, as is, without any modification, neither to the manhole cover, nor to the manhole cover ring, or to the pavement surrounding the manhole exit point.
Thus, in accordance with one aspect of the invention, the body of the metallic manhole cover, for example, a manhole cover that has one or more holes is used as an antenna for the 2.45GHz ISM (Instrumentation, Scientific and Medical) band. In particular, the opening formed between the circumference of the hole of the manhole cover and the
Three examples of commercially available manhole antenna are: 1) Teledyne Technologies Incorporated, Lincoln, NE, USA, 2103Gi module, in-street antenna model 68-2000-086 and manhole cover antenna model 68-2000-088. 2) Hach Company, Loveland, CO, USA, Traffic rated manhole lid GSM quad, 5255400 and Traffic rated in-road/burial antenna GSM dual 6683000. 3) Optimum Instruments Inc., Edmonton Alberta, Canada, Digital Cellular (ANT-ML-8619), ISM Spread Spectrum (ANT-ML-902), and Bluetooth, Wifi, ZigBee (ANT-ML-2400).
The closest one to this invention will be the one that machine a slot into the cover using the cover as the ground plane. In addition to the disadvantage of having to modify the cover, this slotted type antenna will only operate at one frequency, whereas GSM must function at 4 bands.
Therefore, the main advantages of this invention are: no modification of the cover, easy to install, works on any type of cover (as long as there is 1 inch, approximately, diameter hole) and bi-directional radiation pattern.
SUMMARY OF THE INVENTION
According to the present invention there is provided a method of transforming the metallic manhole cover into a wireless RE antenna, as is, without any modification, neither to the manhole cover, nor to the manhole cover ring, or to the pavement surrounding the manhole exit point.
Thus, in accordance with one aspect of the invention, the body of the metallic manhole cover, for example, a manhole cover that has one or more holes is used as an antenna for the 2.45GHz ISM (Instrumentation, Scientific and Medical) band. In particular, the opening formed between the circumference of the hole of the manhole cover and the
3 antenna coupling element form the desired antenna. In this case, being symmetrical in reference to the manhole cover, the radiation pattern of such desired antenna is bidirectional.
As an added benefit, the radiation pattern is quasi omnidirectional (+/-3dB
maximum) and independent of both, the dimension and shape of the hole and the positioning of the hole within the manhole cover hole geometry.
In a rare alternative embodiment, when a manhole cover does not have any hole, a 1 inch hole can be made on the cover.
As in the case of wireless RF communication system, the same embodiment applies at frequencies similar to the 2450MHz ISM band, that are GSM quad band (850, 900, and 1900 MHz), 902-928MHz ISM band and 1610-1626.5MHz Iridium satellite band.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:-Figure 1 is a picture of the manhole cover showing to the right the antenna coupling device (in black), held in place with foam (in blue).
Figure 2 is a close view of figure 1.
Figure 3 is a picture of the manhole cover positioned in the street. A foam (in blue) cover hides the antenna coupling device.
Figure 4 shows a 3D view of the radiation pattern at 2450MHz obtained using FDTD
computer modeling of a manhole cover extended approximately lmeter below grade with concrete.
Figure 5 shows a 3D view of the radiation pattern at 2450MHz obtained using FDTD
computer modeling of a manhole cover surrounding with the cover rim.
As an added benefit, the radiation pattern is quasi omnidirectional (+/-3dB
maximum) and independent of both, the dimension and shape of the hole and the positioning of the hole within the manhole cover hole geometry.
In a rare alternative embodiment, when a manhole cover does not have any hole, a 1 inch hole can be made on the cover.
As in the case of wireless RF communication system, the same embodiment applies at frequencies similar to the 2450MHz ISM band, that are GSM quad band (850, 900, and 1900 MHz), 902-928MHz ISM band and 1610-1626.5MHz Iridium satellite band.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:-Figure 1 is a picture of the manhole cover showing to the right the antenna coupling device (in black), held in place with foam (in blue).
Figure 2 is a close view of figure 1.
Figure 3 is a picture of the manhole cover positioned in the street. A foam (in blue) cover hides the antenna coupling device.
Figure 4 shows a 3D view of the radiation pattern at 2450MHz obtained using FDTD
computer modeling of a manhole cover extended approximately lmeter below grade with concrete.
Figure 5 shows a 3D view of the radiation pattern at 2450MHz obtained using FDTD
computer modeling of a manhole cover surrounding with the cover rim.
4 Figure 6 shows a 2D view of the radiation pattern. The green and the red lines represent radiation pattern coverage, 0 is toward the sky and 180' is toward the bottom (into the hole).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In figures 1, 2 and 3, the antenna coupling element is centered within one of multiple holes of the manhole cover. Since the optimum position of the antenna coupling element is also centered within the axis of the hole, and is combined to an antenna coupling element with length shorter than the manhole cover thickness, this design allows the street side end of the antenna coupling element to be recessed from the manhole cover surface. This is the main design feature of the invention taking advantage of the relatively large thickness of the manhole cover, often made of cast iron.
Not shown in any figure, for the one band 2450 MHz frequency application, the antenna coupling element takes the form of a spiral wire antenna with the overall length shorter than the manhole cover thickness. Also not shown in any figure, for the quad band GSM
(850, 900, 1800 and 1900 MHz) frequency application, the antenna coupling element takes the form of a PCB (Printed Circuit Board) antenna with a meandering line for the low band (850 and 900 MHz) frequencies needed to restrict the overall length of the PCB
antenna shorter than the manhole cover thickness.
In figures 4, 5 and 6, the coupling element antenna is an elementary dipole antenna inserted into the air holes of the manhole cover. The manhole cover thickness is 1 inch with 3/4 inch diameter holes. It's computed impedance is Z-24-j5 ohm, that is a low Z-match at resonance. The radiation loss (RL) factor is -8dB with more than 80%
efficiency.
The 3 dimensions of the electric field above and below the manhole metal cover is given in figure 4. It provides sufficient coverage in the X & Y plane, the Z plane dominates with a nominal gain factor of -5dB. The manhole cover is positioned on a concrete stack.
Likewise in figure 4, the three dimensions of the electric field above and below the manhole metal cover positioned on the metal ring is given in figure 5. Here too it provides sufficient coverage in the X & Y plane.
Five prototypes were built using a spiral wire coupling element at 2450 MHz.
Two prototypes were built using a PSB quad band GSM coupling element at 850, 900, 1800 and 1900 MHz.
Field tests revealed that the signal strength radiating on the street side averaged 10dB
stronger than the signal strength radiating below grade. Tests were then performed to determine uniformity of the signal strength. Field tests revealed that the signal strength radiating on both sides of the manhole cover is omnidirectional with less than +/- 3dB
variation. In addition, field testing also revealed that the overall variation is less than +/-6dB with random orientation of the manhole cover over its metal ring.
Other preferred embodiments:
A further application of the invention also applies when the manhole cover thickness is less than the length of the antenna coupling element. In such case, a metal alloy pipe is inserted inside the manhole cover hole to extend the overall manhole thickness beyond the length of the antenna coupling element.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In figures 1, 2 and 3, the antenna coupling element is centered within one of multiple holes of the manhole cover. Since the optimum position of the antenna coupling element is also centered within the axis of the hole, and is combined to an antenna coupling element with length shorter than the manhole cover thickness, this design allows the street side end of the antenna coupling element to be recessed from the manhole cover surface. This is the main design feature of the invention taking advantage of the relatively large thickness of the manhole cover, often made of cast iron.
Not shown in any figure, for the one band 2450 MHz frequency application, the antenna coupling element takes the form of a spiral wire antenna with the overall length shorter than the manhole cover thickness. Also not shown in any figure, for the quad band GSM
(850, 900, 1800 and 1900 MHz) frequency application, the antenna coupling element takes the form of a PCB (Printed Circuit Board) antenna with a meandering line for the low band (850 and 900 MHz) frequencies needed to restrict the overall length of the PCB
antenna shorter than the manhole cover thickness.
In figures 4, 5 and 6, the coupling element antenna is an elementary dipole antenna inserted into the air holes of the manhole cover. The manhole cover thickness is 1 inch with 3/4 inch diameter holes. It's computed impedance is Z-24-j5 ohm, that is a low Z-match at resonance. The radiation loss (RL) factor is -8dB with more than 80%
efficiency.
The 3 dimensions of the electric field above and below the manhole metal cover is given in figure 4. It provides sufficient coverage in the X & Y plane, the Z plane dominates with a nominal gain factor of -5dB. The manhole cover is positioned on a concrete stack.
Likewise in figure 4, the three dimensions of the electric field above and below the manhole metal cover positioned on the metal ring is given in figure 5. Here too it provides sufficient coverage in the X & Y plane.
Five prototypes were built using a spiral wire coupling element at 2450 MHz.
Two prototypes were built using a PSB quad band GSM coupling element at 850, 900, 1800 and 1900 MHz.
Field tests revealed that the signal strength radiating on the street side averaged 10dB
stronger than the signal strength radiating below grade. Tests were then performed to determine uniformity of the signal strength. Field tests revealed that the signal strength radiating on both sides of the manhole cover is omnidirectional with less than +/- 3dB
variation. In addition, field testing also revealed that the overall variation is less than +/-6dB with random orientation of the manhole cover over its metal ring.
Other preferred embodiments:
A further application of the invention also applies when the manhole cover thickness is less than the length of the antenna coupling element. In such case, a metal alloy pipe is inserted inside the manhole cover hole to extend the overall manhole thickness beyond the length of the antenna coupling element.
Claims (7)
1. A method of transforming a manhole cover into a bidirectional antenna, comprising:
an antenna coupling element closely coupled to said manhole cover via one of said manhole cover holes; and relaying a RF (Radio Frequency) signal from below grade to street level; and relaying a RF signal from street level to below grade.
an antenna coupling element closely coupled to said manhole cover via one of said manhole cover holes; and relaying a RF (Radio Frequency) signal from below grade to street level; and relaying a RF signal from street level to below grade.
2. A method as claimed in claim 1, wherein the antenna coupling element is a spiral wire antenna.
3. A method as claimed in claim 1, wherein the antenna coupling element is a PCB
type antenna.
type antenna.
4. A method as claimed in claim 1, wherein the antenna coupling element is a dielectric resonator type antenna.
5. A method as claimed in claims 2, 3 and 4, wherein the manhole cover hole has a diameter smaller than its length.
5. A method as claimed in claims 2, 3 and 4, wherein the manhole cover hole has a diameter smaller than its length.
5. A method as claimed in claim 5, wherein the manhole cover hole has a gap between the antenna coupling element and the hole circumference.
6. A method as claimed in claims 5 to 6, wherein the length of the antenna coupling element is shorter than the manhole cover thickness.
7. A method of sealing the manhole cover hole with high mechanical resistance epoxy while minimizing the antenna detuning effect.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2862457A CA2862457A1 (en) | 2014-09-11 | 2014-09-11 | Device and method for transforming a manhole cover as a bidirectional antenna without making any modification at the manhole cover |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2862457A CA2862457A1 (en) | 2014-09-11 | 2014-09-11 | Device and method for transforming a manhole cover as a bidirectional antenna without making any modification at the manhole cover |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2862457A1 true CA2862457A1 (en) | 2016-03-11 |
Family
ID=55451615
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2862457A Abandoned CA2862457A1 (en) | 2014-09-11 | 2014-09-11 | Device and method for transforming a manhole cover as a bidirectional antenna without making any modification at the manhole cover |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2862457A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020012091A1 (en) | 2018-07-10 | 2020-01-16 | Ej Emea | Device for accessing an underground or overground civil engineering infrastructure having a multi-protocol communication module, and system for managing a fleet of access devices |
| US11512443B2 (en) * | 2017-09-26 | 2022-11-29 | Orange | Manhole cover transparent to radiofrequency signals |
-
2014
- 2014-09-11 CA CA2862457A patent/CA2862457A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11512443B2 (en) * | 2017-09-26 | 2022-11-29 | Orange | Manhole cover transparent to radiofrequency signals |
| WO2020012091A1 (en) | 2018-07-10 | 2020-01-16 | Ej Emea | Device for accessing an underground or overground civil engineering infrastructure having a multi-protocol communication module, and system for managing a fleet of access devices |
| FR3083905A1 (en) | 2018-07-10 | 2020-01-17 | Ej Emea | DEVICE FOR ACCESSING AN UNDERGROUND OR SURFACE INFRASTRUCTURE COMPRISING A MULTI-PROTOCOL COMMUNICATION MODULE, AND SYSTEM FOR MANAGING A PARK OF ACCESS DEVICES |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |
Effective date: 20180911 |