Patent Description:
A phased array antenna is an array of radiating elements in which the relative phases of the signals feeding the antennas are varied to produce a directive radiation pattern. Various applications may use phased array antennas, such as radar or communication systems for commercial or military applications. A phased array antenna may be suitable for use in marine vessels, land vehicles, aircrafts, or space vehicles. For example, a surveillance system for an aircraft may use a phased array antenna.

Phased array antennas may require routine maintenance or removal and replacement of panels of the array that contain the radiating elements. However, conventional radiating element panels are bolted to the front of a mount or support structure such that only the front area of the array is accessible to an operator attempting to perform maintenance. Accordingly, accessing the panels and maintaining the array structure is difficult, especially for larger array structures.

<CIT> discloses a multifunction electronics member combining structural and electronics functions including in one embodiment an elongate longitudinally-extending structural body configured to support a structural load and including a first support base, a stiffening projection, and a first electrical circuit supported by the first support base. The circuit preferably is embedded between the first circuit base and a cover to form an electrically-active, or in some embodiments passive, structural member.

<CIT> discloses a wireless communication electronic assembly that can include a plurality of integrated modules each having a ground plate interfaced to each other and defining a shielding plane. Each ground plate can have a left edge and a right edge opposite each other. A plurality of wireless communication devices can be positioned on one side of the shielding plane, and a plurality of electronic devices can be positioned on the other side of the shielding plane. One or more electromagnetic shielding elements, such as gasket(s), channel strip(s), stamping element(s), etc. can be disposed between the left edge and the right edge of adjacent ground plates to electromagnetically shield the plurality of electronic devices from the plurality of wireless communication devices. The left and right edges can be recessed or offset on one side of the shielding plane. Rows and columns of integrated modules can be interfaced about a plurality of electromagnetic shielding elements.

<CIT> discloses an element support and thermal control arrangement for an active array antenna, preferably modular, using line-replaceable units (LRUs), includes a radiating-side liquid-cooled cold plate lying parallel with a liquid-cooled TR coldplate.

<CIT> discloses an antenna assembly that includes a plurality of separate and distinct antenna modules that are interconnected together to form an antenna layer. Each of the antenna modules may include a support structure including a core frame connected to a core support, and a backskin connected to one or both of the core frame and the core support. The antenna assembly may also include an alignment grid configured to receive and align each of the antenna modules, and/or a matching layer configured to receive and align each of the antenna modules.

Using uniquely configured line replaceable unit (LRU) in an array antenna is advantageous in providing structural rigidity, alignment, and rear access that improves the ability to maintain the array antenna. The array antenna includes a plurality of LRUs that are rigidly connectable and removable relative to a support frame of the array antenna. Each LRU has a right-angle bracket with orthogonal flanges that provide the structural rigidity and predetermined alignment of the LRU when the LRU is mounted to the support frame. Feature of the LRU ensures precise element-to-element alignment as the LRU may include various electrical and/or mechanical elements, such as cooling connections, electrical connections, and RF connections. When the plurality of LRUs are mounted within the array antenna, each LRU is arranged with proper alignment and spacing relative to the other LRUs such that radiating elements of the LRUs are configured to obtain a desired scanning angle of the array antenna.

The support frame is formed to be grid-shaped or window-pane shaped such that the vertical beams are engageable against corresponding horizontal beams of the support frame for alignment of the LRUs. Fasteners are used to secure the flanges of each LRU bracket to corresponding orthogonal beams of the support frame. The LRUs are mounted within windows or openings that are defined by the orthogonal beams and provide rear access to the LRU through the support frame, as compared with conventional array antennas that only enable front access to the array antenna. Providing rear access is particularly advantageous in applications using large aperture array antennas having dimensions, such as lengths, widths, heights, etc. that are at least several meters.

Each LRU includes an RF circuit card panel having both the radiating elements and RF integrated circuit (IC) components arranged on the front side of the LRU, a power conditioning input and output panel (I/O panel) that is attached behind the RF panel. The I/O panel is an electromechanical interface having a front surface which faces the RF panel and a rear surface opposing the front surface. The right-angle mounting bracket extends in a perpendicular direction from the rear surface. The right angle mounting bracket provides two orthogonal flanges meeting at a corner of the rear surface. The arrangement of the bracket is advantageous in that the bracket enables mounting to the support frame while also enabling access to the rear surface of the I/O panel. A pull mechanism or other handling device may be arranged on the rear surface to enable removal and handling of the LRU.

Each opening of the support frame may support a subassembly of four LRUs that are arranged in a puzzle-type arrangement or interlocking arrangement in which the rear surfaces of each I/O panel are adjacent to each other and lay in a common plane. Providing subassemblies of four LRUs per frame opening is advantageous in that the subassembly enables one of the LRUs to be withdrawn rearwardly and then moved laterally toward a center of the subassembly and opening to be completely removed from the array antenna without disturbing the surrounding LRUs and radiating elements. The LRU is configured to enable the rapid removal and/or replacement of the LRU as a self-contained unit.

The LRU configuration is further advantageous in enabling modularity of the array antenna. Using the support frame and mounting brackets of the LRUs, the support frame may be able to support different numbers and arrangements of LRUs. LRUs may be easily removed or added to the support frame. The LRU also enables any suitable mechanical or electrical connections to be incorporated in the LRU, which renders LRUs suitable for different applications. The support frame is also adaptable for mounting to any suitable platform in different applications. For example, the array antenna assembly having the support frame and the LRUs may be feasible for stationary platforms, such as buildings, or moving platforms such as a sea vessels, land vehicles, aircrafts, or space vehicles. Many other applications may be suitable.

According to an aspect of the invention, an array antenna includes a right-angle, rear-accessible, mounting bracket.

According to an aspect of the invention, an array antenna includes a plurality of line replaceable units.

According to an aspect of the invention, an array antenna includes a plurality of line replaceable units that each have an electrotechnical panel and a right-angle mounting bracket.

According to a first aspect, the present disclosure provides a line replaceable unit for an array antenna, the line replaceable unit comprising: a panel having a front surface configured to be electrically and mechanically connected with electronics of the array antenna, and a rear surface opposing the front surface; and a mounting bracket that is attached to the rear surface and extends perpendicular to the rear surface opposite the electronics, wherein the mounting bracket is a right-angle bracket that has at least two mutually orthogonal flanges that are configured to align the line replaceable unit within the array antenna, wherein a right angle is formed between the at least two orthogonal flanges at a corner of the rear surface, and wherein at least one of the orthogonal flanges is configured as an electrical and mechanical interface for one or more additional features of the line replaceable unit, in addition to the panel.

According to an embodiment of any paragraph(s) of this summary, the orthogonal flanges may extend along outer edges of the rear surface, whereby most of the rear surface is exposed.

According to an embodiment of any paragraph(s) of this summary, the two orthogonal flanges may be integrally formed.

According to an embodiment of any paragraph(s) of this summary, at least one of the orthogonal flanges includes at least one of a cooling element or an RF connector.

According to an embodiment of any paragraph(s) of this summary, the line replaceable unit may include a pull mechanism mounted on the rear surface of the panel.

According to a second aspect, the present disclosure provides an array antenna assembly comprising: a frame support structure; and a plurality of line replaceable units according to the first aspect, wherein each of the plurality of line replaceable units includes a plurality of radiating elements disposed on the front surface, wherein the orthogonal flanges of each of the plurality of line replaceable units are engageable with the frame support structure to align the line replaceable unit within the array antenna assembly.

According to an embodiment of any paragraph(s) of this summary, the frame support structure may be grid-shaped and defines a plurality of openings through which the rear surface of each of the line replaceable units is accessible.

According to an embodiment of any paragraph(s) of this summary, each of the openings may be configured to support a subassembly having four line replaceable units.

According to an embodiment of any paragraph(s) of this summary, the subassembly may include two sets of identical line replaceable units, wherein identical line replaceable units are diagonally opposed to each other.

According to an embodiment of any paragraph(s) of this summary, the rear surface of each of the four line replaceable units may lay flat with each other in a common plane.

According to an embodiment of any paragraph(s) of this summary, the array antenna assembly may include a plurality of fasteners that connect the line replaceable units to the frame support structure.

According to an embodiment of any paragraph(s) of this summary, the fasteners may be shear fasteners that are attached between the mounting bracket and the frame support structure.

According to an embodiment of any paragraph(s) of this summary, the frame support structure may include a plurality of orthogonal beams that each have a first mounting surface and a second mounting surface that extends from the first mounting surface, wherein the shear fasteners are engageable against the first mounting surface.

According to a third aspect, the present disclosure provides a method of assembling and maintaining an array antenna assembly according to the second aspect, the method comprising: forming the frame support structure; and mounting the plurality of line replaceable units to the frame support structure by engaging the orthogonal flanges with the frame support structure to align the line replaceable unit within the array antenna.

According to an embodiment of any paragraph(s) of this summary, the method may further include mounting the frame support structure to a support beam on an existing structure.

According to an embodiment of any paragraph(s) of this summary, mounting the plurality of line replaceable units may include arranging the rear surfaces of the plurality of line replaceable units to be accessible through openings defined by a plurality of orthogonal beams of the frame support structure.

According to an embodiment of any paragraph(s) of this summary, mounting the plurality of line replaceable units to the frame support structure may include arranging four line replaceable units to form a subassembly that is configured to fit into one of the openings.

According to an embodiment of any paragraph(s) of this summary, the method may further include removing one of the line replaceable units from the frame supporting structure by accessing the rear surface through the frame support structure.

According to an embodiment of any paragraph(s) of this summary, removing one of the line replaceable units may include moving the line replaceable unit in a rear direction away from a plane in which the other line replaceable units are arranged, and moving the line replaceable unit in a lateral direction away from the frame support structure.

To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.

The principles described herein have particular application in phased array antenna structures. An array antenna assembly that includes individual electromechanical units having right-angle brackets that are rigidly connectable and removable relative to a support frame of the assembly is advantageous in both providing rear access to the units for maintenance and in providing alignment of each unit when mounted. For example, the brackets provide precise element-to-element alignment for any RF connections, electrical connections, and cooling mechanisms of each unit. The array antenna assembly may be suitable for use in various applications that use phased array antennas, such as in radar or communication systems for commercial or military applications. The array antenna assembly may be mounted to any suitable structure or platform, such as a moving vehicle or a stationary building. Still another exemplary application includes power generation for solar cells in which mirror arrays are used. Many other applications may be suitable and the array antenna assembly may be scaled up or down depending on the application.

The array antenna assembly includes a frame support structure that supports a plurality of line replaceable units (LRUs) that are rigidly connectable and removable relative to the frame support structure. Each of the LRUs includes an RF panel having radiating elements, an input and output panel (I/O panel), and a right-angle bracket. The I/O panel has a front surface that faces the RF panel, and a rear surface that opposes the front surface. The right-angle bracket extends outwardly from the rear surface opposite the RF panel. The right-angle bracket includes orthogonal flanges that extend perpendicular to the rear surface and along edges of the rear surface such that the right angle formed by the flanges is located at a corner of the rear surface.

Using the orthogonal flanges enables the bracket to provide alignment of the LRU when engaged with corresponding orthogonal beams of the frame support structure, while also providing access to the rear surface of the I/O panel. Each LRU is removable by being withdrawn from the array antenna assembly in a rear direction, such as by an operator who is located behind the array antenna assembly and pulls the LRU toward him or her. After rearward displacement, the LRU may then be laterally shifted to be completely removed from the frame support structure without interfering with the other LRUs, such that one of the LRUs may be replaced or undergo maintenance.

<FIG> show an exemplary LRU <NUM> for an array antenna assembly according to the present application. The LRU <NUM> includes an I/O interface, or I/O panel <NUM>, and a bracket <NUM> that is attached to the I/O panel <NUM>. The I/O panel <NUM> may be rectangular in shape and have a front surface <NUM>, and a rear surface <NUM> opposing the front surface <NUM>. The front surface <NUM> faces electronics of the LRU <NUM> and the electronics may be in communication with electronics of the front surface <NUM>. The electronics includes a circuit card assembly <NUM>, as best shown in <FIG>, and an RF panel <NUM> having at least one antenna element or radiating element <NUM> and a monolithic microwave integrated circuit (MMIC) <NUM>, as best shown in <FIG>, <FIG>. The LRU <NUM> may further include a cold plate <NUM> in which the circuit card assembly <NUM> is mounted adjacent to the front surface <NUM> of the I/O panel <NUM>. The RF panel <NUM> may be mounted on the opposing side of the cold plate <NUM> relative to the circuit card assembly <NUM>. The I/O panel <NUM> may be configured for both mechanical connection and electrical communication with any other suitable electronics and mechanical devices. For example, other mechanical devices may include different types of cooling devices or heat exchangers that are arranged in the LRU <NUM>.

Each radiating element <NUM> of the RF panel <NUM> is spaced to achieve a desired frequency which may be dependent on the application in which the array antenna is being used. Suitable frequency letter bands include an S band, X band, C band, L band, or UHF band. Any suitable number of radiating elements may be used and the spacing between each radiating element <NUM> may be selected to provide a preferred scan angle. As the electronics are mounted on the front surface <NUM> of the LRU <NUM>, the front side of the LRU <NUM> is used for RF communication of the array antenna. In an exemplary embodiment, the RF panel <NUM> may be castellated on a top edge <NUM> and a bottom edge <NUM> of the RF panel <NUM> to accommodate triangular element spacing. In still other exemplary embodiments, the RF panel <NUM> may be a segmented RF radiator panel having a square or rectangular element spacing.

The I/O panel <NUM> is configured for electrical communication with the circuit card assembly <NUM> and housing the circuit card assembly <NUM>, such that the I/O panel <NUM> provides an electromechanical interface for the LRU <NUM>. The I/O panel <NUM> may further include any suitable power and signal I/O <NUM>, as shown in <FIG> and <FIG>. When the LRU <NUM> is assembled within the array antenna assembly, the rear surface <NUM> of the I/O panel <NUM> is accessible such that the power and signal I/O <NUM> is also accessible. The I/O panel <NUM> being accessible refers to an operator, which may be a manual operator or an automatic operator, being able to contact the I/O panel <NUM> and physically move the LRU <NUM>. A pull mechanism or handling device, such as a foldable handle <NUM>, may also be pivotably mounted to the rear surface <NUM> and accessible for removal of the LRU <NUM> from the assembly as will be described further below. Any other suitable accessible attachment or hardware that enables handling of the LRU <NUM> may be provided. For example, other pull mechanisms such as knobs or cables may be used.

The bracket <NUM> of the LRU <NUM> extends perpendicular to the rear surface <NUM> of the I/O panel <NUM> in a direction that is opposite to the electronics of the LRU <NUM>. The bracket <NUM> includes at least two orthogonal flanges <NUM>, <NUM> that are straight and meet at a corner <NUM> such that the orthogonal flanges <NUM>, <NUM> are formed at a <NUM> degree or right angle relative to each other. The orthogonal flanges <NUM>, <NUM> may be formed integrally with each other or as separate components that are adjoined using any suitable joining process, such as welding. Similar to the I/O panel <NUM>, the orthogonal flanges <NUM>, <NUM> may also be configured as electromechanical interfaces that support any suitable additional mechanical or electrical features of the LRU <NUM>. The orthogonal flanges <NUM>, <NUM> may be configured to support RF connections, other electrical connections, or cooling mechanisms. For example, one orthogonal flange <NUM> may be configured to support a beam former feed through <NUM> that is in electrical communication with the radiating elements of the RF panel <NUM>. Another orthogonal flange <NUM> may be configured to support a cooling mechanism <NUM> such as supply and/or return lines for cooling the electronics of the LRU <NUM>. The orthogonal flanges <NUM>, <NUM> may be configured to support other electrical or mechanical features of the LRU <NUM> and the features may be dependent on the application.

Each of the orthogonal flanges <NUM>, <NUM> extends along a corresponding outer edge or perimeter of the rear surface <NUM> of the I/O panel <NUM>, such that most of the surface area of the rear surface <NUM> is exposed or accessible. The corner <NUM> at which the right angle between the orthogonal flanges <NUM>, <NUM> is formed is thus located at a corner of the rear surface <NUM>. As shown in <FIG>, the first orthogonal flange <NUM> extends in a direction in which the height H of the I/O panel <NUM> extends and the first orthogonal flange <NUM> may extend along at least most of the distance of the height H. The second orthogonal flange <NUM> extends in a direction in which the width W of the I/O panel <NUM> extends and the second orthogonal flange <NUM> may extend along at least most of the distance of the width W.

The I/O panel <NUM> may have any suitable height H and width W, and the height H and width W of the I/O panel <NUM> may define the height and width of the entire LRU <NUM>. For example, the height H and the width W may be greater than <NUM> meters (<NUM> foot). The height H and the width W may have a length that is between <NUM> meters and <NUM> meters (between <NUM> and <NUM> feet). The height H may be greater than the width W such that the I/O panel <NUM> is rectangular in shape, but in other exemplary embodiments, the I/O panel <NUM> may have equivalent dimensions such that the I/O panel <NUM> is square-shaped. The bracket <NUM> may extend from the I/O panel <NUM> by a distance D that is less than the width W or the height H. The dimensions are merely exemplary and many other dimensions may be suitable. The I/O panel <NUM> and the bracket <NUM> may be formed of any suitable material and manufactured using any suitable manufacturing process. Metal materials may be suitable. The LRU <NUM> may also have any suitable weight which may be dependent on the electrical components or cooling components being supported by the LRU <NUM>. In an exemplary application, the LRU <NUM> may weigh between <NUM> and <NUM> kilograms (between <NUM> and <NUM> pounds), but the LRU <NUM> may be sized up or down depending on the application.

Referring in addition to <FIG>, the LRU <NUM> is secured to a frame support structure <NUM> using any suitable fastening mechanism. The bracket <NUM> includes at least one fastener-receiving hole <NUM> formed on the bracket <NUM>. A plurality of fastener-receiving holes may be provided and the fastening mechanism may include a plurality of shear fasteners <NUM>, <NUM>, <NUM>, as shown in <FIG> and <FIG>, that are each received within the corresponding fastener-receiving hole <NUM>. Other suitable fasteners include bolts, pins, screws, and nuts and any suitable number of fasteners may be used. For example, three shear fasteners <NUM>, <NUM>, <NUM> may be used and the shear fasteners <NUM>, <NUM>, <NUM> may be arranged at opposite locations along the bracket <NUM>. For example, the middle shear fastener <NUM> may be arranged at the corner <NUM> of the bracket <NUM> and aligned with the shear fastener <NUM> along the length of the orthogonal flange <NUM>. The middle shear fastener <NUM> may be aligned with the shear fastener <NUM> along a length of the other orthogonal flange <NUM>. The shear fasteners <NUM>, <NUM>, <NUM> may be arranged to extend in a direction that is perpendicular to the rear surface <NUM> of the I/O panel <NUM>. The shear fasteners <NUM>, <NUM>, <NUM> extend through the corresponding orthogonal flange <NUM>, <NUM> to engage the frame support structure <NUM> and secure the LRU <NUM> to the frame support structure <NUM>.

The frame support structure <NUM> is configured to support a plurality of LRUs when each LRU <NUM> is secured to the frame support structure <NUM> with the fastening mechanism. The frame support structure <NUM> may be sized to accommodate any number or arrangement of LRUs and the size may be dependent on the application. Advantageously, the frame support structure <NUM> may be formed to enable adding or removing LRUs such that the frame support structure <NUM> in conjunction with the LRUs enables modularity of an array antenna construction. The frame support structure <NUM> is grid-shaped or window-pane shaped, and formed of a plurality of orthogonal beams <NUM>, <NUM> that extend parallel and perpendicular to each other. As shown in <FIG>, groups of four orthogonal beams <NUM>, <NUM> each define a window or opening <NUM> through which the rear surface <NUM> of each LRU <NUM> is accessible when assembled. The frame support structure <NUM> includes horizontal and vertical orthogonal beams <NUM>, <NUM>, respectively, such that each opening <NUM> is rectangular in shape. Each group of beams <NUM>, <NUM> includes two vertical beams and two horizontal beams. The beams being horizontal and vertical refers to a general orientation of the frame support structure <NUM> when in an upright and vertical orientation. In operation, when the frame support structure <NUM> is assembled, the horizontal and vertical beams may be angled relative to a horizontal and vertical direction as the entire frame support structure <NUM> may have an angled orientation.

As shown in <FIG>, the orthogonal beams <NUM>, <NUM> each have a LRU mounting surface <NUM> that protrudes horizontally and vertically from the corresponding beam <NUM>, <NUM> having a vertical beam portions and a horizontal beam portion <NUM>. The LRU mounting surface <NUM> provides a surface for engagement by the three shear fasteners <NUM>, <NUM>, <NUM> of the LRU <NUM> that engage the LRU mounting surface <NUM> through the bracket <NUM>. Each bracket <NUM> is mounted to two orthogonal mounting surfaces corresponding to a vertical beam <NUM> and corresponding to a horizontal beam <NUM>. The engagement between the frame support structure <NUM> and the bracket <NUM> of each LRU <NUM> is advantageous in that the orthogonal flanges <NUM>, <NUM> of the bracket <NUM> are aligned with the corresponding orthogonal beams <NUM>, <NUM> of the frame support structure <NUM> to ensure more precise alignment of the LRUs as compared with conventional mounting devices. The LRU mounting surface <NUM> may also provide electrical/RF interconnectors <NUM> and liquid quick disconnect couplings <NUM>.

The frame support structure <NUM> may further include a plurality of attachment points <NUM>, <NUM> that are attached to one side of the frame support structure <NUM> for attaching the frame support structure <NUM> to a side of a building or other suitable platform. The attachment points <NUM>, <NUM> may be arranged at junctions of the frame support structure <NUM> at which the orthogonal beams <NUM>, <NUM> meet. The attachment points <NUM>, <NUM> may be attached to the frame support structure using any suitable attachment mechanism or manufacturing process. For example, the attachment points <NUM>, <NUM> may be welded to the frame support structure <NUM>. Any suitable number of attachment points <NUM>, <NUM> may be provided and the number of attachment points <NUM>, <NUM> may be dependent on the application. The entire frame support structure <NUM> may be formed using any suitable manufacturing process and formed of any suitable material. Metal materials, such as carbon sheet steel, may be suitable materials for the frame support structure <NUM>.

Referring now to <FIG>, an exemplary array antenna assembly <NUM> is shown. The array antenna assembly <NUM> includes a plurality of LRUs being attached to and supported by a frame support structure <NUM>. <FIG> shows the front side of the array antenna assembly <NUM> and <FIG> shows the rear side of the array antenna assembly <NUM>. Using the LRU <NUM> having the right-angle bracket <NUM> is advantageous in that the interface between the frame support structure <NUM> and the LRUs provides planarity and precise element spacing for each RF panel <NUM>, while also enabling access to the rear surface <NUM> of each LRU <NUM>. Thus, an operator can easily perform maintenance or replace an LRU <NUM> without having to access the front side of the array antenna assembly <NUM>. The RF panels may be arranged in a horizontal or x-direction and in a vertical or y-direction and the LRUs are accessible in a z-direction from the rear surface <NUM>. The x, y, and z-directions refer to a general orientation of the array antenna assembly <NUM> when in a vertical upright orientation. In operation, when the array antenna assembly <NUM> is assembled and in use, the array antenna assembly <NUM> may be angled.

Any suitable number of LRUs may be provided and the number of LRUs may be dependent on the application. In the exemplary embodiment shown in <FIG>, the array antenna assembly <NUM> has <NUM> LRUs that each have <NUM> antenna elements. In another exemplary embodiment, <NUM> LRUs with <NUM> antenna elements may be used in the array antenna assembly. The LRUs may be formed in uniform columns and rows, or, as shown in <FIG>, some rows and columns may include more or fewer LRUs depending on the application. Many arrangements of the LRUs are suitable and the arrangement of the LRUs and antenna elements may depend on a preferred scanning angle of the array antenna. The array antenna assembly <NUM> may have any suitable size. For example, the array antenna assembly <NUM> may provide an antenna aperture having a diameter that is between <NUM> and <NUM> meters (between <NUM> and <NUM> feet). The frame support structure <NUM> may have any suitable area dimensions to support a corresponding plurality of LRUs.

The assembled array antenna assembly <NUM> may be configured to support additional mechanical or electrical features such as at least one vertical beam former <NUM> and a cooling, signal and power distribution system <NUM>. Each vertical beam former <NUM> may be attached to a corresponding vertical orthogonal beam <NUM> and extend in the vertical direction or y-direction. The cooling, signal and power distribution system <NUM> may include supply and return lines that are supported within hollow cavities of the frame support structure <NUM> such that the cooling and power distribution system <NUM> is spread over the entire area of the array antenna assembly <NUM>. The cooling and power distribution system <NUM> may be in communication with each LRU <NUM>.

Referring in addition to <FIG>, each opening <NUM> of the frame support structure <NUM> is configured to receive four LRUs that are arranged adjacent to each other to form a subassembly <NUM> that may be rectangular in shape. The four LRUs may fit together in a puzzle-type arrangement such that an edge 32a of each I/O panel <NUM> of an LRU <NUM> engages the edge 32a of an adjacent I/O panel <NUM>. The edges engage both in the horizontal and vertical direction. Each rear surface <NUM> of the I/O panels of the four LRUs are flat with each other and extend in a common plane, such that the precise alignment of each LRU <NUM> is ensured. Each subassembly <NUM> may include two sets of identical or nearly identical LRUs 30a, 30b and the identical LRUs 30a, 30b are arranged diagonally relative to each other within the subassembly <NUM>. For example, the first set of LRUs may include an LRU 30a and the second set of LRUs may include an LRU 30b, with the LRU 30a having a non-identical LRU 30b arranged adjacent to the LRU 30a in the vertical and horizontal direction. Similarly, the LRU 30b has a non-identical LRU 30a arranged adjacent to the LRU 30b in the vertical and horizontal direction. In other exemplary embodiments, the frame support structure <NUM> and LRUs may be configured in other arrangements and subassemblies. For example, all of the LRUs may be identical or nearly identical.

The LRUs 30a, 30b are arranged such that a set of non-identical LRUs 30a, 30b share a corresponding vertical beam <NUM> and another set of non-identical LRUs 30a, 30b share a corresponding horizontal beam <NUM>. For example, the shear fasteners <NUM>, <NUM> of the LRU 30b may be attached to the LRU mounting surface <NUM> of the horizontal beam <NUM> and the shear fasteners <NUM>, <NUM> of the LRU 30b may be attached to the LRU mounting surface of the vertical beam <NUM>. The shear fastener <NUM> is arranged at the junction between the horizontal beam <NUM> and the vertical beam <NUM>. The shear fasteners 74a, 76a of the LRU 30a may be arranged on the same vertical beam <NUM> as the shear fasteners <NUM>, <NUM> of the LRU 30b. The shear fasteners 72a, 74a of the LRU 30a may be arranged along a horizontal beam 78a that is parallel with the horizontal beam <NUM> and opposite the subassembly <NUM> of LRUs relative to the horizontal beam <NUM>. The shear fastener 74a of the LRU 30a is arranged at the junction between the vertical beam <NUM> and the horizontal beam 78a.

Positioning the bracket <NUM> within the frame support structure <NUM> may be further aided using any suitable assembly aid <NUM> that is configured to engage with the bracket <NUM> and prevent lateral shifting of the LRU <NUM>. The assembly aid <NUM> may be configured to lead the fasteners <NUM>, <NUM>, <NUM> into corresponding fastener receiving holes. In an exemplary embodiment, the assembly aid <NUM> may be formed as a block or similar protrusion that is attached to the LRU mounting surface <NUM> and a horizontal beam portion <NUM> of a corresponding one of the orthogonal beams <NUM>, <NUM>. One of the orthogonal flanges <NUM>, <NUM> of the bracket <NUM> may include a complementary recess <NUM> that at least partially receives the assembly aid <NUM> when the LRU <NUM> is assembled into the frame support structure <NUM>. The frame support structure <NUM> may include a plurality of assembly aids that are spaced along the orthogonal beams <NUM>, <NUM>. Assembly aids may be arranged on the horizontal beams, the vertical beams, or both. Other suitable assembly aids, such as clamps, couplers, and fasteners, may also be used.

Providing two sets of identical or nearly identical LRUs 30a, 30b is further advantageous in that the arrangement enables the position of each pull mechanism or handle <NUM> to be centered or in an area of the opening <NUM> that is most accessible to the operator. For example, each handle <NUM> may be arranged proximate a corner <NUM> of the corresponding LRU <NUM> that is distally opposite the corner at which the bracket <NUM> forms the right-angle. Accordingly, each corner <NUM> of the four LRUs <NUM>, 30a, 30b are engageable in a central location of the corresponding opening <NUM> and the handle <NUM> of each LRU <NUM> are arranged proximate to each other at the central location, with the brackets of the LRUs forming a rectangular outer perimeter of the subassembly <NUM>. Advantageously, all four LRUs may be accessed and undergo maintenance by the operator from the same or a single position or location of the operator.

Referring in addition to <FIG> and <FIG>, the removal operation of an LRU <NUM> from the frame support structure <NUM> is schematically shown. <FIG> shows the subassembly <NUM> of LRUs when assembled and <FIG> shows one of the LRUs <NUM> being removed from the subassembly <NUM>. <FIG> shows a top view of the movement of the LRU <NUM> being removed. The fasteners <NUM>, <NUM>, <NUM> corresponding to the LRU <NUM> are preliminarily removed and the LRU <NUM> is first extracted in the rear direction or z-direction such that the LRU <NUM> is displaced rearwardly and outwardly relative the other LRUs. In an exemplary application, the LRU <NUM> may be moved in the rear direction by a distance that is approximately <NUM> centimeters (<NUM> inches). The LRU <NUM> may then be moved in a lateral direction, or in the x-direction and y-direction towards the central location of the subassembly <NUM>, such that the LRU <NUM> may then be entirely removed from the subassembly <NUM>, while the remaining LRUs remain in place. In a similar but reverse operation, the LRU <NUM> may be replaced or reattached to the subassembly <NUM> after maintenance is performed. The LRU <NUM> may be rotated in the x-y direction to slide the LRU <NUM> in and out of place. Using the LRU <NUM> is further advantageous in that the RF panel <NUM> and additional electrical and mechanical components of the LRU <NUM> may be removed as a single and self-contained unit.

Referring now to <FIG>, an exemplary array antenna assembly <NUM>' is shown in an assembled state on a side of a stationary building. The exemplary array antenna assembly <NUM>' has <NUM> LRUs and <NUM> antenna elements, but many other configurations are suitable. The LRUs have a rectangular arrangement. <FIG> show the LRUs without each RF panel <NUM> in place, and a subassembly <NUM> of four LRUs having the RF panel <NUM> is shown. When assembled, an RF panel <NUM> will be configured for each LRU <NUM>, similar to the arrangement shown in <FIG>. The array antenna assembly <NUM>' has a surface area that is between <NUM> and <NUM><NUM> and the assembly <NUM>' is mounted to at least one support beam <NUM> of the building. The frame support structure <NUM> is connected between the LRUs and the support beam <NUM>. The support beam <NUM> may extend parallel with each vertical orthogonal beam <NUM> of the frame support structure <NUM> such that the array antenna assembly <NUM>' extends substantially parallel with a plurality of support beams of the building.

The frame support structure <NUM> is connected to the support beam <NUM> by any suitable connection. As best shown in <FIG>, a screw-type support <NUM> may be bolted or attached to the beam <NUM> such that the attachment points <NUM>, <NUM> of the frame support structure <NUM> (as also shown in <FIG>) may be screwed in to each screw-type support <NUM>. Other types of supports or attachment devices may be suitable. During an exemplary assembly process for the array antenna assembly <NUM>', the LRUs may be assembled using a crane. Using the screw-type support <NUM> is advantageous in that the support <NUM> may be adjustable to adjust for different parameters in the x, y, and z-directions. Although a stationary building is described, the array antenna assembly <NUM>' may be suitable for mounting to another stationary platform or a moving platform such as a sea vessel, land vehicle, aircraft, or space vehicle.

When assembled and access of an LRU <NUM> is desired, an operator <NUM> may be positioned on a deck <NUM> of the building that is fixed with the support beams. When the operator <NUM> is on the deck <NUM>, the operator <NUM> faces the rear side of the array antenna assembly <NUM>' which is opposite to the side of the array antenna assembly <NUM>' on which the antenna elements are located. The operator <NUM> is able to reach through the opening <NUM> of the frame support structure <NUM> and pull the LRU <NUM> in the rearward direction toward the operator <NUM> and away from the array antenna assembly <NUM>' such that maintenance can be performed and the LRU <NUM> can be placed back into the subassembly <NUM>. The LRU <NUM> can be replaced without disturbing the other LRUs in the array antenna assembly <NUM>'. The operator <NUM> may grab a pull mechanism or handle of the LRU <NUM>, as shown in <FIG> and <FIG>. Although a manual operator is described, the rear side of the array antenna assembly <NUM>' may also be accessible by an automatic machine, such as a robot configured to perform routine or automated maintenance on the array antenna assembly <NUM>'.

Referring now to <FIG>, a flowchart of a method <NUM> of assembling and maintaining an array antenna assembly <NUM>, <NUM>' (shown in <FIG>, and <FIG>) is shown. Step <NUM> of the method <NUM> includes forming a frame support structure <NUM> (shown in <FIG>). Step <NUM> may further include mounting the frame support structure <NUM> to a support beam <NUM> (shown in <FIG>) on an existing structure, such as a stationary or moving platform. Step <NUM> of the method <NUM> includes mounting a plurality of LRUs (shown in <FIG>) to the frame support structure <NUM>. Each LRU <NUM> has an I/O panel <NUM> with a front surface <NUM> and a rear surface <NUM>, and a bracket <NUM> extending perpendicular from the rear surface <NUM>. The bracket <NUM> has orthogonal flanges <NUM>, <NUM> that provide a predetermined alignment of the LRUs. Step <NUM> may further include arranging four LRUs per an opening <NUM> of the frame support structure <NUM> (shown in <FIG>) to form the subassembly <NUM> (shown in <FIG> and <FIG>) and a plurality of subassemblies.

Step <NUM> of the method <NUM> includes arranging the LRU to be rear accessible, such that a rear surface <NUM> of the I/O panel <NUM> (shown in <FIG> and <FIG>) may be accessed for removing the entire LRU <NUM> from the array antenna assembly <NUM>, <NUM>'. Arranging the LRUs to be rear accessible includes arranging the rear surface <NUM> to be accessible through the opening <NUM> defined by the orthogonal beams <NUM>, <NUM> of the frame support structure <NUM>. Step <NUM> of the method <NUM> includes removing one LRU <NUM> by accessing the rear surface <NUM> of the LRU <NUM> through the frame support structure <NUM>. Step <NUM> may include moving the LRU <NUM> in a rear direction away from the other LRUs and then moving the LRU <NUM> in a lateral direction away from the frame support structure <NUM> such that the LRU may be removed and replaced, or undergo maintenance and be placed back into the array antenna assembly <NUM>, <NUM>'.

Claim 1:
A line replaceable unit (<NUM>) for an array antenna, the line replaceable unit comprising:
a panel (<NUM>) having a front surface (<NUM>) configured to be electrically and mechanically connected with electronics of the array antenna, and a rear surface (<NUM>) opposing the front surface; and
a mounting bracket (<NUM>) that is attached to the rear surface and extends perpendicular to the rear surface opposite the electronics, wherein the mounting bracket is a right-angle bracket that has at least two mutually orthogonal flanges (<NUM>, <NUM>) that are configured to align the line replaceable unit within the array antenna, wherein a right angle is formed between the at least two orthogonal flanges at a corner of the rear surface, and
wherein at least one of the orthogonal flanges is configured as an electrical and mechanical interface for one or more additional features of the line replaceable unit, in addition to the panel.