Abstract:
A stripline antenna feed network is described. The stripline antenna feed network may comprise a first stripline layer comprising one or more reactive splitters and one or more matched splitters; and a second stripline layer comprising one or more reactive splitters. A method of manufacturing a stripline antenna feed network may comprise operably coupling a first stripline layer comprising one or more reactive splitters and one or more matched splitters to a second stripline layer comprising one or more reactive splitters.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to the transmission and reception of radio frequency signals and, more particularly to a stripline antenna feed network. 
     BACKGROUND OF THE INVENTION 
     In many telecommunications applications, microstrip antennas are employed. There are several types of microstrip antennas (also known as printed antennas), the most common of which is the microstrip patch antenna. A microstrip patch antenna is a narrowband, wide-beam antenna fabricated by etching an antenna element pattern in metal trace bonded to an insulating substrate. Because such antennas may be low profile, mechanically rugged and conformable, they are often employed on aircraft and spacecraft, or are incorporated into mobile radio communications devices. 
     SUMMARY OF THE INVENTION 
     A stripline antenna feed network is described. 
     The stripline antenna feed network may comprise: (a) a first stripline layer comprising one or more reactive splitters and one or more matched splitters; and (b) a second stripline layer comprising one or more reactive splitters. 
     A method of manufacturing a stripline antenna feed network may comprise: (a) operably coupling a first stripline layer comprising one or more reactive splitters and one or more matched splitters to a second stripline layer comprising one or more reactive splitters. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The numerous objects and 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  depicts a reactive/matched stripline feed network. 
         FIG. 2  depicts a reactive/matched printed circuit board layer. 
         FIG. 3  depicts a reactive stripline feed network. 
         FIG. 4  depicts a reactive printed circuit board layer. 
         FIG. 5  depicts a slot radiator unit cell. 
         FIG. 6  depicts a slot coupling layer. 
         FIG. 7  depicts a dipole unit cell. 
         FIG. 8  depicts a dipole layer. 
         FIG. 9  depicts a dipole unit cell. 
         FIG. 10  depicts a dipole layer. 
         FIG. 11  depicts a cross-sectional view of a stripline antenna feed network. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following discussion is presented to enable a person skilled in the art to make and use the present teachings. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the present teachings. Thus, the present teachings are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the present teachings. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of the present teachings. Reference will now be made, in detail, to presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. 
     A stripline antenna feed network as described herein may include a reactive/matched stripline feed network  100  and a reactive stripline feed network  300 . 
     Referring to  FIG. 1 , the reactive/matched stripline feed network  100  may include at least one reactive splitter  102  and at least one matched splitter  104  (e.g. Wilkinson-type splitters). A reactive splitter may be a 4:1 reactive splitter  302 A (as shown in  FIG. 3 ). A matched splitter  104  may be a 2:1 matched splitter. A matched splitter  104  may include an embedded resistor  105 . An embedded resistor  105  may include a thin-film resistor-conductor layer. Numerous thin-film resistor-conductor layers may be used. For example, an embedded resistor  105  may include Ohmega-Ply® resistor-conductor material having an impedance of 25 ohms/square as manufactured by Ohmega Technologies, Inc. The reactive/matched stripline feed network  100  may include an input/output feed line  106  providing input/output signals to the reactive/matched stripline feed network  100 . The feed lines of the reactive stripline feed network  300  may be coupled to the reactive/matched stripline feed network  100  by at least one vertical transition  103 . The vertical transition  103  may include a circuit board via. 
     Referring to  FIG. 2 , a reactive/matched PCB layer  200  is illustrated. The reactive/matched PCB layer  200  may include one or more instances of the reactive/matched stripline feed network  100 . The reactive/matched PCB layer  200  may further include a combiner  201  which may combine signals transceived from the reactive/matched PCB layer  200 . The reactive/matched PCB layer  200  may include a vertical transition  202  by which signals may be transceived to a conductive layer  701 . 
     Referring to  FIG. 3 , the reactive stripline feed network  300  may include at least one reactive splitter  302  for splitting and/or combining signals. The reactive splitter may be a 4:1 reactive splitter  302 A and/or a 2:1 reactive splitter  302 B. The feed lines of the reactive stripline feed network  300  may have an impedance of about 78 ohms and a line width of about 10 mil. Such a configuration may allow for RF manifolding to be implemented on the same layer as the radiating element feed. The reactive stripline feed network  300  may include a stripline feed network feeding at least one antenna coupling  301 . An antenna coupling  301  may couple feed layer components to a radiator structure (e.g. a dipole antenna structure) located on a separate PCB layer. Numerous antenna couplings may be used. For example, the antenna coupling  301  may include, but is not limited to, slot coupling, probe coupling, proximity coupling, or edge feeding. The feed lines of the reactive stripline feed network  300  may be coupled to the reactive/matched stripline feed network  100  by at least one vertical transition  303 . The vertical transition  303  may include a circuit board via. 
     Referring to  FIG. 4  a reactive PCB layer  400  is illustrated. The reactive PCB layer  400  may include one or more instances of the reactive stripline feed network  300 . For example, the reactive PCB layer  400  may include four instances of the reactive stripline feed network  300 . 
     Referring to  FIG. 5  a slot radiator unit cell  500  is illustrated. The slot radiator unit cell  500  may include a ground plane  501  defining an aperture  502 . The aperture  502  may be configured so as to reduce the size of its footprint in the reactive PCB layer  400  so as to provide a low return loss response over a broad band (e.g. from about 15.2 to about 18.2 GHz). 
     Referring to  FIG. 6 , a slot coupling layer  600  is illustrated. The slot coupling layer  600  may include one or more instances of the slot radiator unit cell  500 . For example, the reactive PCB layer  400  may include 244 instances of the slot radiator unit cell  500  wherein each antenna coupling  301  of the reactive PCB layer  400  couples to a slot radiator unit cell  500  of the slot coupling layer  600 . 
     Referring to  FIG. 7 , a stripline dipole unit cell  700  is illustrated. The stripline dipole unit cell  700  may include at least one strip line element  701 . 
     Referring to  FIG. 8 , a first dipole layer  800  is illustrated. The first dipole layer  800  may include one or more instances of the stripline dipole unit cell  700 . For example, the first dipole layer  800  may include 244 instances of the stripline dipole unit cell  700  wherein each stripline dipole unit cell  700  couples to a slot radiator unit cell  500  of the slot coupling layer  600 . 
     Referring to  FIG. 9 , a stripline dipole unit cell  900  is illustrated. The stripline dipole unit cell  900  may include at least one strip line element  901 . 
     Referring to  FIG. 10 , a second dipole layer  1000  is illustrated. The second dipole layer  1000  may include one or more instances of the stripline dipole unit cell  900 . For example, the second dipole layer  1000  may include 244 instances of the stripline dipole unit cell  900  wherein each stripline dipole unit cell  900  couples to a stripline dipole unit cell  700  of the first dipole layer  800 . 
     Referring to  FIG. 11 , a cross-sectional view of a circuit board  1100  including the reactive stripline feed network  200  and the reactive/matched stripline feed network  100  is illustrated. The circuit board  1100  may include a conductive layer  1101 . The conductive layer  1101  may include a layer selected from numerous conductive compounds. For example, the conductive layer  1101  may include a copper layer. 
     The circuit board  1100  may include at least one laminate layer  1102  (e.g. a laminate layer  1102 A, a laminate layer  1102 B, a laminate layer  1102 C, a laminate layer  1102 D, and a laminate layer  1102 E). The laminate layer  1102  may include a layer selected from numerous compositions. For example, the laminate layer  1102  may include, but is not limited to, FR-4, FR-2, Composite epoxy materials, CEM-1,5, Polyimide, GETEK, BT-Epoxy, Cyanate Ester, Pyralux, Polytetrafluoroethylene, and the like. A laminate layer  1102  may include CLTE™ compositions manufactured by Arlon®, Inc. The laminate layer may have, but is not limited to, a dielectric constant of from about 2.9 to about 3.0. 
     The reactive stripline feed network  300  disposed on reactive PCB layer  400  may be coupled to feed lines of the reactive/matched stripline feed network  100  disposed on reactive/matched PCB layer  200  by at least one vertical transition  103 / 303 . The vertical transition  103 / 303  may include a circuit board via. The reactive stripline feed network  300  disposed on reactive PCB layer  400  may be coupled to the conductive layer  1101  by at least one vertical transition  302 . The vertical transition  302  may include a circuit board via. 
     It is believed that the present invention and many of its attendant advantages will be understood from the foregoing description, and 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.