Patent Publication Number: US-11043727-B2

Title: Substrate integrated waveguide monopulse and antenna system

Description:
BACKGROUND 
     As is known in the art, some monopulse radar systems utilize analog monopulse antenna systems comprising multi-layer printed circuit boards (PCBs). The multi-layer PCBs include substrate cores and layers which are bonded together. For example, such PCBs can have a six (6)-layer, (4) core multi-layer configuration. The PCBs also include external multiple radio frequency (RF) connectors (e.g. GPPO connectors) to allow coupling with a transceiver and other circuitry. 
     As is also known, as the number of layers in the PCB increases, the cost to fabricate monopulse antenna systems increases along with the volume they occupy. Additionally, multi-layer PCB monopulse antenna system designs typically include a series of conductive vias (or more simply “vias”). In such designs, some vias can extend through some layers and others can extend through all the layers of the PCB. Such designs increase manufacturing complexity and thus increase manufacturing time and expense. Further, such multi-layer PCB monopulse circuits often utilize external RF connectors which add to the cost and footprint of the monopulse antenna systems. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features or combinations of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
     Described herein is a substrate having a monopulse waveguide circuit integrated therein. A substrate integrated waveguide monopulse antenna allows for a monopulse antenna system in a single substrate layer configuration. 
     In one aspect, a substrate integrated waveguide monopulse antenna comprises, a substrate having first and second opposing surfaces, a plurality of antenna elements disposed on one of the substrate surfaces, and a plurality of conductive vias disposed through the substrate to form a plurality of hybrid couplers, and a plurality of output couplers. The hybrid couplers are arranged such that they are capable of providing signals to and receiving signals from the antenna elements. Further the hybrid couplers are arranged around a perimeter of a substrate and configured to form a radio frequency (RF) “wrap-around” monopulse circuit. 
     In embodiments, the plurality of output couplers are coupled to one or more outputs and the plurality of output couplers are capable of providing signals to/from one or more outputs of the substrate integrated waveguide monopulse antenna to/from the hybrid couplers. Thus, the plurality of output couplers provide a means for providing signals to/from the substrate integrated waveguide monopulse antenna. 
     In embodiments, the plurality of antenna elements are provided on the first surface of the substrate. In embodiments, the plurality of antenna elements are provided on the second surface of the substrate. In embodiments, the plurality of conductive via holes extend through said substrate and extend between the first and second surfaces of said substrate. The plurality of conductive via holes are also arranged to form a plurality of resonant cavities with at least one resonant cavity coupled to each of the antenna elements such that the resonant cavities are capable of providing RF signals to and/or receiving RF signals from the antenna elements. The conductive vias form the plurality of hybrid couplers within the substrate and in embodiments, two of the plurality of resonant cavities are coupled to at least one port of the plurality of hybrid couplers. In embodiments The plurality of output couplers are provided on the second surface of the substrate. 
     In embodiments, a first conductive material can be disposed on the first surface of said substrate and can correspond to a conductive layer disposed on the first surface of said substrate. The plurality of antenna elements can be provided as slot antenna elements formed in the first conductive layer. The plurality of slot antenna elements can include a plurality of dogbone couplers. 
     The plurality of output couplers can be slotted output couplers. The second conductor on the second surface of the substrate can correspond to a ground plane layer. Each output coupler can be coupled to at least one port of said plurality of hybrid couplers. 
     The substrate integrated waveguide monopulse antenna can further comprise a transceiver that has first and second opposing surface. At least a portion of the first surface of the transceiver can be configured to couple to at least one of the plurality of output couplers. 
     The second surface of the substrate can be configured to lie flat on the first surface of the transceiver when the at least said portion of the first surface of the transceiver is coupled to said at least one of the plurality of output couplers. 
     The transceiver can be disposed under the second surface of the substrate. 
     In another aspect, a substrate integrated waveguide monopulse antenna comprises a substrate, a first conductive layer, a second conductive layer, a plurality of conductive via holes, and a plurality of slotted output couplers. The substrate has first and second opposing surface. A first side of the substrate is configured to couple with a seeker antenna comprising a plurality of slot antennas. The seeker antenna can further comprise a dichroic lens and a dish. The first conductive layer is disposed on the first surface of said substrate and is configured to receive the plurality of slot antenna elements. A second conductive layer is disposed on the second surface of said substrate. A plurality of conductive via holes extend through the substrate and extend between the first and second conductive layers. The plurality of via holes are arranged to form a plurality of resonant cavities and a plurality of hybrid couplers. At least one resonant cavity is coupled to each of said slot antenna elements. The plurality of slotted output couplers are provided in the second conductive layer. Two of the plurality of resonant cavities are coupled to at least one port of said plurality of hybrid couplers. Each slotted output coupler can be coupled to at least one port of said plurality of hybrid couplers. 
     The substrate integrated waveguide monopulse antenna can further comprise a transceiver. The transceiver can have first and second opposing surfaces, and at least a portion of the first surface of the transceiver can be configured to couple to at least one of the plurality of slotted output couplers. The transceiver can be disposed under the second surface of the substrate. 
     The second surface of substrate can be configured to lie flat on the first surface of the transceiver when the at least said portion of the first surface of the transceiver is coupled to said at least one of the plurality of slotted output couplers. 
     In an additional aspect, a substrate integrated waveguide monopulse antenna comprises a substrate, a first conductive layer, a plurality of slot antenna elements, a second conductive layer, and a plurality of conductive via holes. The substrate has first and second opposing surfaces. The first conductive layer is disposed on the first surface of said substrate. The plurality of slot antenna elements is provided in the first conductive layer. The second conductive layer is disposed on the second surface of said substrate. The plurality of conductive via holes extend through the substrate and extend between the first and second conductive layers. The plurality of conductive via holes are also arranged to form a plurality of resonant cavities and a plurality of hybrid couplers. The plurality of conductive via holes are further arranged to couple at least one resonant cavity to at least one port of a hybrid coupler. 
     A plurality of slotted output couplers can be provided in the second conductive layer. The plurality of conductive via holes can be further arranged to couple at least one slotted output coupler to at least one other port of a hybrid coupler. 
     The substrate integrated waveguide monopulse antenna can also comprise a transceiver that includes first and second opposing surfaces. At least a portion of the first surface of the transceiver is configured to couple to at least one of the plurality of slotted output couplers. The transceiver can be disposed under the second surface of the substrate. 
     The second surface of substrate can be configured to lie flat on the first surface of the transceiver when the at least said portion of the first surface of the transceiver is coupled to said at least one of the plurality of slotted output couplers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features and advantages will be apparent from the following more particular description of the embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the embodiments. 
         FIG. 1  is a transparent top view of a substrate integrated waveguide monopulse antenna system, according to some embodiments. 
         FIG. 2  is a top view of an antenna feed network for a substrate integrated waveguide monopulse antenna system, according to some embodiments. 
         FIG. 3  is a top view of a wraparound monopulse for a substrate integrated waveguide monopulse antenna system, according to some embodiments. 
         FIG. 4  is a top view of an output coupling later for a substrate integrated waveguide monopulse antenna system, according to some embodiments. 
         FIG. 5  is a block diagram illustrating a substrate integrated waveguide monopulse antenna system coupled to a transceiver, according to some embodiments. 
         FIG. 6  is a diagram depicting an exemplary seeker antenna, according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Described herein is a monopulse antenna system having a waveguide monopulse integrated into a substrate to provide a “substrate integrated waveguide monopulse antenna.” The system utilizes a “wrap-around” monopulse network and slotted output couplers to interface with a transceiver. It should be appreciated that to promote clarity in the description of the broad concepts, systems and techniques sought to be protected, the systems and techniques have been substantially described in the context of a configuration with slot antenna elements. It is, of course, recognized that the concepts, systems and techniques may operate with other types of antenna elements provided in a layer of the substrate. 
     Referring now to  FIG. 1 , a substrate integrated waveguide monopulse antenna system  100  includes a single substrate  102 . In embodiments, the substrate  102  can be a single monolithic substrate. In alternate embodiments, the substrate can be formed from a plurality of substrates (i.e. a multi-layer substrate) which are bonded or otherwise joined together so as to form or otherwise provide an integrated substrate structure corresponding to the single substrate  102 . The substrate  102  includes first and second, opposing surfaces  102   a ,  102   b  with opposite, opposing sides  103   a ,  103   b ,  103   c ,  103   d  and a thickness. In embodiments, the thickness is based on desired frequency and bandwidth characteristics of the substrate integrated waveguide monopulse antenna system  100 . In other embodiments, a height (i.e., thickness) of the waveguide system  100  is selected to provide a desired impedance range with minimal loss. In further embodiments, a width, via spacing, of the waveguide system  100  is selected based on a desired frequency/bandwidth and electrical impedance. 
     It should be appreciated that to promote clarity in the description of the concepts disclosed herein,  FIG. 1  is presented as a transparent top view of a substrate integrated waveguide monopulse antenna system  100 . Thus, all layers of the substrate  102  are visible. 
     In some embodiments, the opposing surfaces of the substrate  102  may have a rounded shape with various foci, radii, and diameters—e.g. circles, ovals, ellipses, to name a few. In other embodiments, the opposing surfaces of the substrate  102  may have polygonal shape with various sides, widths, lengths, and angles—e.g. triangle, square, rectangle, to name a few. In the illustrative embodiment of  FIG. 1 , the substrate  102  is provided having a circular shape, resulting in the circular top view depicted in  FIG. 1 . According to some embodiments, each opposing surface  102   a ,  102   b  of substrate  102  may have a conductive layer disposed thereon. 
     Substrate integrated waveguide monopulse and antenna system  100  also includes one or more slot antenna elements  108  provided in a first conductive layer disposed over the first surface  102   a  of substrate  102 . Each slot antenna element  108  corresponds to an antenna element provided from one or more holes, or slots formed in the substrate. In the illustrative embodiments of  FIG. 1  system  100  includes slot antennas  108 A-J, while in other embodiments, system  100  may include a different number of slot antennas  108 . 
     Slot antennas  108  are configured, at a first time, to transmit a desired radiation pattern, or transmit beam, according to transmit signals provided to system  100  by a transceiver or other signal source. When transmitting, each slot antenna  108  emits at least a portion of the desired transmit signal in accordance with a transmit beam. Slot antennas  108  are further configured, at a second time, to provide a receive beam. The receive beam receives at least a portion (or an “echo”), of the transmit beam. For example, the receive beam may receive a portion of a transmit signal that has been reflected or otherwise redirected from an object (e.g. a target or other structure). After receiving the receive signal at the slot antennas  108 , the signals are provided to a monopulse circuit. The monopulse circuit will be described in further detail below with reference to  FIGS. 2, 3, and 4 . 
     Substrate integrated waveguide monopulse and antenna system  100  further includes conductive via holes  104 . Conductive vias  104  pass through a first conductive layer disposed over a first surface  102   a  of substrate  102  and extend through substrate  102  to terminate at a second conductive layer disposed over a second, opposing surface  102   b  of substrate  102 . In some embodiments, conductive via holes  104  extend straight through the substrate  102  (i.e. at an angle of ninety (90) degrees relative to the substrate surface), while in other embodiments conductive via holes  104  extend through the substrate in different angles. In the illustrative embodiment of  FIG. 1  conductive via holes  104  extend straight through substrate  102 . 
     Conductive vias  104  extending through substrate  102  are arranged to form at least one via fence. A via fence encompasses rows of via holes  104  spaced apart so as to form an impediment (and ideally a complete barrier or wall) to electromagnetic waves propagating in the substrate. Thus, conductive vias  104  can be used to direct (or channel) the electromagnetic waves in a desired direction. 
     Consequently, the at least one via fence is arranged to form a monopulse circuit comprising at least one 90° hybrid coupler  106  and to form at least one resonant cavity within substrate  102 . In the illustrative embodiment of  FIG. 1 , conductive via holes  104  are arranged into via fences that form a monopulse circuit comprising 90° hybrid couplers  206 A-D and also form resonant cavities  114 A-H in substrate  102 . 
     Resonant cavities  114  comprise via fences arranged as to allow electromagnetic waves (i.e. radio frequency (RF) signals) to propagate oscillate between the via fences. As the RF signals propagate within the resonant cavity, electromagnetic waves at the predetermined resonant frequency of the resonant cavity are reinforced to produce standing waves at the predetermine resonant frequency of the resonant cavity. 
     The vias are also arranged to provide 90° hybrid couplers  106  through which RF signals propagate. Once the RF signals are received, each 90° hybrid coupler  106  are configured to process the RF signals provided thereto to generate and output a sum, azimuth difference, elevation difference, diagonal difference (also referred to as a Q difference), or any combination thereof as detailed in the discussion of  FIG. 3 . 
     Conductive vias  104  are further arranged to form signal paths (e.g. waveguide signal paths) that couple each resonant cavity  114  to at least one port of a 90° hybrid coupler  106  of the monopulse circuit. The signal paths coupling each resonant cavity  114  to at least one port of a 90° hybrid coupler  106  are provided from “fences” of vias (i.e. “via fences”) arranged through which RF signals may be directed from the port of 90° hybrid coupler  106  to resonant cavity  114  or directed from resonant cavity  114  to the port of 90° hybrid coupler  106 . 
     Substrate integrated waveguide monopulse antenna  100  also comprises at least one slotted output coupler  112  provided in a second conductive layer disposed over a second opposite, opposing surface  102   b  of substrate  102 . Slotted output couplers  112  may include electroconductive contacts provided within the second conductive layer, an exposed portion of the second conductive layer, or a cutout of the second conductive layer. In the illustrative embodiment of  FIG. 1 , system  100  includes slotted output couplers  112 A-D, however, in other embodiments, system  100  may include a different number of slotted output couplers  112 . 
     Slotted output couplers  112  are configured to couple with a transceiver or other signal source as detailed in the discussion of  FIG. 5 . Each slotted output coupler  112  is configured to couple the at least one port of at least one of 90° hybrid output coupler  108  of the monopulse circuit to a transceiver or other circuit component. This coupling allows sum, azimuth difference, elevation difference, Q difference—or any combination thereof—signals formed by the monopulse circuit to be coupled between the monopulse and a transceiver or other circuit component (e.g. a transmitter). According to an embodiment, each slotted output coupler  112  may be provided by removing portions of the second conductive layer that form a port of at least one hybrid coupler  112 . It should, however, be appreciated that any additive or subtractive technique may be used to form the output couplers. Similarly, all circuit components described herein may be provided by any additive or subtractive technique. 
     Referring now to  FIG. 2 , an antenna feed network  200  has first and second opposing surfaces  200   a ,  200   b  with slot antennas  208  provided in a first conductive layer disposed over first surface  200   a  of substrate  202 . It should be noted that the conductivity layer disposed over the first surface of substrate  200  corresponds to surface  102   a  of a substrate  202 . Conductive via holes  204  extend through the substrate  202  and are arranged to form at least one resonant cavity  214 . It should be noted that in the illustrative embodiment of  FIG. 2 , only the layers of substrate  202  including conductive via holes  204 , slot antennas  208 , and resonant cavities  214  are presented for clarity. 
     The antenna feed network  200  includes at least one slot antenna  208  situated within each resonant cavity  214  formed by conductive vias  204 . In other words, at least one slot antenna  208  is provided in the first conductive layer disposed over a first surface of substrate  202  so that it is surrounded by the conductive vias  204  arranged to form a resonant cavity  214 . While in the illustrative embodiment of  FIG. 2 , the feed network  200  includes eight resonant cavities  214 A-H and  8  slot antennas  208 A-H, in other embodiments, feed network  200  may include a different number of resonant cavities  214  and slot antennas  208 . Further, while the illustrative embodiment of  FIG. 2  depicts a configuration with one slot antenna ( 208 A,  208 D,  208 G, and  208 J) situated within four resonant cavities ( 214 A,  214 D,  214 E, and  214 H respectfully) and two slot antennas ( 208 B and  208 E,  208 C and  208 F,  208 H and  208 K, and  208 I and  208 L) situated within another four resonant cavities ( 214 B,  214 C,  214 F, and  214 G respectfully), in other embodiments different configurations may be used with a different number of slot antennas  208  within a different number of resonant cavities  214 . 
     As discussed with reference to  FIG. 1  above, integrated monopulse antenna system  100  may be used in either a transmit or receive mode. Thus, during a transmit operation a transmit signal is provided to the antennas  208  (e.g. via a transmit path of the monopulse circuit) to emit a desired radiation pattern. Similarly, in a receive mode of operation, each slot antenna  208  receives reflected portions of the desired transmit signal and couples the received signals through the resonant cavity  214  in which the slotted antenna  208  is situated. 
     For example, in the illustrative embodiment of  FIG. 2 , slot antenna  208 A is configured to emit a portion of a desired transmit signal provided thereto via resonant cavity  214 A. 
     The portions of the desired transmit signal are further provided to each resonant cavity  214  by the monopulse circuit. Each resonant cavity  214  receives portions of the desired transmit signal from at least one 90° hybrid coupler  106  of the monopulse circuit as detailed in the discussion with reference to  FIGS. 3 and 4  below. 
     Similarly, in a receive mode of operation, each slot antenna  208  is configured to couple received signals to the resonant cavity  214  to which the slot antenna  208  is coupled. For example, in the illustrative embodiment of  FIG. 2 , slot antenna  208 A is configured to couple received signals to resonant cavity  214 A. 
     Once the resonant cavities  214  have received the signals provided thereto from a respective slot antenna  208 , a standing wave at the resonant frequency of the resonant cavity  214  is produced. The standing waves formed or otherwise produced by each resonant cavity  214  correspond to the receive signals from respective slot antennas  208  (i.e. the slot antennas  208  coupled to ones of resonant cavities  214 ). The RF energy is coupled to the monopulse circuit. In particular, the received RF signals are coupled from respective ones of the resonant cavities to at least one port of respective ones of circuit elements which comprise the monopulse circuit (e.g. a 90° hybrid coupler, a 0°/180° coupler or any other circuit elements which may be appropriately coupled to form a monopulse circuit). A 90° hybrid coupler will be discussed in further detail below with regards to  FIG. 3 . 
     Referring now to  FIG. 3 , substrate integrated waveguide monopulse antenna system  300  includes a monopulse substrate  302  in which at least portions of at least one monopulse circuit are provided. In the illustrative embodiment described herein, a monopulse circuit comprises four 90° hybrid couplers  306  formed from conductive via holes  304  extending through substrate  302 . Those of ordinary skill in the art will recognize that although in this illustrative embodiment the monopulse circuit comprises four 90° hybrid couplers  306 , other components and configurations may of course also be used. 
     Of course, as described herein by provided the monopulse as described herein, the advantages of a compact substrate integrated waveguide monopulse and antenna system are provided. 
     It should also be noted that in the illustrative embodiment of  FIG. 3 , only layers of substrate  302  including a monopulse circuit comprising conductive via holes  304  and 90° hybrid couplers  306  are shown for clarity. It should also be understood that within a monopulse circuit, conductive via holes  304  arranged to form each 90° hybrid coupler with each coupler having four ports configured to provide or receive electromagnetic signals to or from the monopulse circuit. For example, 90° hybrid coupler  306 A comprises a first port  307 A, a second port  309 A, a third port  311 A, and a fourth port  313 A. According to some embodiments, each 90° hybrid coupler  306  comprises a first adjacent pair of ports  307 ,  309  located at a first end of 90° hybrid coupler  306  and a second adjacent pair of ports  311 ,  313  located at a second, opposite end of 90° hybrid coupler. For example, 90° hybrid coupler  306 A comprises a first pair of ports  307 A,  309 A at a first side of 90° hybrid coupler  306 A and a second pair of ports  311 A,  313 A at a second, opposite side of 90° hybrid coupler  306 . In some embodiments, each adjacent port pair of 90° hybrid coupler  306  may share a via fence formed from conductive via holes  304 . 
     The monopulse substrate  302  includes at least one 90° hybrid coupler  306  having at least one port  309  coupled to at least one resonant cavity  214  and at least one port  313  coupled to at least one other resonant cavity  214 . For example, referring to the illustrative embodiment of  FIG. 1 , a first port of 90° hybrid coupler  106 D is coupled to resonant cavities  114 A and  114 B and a second port at a second, opposite side of 90° hybrid coupler  106 D is coupled to resonant cavities  114 E and  114 F. 
     Further, the 90° hybrid coupler  306  includes at least one port  307  coupled to a port of at least one other 90° hybrid coupler  306  and another port  311  coupled to a port of a further, distinct 90° hybrid coupler  306  (i.e. a 90° hybrid coupler  306  different from the 90° hybrid coupler coupled to the first side). For example, in the illustrative embodiment of  FIG. 1 , a port of 90° hybrid coupler  106 D is coupled to a port of 90° hybrid coupler  106 A and a port of 90° hybrid coupler  106 D is coupled to a port of 90° hybrid coupler  106 C. 
     The monopulse circuit also includes at least one other 90° hybrid coupler  306  with a port  307  coupled to at least one slotted output coupler and a port  311  coupled to at least one other slotted input/output coupler. For example, in the illustrative embodiment of  FIG. 1 , a port of 90° hybrid coupler  106 C is coupled to slotted output coupler  112 D and a port of 90° hybrid coupler  106 C is coupled to slotted input/output coupler  112 C. 
     According to some embodiments, slotted input/output couplers  112  coupled to 90° hybrid couplers  306  may be provided in a second conductive layer disposed over a second surface  302   b  of substrate  302 . The slotted input/output couplers  112  are arranged in the second conductive layer such that they are surrounded by the conductive via holes  304  that form the 90° hybrid couplers  306  to which the slotted input/output couplers  112  are coupled. In other words, in the second conductive layer, slotted couplers  112  are located with via holes  304  that form a coupled 90° hybrid coupler. For example, in the illustrative embodiment of  FIG. 1 , slotted receiver  112 A is arranged on substrate  102  so that it is surrounded by the conductive via holes  104  that form 90° hybrid coupler  106 A. 
     Further, the other 90° hybrid coupler  306  includes at least one port  309  coupled to a port of at least one other 90° hybrid coupler  306  and another port  313  coupled to a port of a different, distinct 90° hybrid coupler  306  (i.e. a 90° hybrid coupler  306  different from the 90° hybrid coupler coupled to the first side). For example, in the illustrative embodiment of  FIG. 1 , a port of 90° hybrid coupler  106 C is coupled to a port of 90° hybrid coupler  106 D and a port of 90° hybrid coupler  106 C is coupled to a port of 90° hybrid coupler  106 B. 
     As discussed above in reference to  FIG. 1 , RF signals are coupled between the antenna elements and the monopulse circuit via resonant cavities  214 . In response to signals provided thereto from the antenna elements (e.g. in response to receive signals) the monopulse circuit generates signals representing a sum, azimuth difference, elevation difference, Q difference. These signals, representing a sum, azimuth difference, elevation difference, Q difference—or any combination thereof, are provided to at least one slotted couplers  112  coupled to the monopulse circuit for output. The monopulse circuit, generates these sum and difference as is generally known. 
     Referring now to  FIG. 4 , substrate integrated monopulse and antenna system  100  ( FIG. 1 ) includes an interface substrate  400  comprising at least one slotted input/output coupler  412  provided there, and at least one port of a 90° hybrid coupler formed from conductive via holes  404  extending through substrate  402 . It should be noted that in the illustrative embodiment of  FIG. 4 , only layers of substrate  402  including conductive via holes  404  and slotted output couplers  412  of system  400  are presented for clarity, in other embodiments, system  400  comprises a substrate integrated waveguide and antenna system such as substrate integrated waveguide and antenna system  100  presented in  FIG. 1 . 
     Each slotted output coupler  412  is provided within a second conductive layer disposed over a surface of substrate  402 . According to some embodiments, the surface  402   b  of substrate  402  over which the second conductive layer is disposed is opposite and opposing to the surface  402   a  of substrate  402  over which a first conductive layer providing slotted antenna elements  108  is disposed. For example, in the illustrative embodiment of  FIG. 1 , slot antennas  108 A-L are provided in a first conductive layer disposed over a first surface  102   a  of substrate  102  and slotted output couplers  112 A-D are provided in a second conductive layer disposed over a second, opposite surface  102   b  of substrate  102 . 
     Each slotted output coupler  412  is coupled to the monopulse circuit via at least one port of a 90° hybrid coupler. This coupling comprises a via fence formed by conductive via holes  404 . For example, in the illustrative embodiment of  FIG. 1 , slotted output coupler  112 A is coupled to a port of 90° hybrid coupler  106 A. Each slotted output coupler  412  is configured to deliver electromagnetic waves to the monopulse circuit via a coupled 90° hybrid coupler  106  and receive electromagnetic waves from the monopulse circuit via a coupled 90° hybrid coupler  106 . 
     According to some embodiments, each slotted output coupler  412  is further configured to couple with a transceiver. Each slotted output coupler  412  may couple with the transceiver via contact, wiring, wirelessly—or any combination thereof. While coupled to the transceiver, each slotted output coupler  412  is configured to receive electromagnetic waves from the transceiver and provide electromagnetic waves to the transceiver. In some embodiments, at a first time, the transceiver may generate a transmit beam to be emitted by substrate integrated monopulse and antenna system  400 . The transceiver is configured to provide portions of the transmit beam to at least one slotted output coupler  412 . The slotted output coupler  412  is configured to provide the portions of the transmit beam to the monopulse circuit via coupled port of a 90° hybrid coupler  106 . 
     According to some embodiments, at a second time, at least one slotted output coupler  412  receives signals representing sum, azimuth difference, elevation difference, Q difference—or any combination thereof—from the monopulse circuit. Each slotted output coupler  412  is then configured to provide the signals to the coupled transceiver. 
     Referring now to  FIG. 5 , substrate integrated monopulse antenna system  502  is configured to couple with at least a portion of transceiver  514  via at least one slotted output coupler of substrate integrated monopulse antenna  502 . In some embodiments, substrate integrated monopulse antenna system  502  may couple to at least a portion of transceiver  514  using each slotted output coupler  112 , while in other embodiments fewer slotted output couplers  122  may be used. When substrate integrated monopulse and antenna system  502  is coupled to at least a portion of transceiver  514  via slotted output couplers  112 , integrated monopulse antenna  502  is configured to receive at least portions of a transmit beam from transceiver  514  and provide signals representing a sum, azimuth difference, elevation difference, Q difference—or any combination thereof—to transceiver  514 . 
     According to some embodiments, transceiver  514  comprises a first surface and a second, opposing surface with a thickness between the two surfaces. In some embodiments, substrate integrated monopulse antenna  502  is configured so that when coupled to at least a portion of transceiver  514  via slotted output couplers, a surface of substrate integrated monopulse and antenna system  502  lies flat on at least a portion of a surface of transceiver  514 . In other embodiments, the entirety of one surface of substrate integrate monopulse antenna system  502  is in continuous contact with at least a portion of a surface of transceiver  514 , while in other embodiments at least a portion of a surface of the substrate integrated monopulse antenna system  502  is in continuous contact with a surface of transceiver  514 . In the illustrate embodiment of  FIG. 5 , substrate integrated monopulse antenna system  502  lies flat on a surface of transceiver  514  with a surface of system  502  being in continuous contact with a surface of transceiver  514 . 
     In some embodiments, substrate integrated monopulse antenna system  502  is configured to couple to at least a portion of transceiver  514  directly without the use of external connectors, cable, wires, or any combination thereof. 
     Referring now to  FIG. 6 ,  FIG. 6  illustrates an exemplary embodiment of a seeker antenna  600  comprising slot antennas  618 . Seeker antenna  600  comprises dish  620 , dichroic lens  618 , slot antennas  616 , and housing  622 . Housing  622  encases seeker antenna  600  and may comprises a plastic, metal, alloy, carbon, dielectric material, or any combination thereof—to name a few examples. 
     According to some embodiments, substrate integrated waveguide and monopulse antenna system  100  may be configured to receive signals from antennas  616  of seeker antenna  600  so that antennas  616  are provided in a conductive layer disposed over a first surface of substrate  102 . In other words, antennas  616  of seeker antenna  600  may comprise slot antennas  116  of substrate integrated waveguide monopulse and antenna system  100 . Portions of a desired radiation pattern transmitted by antennas  616  pass through dichroic lens  618  and are collected by dish  620  to form the desired radiation pattern. The dichroic lens  618  may be an optional element. For example, the dichroic lens can be used in aperture systems having a common dish that collects energy for multiple sensors, e.g., radar and infrared. In such embodiments, the dichroic lens  618  separates and distributes appropriate portions of the received signals to appropriate sensors. Dichroic lens  618  comprises a dichroic material that acts as a filter when portions of the desired radiation pattern are passed through. Further, dish  620  is configured to receive echoes that are passed through dichroic lens  618  and delivered to slot antennas  618 . 
     In embodiments, the seeker antenna  600  can be used to transmit radio frequency energy and subsequently collect returning energy from that transmission that has been reflected by target like objects. A monopulse comparator (not shown) of the antenna a system  100  divides the antenna into four quadrants, then combines and compares the detected signals in four ways: 1) summation of the four quadrants (e.g., upper, lower, left, and right), 2) difference between upper and lower quadrants, 3) difference between left and right quadrants, and 4) a diagonal difference of the quadrants. These signals are then directed to a receiver and processor in order to determine a relative target angle and distance. 
     As used herein, the term “waveguide” is used to describe any system of material boundaries or structures for guiding electromagnetic waves. 
     As used herein, the term “conductive via hole” (or “conductive vias” or more simply a “via”) is used to describe a signal path with extends through (rather than along a surface of) one or more circuit boards or through an entire substrate to electrically connect conductors (e.g. ground planes on opposing sides of a substrate). In embodiments to be described hereinbelow, a conductive via hole passes through a first conductive layer disposed over a first surface of a substrate and terminates at a second conductive layer disposed over a second surface of the substrate. 
     It should also be appreciated that, as used herein, relational terms, such as “first,” “second,” “top,” “bottom,” “left,” “right,” and the like, may be used to distinguish one element or portion(s) of an element from another element or portion(s) of the element without necessarily requiring or implying any physical or logical relationship or order between such elements. 
     Comprise, include, and/or plural forms of each are open ended and include the listed parts and can include additional parts that are not listed. And/or is open ended and includes one or more of the listed parts and combinations of the listed parts. 
     One skilled in the art will realize the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting of the invention described herein. Scope of the invention is thus indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.