Abstract:
The present invention is directed to an antenna assembly. The antenna assembly may include multiple sets of radiators (ex.—antenna elements) with each set of radiators being fed by its own RF feed network. The multiple sets of radiators may be arranged in a stackable configuration for providing a low profile antenna assembly which concurrently supports multiple frequency bands (exs.—L band, C band, K u  band).

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of antenna technology and particularly to a stackable antenna concept for multiband operation. 
     BACKGROUND OF THE INVENTION 
     A number of currently available Radio Frequency (RF) configurations may implement multiple RF systems (ex.—antennas) on a single platform. These multiple antennas on the single platform add cost, weight, drag and configuration problems for such RF configurations. Further, for many of these currently available systems, providing separate bands has required separate antenna installations and has required separate connections to separate radios. Previously, Ultra-wideband (UWB) antennas have been implemented to obviate some of the above-referenced problems. However, UWB antennas are typically large and often require a diplexor to connect multiple radios. 
     Thus, it would be desirable to provide an antenna system which obviates the problems associated with currently available RF system implementations. 
     SUMMARY OF THE INVENTION 
     Accordingly, an embodiment of the present invention is directed to an antenna assembly, including: a first feed board, the first feed board including a ground plane; a first plurality of radiators, the first plurality of radiators being connected to the first feed board; a first RF feed, the first RF feed being connected to the first feed board and the first plurality of radiators, the first RF feed configured for feeding the first plurality of radiators via the first feed board, wherein the first plurality of radiators, in response to receiving said feeding, is configured for radiating electromagnetic energy in a radiation pattern; a second feed board, the second feed board including a ground plane, the second feed board being connected to and stacked upon the first plurality of radiators; a second plurality of radiators, the second plurality of radiators being connected to the second feed board; a second RF feed, the second RF feed being connected to the second feed board and the second plurality of radiators, the second RF feed configured for feeding the second plurality of radiators via the second feed board, wherein the second plurality of radiators, in response to receiving said feeding from the second RF feed, is configured for radiating electromagnetic energy in a radiation pattern; a third feed board, the third feed board including a ground plane, the third feed board being connected to and stacked upon the second plurality of radiators; an antenna element, the antenna element being connected to the third feed board; and a third RF feed, the third RF feed being connected to the third feed board and the antenna element, the third RF feed being configured for feeding the antenna element via the third feed board, wherein the antenna element, in response to receiving said feeding from the third RF feed, is configured for radiating electromagnetic energy in a radiation pattern, wherein the first plurality of radiators is configured for operating over a first frequency band, the second plurality of radiators is configured for operating over a second frequency band, and the antenna element is configured for operating over a third frequency band. 
     A further embodiment of the present invention is directed to an antenna device, including: a housing; and an antenna assembly, the antenna assembly being connected to and at least substantially contained within the housing, the antenna assembly including: a first feed board, the first feed board including a ground plane; a first plurality of radiators, the first plurality of radiators being connected to the first feed board; a first RF feed, the first RF feed being connected to the first feed board and the first plurality of radiators, the first RF feed configured for feeding the first plurality of radiators via the first feed board, wherein the first plurality of radiators, in response to receiving said feeding, is configured for radiating electromagnetic energy in a radiation pattern; a second feed board, the second feed board including a ground plane, the second feed board being connected to and stacked upon the first plurality of radiators, a second plurality of radiators, the second plurality of radiators being connected to the second feed board and a second RF feed, the second RF feed being connected to the second feed board and the second plurality of radiators, the second RF feed configured for feeding the second plurality of radiators via the second feed board, wherein the second plurality of radiators, in response to receiving said feeding from the second RF feed, is configured for radiating electromagnetic energy in a radiation pattern; a third feed board, the third feed board including a ground plane, the third feed board being connected to and stacked upon the second plurality of radiators; an antenna element, the antenna element being connected to the third feed board; and a third RF feed, the third RF feed being connected to the third feed board and the antenna element, the third RF feed being configured for feeding the antenna element via the third feed board, wherein the antenna element, in response to receiving said feeding from the third RF feed, is configured for radiating electromagnetic energy in a radiation pattern; at least one radio, the at least one radio being at least substantially contained within the housing and being connected to the first RF feed, the second RF feed and the third RF feed; and at least one of: a power cord and a USB cable for electrically connecting the antenna device to a second device, wherein the first plurality of radiators is configured for operating over a first frequency band, the second plurality of radiators is configured for operating over a second frequency band and the antenna element is configured for operating over a third frequency band. 
     A still further embodiment of the present invention is directed to an antenna assembly, including: a first feed board, the first feed board including a ground plane; a first plurality of radiators, the first plurality of radiators being connected to the first feed board; a first RF feed, the first RF feed being connected to the first feed board and the first plurality of radiators, the first RF feed configured for feeding the first plurality of radiators via the first feed board, wherein the first plurality of radiators, in response to receiving said feeding, is configured for radiating electromagnetic energy in a radiation pattern; a second feed board, the second feed board including a ground plane, the second feed board being connected to and stacked upon the first plurality of radiators; an antenna element, the antenna element being connected to the second feed board; and a second RF feed, the second RF feed being connected to the second feed board and the antenna element, the second RF feed configured for feeding the antenna element via the second feed board, wherein the antenna element, in response to receiving said feeding from the second RF feed, is configured for radiating electromagnetic energy in a radiation pattern, wherein the first plurality of radiators is configured for operating over a first frequency band and the antenna element is configured for operating over a second frequency band. 
     A further embodiment of the present invention is directed to an antenna assembly, including: a feed board, the feed board including a ground plane; a plurality of radiators, the plurality of radiators being connected to the feed board, the plurality of radiators being generally wedge-shaped radiators, the plurality of radiators being arranged in a generally circular arrangement on the feed board; an RF feed, the RF feed being connected to the feed board and the plurality of radiators, the RF feed configured for feeding the plurality of radiators via the feed board, wherein the plurality of radiators, in response to receiving said feeding from the RF feed, is configured for radiating electromagnetic energy in a radiation pattern. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the general description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which: 
         FIG. 1  is a view of an antenna assembly in accordance with an exemplary embodiment of the present invention; 
         FIG. 2  is a view of an antenna device implementing the antenna assembly of  FIG. 1  in accordance with an exemplary embodiment of the present invention; and 
         FIG. 3  is a cross-sectional view of a feed board of the antenna assembly of  FIG. 1  in accordance with an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. 
     Referring to  FIG. 1 , an antenna assembly  100  in accordance with an exemplary embodiment of the present invention is shown. In an exemplary embodiment of the present invention, the antenna assembly  100  includes a first Radio Frequency (RF) substrate  102  (ex.—a first feed board  102 ). For example, the first feed board  102  may be formed of Printed Circuit Board (PCB) material. In still further embodiments of the present invention, the first feed board  102  may include a power divider  104  (ex.—a 1:N power divider, N being the number of radiators connected to the power divider). 
     In exemplary embodiments of the present invention, the antenna assembly  100  further includes a first plurality of (ex.—3 or more) antenna elements or radiators  106 . For instance, the radiators  106  included in the first plurality of radiators  106  may be generally wedge-shaped or generally triangular-shaped radiators  106  as shown in the illustrated embodiment in  FIG. 1 , or may be one or more of various other shapes. In further embodiments of the present invention, the radiators  106  included in the first plurality of radiators  106  may be connected to (exs.—may be mounted upon or supported upon) a first surface  108  (ex.—a top surface  108 ) of the first feed board  102  and may further be electrically connected to the first feed board  102 . In still further embodiments of the present invention, the antenna assembly  100  may further include a first ground plane  110 . The first ground plane  110  may be configured upon a second surface  112  (ex.—a bottom surface) of the first feed board  102 , the second surface  112  being configured generally opposite the first surface  108 . For instance, the first ground plane  110  may be a metal layer, metallization layer and/or metal foil layer (ex.—95% copper foil layer) which has been formed upon (ex.—patterned upon) the bottom surface  112  of the first feed board  102 . In further embodiments, the radiators  106  included in the first plurality of radiators  106  may be electrically connected to the first ground plane  110  via the first feed board  102 . 
     In current exemplary embodiments of the present invention, the antenna assembly  100  further includes a second RF substrate  114  (ex.—a second feed board  114 ). For example, the second feed board  114  may be formed of PCB material. In further embodiments of the present invention, the second feed board  114  may include a power divider (ex.—a 1:N power divider, N being the number of radiators connected to the power divider)  116 . In still further embodiments of the present invention, the second feed board  114  may include a first surface  118  (ex.—a top surface  118 ) and a second surface  120  (ex.—a bottom surface  120 ), the second surface  120  being configured generally opposite the first surface  118 . 
     In exemplary embodiments of the present invention, the antenna assembly  100  may further include a second ground plane  122 . The second ground plane  122  may be configured upon the second (ex.—bottom) surface  120  of the second feed board  114 . For instance, the second ground plane  122  may be a metal layer which has been formed upon (ex.—patterned upon) the bottom surface  120  of the second feed board  114 . In further embodiments of the present invention, the radiators  106  included in the first plurality of radiators  106  may be connected to the second ground plane  122 . In still further embodiments of the present invention, the second feed board  114  may be supported upon (exs.—mounted upon, stacked upon) the radiators  106  included in the first plurality of radiators  106 . 
     In current exemplary embodiments of the present invention, the first feed board  102  may be configured with a first feed aperture  124  (ex.—a feed port  124 ). The first feed aperture  124  may be configured for receiving a first RF feed  126 , the first RF feed  126  configured for being connected to the power divider  104  of the first feed board  102 . In further embodiments of the present invention, the first feed board  102 , the power divider  104  and the first RF feed  126  may be included as part of and/or may form a first feed network which is configured for feeding (ex.—providing a feed to) the radiators  106  included in the first plurality of radiators  106 . For example, the first feed network may be a microstrip or stripline feed network. In still further embodiments of the present invention, the radiators  106  included in the first plurality of radiators  106  may be configured, based upon the feed provided by the first feed network, for radiating electromagnetic energy in a radiation pattern. In further embodiments of the present invention, the design of the first feed network may determine the shape of the radiation pattern provided by the radiators  106  included in the first plurality of radiators  106 . For example, in at least one exemplary embodiment of the present invention, the first feed network may be configured for feeding the radiators  106  of the first plurality of radiators  106  in-phase, thereby causing the radiators  106  included in the first plurality of radiators  106  to provide an omni-directional radiation pattern (ex.—an omni-directional beam). In alternative embodiment(s) of the present invention, the first feed network may be configured for feeding the radiators  106  of the first plurality of radiators  106  out-of-phase, thereby allowing the antenna assembly  100  to produce a directional beam. 
     In exemplary embodiments of the present invention, the antenna assembly  100  may further include a second plurality of (ex.—3 or more) antenna elements or radiators  128 . For instance, the radiators  128  included in the second plurality of radiators  128  may be generally wedge-shaped or generally triangular-shaped radiators  128 , as shown in the illustrated embodiment of  FIG. 1 , or may be one or more of various other shapes. In further embodiments of the present invention, the radiators  128  included in the second plurality of radiators  128  may be connected to (exs.—mounted upon or supported upon) the top surface  118  of the second feed board  114 , and may further be electrically connected to the second feed board  114 . In still further embodiments of the present invention, the radiators  128  included in the second plurality of radiators  128  may be electrically connected to the second ground plane  122  via the second feed board  114 . 
     In current exemplary embodiments of the present invention, the antenna assembly  100  further includes a third RF substrate  130  (ex.—a third feed board  130 ). For example, the third feed board  130  may be formed of PCB material. In further embodiments of the present invention, the third feed board  130  may include a first surface  132  (ex.—a top surface  132 ) and a second surface  134  (ex.—a bottom surface  134 ), the second surface  134  being configured generally opposite the first surface  132 . 
     In exemplary embodiments of the present invention, the antenna assembly  100  may further include a third ground plane  136 . The third ground plane  136  may be configured upon the second (ex.—bottom) surface  134  of the third feed board  130 . For instance, the third ground plane  136  may be a metal layer which has been formed upon (ex.—patterned upon) the bottom surface  134  of the third feed board  130 . In further embodiments of the present invention, the radiators  128  included in the second plurality of radiators  128  may be connected to the third ground plane. In still further embodiments of the present invention, the third feed board  130  may be supported upon (exs.—may be mounted upon, stacked upon) the radiators  128  included in the second plurality of radiators  128 . 
     In current exemplary embodiments of the present invention, the first feed board  102  may be configured with a second feed aperture  138 . The second feed aperture  138  may be configured allowing passage of a second RF feed  140  through or via the second feed aperture  138 . For example, the second feed aperture  138  may be a generally central-located channel formed through the first feed board  102 , extending longitudinally through the top surface  108  and ground plane  110  of the first feed board  102 . In further embodiments of the present invention, the second RF feed  140  may be configured for being positioned (exs.—threaded, routed) through the second feed aperture  138  and connected to the power divider  116  of the second feed board  114  via a first feed aperture  142  of the second feed board  114 . The second feed board  114 , power divider  116  and the second RF feed  140  may be included as part of and/or may form a second feed network which is configured for feeding (ex.—providing a feed to) the radiators  128  included in the second plurality of radiators  128 . For example, the second feed network may be a microstrip or stripline feed network. 
     In further embodiments of the present invention, the radiators  128  included in the second plurality of radiators  128  may be configured, based upon the feed provided by the second feed network, for radiating electromagnetic energy in a radiation pattern. In still further embodiments of the present invention, the design of the second feed network may determine the shape of the radiation pattern provided by the radiators  128  included in the second plurality of radiators  128 . For example, in at least one exemplary embodiment of the present invention, the second feed network may be configured for feeding the radiators  128  of the second plurality of radiators  128  in-phase, thereby causing the radiators  128  included in the second plurality of radiators  128  to provide an omni-directional radiation pattern (ex.—an omni-directional beam). In alternative embodiment(s) of the present invention, the second feed network may be configured for feeding the radiators  128  of the first plurality of radiators  128  out-of-phase, thereby allowing the antenna assembly  100  to produce a directional beam. 
     In exemplary embodiments of the present invention, the first feed board  102  may be configured with a third feed aperture  144 . The third feed aperture  144  may be configured for allowing passage of a third RF feed  146  through or via the third feed aperture  144 . For example, the third feed aperture  144  may be a generally central-located channel formed through the first feed board  102 , extending longitudinally through the top surface  108  and ground plane  110  of the first feed board  102 . In further embodiments of the present invention, the third RF feed  146  may be configured for being positioned (exs.—threaded, routed) through the third feed aperture  144 . In still further embodiments of the present invention, the second feed board  114  may include a second feed aperture  148 , said second feed aperture  148  being a longitudinally extending channel formed through the second feed board  114  (ex.—formed through the top surface  118  of the second feed board  114  and the ground plane  122  of the second feed board). As mentioned above, the third RF feed  146  may be configured for being positioned (exs.—threaded, routed) through the third feed aperture  144  of the first feed board  102 , and in further exemplary embodiments of the present invention, is further configured for being positioned (exs.—threaded, routed) through the second feed aperture  148  of the second feed board  114 . 
     In current exemplary embodiments of the present invention, an antenna element  150  may be connected to (exs.—mounted upon or supported upon) the top surface  132  of the third feed board  130 . For example, the antenna element  150  may be a monopole antenna element  150 . In alternative embodiments of the present invention, the antenna element  150  may be a more complex antenna type. In further embodiments of the present invention, the antenna element  150  may be electrically connected to the third ground plane  136  via the third feed board  130 . In still further exemplary embodiments of the present invention, the third feed board  130  includes a feed aperture  152  (ex.—feed port  152 ). As mentioned above, the third RF feed  146  may be configured for being positioned (exs.—threaded, routed) through the third feed aperture  144  of the first feed board  102 , through the second feed aperture  148  of the second feed board  114 , and in further exemplary embodiments of the present invention, is further configured for being received by the feed aperture  152  of the third feed board  130 . In further embodiments of the present invention, the third RF feed  146  and third feed board  130  may form a third feed network  315  which is configured for feeding (ex.—providing a feed to) antenna element  150 . For example, the third feed network  315  may be a microstrip or stripline feed network. In still further embodiments, the antenna element  150  may be configured, based upon the feed provided by the third feed network  315  for radiating electromagnetic energy in a radiation pattern. 
     In exemplary embodiments of the present invention, the first plurality of radiators  106 , the second plurality of radiators  128  and antenna element  150  may each be broadband (ex.—30 to 50 percent bandwidth). In further embodiments of the present invention, the stackable antenna assembly  100  of may be configured for supporting multiple frequency bands (ex.—may be a multiband antenna  100 ). For instance: the first RF feed  126  may be a low band RF feed  126  (ex.—a L band RF feed) and the first plurality of radiators  106  may be configured for operating over the L band range of frequencies (exs.—within the 1 Gigahertz (GHz) to 2 GHz frequency band); the second RF feed  140  may be a mid band RF feed  140  (ex.—a C band RF feed) and the second plurality of radiators  128  may be configured for operating over the C band range of frequencies (ex.—within the 4 GHz to 8 GHz frequency band); the third RF feed  146  may be a high band RF feed  146  (ex.—a K u  band RF feed) and antenna element  150  may be configured for operating over the K u  band range of frequencies (ex.—within the 12 GHz to 18 GHz frequency band). In alternative embodiments of the present invention, the stackable antenna assembly  100  may be configured with additional radiators/antenna elements, feed boards, and RF feeds as needed for supporting additional (ex.—more than 3) frequency bands. 
     In current exemplary embodiments of the present invention, the top surface  118  of the second feed board  114  may be a high impedance surface. For instance, the top surface  118  of the second feed board  114  may include or may be at least partially formed of metal (exs.—corrugated metal, aluminum), said metal having grooves  154  (ex.—¼ wavelength-deep grooves) formed therein (as shown in  FIG. 3 ). In still further embodiments of the present invention, the high impedance surface (ex.—the top surface  118  of the second feed board  114 ) may prevent scattering effects caused by the first plurality of radiators  106  from adversely affecting performance of the second plurality of radiators  128  and antenna element  150 . For example, the grooves  154  may act as a choke for changing the phase of reflection of signals and for mitigating undesired scattering caused by the first plurality of radiators  106 . 
     In exemplary embodiments of the present invention, the first plurality of radiators  106 , the second plurality of radiators  128  and antenna element  150  may each be configured for providing monopole-like radiation patterns (ex.—0 dBi). In further embodiments of the present invention, each radiator  106  included in the first plurality of radiators  106 , each radiator  128  included in the second plurality of radiators, and antenna element  150  may be configured (ex.—shaped) to provide optimal bandwidth and may be further configured (ex.—sized) for minimizing the profile of the antenna assembly  100 . For example, each radiator  106  included in the first plurality of radiators  106  may be sized so that the distance between the first feed board  102  and the second feed board  114  is approximately ⅛ lamda in height, while the first feed board  102  may have a diameter of ½ lamda. 
     In current exemplary embodiments of the present invention, one or more of the first RF feed  126 , the second RF feed  140  and the third RF feed  146  may each include or may each be at least partially enclosed in (ex.—fed through) a protective casing (exs.—a conduit, hollow casing). For example, in the illustrated embodiment of the present invention shown in  FIG. 1 , a conduit  156  surrounding the second RF feed  140  may function as a central post  156  upon which the second feed board  114  may be at least partially supported and around which the first plurality of radiators  106  may be located or positioned. Further, a conduit  158  surrounding the third RF feed  146  may function as a central post  158  upon which the third feed board  130  may be at least partially supported and around which the second plurality of radiatiors  128  may be configured. In alternative embodiments of the present invention, the number of conduits which are implemented for protecting the RF feeds ( 126 ,  140 ,  146 ) may vary, for instance, one conduit may be used to enclose multiple feeds, etc. In further alternative embodiments of the present invention, the number of feed apertures implemented in the feed boards ( 102 ,  114 ,  130 ) may vary as well, for instance, one feed aperture may allow for passage of multiple RF feeds, etc. 
     In exemplary embodiments of the present invention, the antenna assembly  100  may include one or more radios  160 , the one or more radios  160  configured for being connected to the RF feeds ( 126 ,  140 ,  146 ). In further embodiments of the present invention, the antenna assembly  100  may be implemented as part of an antenna device  300  as shown in  FIG. 2 . The antenna device  300  may include a housing (ex.—a low-profile, circular puck-shaped housing  302 ) which is configured for enclosing (ex.—at least substantially containing and being connected to) the antenna assembly  100 . In further embodiments, the antenna device  300  may include a power cord or USB cable  304  configured for electrically connecting the antenna device  300  (ex.—the antenna assembly  100  of the antenna device  300 ) to a computer. 
     In current exemplary embodiments of the present invention, the antenna assembly  100  and antenna device  300  may be implemented in various applications. For example, the antenna assembly  100  and antenna device  300  may be configured for implementation in or with: military systems; Traffic Collision Avoidance Systems (TCAS), Ultra High Frequency Communication (UHF com) systems, Mini Common Data Link (MiniCDL) antenna systems, Quint Networking Technologies (QNT) systems, Remotely Operated Video Enhanced Receiver (ROVER) systems, and/or Global Positioning System (GPS) systems. The integrated hardware of the antenna assembly  100  as disclosed herein provides significant Size Weight and Power (SWAP) over implementing separate antenna assemblies. 
     It is believed that the present invention and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes.