Abstract:
Disclosed are apparatus and methodology subject matters relating to an antenna configured for mounting under the glass in a utility meter. The antenna is configured as a patch antenna where a radiating element is mounted on one side of a plastic substrate while a conductive ground plane element is mounted on the other side of the substrate. The ground plane element faces the meter electronics and thereby provides protection to the electronics from the electromagnetic field of the antenna. Both the radiating element and ground plane element may be provided by hot stamping conductive material directly on to the front and rear surfaces of the substrate. The antenna may be feed by a microstrip feedline mounted on the printed circuit board supporting other meter components.

Description:
PRIORITY CLAIM  
       [0001]     This application claims the benefit of previously filed U.S. Provisional Patent Application entitled “RF LOCAL AREA NETWORK ANTENNA DESIGN,” assigned U.S. Ser. No. 60/845,061, filed Sep. 15, 2006, and which is hereby incorporated herein by reference in its entirety for all purposes. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present technology relates to utility meters. More particularly, the present technology relates to an aperture coupled patch antenna design for incorporation within meters within an open operational framework employing a radio frequency local area network (RF LAN).  
       BACKGROUND OF THE INVENTION  
       [0003]     The general object of metrology is to monitor one or more selected physical phenomena to permit a record of monitored events. Such basic purpose of metrology can be applied to a variety of metering devices used in a number of contexts. One broad area of measurement relates, for example, to utility meters. Such role may also specifically include, in such context, the monitoring of the consumption or production of a variety of forms of energy or other commodities, for example, including but not limited to, electricity, water, gas, or oil.  
         [0004]     More particularly concerning electricity meters, mechanical forms of registers have been historically used for outputting accumulated electricity consumption data. Such an approach provided a relatively dependable field device, especially for the basic or relatively lower level task of simply monitoring accumulated kilowatt-hour consumption.  
         [0005]     The foregoing basic mechanical form of register was typically limited in its mode of output, so that only a very basic or lower level metrology function was achieved. Subsequently, electronic forms of metrology devices began to be introduced, to permit relatively higher levels of monitoring, involving different forms and modes of data.  
         [0006]     In the context of electricity meters specifically, for a variety of management and billing purposes, it became desirable to obtain usage data beyond the basic kilowatt-hour consumption readings available with many electricity meters. For example, additional desired data included rate of electricity consumption, or date and time of consumption (so-called “time of use” data). Solid state devices provided on printed circuit boards, for example, utilizing programmable integrated circuit components, have provided effective tools for implementing many of such higher level monitoring functions desired in the electricity meter context.  
         [0007]     In addition to the beneficial introduction of electronic forms of metrology, a variety of electronic registers have been introduced with certain advantages. Still further, other forms of data output have been introduced and are beneficial for certain applications, including wired transmissions, data output via radio frequency transmission, pulse output of data, and telephone line connection via such as modems or cellular linkups.  
         [0008]     The advent of such variety and alternatives has often required utility companies to make choices about which technologies to utilize. Such choices have from time to time been made based on philosophical points and preferences and/or based on practical points such as, training and familiarity of field personnel with specific designs.  
         [0009]     Another aspect of the progression of technology in such area of metrology is that various retrofit arrangements have been instituted. For example, some attempts have been made to provide basic metering devices with selected more advanced features without having to completely change or replace the basic meter in the field. For example, attempts have been made to outfit a basically mechanical metering device with electronic output of data, such as for facilitating radio telemetry linkages.  
         [0010]     Another aspect of the electricity meter industry is that utility companies have large-scale requirements, sometimes involving literally hundreds of thousands of individual meter installations, or data points. Implementing incremental changes in technology, such as retrofitting new features into existing equipment, or attempting to implement changes to basic components which make various components not interchangeable with other configurations already in the field, can generate considerable industry problems.  
         [0011]     Electricity meters typically include input circuitry for receiving voltage and current signals at the electrical service. Input circuitry of whatever type or specific design for receiving the electrical service current signals is referred to herein generally as current acquisition circuitry, while input circuitry of whatever type or design for receiving the electrical service voltage signals is referred to herein generally as voltage acquisition circuitry.  
         [0012]     Electricity meter input circuitry may be provided with capabilities of monitoring one or more phases, depending on whether monitoring is to be provided in a single or multiphase environment. Moreover, it is desirable that selectively configurable circuitry may be provided so as to enable the provision of new, alternative or upgraded services or processing capabilities within an existing metering device. Such variations in desired monitoring environments or capabilities, however, lead to the requirement that a number of different metrology configurations be devised to accommodate the number of phases required or desired to be monitored or to provide alternative, additional or upgraded processing capability within a utility meter.  
         [0013]     More recently a new ANSI protocol, ANSI C12.22, is being developed that may be used to permit open protocol communications among metrology devices from various manufacturers. C12.22 is the designation of the latest subclass of the ANSI C12.xx family of Meter Communication and Data standards presently under development. Presently defined standards include ANSI C12.18 relating to protocol specifications for Type 2 optical ports; ANSI C12.19 relating to Utility industry Meter Data Table definitions; and ANSI C12.21 relating to Plain Old Telephone Service (POTS) transport of C12.19 Data Tables definition. It should be appreciated that while the remainder of the present discussion may describe C12.22 as a standard protocol, that, at least at the time of filing the present application, such protocol is still being developed so that the present disclosure is actually intended to describe an open protocol that may be used as a communications protocol for networked metrology and is referred to for discussion purposes as the C12.22 standard or C12.22 protocol.  
         [0014]     C12.22 is an application layer protocol that provides for the transport of C12.19 data tables over any network medium. Current standards for the C12.22 protocol include: authentication and encryption features; addressing methodology providing unique identifiers for corporate, communication, and end device entities; self describing data models; and message routing over heterogeneous networks.  
         [0015]     Much as HTTP protocol provides for a common application layer for web browsers, C12.22 provides for a common application layer for metering devices. Benefits of using such a standard include the provision of: a methodology for both session and session-less communications; common data encryption and security; a common addressing mechanism for use over both proprietary and non-proprietary network mediums; interoperability among metering devices within a common communication environment; system integration with third-party devices through common interfaces and gateway abstraction; both 2-way and 1-way communications with end devices; and enhanced security, reliability and speed for transferring meter data over heterogeneous networks.  
         [0016]     To understand why utilities are keenly interested in open protocol communications; consider the process and ease of sending e-mails from a laptop computer or a smart phone. Internet providers depend on the use of open protocols to provide e-mail service. E-mails are sent and received as long as e-mail addresses are valid, mailboxes are not full, and communication paths are functional. Most e-mail users have the option of choosing among several Internet providers and several technologies, from dial-up to cellular to broadband, depending mostly on the cost, speed, and mobility. The e-mail addresses are in a common format, and the protocols call for the e-mail to be carried by communication carriers without changing the e-mail. The open protocol laid out in the ANSI C.12.22 standard provides the same opportunity for meter communications over networks.  
         [0017]     In addition, the desire for increased communications capabilities as well as other considerations including, but not limited to, a desire to provide improved radio frequency transmission range for individual metrology components in an open operational framework, leads to requirements for improved antenna components for metrology devices including meters installed in such systems.  
         [0018]     As such, it is desired to provide an improved antenna for coupling utility meters by radio frequency signals to other system components in an open operational framework.  
         [0019]     While various aspects and alternative embodiments of antenna configurations may be known in the field of utility metering, no one design has emerged that generally encompasses the above-referenced characteristics and other desirable features associated with utility metering technology as herein presented.  
       SUMMARY OF THE INVENTION  
       [0020]     In view of the recognized features encountered in the prior art and addressed by the present subject matter, an improved radio frequency antenna configuration for incorporation within a metrology device for use in an open operational framework has been provided.  
         [0021]     In an exemplary arrangement, an antenna has been provided to permit transmission of information between a utility meter and an operational application through a network.  
         [0022]     In one of its simpler forms, the present technology provides a patch antenna structure to permit omni-directional transmission of radio frequency signals between a local area network and a meter installed within the service area of the local area network of a utilities service provider.  
         [0023]     One positive aspect of the antenna is that it provides an improved, protected mounting arrangement “under the glass” of a utility meter.  
         [0024]     Another positive aspect of this type of antenna is that simplified construction techniques may be employed to produce conductive elements for the antenna.  
         [0025]     Yet another positive aspect of the antenna is that it isolates non-radio frequency circuitry for the electromagnetic field generated by the antenna.  
         [0026]     One exemplary present embodiment relates to an improved antenna for mounting under the glass of utility meters for coupling thereof by radio frequency signals to other system components in an open operational framework. Such antenna preferably may comprise an insulating substrate and first and second conductive layers. More preferably, such insulating substrate may have major front and rear surfaces, and respective lateral ends. At the same time, such first conductive layer preferably may be secured on the rear surface of such substrate, and may define a slot shaped opening therein, with such first conductive layer except for the slot shaped opening thereof covering substantially the entire rear surface of such substrate. Also, such second conductive layer may preferably be secured on the front surface of such substrate, and preferably may cover substantially equally portions of such substrate from the slot shaped opening of such first conductive layer toward the lateral ends of such substrate but short of such lateral ends so as to leave predetermined substantially equal area substrate portions left uncovered on such substrate front surface.  
         [0027]     Still further present alternatives to such exemplary embodiment may involve the inclusion of additional features, for example, such as providing such insulating substrate as generally arc-shaped; and such providing such first conductive layer as a conductive ground plane element for such antenna, configured for facing the electronics of an associated utility meter, while such second conductive layer comprises a radiating element of such antenna. With such structure in combination with a utility meter associated non-radio frequency electronics of such utility meter are preferably isolated from an electromagnetic field generated by such antenna while permitting omni-directional transmission of radio frequency signals via such antenna to other system components in an open operational framework.  
         [0028]     Other present exemplary embodiments more directly relate to a meter with an under the glass antenna for use with an open operational framework employing a radio frequency local area network. Such a meter may preferably comprise a metrology printed circuit board including components relating to the collection and display of metrology information; radio transmission components received on such circuit board; a microstrip feedline connected with such radio transmission components and received on the circuit board; and an antenna secured to the printed circuit board for support thereof, and electrically grounded thereto. In the foregoing exemplary embodiment, preferably such antenna may include an insulating substrate, with respective first and second conductive layers on opposite surfaces of such substrate, and with such antenna positioned relative to the circuit board and the microstrip feedline received thereon for inductive coupling therewith.  
         [0029]     It is to be understood that the present subject matter equally relates to various present methodologies. One exemplary such present embodiment relates to methodology for providing a patch antenna for mounting under the glass of utility meters for coupling thereof by radio frequency signals to other system components in an open operational framework. Such exemplary methodology may comprise providing an insulating substrate having major front and rear surfaces, and respective lateral ends; securing a first conductive layer on such rear surface of the substrate, covering substantially the entire rear surface of such substrate except for a slot shaped opening defined in such first conductive layer; and securing a second conductive layer on such front surface of the substrate, such that substantially equal portions of such substrate are covered from the slot shaped opening of such first conductive layer toward the lateral ends of such substrate but short of such lateral ends so as to leave predetermined substantially equal area substrate portions left uncovered on the substrate front surface.  
         [0030]     Other exemplary present methodology relates to methodology for providing a meter with an under the glass antenna for use with an open operational framework employing a radio frequency local area network. Such present exemplary methodology may comprise providing a metrology printed circuit board having thereon components relating to the collection and display of metrology information; providing radio transmission components on such circuit board; supporting on such circuit board a microstrip feedline connected with such radio transmission components; providing an antenna including an insulating substrate, and respective first and second conductive layers on opposite surfaces of such substrate; and securing the antenna to the printed circuit board for support thereof, and electrically grounded thereto, and with such antenna positioned relative to the circuit board and the microstrip feedline received thereon for inductive coupling therewith. It is to be understood of all the present exemplary methodologies that other present methodologies may be provided by various inclusions of other exemplary method features otherwise disclosed herein, each such variations constituting further present methodologies.  
         [0031]     Additional objects and advantages of the present subject matter are set forth in, or will be apparent to, those of ordinary skill in the art from the detailed description herein. Also, it should be further appreciated that modifications and variations to the specifically illustrated, referred and discussed features and elements hereof may be practiced in various embodiments and uses of the present subject matter without departing from the spirit and scope of the subject matter. Variations may include, but are not limited to, substitution of equivalent means, features, or steps for those illustrated, referenced, or discussed, and the functional, operational, or positional reversal of various parts, features, steps, or the like.  
         [0032]     Still further, it is to be understood that different embodiments, as well as different presently preferred embodiments, of the present subject matter may include various combinations or configurations of presently disclosed features, steps, or elements, or their equivalents including combinations of features, parts, or steps or configurations thereof not expressly shown in the figures or stated in the detailed description of such figures. Additional embodiments of the present subject matter, not necessarily expressed in the summarized section, may include and incorporate various combinations of aspects of features, components, or steps referenced in the summarized objects above, and/or other features, components, or steps as otherwise discussed in this application. Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the remainder of the specification. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0033]     A full and enabling disclosure of the present subject matter, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:  
         [0034]      FIG. 1  is an edge view of an exemplary antenna constructed in accordance with the present subject matter attached to a metrology printed circuit board;  
         [0035]      FIG. 2  is a front plan view of an exemplary antenna in accordance with the present subject matter seen from the perspective of section  2 - 2  of  FIG. 1 ;  
         [0036]      FIG. 3  is a rear plan view of an exemplary antenna constructed in accordance with the present subject matter seen from the perspective of section  3 - 3  of  FIG. 1 ;  
         [0037]      FIG. 4  is an isometric view of a utility meter incorporating an antenna constructed in accordance with the present subject matter; and  
         [0038]      FIG. 5  is a block diagram overview illustration of an Advanced Metering System (AMS) in accordance with the present subject matter.  
         [0039]     Repeat use of reference characters throughout the present specification and appended drawings is intended to represent same or analogous features or elements of the present subject matter. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0040]     As discussed in the Summary of the Invention section, the present subject matter is particularly concerned with the provision of an improved radio frequency antenna configuration for incorporation within a metrology device for use in an open operational framework.  
         [0041]     Selected combinations of aspects of the disclosed technology correspond to a plurality of different embodiments of the present subject matter. It should be noted that each of the exemplary embodiments presented and discussed herein should not insinuate limitations of the present subject matter. Features or steps illustrated or described as part of one embodiment may be used in combination with aspects of another embodiment to yield yet further embodiments. Additionally, certain features may be interchanged with similar devices or features not expressly mentioned which perform the same or similar function.  
         [0042]     Reference will now be made in detail to the presently preferred embodiments of the subject antenna. Referring now to the drawings, and referring first to  FIG. 5  there is illustrated a block diagram overview of an Advanced Metering System (AMS)  500  in which an antenna constructed in accordance with the present subject matter may be installed along with certain of the metrology components.  
         [0043]     Advanced Metering System (AMS)  500  is designed to be a comprehensive system for providing advanced metering information and applications to utilities. AMS  500  is build around industry standard protocols and transports, and is designed to work with standards compliant components from third parties.  
         [0044]     Major components of AMS  500  include meters  542 ,  544 ,  546 ,  548 ,  552 ,  554 ,  556 ,  558 ; one or more radio networks including RF local area network (RF LAN)  562  and accompanying Radio Relay  572  and power line communications neighborhood area network (PLC NAN)  564  and accompanying PLC Relay  574 ; an IP based Public Backhaul  580 ; and a Collection Engine  590 . Other components within AMS  500  include a utility LAN  592  and firewall  594  through which communications signals to and from Collection Engine  590  may be transported from and to meters  542 ,  544 ,  546 ,  548 ,  552 ,  554 ,  556 ,  558  or other devices including, but not limited to, Radio Relay  572  and PLC Relay  574 .  
         [0045]     AMS  500  is configured to be transportation agnostic or transparent; such that meters  542 ,  544 ,  546 ,  548 ,  552 ,  554 ,  556 ,  558  may be interrogated using Collection Engine  590  regardless of what network infrastructure lay in between. Moreover, due to this transparency, the meters may also respond to Collection Engine  590  in the same manner.  
         [0046]     As illustrated in  FIG. 5 , Collection Engine  590  is capable of integrating Radio, PLC, and IP connected meters. To facilitate this transparency, AMS  500  uses ANSI C12.22 meter communication protocol for networks. C12.22 is a network transparent protocol, which allows communications across disparate and asymmetrical network substrates. C12.22 details all aspects of communications, allowing C12.22 compliant meters produced by third parties to be integrated into a single advanced metering interface (AMI) solution. AMS  500  is configured to provide meter reading as well as load control / demand response, in home messaging, and outage and restoration capabilities. All data flowing across the system is sent in the form of C12.19 tables. The system provides full two-way messaging to every device; however, many of its functions may be provided through broadcast or multicast messaging and session-less communications.  
         [0047]     In accordance with the present subject matter, the disparate and asymmetrical network substrates may be accommodated by way of a native network interface having the capability to plug in different low level transport layers using NET interfaces. In accordance with an exemplary configuration, Transmission Control Protocol/Internet Protocol (TCP/IP) may be employed and may involve the use of radio frequency transmission as through RF LAN  562  via Radio Relay  572  to transport such TCP/IP communications. It should be appreciated that TCP/IP is not the only such low-level transport layer protocol available and that other protocols such as User Datagram Protocol (UDP) may be used.  
         [0048]     With reference now to  FIGS. 1, 2  and  3 , edge, front plan, and rear plan views respectively of a patch antenna  100  constructed in accordance with the present subject matter are illustrated. In an exemplary embodiment a patch antenna  100  may be constructed by first providing a generally arc-shaped, insulating substrate  140  having major front and back surfaces. Electrically conductive material may be secured on both the front and rear major surfaces in a manner to be described later.  
         [0049]     In accordance with an exemplary embodiment of the present subject matter, patch antenna  100  may be formed by providing a first conductive layer  102  on the rear major surface of substrate  140  covering substantially the entire rear portion of substrate  140  except for a slot shaped portion  120  removed from first conductive layer  102  (and creating a corresponding slot shaped opening) starting at a first edge  150  of substrate  140  and extending toward but not reaching a second edge  152 . As most clearly illustrated in  FIG. 3 , substrate material  140  may be seen behind slot  120 . First conductive layer  102  may be soldered to traces secured to a perimeter portion of printed circuit board  110  as illustrated at  112 ,  114 . Soldering of first conductive layer  102  to traces on printed circuit board  110  provides, among other things, a convenient mounting technique for mounting the antenna to the meter.  
         [0050]     A second conductive element  130  may be secured to the front portion of substrate  140 . Second conductive element  130  may be affixed to the front major surface of substrate  140  and extends from first edge  150  of substrate  140  to second edge  152  of substrate  140  and covers substantially equally portions of substrate  140  from the slot  120  (on the rear side of substrate  140 ) toward lateral ends  164 ,  166  of substrate  140  but short of the lateral ends  164 ,  166  leaving substantially equal area substrate portion  154 ,  156  left uncovered. Second electrically conductive element  130  forms the radiating element for patch antenna  100  and may be approximately half-wavelength of the operating frequency of the antenna in length.  
         [0051]     First and second electrically conductive elements  102 ,  130  may both correspond to any suitable electrically conductive material that may be adhered in any suitable fashion to substrate material  140 . Suitable materials for conductive elements  102  and  130  may include, but are not limited to, aluminum, copper, and brass. Substrate material  140  may correspond to any suitable non-conductive or insulating material and may correspond to a transparent plastic material.  
         [0052]     In accordance with the present subject matter, conductive elements  102 ,  130  may be secured to substrate  140  in any suitable manner including, but not limited to, mechanical devices including screws, and pop rivets, as well as by adhesives. In a particularly advantageous embodiment, conductive elements  102 ,  130  may be formed by hot stamping conductive material directly on to the front and rear surfaces of substrate  140 .  
         [0053]     With further reference to  FIG. 1 , it will be noticed that a microstrip  122  may be formed on one surface of printed circuit board  110 . Microstrip  122  is place on the printed circuit board  110  so that when substrate  140  and its attached first and second conductive elements  102 ,  130  are secured to printed circuit board  110 , microstrip  122  will be positioned perpendicularly across a generally central portion of the gap created by slot  120  in first conductive element  102 . In this manner microstrip  122  operates as a feedline for patch antenna  100  so that an inductive aperture coupling to the radiating element corresponding to first conductive element  102  is formed. The use of an inductive aperture coupling as opposed to more traditional conductive coupling provides for galvanic isolation of the patch and permits feeding the patch from the non-coplanar printed circuit board  110 .  
         [0054]     With reference now to  FIG. 4 , there is illustrated an isometric view of a utility meter  400  incorporating an antenna constructed in accordance with the present subject matter. As may be seen in  FIG. 4 , utility meter  400  includes a printed circuit board  410  on which may be mounted a number of components relating to the collection and display of metrology information.  
         [0055]     In accordance with the present subject matter, circuit board  410  may include a feedline microstrip  422  (corresponding with microstrip  122  of present  FIG. 1 ) and may include radio transmission circuit components  424 , and may be secured as illustrated by solder connections  412 ,  414  to antenna  100  and conductive traces printed on printed circuit board  410 . The soldered connections  412 ,  414  to printed circuit board  410  provide a solid physical connection of the antenna to printed circuit board  410  as well as an electrical connection to the electrical ground portion of the metrology circuitry associated with meter  400 .  
         [0056]     This electrical connection of first conductive element  102  of patch antenna  100  not only provides a ground plane portion for patch antenna  100  but also provides a shielding function to shield various of the metrology components mounted on printed circuit board  410  and other printed circuit boards associated with meter  400  from radio frequency energy radiated from the patch antenna.  
         [0057]     With further reference to  FIG. 4  it will be noticed that antenna  100  may be mounted with respect to the metrology board of meter  400  so that when the meter is mounted for use within the network, the patch antenna  100  will be positioned at the top of the meter and under the glass enclosure for the meter. Such a location permits an upwardly directed omni-directional radiating pattern from the antenna while protecting the antenna and individuals who may otherwise come in contact with the antenna had it been provided as an external antenna.  
         [0058]     While the present subject matter has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art.