Antenna with integrated feed and shaped reflector

Information

  • Patent Grant
  • 6529167
  • Patent Number
    6,529,167
  • Date Filed
    Wednesday, October 31, 2001
    23 years ago
  • Date Issued
    Tuesday, March 4, 2003
    21 years ago
Abstract
An integrated feed system for an antenna includes a circuit board, a feed network formed on the circuit board, and a plurality of feed elements electrically coupled with the feed network and projecting outwardly therefrom. The circuit board has one or more projecting edge parts for mounting the feed elements. An antenna having one or more reflector elements utilizes the integrated antenna feed system. A corresponding method for the feed system and the antenna is also provided.
Description




FIELD OF THE INVENTION




This invention is directed generally to antenna, and more particularly to a novel feed network integrated with an array of antenna elements and a shaped reflector.




BACKGROUND OF THE INVENTION




Local multipoint distribution service (LMDS) is a broadband wireless point-to-multipoint communication system that can be used to provide digital two-way voice, data, Internet, and video services. In such a definition, “local” denotes that propagation characteristics of signals in this system limit the potential coverage area to that of a single cell site. For example, field trials conducted in metropolitan centers limit the range of transmitters in these systems to approximately five miles. “Multipoint” indicates that base station signals are transmitted in a point-to-multipoint or broadcast method; whereas, the wireless return path, from subscriber to the base station, is a point-to-point transmission. “Distribution” refers to the distribution of signals, which may consist of simultaneous voice, data, Internet, and video traffic. “Service” implies the subscriber nature of the relationship between the operator and the customer or the services offered through an LMDS network that are entirely dependent on the operator's choice of business.




For LMDS, or other similar point-to-multipoint applications, base station antennas are required to deliver services over one or more sectors within a cell site. To meet this requirement, antennas should have reasonably high gain characteristics and meet a specified azimuth beamwidth to provide the desired sector coverage. Furthermore, it is desirable to provide a relatively rugged and reliable antenna structure since such systems are often deployed in an urban environment. Ideally, such an antenna structure should have relatively simple and few parts and be relatively easy and inexpensive to manufacture and to install and maintain in the field.




Therefore, a significant need exists in the art for an improved antenna that has desirable azimuth beamwidth characteristics that has relatively few and uncomplicated parts. It is also desirable that any such antenna be straightforward and inexpensive to manufacture and install and maintain. It is s till further desirable, that such an improved antenna has applicability within an LMDS system.











BRIEF DESCRIPTION OF THE DRAWINGS




The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention.





FIG. 1

is an exploded view of a vertically polarized antenna in accordance with one embodiment of the present invention;





FIG. 2

is a photograph of another embodiment of the present invention for installation; such as in an urban environment, with the radome cover and polarizing sheet removed;





FIG. 3

is an enlarged perspective view of a shaped reflector element of an antenna in accordance with one embodiment of the invention;





FIG. 4

is an enlarged plan view of one embodiment of a circuit board and feed network for an antenna;





FIG. 5

is an enlarged elevation of a portion of the circuit board and feed network of the embodiment of

FIG. 4

;





FIG. 6

is a fragmentary view, similar to

FIG. 4

, showing an alternative embodiment of a portion of the feed network for the antenna;





FIG. 7

is a sectional view of a vertically polarized 60 degree sector 10 GHz LMDS antenna with the radome removed in accordance with another embodiment of the present invention;




Similar to

FIG. 7

,

FIG. 8

is a sectional view of a vertically polarized 90 degree 10 GHz LMDS antenna with the radome removed in accordance with another embodiment of the present invention;





FIG. 9

is an exploded view of a horizontally polarized antenna in accordance with another embodiment of the present invention;





FIGS. 10 and 11

are enlarged partial views, showing bowtie dipole feed elements for a horizontally polarized antenna consistent with one embodiment of the invention.





FIG. 12

is a simplified partial perspective view through a shaped reflector element and feed network for a horizontally polarized antenna having microstrip patch feed elements in accordance with one embodiment of the present invention;





FIG. 13

is a simplified, sectional view of a shaped reflector element and feed network for a horizontally polarized antenna in accordance with one embodiment of the present invention;





FIG. 14

is a simplified, partial perspective view of reflector and feed elements for a horizontally polarized 90 degree 10 GHz LMDS antenna in accordance with another embodiment of the present invention;




Similar to

FIG. 14

,

FIG. 15

is a sectional view of a horizontally polarized 90 degree sector azimuth 10 GHz LMDS antenna with the radome removed in accordance with another embodiment of the present invention;





FIG. 16

is a simplified, partial perspective view of reflector and feed elements for a horizontally polarized 60 degree sector azimuth 10 GHz LMDS antenna in accordance with another embodiment of the present invention;











Similar to

FIG. 16

,

FIG. 17

is a sectional view of a horizontally polarized 60 degree sector azimuth 10 GHz LMDS antenna with the radome removed in accordance with another embodiment of the present invention.




DETAILED DESCRIPTION




To address the needs in the art, and in accordance with the present invention, a shaped reflector antenna, excited by a linear array of dipole elements or dipoles, is disclosed to address the above-described need in LMDS systems, such as systems operating on the 10.15-10.65 GHz LMDS band. In one embodiment of the invention, the antenna and associated components and housing is roughly the size and shape of a “pizza box,” (e.g., a rectilinear “box” on the order of one foot square with thickness of on the order of a few inches) and can be readily modified to cover any desired sector beamwidth (e.g., 30 to 90 degrees), with a narrow, shaped elevation pattern.




It will be appreciated that other modifications could be made to this antenna for use in other frequency bands and for other purposes and services without departing from the spirit of the invention. Similarly, various different modulation schemes and/or other types of services could also be provided in accordance with the disclosed embodiment without departing from the spirit of the invention.




Referring now more particularly to the drawings,

FIG. 1

shows an exploded view of a vertically polarized antenna embodiment referenced above employing an integrated feed system in accordance with one embodiment of the present invention. The antenna structure is designated generally by reference numeral


10


. The integrated feed system or network is designated generally by reference numeral


12


. Connectivity to the feed system


12


is provided via coaxial connectors


14


; however, various other connectors may be used without departing from the spirit of the invention. The feed system


12


includes a flat substantially planar circuit board


16


that may be a sheet of dielectric circuit board material. One suitable such board material is on the order of 0.030 inches thick. Other thicknesses may be used without departing from the invention. However, such a thickness has been found to be suitable for applications in the 10.15-10.65 GHz LMDS band. The board


16


is shaped and formed for the purposes of the invention as shown in FIG.


1


.




Etched or otherwise formed or deposited on the front surface of the circuit board


16


and visible in

FIG. 1

, is an electrically conductive microstrip pattern that forms a feed network


18


. The pattern for the feed network


18


may be deposited in copper or other suitable conductive material by any suitable process. Referring to

FIGS. 2

,


4


, and


5


, the microstrip feed network


18


,


18




a


feeds or is electrically coupled to a plurality of feed or radiating elements


20


. In the illustrated embodiment those radiating elements


20


have portions that are configured as dipole elements. The feed network


18


and elements


20


are duplicated on the other half of board


16


as elements


18




a


,


20




a


. In

FIGS. 1

,


2


and


4


, the dipole elements


20


,


20




a


are deposited on projecting fingers


22


,


22




a


of the circuit board


16


which project outwardly from sides of board


16


and from the corresponding feed networks


18


,


18




a


. In the embodiment of

FIG. 1

, the feed networks


18


,


18




a


, and elements


20


,


20




a


are shown positioned on both lateral edges of the circuit board


16


; however, the elements


18


,


20


may also only be on one side. These projecting fingers


22


,


22




a


are routed, cut or otherwise formed in the same sheet of dielectric material which forms the rest of circuit board


16


. In accordance with conventional practice, baluns or balun regions


23


,


23




a


are formed on the circuit board


16


in the area in which the feed networks


18


,


18




a


join the projecting feed or radiating elements


20


,


20




a


, which in the embodiment of

FIGS. 1

,


2


, and


4


-


6


are dipole elements or dipoles. Like the feed networks


18


,


18




a


, the dipole elements


20


,


20




a


and baluns


23


,


23




a


are formed by a conductive microstrip pattern.




In the illustrated embodiment, corresponding feed networks and feed elements (similar to the feed networks


18


,


18




a


and feed elements


20


,


20




a


) are formed on the opposite or back surface of the circuit board


16


, which is not visible in FIG.


1


. On one surface of the circuit board


16


the dipole elements defining the feed elements


20


,


20




a


project in one direction on fingers


22


,


22




a


, for example, as indicated by the reference numeral


24


. Referring to

FIGS. 4-6

, the dipole elements


20


,


20




a


, on one surface of the circuit board


16


have a portion


24


that extends generally upwardly with the board oriented as shown. On the opposite surface of the circuit board


16


, the elements


20


,


20




a


include a portion


26


which extends generally downwardly in an opposite direction to portion


24


. The microstrip patterns forming the feed networks


18


,


18




a


and the feed elements


20


,


20




a


align with each other, as do the portions


24


,


26


, which are shown linearly aligned in

FIGS. 4-6

.

FIGS. 4-6

are essentially illustrated as if the circuit board


16


is clear, so that both portions


24


,


26


are visible and shown extending in opposite directions.

FIG. 1

shows one surface with only portions


24


illustrated. The corresponding portions


24


,


26


deposited on the front and back sides of the circuit board


16


collectively define a dipole element, referred to as dipole


25


. In order to accommodate the respective dipole elements


25


, the finger


22


is somewhat wider in regions


28


, as shown in

FIGS. 4-6

, where these elements are deposited or otherwise formed. Thus, the circuit board


16


, feed networks


18


,


18




a


, and dipole elements


20


,


20




a


with dipole elements


25


together form an integrated antenna feed network that is a unitary structure and is relatively straightforward and inexpensive to manufacture.




A second aspect of the invention involves reflector elements


30


,


32


used in conjunction with the feed networks


18


,


18




a


and elements


20


,


20




a


. In the embodiment of

FIG. 1

, dual reflectors elements or panels


30


,


32


are used. Referring to

FIG. 4

, the fingers


22


,


22




a


bearing dipole elements


25


will overlay the reflector elements


30


,


32


, shown in

FIGS. 1-2

. Referring to

FIG. 4

, outermost edge strips


27


,


27




a


of circuit board


16


are cut away or otherwise removed prior to assembly of the feed network


12


with the reflector elements


30


,


32


. This allows the fingers


22


,


22




a


to move through slots in the reflector elements


30


,


32


.




Referring once again to

FIG. 1

, in order to conveniently position fingers


22


,


22




a


and dipole elements


25


relative to the reflector elements


30


,


32


in such a manner as to suspend the dipole elements


25


at a desired position relative to the reflector element surfaces


31


and overlaying the reflector elements


30


,


32


, a number of through slots or apertures


34


,


36


are formed in the reflectors. In this embodiment, the apertures


34


through the reflector elements are generally cross or “plus sign” shaped as shown in

FIGS. 1-3

; however, the apertures


34


may be any shape which allows the fingers


22


,


22




a


to pass through the reflector elements


30


,


32


without the feed networks


18


,


18




a


contacting the reflectors when assembled. As seen in

FIG. 3

, the vertical arm or portion


37


of each of these apertures


34


is relatively narrow, and preferably just wide enough to allow passage of the thin material of the fingers


22




a


,


22


therethrough, such as 0.030 inch thick fingers from a circuit board


16


. The length of each vertical aperture portion


37


is also sufficient to allow the circuit board portion


28


with the dipole elements


25


to pass therethrough. The horizontal arm or portion


39


of each these apertures


34


are somewhat wider. The wider width of aperture portions


39


is in order to prevent or minimize interaction between the metal surfaces of the reflector elements


30


,


32


and the feed networks


18


,


18




a


and dipole elements


25


that are deposited on both sides of the fingers


22


,


22




a.






As shown in

FIGS. 1 and 3

, the outer end of fingers


22


,


22




a


are supported by additional through apertures


36


in the outer edges of reflector elements


30


,


32


. The elongated fingers are inserted into the apertures


36


to provide additional support. However, these additional apertures


36


may be omitted without departing from the scope of the invention. In this case, the elongated portion of the fingers


22


,


22




a


past the dipole elements


25


may be trimmed. In

FIG. 3

, the apertures are shown in phantom in a portion of the shaped reflector


32


.





FIG. 1

also illustrates a radome including a metallic back cover


40


and a radome cover


42


. A sheet of polarizing material


44


may be optionally mounted inside the radome cover


42


. In the embodiment illustrated in

FIG. 1

, the polarizing sheet


44


is configured to reduce the cross-polarized antenna response. However, it will be appreciated that by rotating the dipoles 90 degrees and reconfiguring the polarizing sheet, and as will be shown in conjunction with the discussion of

FIG. 9

, horizontal polarization is possible without departing from the scope of the invention.




It will also be appreciated that the embodiments illustrated in conjunction with this disclosure are for implementations requiring two antennas similarly polarized, within a single housing. This is for applications that require redundancy. However, if both horizontal and vertical polarizations were desired, the two antennas could be configured to so as to provide both horizontal and vertical polarization within a single antenna structure according to principles of the invention. For example, one-half of the antenna structure shown in

FIG. 1

may have components configured for one polarization and the other half of the antenna structure might provide the other polarization. Similarly, if only one antenna were desired, the structures of the embodiments illustrated herein could be divided in half, corresponding to substantially one-half of the structure of

FIG. 1

along an imaginary vertical centerline.




Referring to

FIG. 2

, a photograph of an embodiment of an antenna consistent with the present invention is shown with the radome cover


42


and the polarizing sheet


44


removed. As depicted,

FIG. 2

shows how the elements of the antenna appear when the antenna structure is assembled. One particular aspect of the described embodiment is the feed method, which integrates a feed network


18


with an array of dipole elements


25


on a single circuit board


16


. The dipole elements


25


, residing on fingers


22


,


22




a


routed or otherwise formed on the board edges slide through apertures


34


,


36


provided in the sides of the shaped reflectors


30


,


32


. The reflectors


30


,


32


, in the embodiment disclosed are plastic, and have a suitable metallic reflective coating, such as aluminum, copper or a reflective paint; however, other fabrication methods, such as sheet metal, will function in a similar manner.




Referring now to

FIG. 3

, an enlarged perspective view of the reflector element


32


of

FIGS. 1 and 2

is shown. It should be appreciated that reflector element


32


may be used as either element


30


or


32


in the embodiment of

FIGS. 1 and 2

by merely reversing the orientation of the panel, since the reflector elements thereof are symmetrically formed for either side of the antenna structures in antenna


10


. That is, one of an identical pair of elements


30


may be rotated 180 degrees, while facing in the same direction to achieve the configuration of the panels


30


,


32


, as shown. This reduces the parts count when manufacturing an antenna in accordance with the aspects of the invention.




To utilize the antenna


10


disclosed herein for specific applications and frequency bands, the length of the dipoles may be selected to radiate at a desired frequency as will be known to a person of ordinary skill in the art. For example, for use in the 10 GHz LMDS signal band the dipole elements


25


may be 1.16 centimeters long. Similarly, the shape of the reflector elements


30


,


32


may be selected so as to shape the radiation pattern of the dipole elements also as known to one of ordinary skill in the art. For example, the shape of the reflectors may be formed to obtain a desired azimuth beamwidth of 60 or 90 degrees.




Referring now to

FIG. 7

, a sectional view of an embodiment of the present invention is illustrated for a vertically polarized 10 GHz LMDS antenna with an azimuth beam width of 60 degrees. In this illustration, the radome has been removed to further illustrate the reflector elements


70


. As will be appreciated by one of ordinary skill in the art, the shape of the reflector elements


70


has been formed so as to provide a desired azimuth beamwidth of 60 degrees. In addition, structural support ribs


72


have been added to the reflector elements


70


to further stabilize the positioning of the reflector elements


70


relative to integrated feed system


12


.




Referring now to

FIG. 8

, a sectional view of an embodiment of the present invention is illustrated for a vertically polarized 10 GHz LMDS antenna with an azimuth beam width of 90 degrees. In this illustration, as in

FIG. 7

, the radome has been removed to further illustrate the reflector elements


72


. Similar to the embodiment of

FIG. 7

, the reflector elements


74


of the embodiment of

FIG. 8

have been formed so as to provide a desired azimuth beamwidth of 90 degrees. Also like the reflector elements


70


of

FIG. 7

, the reflector elements


74


of

FIG. 8

have structural support ribs


72


.





FIGS. 9-11

illustrate an alternative embodiment of the invention.

FIG. 9

shows an exploded view of an antenna embodiment referenced above for a horizontally polarized 10 GHz LMDS antenna with an azimuth beamwidth of 90 degrees. Similar to the embodiment of

FIG. 1

, the antenna


110


in

FIG. 9

employs an integrated feed system or network


112


with a feed network


118


electrically coupled to feed or radiating elements


120


located on fingers


122


. Also, like the embodiment of

FIG. 1

, the radiating elements


120


are configured as dipole elements, and deposited on the front and back sides of the circuit board


116


. However, the projecting fingers


122


are somewhat shorter in the embodiment of

FIGS. 9-11

. Further, the feed network


118


and elements


120


are duplicated on the other side of circuit board


116


as elements


118




a


,


120




a


. However, in comparison to the embodiment of

FIG. 1

, the radiating elements


120


,


120




a


have been rotated 90 degrees and when used in conjunction with reflector elements


130


,


132


provide an antenna


110


with horizontal polarization with an azimuth beamwidth of 90 degrees.




An optional polarizing sheet may be used. The polarizing sheet


144


for horizontally polarized embodiments of the present invention may consist of a mylar sheet, approximately 0.006 inches thick, with parallel etched copper strips or wires


145


, approximately 0.015 inches wide, located approximately every 0.043 inches. The polarizing sheet


144


may be placed so that the strips


145


run vertically as shown in FIG.


9


. The polarizing sheet


144


functions to filter the cross-polarized radiation from the antenna response, in effect, “cleaning up” the polarization. Although this polarized sheet


144


may be used for the embodiment of the invention shown in

FIG. 9

, variations in the polarizing sheet for other embodiments are possible without departing from the spirit of the invention.




More particularly, and as best illustrated in

FIGS. 10 and 11

, radiating elements


120


comprising “bowtie” dipoles are illustrated. The bowtie dipoles are formed on either side of the projecting fingers


122


of the circuit board


116


. The bowtie dipole elements on the top surface of the finger


122


are indicated by reference numeral


124


in

FIGS. 10 and 11

. The bowtie dipole element on the bottom side of the finger


122


is not visible in

FIG. 10

; but is shown in

FIG. 11

, as the finger


122


has been removed to illustrate the bowtie elements


124


,


126


and their respective feed lines


120


,


121


formed on either side of the finger


122


. Other embodiments of the present invention may use simple straight dipole elements without departing from the spirit of the invention.




Referring now to the embodiments shown in

FIGS. 12 and 13

, and as alluded to, another aspect of the invention involves alternative radiating elements. In the embodiment of

FIG. 12

, patches elements


56


etched on a circuit board


50


located in the bottom of a trough waveguide


52


are employed. As illustrated, microstrip patch elements


56


are fed by microstrip transmission lines


57


that are mounted or formed on fingers


22


, and fitted as feed elements in a trough waveguide


52


formed in the surface of the shaped reflector panel


32




a


. As also illustrated in

FIG. 12

, the trough waveguide


52


does not have a constant width, but remains narrow enough to inhibit propagation of higher order modes.




Referring now to

FIG. 13

, probe-feed radiating elements


58


are employed. In

FIG. 13

, probe-feed radiating elements


58


are formed in the end of a microstrip feed line


59


. The straight microstrip line is formed on the surface of fingers


22


that extends through openings


54


in the side of the waveguide


52


formed in the surface of the shaped reflector panel


32


. As illustrated for this particular embodiment, the microstrip feed line is formed on the top surface of fingers


22


. Also formed on the fingers


22


is a ground plane


51


. This embodiment requires either direct ground plane


51


to metallized reflector


32


contact, or capacitive coupling at the point where the ground plane


51


enters the trough waveguide


52


. As shown in this particular embodiment, the ground plane


51


is formed on the bottom surface of the fingers


22


. However, a microstrip feed line could be formed on the bottom and a ground plane formed on the top without departing from the scope of the invention. In such a scenario, the fingers


22


would be shifted upwardly to maintain the aforementioned ground contact or coupling. Unlike the embodiment shown in

FIG. 12

, the trough waveguide


52


of the embodiment of

FIG. 13

has walls that remain at a constant width selected to prevent propagation of higher order modes.




The reflector element


32


, as viewed in cross-section, is curvilinear, i.e., with a smoothly, continuously curved or “wavy” form. Asymmetry in the radiated fields excites an evanescent higher order trough waveguide mode that is attenuated by the distance or depth


55


. This depth


55


from the open end of the trough waveguide


52


to the radiating element


56


may be adjusted to obtain symmetric azimuth sector patterns; for 10 GHz, one embodiment sets this depth


55


at 0.319 inches. The trough waveguide


52


should be conveniently sized to transmit only the lowest mode effectively. For applications in the 10 GHz LMDS band, the width


53


has been found to be approximately 1.29 centimeters. While this is shown for a probe element


58


of

FIG. 13

, the aforementioned is also valid for the bowtie dipole elements in

FIGS. 10-11

and for patch elements used in the embodiment of FIG.


12


.




The small through openings


54


are formed at regular intervals along the length of the trough waveguide


52


formed in the reflector


32


to accommodate the fingers


22


carrying the probes


58


, that may be the same in number and have the same relative spacing as the fingers


22


bearing the dipole elements shown in

FIG. 1

, for example. The patches


56


may be similarly formed in the bottom of the trough waveguide


52


on the same circuit boards


16


,


116


on the outwardly projecting fingers


22


,


122


thereof, as were illustrated in previous embodiments. Thus, the microstrip probe/patch array is used to excite the trough waveguide


52


of the reflectors


32


,


32




a.






As illustrated in the horizontally polarized embodiments disclosed herein, chokes may be utilized, such as edge chokes formed by alternating ribs


60


, and grooves


62


to provide additional control of the radiation pattern. Edge chokes function to prevent or “choke off” electric currents on the reflector edges from wrapping around to the back sides of the reflector and degrading the radiation pattern with unpredictable reactions.




Referring now to

FIG. 14

, a simplified, partial perspective view of a reflector element


80


and feed elements


84


, such as bowtie dipole elements


124


,


126


shown in the embodiment of

FIGS. 10 and 11

, for a horizontally polarized 90 degree 10 GHz LMDS antenna in accordance with another embodiment of the present invention is illustrated. In this embodiment the reflector elements


80


have been shaped to provide a desired azimuth beamwidth of 90 degrees housed within radome


82


. Also, as illustrated in

FIG. 14

, edge chokes in the form of alternating ribs


86


and grooves


88


, have been included to provide additional radiation pattern control.




Referring now to

FIG. 15

, a sectional view of the embodiment of

FIG. 14

is illustrated for the horizontally polarized 10 GHz LMDS antenna with an azimuth beamwidth of 90 degrees. In this illustration, the radome has been removed to further illustrate the reflector elements


80


. As will be appreciated by one of ordinary skill in the art, the shape of the reflector elements


80


has been formed so as to provide a desired azimuth beamwidth of 90 degrees. In addition, structural support ribs


72


have been added to the reflector elements


80


to further stabilize the positioning of the reflector elements


80


relative to the feed elements


84


.




Similar to the embodiment of

FIGS. 14 and 15

, the embodiment of the present invention shown in

FIG. 16

is for a horizontally polarized 60 degree 10 GHz LMDS antenna. A simplified, partial perspective view of a reflector element


90


and feed elements


94


, such as patch elements


56


shown in the embodiment of

FIGS. 12 and 13

, within radome


92


is illustrated. Also, as an alternative aspect of the present invention, edge chokes in the form of alternating ribs


96


and grooves


98


, have been include to provide additional radiation pattern control.




Referring now to

FIG. 17

, a sectional view of the embodiment of

FIG. 16

is illustrated. In this illustration, as in

FIG. 15

, the radome has been removed to further illustrate the reflector elements


90


. Also similar to the embodiment of

FIGS. 14 and 15

, the reflector elements


90


have been formed so as to provide a desired azimuth beamwidth of 60 degrees. Once again, structural support ribs


72


have been provided.




Therefore, it may be seen that the invention outlined herein is useful from several viewpoints. It provides an improved antenna with a specified azimuth beamwidth. It has relatively simple and few parts. It is also relatively easy and inexpensive to manufacture. It is also easy to install and maintain. Thus, it achieves high performance in an aesthetically pleasing package.




While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicant's general inventive concept.



Claims
  • 1. An integrated feed system for an antenna comprising:a circuit board; a first feed network formed on the circuit board; and a plurality of feed elements formed on the circuit board and electrically coupled with the first feed network and projecting outwardly therefrom, the board having a plurality of projecting fingers which mount the feed elements.
  • 2. The feed system of claim 1, wherein the first feed network comprises a microstrip network.
  • 3. The feed system of claim 1, wherein the feed elements are dipole elements.
  • 4. The feed system of claim 3, wherein a microstrip feed network and dipole elements are formed on opposite surfaces of the circuit board.
  • 5. The feed system of claim 3, wherein the dipole elements are configured for vertical polarization.
  • 6. The feed system of claim 3, wherein the dipole elements are configured for horizontal polarization.
  • 7. The feed system of claim 1, wherein the feed elements are microstrip patch elements.
  • 8. The feed system of claim 1 wherein a second feed network is formed on the circuit board, and one or more second feed elements project from the second feed network in a direction opposite the feed elements projecting from the first feed network.
  • 9. The feed system of claim 8, wherein the second feed network comprises a microstrip network.
  • 10. The feed system of claim 8, wherein the second feed elements are dipole elements.
  • 11. The feed system of claim 8, wherein the second feed elements are microstrip patch elements.
  • 12. An antenna comprising:a shaped reflector element; and a feed system comprising: a circuit board, a feed network formed on the circuit board; and, a plurality of feed elements electrically coupled with the feed network and projecting outwardly therefrom, the board having projecting fingers which mount the feed elements, the fingers being positioned for suspending the feed elements above the reflector element.
  • 13. The antenna of claim 12, wherein the reflector element includes at least one slot formed therein, a finger projecting through the slot for suspending the feed element.
  • 14. The antenna of claim 12, wherein the feed network comprises a microstrip network.
  • 15. The antenna of claim 12, wherein the feed elements are dipole elements.
  • 16. The antenna of claim 12, wherein the feed element s are microstrip patch elements.
  • 17. The antenna of claim 15, wherein a microstrip feed network and the dipole elements are formed on opposite sides of the circuit board.
  • 18. The antenna of claim 15, wherein the dipole elements are configured for vertical polarization.
  • 19. The antenna of claim 15 wherein the dipole elements are configured for horizontal polarization.
  • 20. The antenna of claim 12, wherein a second feed network is also formed on the circuit board and one or more second feed elements project from the second feed network in a direction opposite the feed elements projecting from the first feed network.
  • 21. The antenna of claim 20, wherein the second feed elements are dipole elements.
  • 22. The antenna of claim 12, wherein the reflector element comprises a curvilinear shaped surface having a smoothly curved cross-section.
  • 23. The antenna of claim 12, wherein the reflector element includes a trough waveguide having at least one slot formed therein for receiving a finger therethrough.
  • 24. The antenna of claim 12, wherein the reflector element has a plurality of chokes formed on an outer edge thereof.
  • 25. The antenna of claim 12, further comprising:a second reflector element; and, the feed system further comprising: a second feed network formed on the circuit board; and, a second plurality of feed elements electrically coupled with the second feed network and projecting outwardly therefrom, the board having projecting fingers which mount the second feed elements; and, the second feed element fingers being positioned for suspending the second feed elements above the second reflector element; and, the first and second reflector elements having slots formed therein, the fingers projecting therethrough for suspending the feed elements.
  • 26. The antenna of claim 25, wherein the first and second reflector elements each comprise a curvilinear shaped surface.
  • 27. The antenna of claim 26, wherein the first and second reflector elements each include a trough waveguide.
  • 28. The antenna of claim 27, wherein the second plurality of feed elements are dipole elements.
  • 29. The antenna system of claim 25 wherein the first plurality of feed elements is configured for one of vertical and horizontal polarization and the second plurality of feed elements is configured for the other of vertical and horizontal polarization.
  • 30. The antenna of claim 27, wherein each reflector element has a plurality of chokes formed on outer edges thereof.
  • 31. An integrated feed method for an antenna comprising:with a feed network formed on the circuit board, feeding a plurality of feed elements also formed on the circuit board; and, positioning the feed elements on a plurality of fingers projecting outwardly from an edge of the circuit board.
  • 32. The method of claim 31 further comprising reflecting signals from the feed elements with a reflector element and suspending the feed elements over the reflector element.
  • 33. The method of claim 32 further comprising projecting the fingers carrying the feed elements through slots formed in the reflector element to suspend the feed elements over the reflector element.
  • 34. The method of claim 32, wherein the reflector element surface comprises a curvilinear surface.
  • 35. The method of claim 32, wherein the reflector element includes a trough waveguide, the method further comprising suspending the feed elements in the trough.
  • 36. The method of claim 32, wherein the reflector element includes a plurality of chokes on an outer edge thereof.
  • 37. The method of claim 31, wherein the feed network is a microstrip feed network.
  • 38. The method of claim 31 wherein the feed elements are dipole elements.
  • 39. The method of claim 38, wherein the dipole elements are configured for horizontal polarization.
  • 40. The method of claim 38, wherein the dipole elements are configured for vertical polarization.
  • 41. The method of claim 31, wherein the feed elements are microstrip patch elements.
  • 42. The method of claim 32, further comprising:feeding a second plurality of feed elements formed on the circuit board with a second feed network formed on the circuit board, positioning the second plurality of feed elements on a plurality of fingers projecting in a direction opposite to the fingers carrying the first feed elements.
  • 43. The method of claim 42, wherein the second plurality of feed elements are dipole elements.
  • 44. The method of claim 42, wherein the second plurality of feed elements are microstrip patch elements.
  • 45. The method of claim 42 further comprising configuring the first plurality of feed elements for one of vertical polarization and horizontal polarization and configuring the second plurality of feed elements for the other of vertical polarization and horizontal polarization.
  • 46. The method of claim 42 further comprising reflecting signals from the second plurality of feed elements with a second reflector element and suspending the second plurality of feed elements over the reflector element.
  • 47. The method of claim 46 further comprising projecting the fingers carrying the second feed elements through slots formed in the second reflector element.
  • 48. The method of claim 46, wherein at least one of the reflector elements includes a plurality of chokes on an outer edge thereof.
  • 49. The method of claim 31, wherein the feed network and the feed elements are formed on opposite sides of the circuit board.
CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the priority date of U.S. Provisional application, Serial No. 60/244,938, filed Nov. 1, 2000, under the same title. The disclosure of the provisional application is incorporated herein by reference in its entirety.

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Entry
Bjorn Lindmark, Peter Slattman and Anders Ahfeldt, Genetic Algorithm Optimization of Cylindral Reflectors for Aperture-Coupled Patch Elements, IEEE, 1999.
Peter Slattman and Bjorn Lindmark, Moment Method Analysis of an Aperture Coupled Patch Antenna in a Cylindrical PEC Structure with Arbitrary Cross Section, 2000 AP Symposium; Salt Lake City.
Provisional Applications (1)
Number Date Country
60/244938 Nov 2000 US