Abstract:
An antenna array core comprising a plurality of microwave modules, a control layer, a mounting layer, and a signal distribution layer. The control layer is capable of distributing control signals to the plurality of microwave modules. The plurality of microwave modules are attached to an upper surface of the mounting layer and the mounting layer is made from a heat conductive material capable of cooling the plurality of microwave modules. The signal distribution layer is located below the mounting layer, wherein the signal distribution layer is capable of transmitting microwave signals to the plurality of microwave modules and wherein the arrangement of the plurality of microwave modules on the mounting layer, the control layer, and the wave distribution network form a layered architecture for the antenna core. The architecture is a balance between, size, thermal control, manufacturability, cost, and performance so as to be a unique solution.

Description:
[0001]    This invention was made with United States Government support under Agreement No. N00014-02-C-0068 awarded by DARPA. The Government has certain rights in the invention. 
     
    
     BACKGROUND INFORMATION 
       [0002]    1. Field 
         [0003]    The present disclosure is directed towards antennas and in particular to phased array antennas. Still more particularly, the present disclosure relates to an active electrically scanning phased array antenna. 
         [0004]    2. Background 
         [0005]    A phased array is a group of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions. A beam pointing in a transmit phased array antenna is achieved by controlling the phase and timing of the transmitted signal from each antenna element in the array. The combined individual radiated signals combine to form the constructive and destructive interference patterns of the array. A phased array may be used to point a fixed beam, or to scan the beam rapidly in azimuth or elevation. 
         [0006]    One type of phased array antenna is a wide scanning Q-band phased array antenna. This type of antenna may be used to facilitate communications among land, sea, and air-based mobile platforms and fixed ground locations, typically via satellite. In one example, a wide scanning Q-band phased array antenna may be used on an ocean-going vessel, such as a submarine, to transmit communications signals to the Milstar satellite constellation. In designing this type of antenna, many antenna elements are required to be placed in a grid pattern with a pitch of approximately one-half of the wave length. 
         [0007]    The resulting element size for this type of antenna may be on the same order as the size of monolithic microwave integrated circuit (MMIC) chips used for signal processing and amplification. These types of requirements push the boundaries of hermitic microelectronic packaging and create problems for heat dissipation or removal. Further, the high frequency needed for the microwave signals also increases the challenge in distributing a microwave signal to all elements without incurring excessive loss. 
         [0008]    Therefore, it would be advantageous to have an improved phased array antenna architecture. 
       SUMMARY 
       [0009]    The advantageous embodiments provide an antenna array core comprising a plurality of radio frequency modules, a control layer, a mounting layer, and a signal distribution layer. The control layer is capable of distributing control signals to the plurality of radio frequency modules. The plurality of radio frequency modules are attached to an upper surface of the mounting layer and the mounting layer is made from a heat conductive material capable of cooling the plurality of radio frequency modules. The signal distribution layer is located below the mounting layer, wherein the signal distribution layer is capable of transmitting radio frequency signals to the plurality of radio frequency modules and wherein the arrangement of the plurality of radio frequency modules on the mounting layer, the control layer, and the wave distribution network form a layered architecture for the antenna core. 
         [0010]    The different advantageous embodiments also provide an antenna comprising a housing and a set of antenna array core modules. The set of antenna array core modules are located in the housing, wherein each antenna array core comprises a plurality of radio frequency modules, a control layer, a mounting layer, and a signal distribution layer. The control layer is capable of distributing control signals to the plurality of radio frequency modules. The plurality of radio frequency modules are attached to an upper surface of the mounting layer and the mounting layer is made from a heat conductive material capable of cooling the plurality of radio frequency modules. The signal distribution layer is located below the mounting layer, wherein the signal distribution layer is capable of transmitting radio frequency signals to the plurality of radio frequency modules and wherein the arrangement of the plurality of radio frequency modules on the mounting layer, the control layer, and the wave distribution network form a layered architecture for the antenna core. 
         [0011]    Other advantageous embodiments provide a radio frequency module comprising a structural element, an antenna radiator board, a plurality of circuits, a divider network, and a set of flexible circuits. The structural element has a first end and a second end, wherein the first end is opposite to the second end. The antenna radiator board is attached to the first end of the structural element, wherein the antenna radiator board includes a plurality of radio frequency radiating elements. The plurality of circuits are attached to the structural element and are electrically connected to the antenna integrated printed wiring board. The plurality of circuits are capable of controlling radio frequency signals radiated by the plurality of radio frequency radiating elements in the antenna radiator board. The divider network has a single input and a plurality of outputs, wherein the divider network is attached to the structural element and is electrically connected to the plurality of circuits, and the divider network conducts radio frequency signals received from the single input to the plurality of outputs, which are connected to the plurality of circuits in the ceramic package at the plurality of outputs. The set of flexible circuits each have a first end and a second end, wherein the set of flexible circuits have a plurality of circuit pads located on the second end of the structural element and a plurality of connections at the second end of the flex circuit in which the plurality of connections are electrically connected to the plurality of circuits, wherein the set of flexible circuits are connected to the second end in a manner that a surface of the second is exposed to form an exposed surface on the second end such that the exposed surface dissipates heat in an amount sufficient to maintain a selected operating temperature. 
         [0012]    The features, functions, and advantages can be achieved independently in various illustrative embodiments or may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0013]    The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an advantageous embodiment of the present invention when read in conjunction with the accompanying drawings, wherein: 
           [0014]      FIG. 1  is a diagram of an electronically scanned antenna in accordance with an advantageous embodiment; 
           [0015]      FIG. 2  is an exploded front view of an antenna in accordance with an advantageous embodiment; 
           [0016]      FIG. 3  is an exploded rear view of an antenna in accordance with an advantageous embodiment; 
           [0017]      FIG. 4  is a diagram illustrating an array core in accordance with an advantageous embodiment; 
           [0018]      FIG. 5  is a diagram illustrating an array core architecture for an antenna in accordance with an advantageous embodiment; 
           [0019]      FIG. 6  is an exploded view of an array core in accordance with an advantageous embodiment; 
           [0020]      FIG. 7  is a cross-sectional view of an array core in accordance with an advantageous embodiment; 
           [0021]      FIG. 8  is a diagram of a microwave module in accordance with an advantageous embodiment; 
           [0022]      FIG. 9  is a bottom view of a diagram of a microwave module in accordance with an advantageous embodiment; 
           [0023]      FIG. 10  is a diagram illustrating an exploded view of a module in accordance with an advantageous embodiment; and 
           [0024]      FIG. 11  is a cross-section of a microwave gasket located between a honeycomb wave guide and a radiating element in an antenna integrated wiring board in accordance with an advantageous embodiment. 
       
    
    
     DETAILED DESCRIPTION  
       [0025]    With reference now to the figures, and in particular with reference to  FIG. 1 , a diagram of an electronically scanned antenna is depicted in accordance with an advantageous embodiment. In this example, antenna  100  is an electronically scanned phased array antenna. Antenna  100  contains one or more array cores containing antenna modules and other components. In these particular examples, antenna  100  is a Q-band array antenna. 
         [0026]    Turning next to  FIG. 2 , an exploded front view of an antenna is depicted in accordance with an advantageous embodiment. In this example, antenna  100  is shown in an exploded isometric view. As can be seen in this depicted illustration, antenna  100  includes housing  200 , cooling loop fittings  202 , auxiliary power converter  204 , array core  206 , main power converter  208 , thermal expansion ring  210 , shim  212 , antenna controller  214 , rear cold plate  216 , structural expansion ring  218 , and rear cover  220 . 
         [0027]      FIG. 3  depicts an exploded rear view of an antenna in accordance with an advantageous embodiment. In this exploded rear view of antenna  100 , additional components are visible. These additional components include pump  300 , main cold plate  302 , and heat sinks  304 . 
         [0028]    Housing  200 , structural expansion ring  218 , and rear cover  220  form an array enclosure for antenna  100 . 
         [0029]    Main power converter  208  and auxiliary power converter  204  provide power in the voltages required by antenna  100 . Antenna controller  214  is a component that is part of a control system for controlling the emission of microwave signals by array core  206 . More specifically, this component generates instructions in the form of control signals. These signals are used by array core  206  to control the manner in which microwave signals are transmitted. For example, this component distributes phase shifting data to the phase shifters in array core  206 . 
         [0030]    Pump  300 , rear cold plate  216 , main cold plate  302 , as well as the tubing, hoses, and various fittings used to connect these components to each other form a cooling system for antenna  100 . This cooling system removes heat from array core  206 . 
         [0031]    Array core  206  is the actual antenna component in antenna  100 . In this example, only a single core is depicted. The architecture of array core  206  is such that a set array cores, such as array core  206 , may be put together within an antenna to form arrays of various sizes and configurations. A set of array cores is a set of one ore more array cores. 
         [0032]    Turning now to  FIG. 4 , a diagram illustrating an array core is depicted in accordance with an advantageous embodiment. In this example, array core  206  includes amplifier block  400 , waveguide distribution network  402 , cold plate  404 , pressure plate  406 , shim  408 , power and control distribution board  410 , button contact assembly  412 , frame  414 , shim  416 , and sub-honeycomb plate  418 . 
         [0033]    Array core  206  has an architecture that provides a number of different features that differ depending on the particular implementation of this architecture. One feature is an ability to scale the number of cores to create antennas with different numbers of microwave modules. An example of another feature present with this type of core is more efficient heat removal for microwave modules in array core  206 , resulting in lower operating temperature. This layered architecture also provides for more efficient heat removal for other components, such as power and control distribution board  410  and amplifier block  400 . 
         [0034]    The different advantageous embodiments provide an antenna array core having microwave modules. A control layer is present that is capable of distributing control signals to the microwave modules. The microwave modules are attached to an upper surface of a mounting layer in which the mounting layer is made from a heat conductive material and includes an ability to cool the microwave modules. A signal distribution layer is located below the mounting layer in which the signal distribution layer is capable of transmitting microwave signals to the microwave modules. 
         [0035]    Turning now to  FIG. 5 , a diagram illustrating an array core architecture for an antenna is depicted in accordance with an advantageous embodiment. Array core architecture  500  is an example of the architecture used to implement array core  206  in  FIG. 4 . In this depicted example, array core architecture  500  is a layered architecture. These layers include microwave modules layer  502 , control layer  504 , mounting layer  506 , signal distribution layer  508 , and amplifier layer  510 . 
         [0036]    In the illustrative examples, microwave modules layer  502  contains different microwave modules used to transmit microwave signals. Control layer  504  provides the direct current power and control signals used to operate the modules in microwave modules layer  502 . Mounting layer  506 , in these examples, provides a physical structure for mounting the modules within microwave modules layer  502 . Additionally, mounting layer  506  also provides a cooling structure for microwave modules layer  502 . Signal distribution layer  508  is used to supply the microwave signals that are transmitted by microwave modules layer  502 . Amplifier layer  510  is used to amplify signals distributed by signal distribution layer  508 . The layered components in array core architecture  500  allows for an antenna to be created using multiple antenna array cores to form different sized and shaped antennas. 
         [0037]    The illustration of array core architecture  500  is provided for purposes of illustrating an example of a layered architecture that may be implemented in the different advantageous embodiments. This illustrative example is not meant to limit the manner in which different layers may be structured or organized. 
         [0038]    For example, mounting layer  506  may be a single component that includes both structural and cooling features for microwave modules layer  502 . Alternatively, mounting layer  506  may be formed from two components, such as a pressure plate and a cold plate. Further, the order in which these different layers are organized may vary. For example, amplifier layer  510  may be located above signal distribution layer  508  depending on the particular implementation. In addition, some or all of signal distribution layer  508  may be integrated into amplifier layer  510 . 
         [0039]    With reference to  FIG. 6 , an exploded view of an array core is depicted in accordance with an advantageous embodiment. In this example, in the exploded view of array core  206 , additional components in array core  206  are visible. These components include modules  600 , temperature sensor  602 , coaxial transmission lines  604 , and microwave gasket  606 . 
         [0040]    Still, with reference to  FIG. 6 , this exploded view of array core  206  provides an example of the layered architecture for array core architecture  500  in  FIG. 5 . Modules  600  are microwave modules in microwave modules layer  502  in  FIG. 5 . 
         [0041]    Power and control distribution board  410  is an example of a component in control layer  504  in  FIG. 5 . Power and control distribution board  410  distributes control signals and DC power to modules  600 . This component does not carry microwave signals in this illustrative embodiment. Button contact assembly  412  is another example of a component in control layer  504  of  FIG. 5 . The button contact assembly  412  provides an electrical connection between power and control distribution board  410  and modules  600 . 
         [0042]    Pressure plate  406  and cold plate  404  are part of mounting layer  506  in  FIG. 5  in this depicted example. Waveguide distribution network  402  is an example of a component in signal distribution layer  508  in  FIG. 5 . Pressure plate  406  is a structural component of array core  206 . Pressure plate  406  provides the structure on which modules  600  are fastened or attached to in array core  206 . Pressure plate  406  also acts as a primary heat sink for modules  600  inside array core  206  as well as an electrical ground. Cold plate  404  is used to provide cooling to modules  600  and amplifier block  400  in these examples. Amplifier block  400  is an example of a component located in amplifier layer  510  in  FIG. 5 . Amplifier block  400  amplifies a microwave signal that is received by array core  206  for transmission. 
         [0043]    In these illustrative examples, other components are present in addition to the basic layers illustrated in array core architecture  500  in  FIG. 5 . 
         [0044]    Coaxial transmission lines  604  is a component used to transmit microwave signals from waveguide distribution network  402  to modules  600 . These components act as a connector between these two components. Temperature sensor  602  is mounted on the edge of pressure plate  406  and is used to report the temperature of pressure plate  406 . 
         [0045]    Button contact assembly  412  provides electrical interconnections between power and control distribution board  410  and modules  600 . An example of the type of interconnect that may be used in button contact assembly  412  are available from Cinch Connectors. A particular type of interconnect that may be used from Cinch Connectors is “CIN::ATSE”. Shim  408  is located between pressure plate  406  and power and control distribution board  410 . The thickness of this component may be varied. This component is used to compensate for variations in the thickness of power and control distribution board  410  that occur due to variations in the manufacturing process. This component ensures that contacts in button contact assembly  412  are properly compressed. 
         [0046]    Frame  414  is a structural component used to protect modules  600  and plays a role in holding the array core assembly in the housing of the antenna. Shim  416  is located between sub-honeycomb plate  418  and frame  414 . This component is used to adjust for manufacturing tolerances and ensure proper compression of microwave gasket  606 . 
         [0047]    Microwave gasket  606  ensures that each radiating elements in modules  600  is properly grounded to an associate waveguide in sub-honeycomb plate  418 . This gasket compensates for variations in module height to allow for correct transmission of electromagnetic signals. Sub-honeycomb plate  418  contains circular waveguides. In these examples, the circular waveguides are loaded with a cross-linked polystyrene. Sub-honeycomb plate  418  is used to compress microwave gasket  606  and provide an interface to the antenna housing and aperture. In an alternate embodiment, sub-honeycomb plate  418  may be combined with housing  200 . 
         [0048]    As can be seen in this exploded view of array core  206 , the configuration and design of components are such to allow for layers to be placed over each other. This type of configuration provides a number of different features that may be present in different combinations depending on the particular advantageous embodiment. 
         [0049]    One feature present in different embodiments is more efficient heat removal. In this architecture, as illustrated in  FIGS. 4-6 , modules  600  are connected to pressure plate  406  via a metal-to-metal interface that provides a thermal path from modules  600  to the surrounding structure. The design of modules  600  also contributes to improved heat dissipation when implemented in some of the advantageous embodiments. 
         [0050]    In the depicted examples, the metal-to-metal contact between modules  600  and pressure plate  406  is increased by sending power and control signals to modules  600  through power and control distribution board  410 , while sending microwave signals for transmission from waveguide distribution network  402  to modules  600  using coaxial transmission lines  604 . This type of configuration is in contrast to many current designs in which the same circuit board provides power, control signals, and the microwave signals. This type of board is placed between these parts to provide for microwave distribution. This type of circuit board acts as an insulator and reduces the cooling for modules  600 . 
         [0051]    Thus, the distribution of the microwave signals is provided through a lower layer, containing waveguide distribution network  402 . Further, power and control distribution board  410  does not include microwave signals. As a result, modules  600  may make metal-to-metal contact to pressure plate  406 . Further, by distributing these different functionalities to different layers, a smaller foot print is possible for array core  206  than would be possible if the functions were combined into a single component. Additionally, by not including any microwave signals in this component, more standard materials may be used rather than exotic materials that are required to carry microwave signals in a circuit board. 
         [0052]    With reference next to  FIG. 7 , a cross-sectional view of an array core is depicted in accordance with an advantageous embodiment. In  FIG. 7 , the cross-sectional view of array core  206  shows installed coaxial transmission lines  604  in a cross-section. Coaxial transmission lines  604  provide a connection between waveguide distribution network  402  and modules  600 . Coaxial transmission lines  604  carry the microwave signals that are distributed by waveguide distribution network  402  to modules  600  for transmission by radiating elements in modules  600 . This type of connection provides for less loss in the transmission of signals within array core  206  in contrast to presently used stripline power divider network in a circuit board. 
         [0053]    Still referring to  FIG. 7 , coaxial transmission lines  604  extend through channels in cold plate  404  and pressure plate  406 . Examples of these channels are channels  700 ,  702 ,  704 , and  706 . The use of coaxial transmission lines  604  and channels  700 ,  702 ,  704 , and  706  are part of the mechanism for using a layered architecture for array core  206 . 
         [0054]    Any type of coaxial transmission lines may be used that are sufficient to carry the desired microwave signals from waveguide distribution network  402  to modules  600 . In these examples, coaxial transmission lines  604  are implemented using bullet connector assemblies. In the depicted example, thirty-two bullet connector assemblies form coaxial transmission lines  604 . These bullet connector assemblies carry microwave signals in which each module in modules  600  have two bullet connector assemblies to provide signals. Each bullet connector assembly consists of three components. Two components are male receptacle connectors mounted to the waveguide distribution network  402  and modules  600  respectively. The third component, the actual bullet connector, is a female-to-female in-series coaxial adapter that connects the other two components to one another. Any type of bullet connector system may be used for this particular embodiment. Examples are the Gore 100 system available from W.L. Gore Inc., and the G3PO system available from Corning-Gilbert Inc. 
         [0055]    Thus, different illustrative embodiments provide a layered architecture that provides a number of different features. In these examples, the layers include modules  600 , pressure plate  406 , cold plate  404 , waveguide distribution network  402 , amplifier block  400 , and bullet coaxial connector  602 . These components are arranged in a layered architecture that allows flexibility and scaling designs. Rather than having components that are side-by-side, the layered architecture or design of array core  206  allows for many different numbers of modules to be put together to create modules that may be able to fit into different sized and shaped housings. Any number of modules may be combined to result in an antenna of desired size. 
         [0056]    Another feature present in array core  206  is an all metal heat path that extends from the bottom of the package assembly in the microwave module to cold plate  404 . The configuration of the individual modules in modules  600  also contribute to providing the all metal heat path. 
         [0057]    Turning next to  FIG. 8 , a diagram of a microwave module is depicted in accordance with an advantageous embodiment. In this example, module  800  is a microwave module used in an antenna. Of course, module  800  may be implemented for use for other radio frequency transmissions other than microwave transmissions. 
         [0058]    In particular, module  800  is an example of a microwave module in modules  600  in  FIG. 6 . As illustrated, module  800  contains mandrel  802 , which is a structural component on which different components are attached or placed to form module  800 . In these examples, antenna integrated printed wiring board (AIPWB)  804 , ceramic package lid  806 , grounding cover  808 , flexible circuit  810 , flexible circuit  811 , and connector  812  are located on mandrel  802  of module  800 . 
         [0059]      FIG. 9  is a bottom view of module  800 . In this view, flexible circuit  811  and  810 , and connector  812  are located at end  900  of mandrel  802 , which is a bottom end in these examples. Flexible electronics is a technology for building electronic circuits in which electronic devices may be placed or deposited on flexible substrates, such as plastic. Flexible electronics are also referred to as “flex circuits”, “flexible circuits”, or “flexible printed circuit boards”. The design and configuration of flexible circuit  810 , flexible circuit  811  and connector  812  are such that portions of surface  902  on end  900  are exposed on mandrel  802 . 
         [0060]    With reference now to  FIG. 10 , a diagram illustrating an exploded view of module  800  in  FIG. 8  is depicted in accordance with an advantageous embodiment. The module is shown in an exploded view in which other components can be seen. The module also includes ceramic package  1000 , which is covered by ceramic package kovar lid  806 . Spacer  1002  provides spacing between antenna integrated printed wiring board  804  and mandrel  802 . Divider network  1004  is mounted to mandrel  802 . 
         [0061]    Mandrel  802  is a structural element that forms the structural core of the module. In these examples, mandrel  802  is made of a heat conductive material. In particular, mandrel  802  is made of aluminum in the illustrative embodiments. Mandrel  802  provides a heat path from ceramic package  1000  to surface  902  on end  900 . Further, mandrel  802  also provides a return ground path from ceramic package  1000  to a pressure plate in the antenna array core. As illustrated, mandrel  802  is shown as being about rectangular and about planar in the depicted example. The shape and the proportions of mandrel  802  may vary depending on the implementation. For example mandrel  802  may be more of a square than generally being rectangular. 
         [0062]    Next, antenna integrated printing wiring board  804  is a specific example of an antenna radiator board that may be used in the module. This type of antenna radiator board includes microwave radiating elements. In other implementations, these radiating elements may transmit electromagnetic energy at other frequencies. Antenna integrated printed wiring board  804  is a rigid-flex board. A rigid-flex board is one that contains both rigid and flexible layers. The flexible layers may bend ninety degrees, in these examples, to form an interconnect with ceramic package  1000 . 
         [0063]    Ceramic package  1000  is a carrier containing power amplifier circuits, driver amplifier circuits, phase shifter circuits, and other types of circuits. These types of circuits may be implemented using monolithic microwave integrated circuits and other types of application specific integrated circuits. These circuits are used to amplify and control the emission of microwave signals received from divider network  1004 . In this particular illustration, the ceramic package substrate is composed of multi-layer low-temperature co-fired ceramic. A gold-plated seal ring made of kovar is attached to one side of the ceramic package substrate with gold-tin solder to complete the package. The seal ring facilitates attachment of the lid  806  once internal electronic circuits have been installed. Although a ceramic material is used in this illustration, this carrier may be implemented using other types of materials depending on the implementation. Other candidate materials include but are not limited to organic circuit board materials such as Rogers 4003, Rogers 5880, Teflon (PTFE), and liquid crystal polymer (LCP). 
         [0064]    Divider network  1004  is a circuit board that performs signal division within the module. A single input is received from a waveguide distribution network through a bullet connector connected to connector  812 . In this example, divider network  1004  divides a microwave signal into eight signals. Divider network  1004  may be based on an alumina substrate or any other suitable substrate for carrying microwave signals. Though alumina is used for the substrate in this example, the substrate may also be composed of other materials. In particular, the substrate may be composed of an organic board material such as Rogers 5880 or Rogers 4003. 
         [0065]    Further, flexible circuits  810  and  811  in  FIG. 8  are used to receive both direct current power and control signals from a control board, such as power and control distribution board  410  in  FIG. 4 . By not carrying microwave signals, flexible circuits  810  and  811  may be configured to have a smaller foot print and expose more portions of surface  902  in  FIG. 9  on end  900 . The result is lower overall thermal resistance from modules  600  to pressure plate  406 , resulting in lower operating temperature in the module. 
         [0066]    In these illustrative examples, the module employs the use of a rigid-flex antenna interface printed wiring board to carry microwave signals from ceramic package  1000  to the radiating elements. The use of the flexible circuit portion of antenna integrated printed wiring board  804  allows for the elimination of a non-standard wire bond that connects two perpendicular surfaces. Further, the input and output architecture using bullet connectors and flexible circuits, such as flexible circuit  810  and  811 , allows for additional portions of surface  902  on end  900  of mandrel  802  to be exposed. In this manner, improvements in cooling are provided through the metal surface that is exposed at surface  902  on end  900  of mandrel  802 . By using connector  812  and eliminating the need for a flexible circuit or other circuits to carry microwave signals to the module, the portion of the area of surface  902  that is exposed on end  900  is increased. 
         [0067]    By increasing the exposed portions at this end of the module, the thermal resistance is decreased to increase the amount of heat that may be conducted away from the module per degree temperature difference between the module and pressure plate  406  in  FIG. 4 . The heat dissipated remains constant in these examples. Reducing operating temperature for a given heat dissipation is one of the different features provided in these embodiments. In these examples, the heat dissipation is accomplished by reducing system thermal resistance, which is also called thermal impedance. The result is a decrease in operating temperature for the module. In these examples, the surface area of surface  902  on end  900  is around sixty to ninety percent of the entire surface area possible. In this manner, the exposed surface dissipates heat in an amount sufficient to maintain a desired or selected operating temperature. Surface  902  of end  900  is attached or connected to pressure plate  406  in  FIG. 4  and provided for a metal-to-metal contact. Previously, a printed wiring board was present between the module and pressure plate  406  in  FIG. 4 . This type of board was used to distribute microwave signals and acted as an insulator, reducing the amount of cooling possible for the module. 
         [0068]    Turning next to  FIG. 11 , a cross-section view of a microwave gasket located between a honeycomb wave guide and a radiating element in an antenna integrated wiring board is depicted in accordance with an advantageous embodiment. In this example, gasket  1100  is a radio frequency gasket that is located between sub-honeycomb plate  1102  and antenna integrated printed wiring boards (AIPWB), such as antenna integrated printed wiring boards  1104  and  1106 . In particular, gasket  1100  is a microwave gasket in these examples. Sub-honeycomb plate  1102  is similar to sub-honeycomb plate  418  in  FIG. 4 . Antenna integrated printed wiring board (AIPWB)  1104  and  1106  are similar to antenna integrated printed wiring board  804  in  FIG. 8 . 
         [0069]    Gasket  1100  comprises a sheet material with holes cut or formed in gasket  1100  following the pattern of the apertures in sub-honeycomb plate  1102 . Gasket  1100  is compressible and is shown in a compressed state in this example. 
         [0070]    Gasket  1100  is made of an electrically conductive conformal material in these particular embodiments. In one embodiment, gasket  1100  is constructed of a conductive foam that is laminated to a thin copper sheet. The copper sheet has an electrically conductive pressure sensitive adhesive applied to the side opposite the foam. The foam is made of an elastomeric material that is plated with a thin layer of metal. A material matching this description is GS8000 material, manufactured by W.L. Gore Inc. In another embodiment, gasket  1100  consists of a composite material consisting of a rubber sheet with conductive fibers running through it. A material matching this description is Soft Shield 4800, manufactured by Chomerics, a division of Parker Hannifin Corporation. There may be other materials available that may be used to manufacture gasket  1100 , including some conformable materials originally designed to shield against electromagnetic interference (EMI). Because such materials were designed for a somewhat different purpose, not all conformal EMI gaskets will function correctly in this application. Materials are selected through testing these materials to determine if they simulate a solid metal conductor at microwave frequencies. 
         [0071]    As can be seen in this perspective cross-section view, gasket  1100  includes a number of holes or channels, such as channels  1108  and channels  1110 , that are cut out to provide a channel from sub-honeycomb plate  1102  to radiating elements in components, such as antenna integrated printed wiring boards  1104  and  1106 , and radiating elements  1109  and  1111 . Gasket  1100  is attached to surface  1124  of sub-honeycomb plate  1102  with a pressure-sensitive adhesive in these examples. 
         [0072]    Sub-honeycomb plate  1102  is made of aluminum although other conductor materials may be used. Further, sub-honeycomb plate  1102  contains channels, such as channels  1112 ,  1114 , and  1116 . A dielectric, such as dielectric plugs  1118 ,  1120 , and  1122  is present in each of these channels in sub-honeycomb plate  1102 . Sub-honeycomb plate  1102 , with the included channels and the dielectric inserts, generally forms a multiplicity of waveguides corresponding to the radiating elements in antenna integrated printed wiring boards  1104  and  1106 . Surface  1124  of sub-honeycomb plate  1102  serves as a waveguide flange; that is, a surface for mating with a similar structure on another waveguide. The top surfaces of antenna integrated printed wiring boards, including antenna integrated printed wiring boards  1104  and  1106 , also serve as waveguide flanges. Gasket  1100  is inserted between the flange-like surfaces  1124  of sub-honeycomb plate  1102 , and the upper surfaces of various antenna integrated printed wiring boards, including antenna integrated printed wiring boards  1104  and  1106 . 
         [0073]    The dielectric extends beyond bottom surface  1124  of sub-honeycomb plate  1102  into the channels in gasket  1100 . In these examples, air gaps are present between dielectric inserts such as  1118 ,  1120 , and  1122  on one hand, and antenna integrated printed wiring boards such as  1104  and  1106  on the other. For example, air gap  1126  is present between dielectric plug  1118  and radiating element  1128  in antenna integrated printed wiring board  1104 . Air gaps are the undesirable result of varying module height. Air gaps result in a discontinuity between the waveguides in sub-honeycomb plate  1102  and the waveguides in antenna integrated printed wiring boards  1104  and  1106 . Varying module height occurs due to manufacturing variations. Using a conformable conductive gasket, such as gasket  1100 , that expands functions to minimize or eliminate the air gaps between waveguide flanges, in the conductive region. Air gaps, such as air gap  1126 , do not have much impact as long as they are shorter than ¼ wavelength. Gasket  1100  is used to provide a ground between antenna integrated printed wiring boards  1104  and  1106  and sub-honeycomb plate  1102 . Gasket  1100  joins these two waveguides together so they operate as one waveguide. 
         [0074]    In these examples, radiating elements  1109  and  1111  contain embedded waveguide structures that radiate signals into the waveguides in sub-honeycomb plate  1102 . As an example, radiating element  1111 , channel  1116 , and channel  1110  are cylindrical in nature with the cylinder axis oriented from bottom to top, and jointly represent a circular waveguide in cross section that runs from bottom to top in these examples. 
         [0075]    The electrical function of gasket  1100  is to create a continuous electrical ground around the perimeter of each waveguide from the top surface of the antenna integrated printed wiring boards, such as antenna integrated printed wiring boards  1104  and  1106 , to bottom surface  1124  of sub-honeycomb plate  1102 , thus connecting the waveguide structure embedded in the antenna integrated printed wiring boards to the waveguide structure embedded in sub-honeycomb plate  1102 . Gasket  1100  prevents signals from one radiating element from interfering with or coupling with signals from another radiating element or probe, eliminating an unwanted case of what is generally known as mutual coupling between array elements. Gasket  1100  also prevents signals from escaping back down to other components, such as chip carriers  1130 ,  1132 ,  1134 , and  1136  or to other locations where these signals might re-enter the chip carrier, creating an undesirable feedback loop and creating an effect generally referred to as oscillation. 
         [0076]    Although the shape of the channels in gasket  1100  is circular in these examples, the shape of these channels may vary. For example, another shape may be a hexagon, or a quadrilateral. Gasket  1100  creates a ground between between antenna integrated printed wiring boards  1104  and  1106  and sub-honeycomb plate  1102  such that an electromagnetic wave may propagate through the waveguides with an acceptable amount of reflection of the interface. 
         [0077]    In the current designs, the bottom surface of dielectric plug  1118  in channel  1114  is coplanar with bottom surface  1124  of sub-honeycomb plate  1102 . In this situation, the compressed height of the grounding gasket  1100  would be equal to the height of air gap  1126 . Air gap  1126  is highly undesirable because it creates a discontinuity in the waveguide; therefore its height must be minimized. But the ability of gasket  1100  to conform to varying air gaps decreases with decreasing gasket thickness. The extension of dielectric, such as dielectric plugs  1118 ,  1120 , and  1122  that extend through gasket  1100 , means that gasket  1100  may be thicker and thus more conformable to air gaps of varying height, while the thickness of air gaps, such as air gap  1126 , is minimized. 
         [0078]    The different features of gasket  1100  alone and in combination prevent the propagation of surface waves among adjacent waveguides and surrounding structures, thus reducing the mutual coupling between adjacent array elements, and reducing the probability of frequency oscillation. The gasket is useful, in part, because of the close proximity of waveguides to each other as shown in this figure. The gasket is also useful, in part, because the distance between sub-honeycomb plate  1102  and antenna integrated wiring boards, including antenna integrated wiring boards  1104  and  1106 , may vary. Also, this single component replaces hundreds of individual grounding springs that are currently used. Although this example shows gasket  1100  between sub-honeycomb plate  1102  and a multiplicity of antenna integrated printed wiring boards, including antenna integrated printed wiring boards  1104  and  1106 , gasket  1100  may be used between other waveguide structures. For example, gasket  1100  may be placed between two sub-honeycomb plates. 
         [0079]    While the depicted embodiments are applicable to a Q-band transmit antenna, the different embodiments also may be applicable to transmit or receive antennas of any frequency from 1 to 100 GHz, particularly if multiple transmit or receive beams are required. Although the depicted embodiments are directed towards microwave transmission, the different embodiments may be applied in any radio frequency transmissions. With implementations using radio frequency transmissions other than microwaves, the different components are selected to provide generation and transmission for the selected radio frequencies. 
         [0080]    The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different advantageous embodiments may provide different advantages as compared to other advantageous embodiments. The embodiment or embodiments selected are chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.