Abstract:
A J-Pole antenna disclosed including: shunt segment extending out of the plane of the J-Pole antenna. A shunt segment extending out of the plane of the J-pole antenna aids in attaching the antenna to a connector and allowing for a reduction in the size of the antenna and connector. The shunt segment also makes the antenna shorter while preserving the same gain and impedance performance as a conventional J-Pole antenna. A connector plate and connector may be used with the antenna having the shunt segment extending out of the plane of the J-Pole antenna. A protective enclosure may be used with the J-Pole antenna and allowing a radiating antenna segment of the J-Pole antenna to extend from the protective enclosure.

Description:
FIELD OF THE INVENTION 
     The field of the invention relates generally to radio frequency (RF) devices and antennas for use with RF devices. 
     BACKGROUND OF THE INVENTION 
     A conventional J-pole antenna is an omnidirectional antenna that can be used for base, mobile and field day stations. It does not need a ground plane, radials or a complicated matching system. 
     A Conventional J-Pole design illustrated in  FIG. 1 . The J-Pole antenna  100  includes of a radiating antenna segment  101  and a quarter-wave matching segment  102 . A feed line  103  connects to the radiating antenna segment. The matching segment  104  is connected to ground. The connection points on the J-Pole antenna between the feed line and ground are chosen to provide sufficient resistance to prevent shorting between the feed line and the ground. In a conventional J-Pole antenna, the shunt segment  105  is formed to extend down below to connection points. Typically, the length A of the radiating antenna segment  101  is ½ the wavelength of the frequency the antenna is designed to operate at. Typically, the length B of the matching segment  102  is ¼ the wavelength the antenna is designed to operate at. 
     Conventional J-pole antennas are made of a conductive tubing, such as copper or aluminum. There are versions made of 300-ohm TV twin lead, which can be rolled up easily into a small package. 
     SUMMARY 
     A J-Pole antenna has a radiating antenna segment, a matching segment, and a shunt segment, where the shunt segment is positioned not to extend away and down from the connection points of a feed line and ground to the J-Pole antenna. Additional embodiments may include a connector and/or connector plate. the connector may be a co-axial type connector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a generalized diagram illustrating a conventional J-pole type antenna. 
         FIG. 2(   a ) is a perspective view of a J-pole antenna and connector, according to one possible embodiment. 
         FIG. 2(   b ) is a detailed perspective view of a J-pole antenna and connector, according to one possible embodiment. 
         FIG. 2(   c ) is an alternate detailed perspective view of a J-pole antenna and connector, according to one possible embodiment. 
         FIG. 2(   d ) is a side view of a J-pole antenna and connector, according to one possible embodiment. 
         FIG. 2(   e ) is a side view of a J-pole antenna and connector, according to one possible embodiment. 
         FIG. 3(   a ) is a cross sectional view of a J-pole antenna and connector with an antenna housing, according to one possible embodiment. 
         FIG. 3(   b ) is a cross sectional view of a telescoping J-pole antenna and connector with an antenna housing, according to one possible embodiment. 
         FIG. 3(   c ) is a cross sectional view of a sectional J-pole antenna and connector with an antenna housing, according to one possible embodiment. 
         FIG. 3(   d ) is a cross sectional view of a folding J-pole antenna and connector with an antenna housing, according to one possible embodiment. 
         FIG. 3(   e ) is a perspective view of an antenna housing illustrating the radiating antenna segment opening, according to one possible embodiment. 
         FIG. 3(   f ) is a perspective view of an antenna housing illustrating the connecting flange and protective enclosure, according to one possible embodiment. 
         FIG. 4(   a ) is a cross sectional view of a telescoping J-pole antenna and connector with a device housing, according to one possible embodiment. 
         FIG. 4(   b ) is a cross sectional view of a sectional J-pole antenna and connector with a device housing, according to one possible embodiment. 
         FIG. 4(   c ) is a cross sectional view of a folding J-pole antenna and device housing, according to one possible embodiment. 
         FIG. 5  graphical illustration of an antenna pattern of one possible embodiment of a J-pole antenna. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2(   a ) is a perspective view of a preferred embodiment of J-Pole antenna  201 , connector plate  202  and connector  203 . The J-Pole antenna  201  includes a radiating antenna segment  204  (also referred to as the radiating segment), a matching segment (or matching stub)  205 , and a shunt segment  206 . The J-Pole antenna  201  is structurally and electrically connected to the connector  203 . The connector  203  is connected to the base plate  202 . In the preferred embodiment the base plate  202  is made from a conductive material, such as a metal, for example, without limitation, aluminum, copper or steel. In one presently preferred embodiment, the connector includes, or is, a coaxial type connector. Unless otherwise noted, the term connector may include a connector housing which provides a secure connection between the antenna and a connector and/or a mounting system. As is known to those skilled in the art, the matching segment (¼ wavelength bottom portion) does not radiate, only the radiating segment  204  radiates, and should be either fully exposed or housed in a random type of enclosure, so as not to block the transmitted or received signals 
     As with conventional J-Pole antennas, the antenna  201  uses a matching segment  205  which is shorter than the radiating segment  204 . In one preferred embodiment the matching segment  205  is ½ the length of the radiating segment. Alternate embodiments may use other detentions for either the radiating or matching segments. In one preferred embodiment the matching segment and radiating segment of the antenna are formed from conductive tubing. Examples of materials that may be used for the conductive tubing include conductive metals like copper and aluminum, but any conductive or partially conductive material capable receiving or transmitting RF signals may be used. Alternate embodiments may have the either, or both, the radiating segment and the matching segment formed form a material in a shape other than a tubing. In one preferred embodiment the radiating segment  204  has a length of ½ the wavelength of the corresponding frequency the antenna is designed to operate at. In one preferred embodiment the matching segment  205  has a length of ¼ the wavelength of the corresponding frequency the antenna is designed to operate at. While the preferred embodiment has the radiating segment of the antenna has a length of ½ the wavelength and the matching segment has a length of ¼ the wavelength of the corresponding frequency the antenna is designed to operate at, alternate embodiments may use a different length for either the radiating segment or the matching segment. 
     As shown in  FIG. 2(   d ) the radiating segment is positioned on the left relative to the bent ¼ wavelength stub of the matching segment and on top of the non-radiating part of the matching segment, as viewed from the perspective of the shunt segment. However, alternate embodiments may have different relative positions for the radiating segment, matching segment and shunt segment. 
       FIG. 2(   b ) and  FIG. 2(   c ) are perspective views illustrating details of the shunt segment  206  and attachment of the antenna J-Pole  201  to the connector  203 . As shown in  FIG. 2(   a ) and further illustrated in  FIGS. 2(   b ) and  2 ( c ), shunt segment  206  is formed to not extend below the electrical connection points between the J-Pole antenna and connector. In the illustrated embodiment, the shunt segment  206  is formed as a loop and extends away from the connector base plate plane  202  to be substantially parallel to the plane formed by the radiating segment  204  and matching segment  205 . In the illustrated embodiment, the radiating segment  204 , the matching segment  205  and the shunt segment  206  are formed from a single piece of conductive tubing. In such an embodiment the shunt segment  206  may be formed from bending the tubing to create a shunt segment at the feed and ground connecting points  207  and  208  at the bottom of the two sections of the matching segment, and such that the shunt segment  206  is substantially parallel to the plane formed from the radiating segment  204  and matching segment  205 . In the presently preferred embodiment, the connecting points  207  and  208  between the J-Pole antenna and the feed line and ground line respectively of the connector are both structural and electrical connections. As illustrated, the connections are by welding or soldering the J-Pole antenna to feed line and ground line of the connector. Alternate embodiments may use other ways of connecting the J-Pole antenna to the connector, including clamps, screws, clips, or another type of attachment system. In another alternative embodiment the structural attachment between the J-Pole antenna and the connector may be separate from the electrical connection between the antenna and the connector. 
     While the embodiment discussed has the radiating segment of the antenna, the matching segment and the shunt segment are formed from a single conductive material, alternate embodiments may be formed from different pieces of conductive material. Additionally, alternate embodiments may have the radiating segment, the matching segment and/or the shunt segment formed from different materials. For example, the shunt segment may be formed from a material of higher resistance than the materials of either, or both, the radiating segment and the matching segment. 
       FIG. 2(   c ) and  FIG. 2(   d ) illustrate the shunt segment  206  formed as a loop segment between the feed line  207  and ground connection  208  of J-Pole antenna  201 .  FIG. 2(   d ) is a side view of the J-Pole antenna  201  illustrating the shunt segment formed to extend substantially parallel to the radiating segment and the matching segment. In the embodiment shown in  FIG. 2(   d ) the feed line connection  207  is shown, and from the perspective in  FIG. 2(   d ) the ground connecting point is positioned behind, and obscured by, the feed line connection  207 . 
       FIG. 2(   e ) is a side view of a J-Pole antenna  210  having a shunt segment positioned away from parallel to the radiating segment  204 . As illustrated shown, J-Pole antennas  201  and  210  illustrate, the shunt segment may be formed to extend away from the connecting points in any number of positions, thereby allowing for shortening of the overall length of the J-Pole antenna. Other embodiments may have the shunt segment formed to be parallel to the connector plate. Still other embodiments of the J-Pole antenna may extend below the connection point of the feed line and the ground, at varying angles form directly below. In the embodiment shown in  2 ( e ) the feed line connection  207  is shown, and from the perspective in  FIG. 2(   e ) the ground connecting point is positioned behind, and obscured by, the feed line connection  207 . 
       FIG. 3(   a ) is a front view of a J-Pole antenna  301  with a connector  302 , having an antenna housing  303  illustrating the positioning of the matching segment  304 . The antenna housing  303  is shown in cut-away form to illustrate the relative positioning of the J-Pole antenna to the antenna housing. In the presently preferred embodiment, the antenna housing is chosen to provide protection to the matching segment while still providing a, relatively, compact housing. The radiating segment of the antenna  305  extends through the opening  306  in the antenna housing. 
       FIG. 3(   b ) is a front view of a J-Pole antenna  310  with a telescoping radiating segment section  311 . As shown, the telescoping section is in the extended position. In the closed position (not shown) the telescoping allows the radiating segment to retract substantially to reduce the exposure of radiating segment from the environment, when the antenna is not in use or not radiating. In one preferred embodiment, the radiating segment retracts such that the tip of the radiating segment is substantially parallel to the outer surface of the antenna housing  303 . The tip of the radiating segment may have a tight nylon, rubber, or plastic cap that fits snugly into the hole of the antenna housing so as to provide a water-proof tight cover when the radiating segment is retracted inwards all the way. While the example radiating segment shown is simply one telescoping segment, alternate embodiments may have any number of telescoping segments. 
       FIG. 3(   c ) is a front view of a J-Pole antenna  320  having a radiating segment  321  as a separable segment  322 . The separable segment may be disconnected from the rest of the J-Pole antenna, thus reducing the chances of damage to the J-Pole antenna, for example during transportation or installation of the J-Pole antenna. The separable segment may attach to the rest of the J-Pole antenna by any means which provides secure electrical and structural contact. In one preferred embodiment the separable segment is attachable by screw threads, for example by screwing the threaded end of the separable segment into a threaded end of the rest of the J-Pole antenna. The J-Pole antenna may also include an antenna housing  323 . The length of the separable segment may be chosen such that the rest of the J-Pole antenna is protected by the antenna housing  323  when the separable segment is not attached. In any event, the separable segment, at a minimum, may include the complete radiating segment. The separable segment may also be provided housing in the form of a cylindrical hollow tubing on the side of the antenna housing (attached or detached) where the separable segment can be stored, in closed or open condition with or without a lid. 
       FIG. 3(   d ) is a perspective view of a J-Pole antenna  330  having an antenna housing (also referred to as the ‘enclosure”)  331  installed and attached to the connector base  332 . The radiating segment  333  extends from the antenna housing  331 . 
       FIG. 3(   e ) is a perspective view of an antenna housing  331  illustrating the radiating segment opening. In the preferred embodiment the antenna housing is formed from a non-conductive material, such as a plastic or nylon. However, alternate embodiments may use any material which provides the desired level of protection and allows operation of the J-Pole antenna. 
       FIG. 3(   f ) is a perspective view of an antenna housing  331  illustrating the connecting flange. In the presently preferred embodiment, the protective enclosure is sized to cover the matching segment and shunt segment. While the connecting flange is used to connect to the connector base via multiple screws or bolts, alternate embodiments could use other attachment mechanisms. 
       FIG. 4(   a ) is a front view of a J-Pole antenna  401  having a radiating segment  402  extending from an electronic device enclosure  403  through a radiating segment opening  404 . The electronic device enclosure  403  is shown in cut-away to illustrate the positioning of electronic device (or devices) and the J-Pole antenna relative to the electronic device enclosure. In the presently preferred embodiment, the electronic device enclosure is formed to enclose and protect electronic devices. For example, the electronic device enclosure may provide protection to electronic devices from the J-Pole antenna segments. The electronic device enclosure may be formed from any material which provides the appropriate protection and/or electronic properties to allow operation of the J-Pole antenna and/or electronic device(s). J-Pole antenna may include a telescoping radiating segment  402 , as show in the extended position, to allow the radiating segment to retract to be protected by the electronic device enclosure, for example during transportation or installation. As shown, electronic device enclosure encloses a commodity meter, a communication device and connector, as may be found in an automated metering network. However, the electronic device enclosure may include or be designed to include any type, number or arrangement of electronic devices. For example, the electronic device enclosure may be housing an RF transceiver, digital controller, signal processor, modem, and other, as typically found in many field RF systems such as relays, gateways, nodal remote RF devices, etc. of any type of wireless and fixed RF networks 
       FIG. 4(   b ) is a front view of a sectional J-pole antenna  411  having a matching segment  416  with a separable radiating segment  417 . The separable segment may be disconnected from the rest of the J-Pole antenna, thus reducing the chances of damage to the J-Pole antenna, for example during transportation or installation of the J-Pole antenna. The separable segment may attach to the rest of the J-Pole antenna by any means which provides secure electrical and structural contact. In one preferred embodiment the separable segment is attachable by screw threads, for example by screwing the threaded end of the separable segment into a threaded end of the rest of the J-Pole antenna. The J-Pole is installed in an electronic device housing  403 . The J-pole antenna  411  is positioned within the device housing such that the separable radiating segment  417  may be attached to the rest of the J-Pole antenna through a radiating segment opening  404 . 
       FIG. 4(   c ) is a front view of a J-Pole antenna  421  having a radiating segment  422  with a pivot (conducting) joint  426 . In the preferred embodiment, J-Pole antenna  421  having the radiating segment  422  with the pivot joint  426  extends from an electronic device enclosure  403  through a radiating antenna opening  404 . In the preferred embodiment, the pivot point and J-Pole antenna are positioned to allow the radiating segment to be positioned substantially parallel to the outside of the electronic device enclosure when in stowed position and swung into position upwards (or downwards) in any direction to obtain the desired antenna radiating characteristics. While the preferred embodiment has the radiating segment with pivot joint used with an electronic device enclosure, alternate embodiments could be used with an antenna housing, or alone without an antenna-housing or an electronic device enclosure. 
       FIG. 5  shows the measured antenna pattern  500  for the J-Pole antenna design according to the features described in this embodiment. Patterns for three frequencies are shown: 902 MHz, 915 MHz (center frequency), and 928 MHz. This frequency band is used by wireless networks offering AMR services. For those skilled in the art, it is immediately obvious that the achieved radiation performance with this design is unchanged 
     The invention has been described with reference to particular embodiments. However, it will be readily apparent to those skilled in the art that it is possible to embody the invention in specific forms other than those of the preferred embodiments described above. This may be done without departing from the spirit of the invention. Thus, the preferred embodiment is merely illustrative and should not be considered restrictive in any way. The scope of the invention is given by the appended claims, rather than the preceding description, and all variations and equivalents which fall within the range of the claims are intended to be embraced therein.