Patent ID: 12224491

DETAILED DESCRIPTION

Illustrations presented herein are not meant to be actual views of any particular aerial vehicle, antenna assembly, waveguide, component, or system, but are merely idealized representations that are employed to describe embodiments of the disclosure. Additionally, elements common between figures may retain the same numerical designation for convenience and clarity.

As used herein, the singular forms following “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

As used herein, the term “may” with respect to a material, structure, feature, or method act indicates that such is contemplated for use in implementation of an embodiment of the disclosure, and such term is used in preference to the more restrictive term “is” so as to avoid any implication that other compatible materials, structures, features, and methods usable in combination therewith should or must be excluded.

As used herein, any relational term, such as “first,” “second,” “third,” etc., is used for clarity and convenience in understanding the disclosure and accompanying drawings, and does not connote or depend on any specific preference or order, except where the context clearly indicates otherwise.

As used herein, the term “substantially” in reference to a given parameter, property, or condition means and includes to a degree that one skilled in the art would understand that the given parameter, property, or condition is met with a small degree of variance, such as within acceptable manufacturing tolerances. By way of example, depending on the particular parameter, property, or condition that is substantially met, the parameter, property, or condition may be at least 90.0% met, at least 95.0% met, at least 99.0% met, or even at least 99.9% met.

As used herein, the term “about” used in reference to a given parameter is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the given parameter, as well as variations resulting from manufacturing tolerances, etc.).

Embodiments of the present disclosure include an antenna assembly functional at relatively high temperatures for extended periods of time. For example, antenna assembly of the present disclosure may maintain structural and operational integrity at temperatures of at least 1000° F., 1100° F., 1200° F., or 1500° F. In some embodiments, the antenna assembly may include log-periodic antenna elements. Furthermore, the antenna assembly may include a planar antenna element (e.g., a planar wave guide) operably coupled to a coaxial cable. The antenna element may include a plurality of slot lines formed in a conductive coating. The plurality of slot lines forms transmission lines for the antenna element. Furthermore, the materials and structure of the antenna assembly, as described herein, enable the antenna assembly to maintain structural and operational integrity at relatively high temperatures.

Furthermore, the antenna assembly of the present disclosure may provide advantages over conventional antenna assemblies. For example, because the antenna assembly maintains structural and operational integrity at relatively high temperatures, the antenna assembly increases operational range of vehicles and/or bodies to which the antenna assembly is attached and with which the antenna assembly is utilized. For instance, the vehicles and/or bodies can be subjected to environments having increased temperatures in comparison to conventional antenna assemblies. Furthermore, the antenna assembly may maintain functionality of the antenna assembly, and as a result, radio frequency communication with external components/controllers even when subjected to unexpected high temperatures. As a result, the antenna assembly provides an increased reliability in comparison to conventional antenna assemblies. Moreover, the antenna assembly increases a number of applications (e.g., uses) of the antenna assembly in comparison to conventional antenna assemblies.

FIG.1shows an aerial vehicle100having a high-temperature, log-periodic antenna assembly102(referred to hereinafter as the “antenna assembly102”) according to one or more embodiments of the present disclosure. As is described in greater detail below, the antenna assembly102may have a structure and materials combination that enables the antenna assembly102to maintain structural and operational integrity at relatively high temperatures for extended periods of time (e.g., several minutes or hours). For example, in some embodiments, the antenna assembly102may continue to operate and function in at least 1000° F., 1100° F., 1200° F., or 1500° F. environments or being subjected to any of the foregoing temperatures for extended periods of time. In some embodiments, the aerial vehicle100may include one or more of a kill vehicle, an unmanned aerial vehicle, a drone, a missile, and aircraft (e.g., airplane), etc. Additionally, in one or more embodiments, the antenna assembly102may be mounted to ground vehicles, marine vehicles, or stationary objects.

Some antenna embodiments of the present invention may be used with a transmitter, a receiver, and/or a transceiver of RF signals. Accordingly, the antenna assemblies102of the present disclosure, which are substantially frequency independent, may function as receiving arrays and may alternatively function as a transmitting arrays, or may function as both transmitting and receiving arrays (i.e., a transceiver array).

The antenna assemblies102may be electrically connected to a radio frequency receiver system or a radio frequency transmitting and receiving system which may be termed a transceiver (which may be disposed within an interior of the aerial vehicle100). An RF receiver may process the electric current from the antenna assemblies102via a low noise amplifier (LNA) and may then down convert the frequency of the waveform via a local oscillator and mixer and may process the resulting intermediate frequency waveform via an adaptive gain control amplifier circuit. The resulting conditioned waveform may be sampled via an analog-to-digital converter (ADC) with the discrete waveform being processed via a digital signal processing module. Where the frequency of the RF waveform is well within the sampling frequency of the conversion rate of the ADC, direct conversion may be employed and the discrete waveform may be processed at a rate comparable to the ADC rate. Receivers may further include signal processing and/or control logic via digital processing modules having a microprocessor, addressable memory, and machine executable instructions. An RF transmitter may process digital waveforms that have been converted to analog waveforms via a digital-to-analog converter (DAC) and may up-convert the analog waveform via an in-phase/quadrature (I/Q) modulator and/or step up the waveform frequency via a local oscillator and mixer, then amplify the up-converted waveform via a high-power amplifier (HPA) and conduct the amplified waveform as electric current to the antenna. Transmitters may further include signal processing and/or control logic via digital processing modules having a microprocessor, addressable memory, and machine executable instructions. Transceivers generally have the functionality of both a receiver and a transmitter, typically share a component or an analog or digital signal processing module, and employ signal processing and/or control logic via digital processing modules having a microprocessor, addressable memory, and machine executable instructions.

FIG.2is a cross-sectional perspective view of the antenna assembly102mounted to a first assembly101aof an aerial vehicle according to one or more embodiments of the present disclosure.FIG.3is a cross-sectional perspective view of the antenna assembly102mounted to a second assembly102aof an aerial vehicle according to one or more embodiments of the present disclosure. As depicted inFIGS.2and3together, in some embodiments, the antenna assembly102may be mounted on or proximate a nose portion of the aerial vehicle100. In additional embodiments, the antenna assembly102may be disposed between the nose portion and a body portion (e.g., a fuselage or body) of the aerial vehicle100. Furthermore, while particular locations are described herein, the antenna assembly102or elements thereof may be disposed anywhere on an aerial vehicle.

FIG.4is a perspective view the antenna assembly102according to one or more embodiments of the present disclosure.FIG.5is an exploded perspective view of the antenna assembly102ofFIG.4. In some embodiments, the antenna assembly102may include a fairing component104, a connection ring106, an insulator sleeve108, an absorber sleeve110, an inner ground sleeve112(referred to hereinafter as “inner sleeve112”), and a plurality of cable assemblies114.

As is described in greater detail below, in some embodiments, the fairing component104may have general hollow, truncated ogive shape and may have a narrow longitudinal end103(i.e., front end) and an opposite, wider longitudinal end105(e.g., back end). In other embodiments, the fairing component104may have a hollow, frusto-conical shape or a hollow cylindrical shape. The connection ring106may have a general annular shape and may be disposed (e.g., disposable) within the fairing component104. In some embodiments, the connection ring106may be integral to a housing (e.g., aerial vehicle) to which the antenna assembly102is attached. In other embodiments, the connection ring106may be separate and distinct from a housing (e.g., aerial vehicle) to which the antenna assembly102is attached. Furthermore, a radially outermost surface of the connection ring106may be sized and shaped to contact an inner surface of the fairing component104, as is described in greater detail below. When the connection ring106is disposed within the fairing component104, the radially outermost surface of the connection ring106may be generally concentric to the inner surface of the fairing component104. Moreover, the connection ring106may be disposable and attachable within the fairing component104at the narrow end103of the fairing component104. Additionally, when attached to the fairing component, the connection ring106may be aligned with an edge of the narrow end103of the fairing component104. As is described in greater detail below, the connection ring106may further provide connection points for mechanically coupling the plurality of cable assemblies114to the fairing component104.

In some embodiments, the insulator sleeve108may also have a truncated ogive shape (or any other shape matching the fairing component104) and may have a shorter longitudinal length than the fairing component104. As a result, the insulator sleeve108may be disposable within the fairing component104, may abut against the connection ring106, and may substantially contact the inner surface of the fairing component104. For instance, the insulator sleeve108may have substantially a same outer diameter as the connection ring106. As is described in further detail below, the insulator sleeve108may at least partially inhibit heat transfer from an exterior of the fairing component104to an interior of the antenna assembly and an interior of the aerial vehicle100. Additionally, in some embodiments, a combination of the longitudinal lengths of the connection ring106and the insulator sleeve108may be less than a longitudinal length of the fairing component104such that a portion of the fairing component104extends past the insulator sleeve108and forms an overhanging portion107that can be bonded to the aerial vehicle100.

The absorber sleeve110may be disposed within the insulator sleeve108and may be concentric to the insulator sleeve108. The absorber sleeve110may have a same longitudinal length as the insulator sleeve108. The absorber sleeve110may serve to absorb extraneous or undesired fields in the cavity (e.g., absorb unwanted standing waves) within a particular range of radio frequencies. Additionally, the absorber sleeve110may also at least partially inhibit heat transfer from an exterior of the fairing component104to an interior of the antenna assembly102and the aerial vehicle100. In some embodiments, the absorber sleeve110may have multiple layers, as is described in greater detail below. Furthermore, the absorber sleeve110may include a low loss, high resistivity ceramic filler, and a high-temperature thermoplastic matrix, which, by absorbing particular radio frequencies, enables smaller antenna elements of the antenna assembly.

The inner sleeve112may be disposed within the absorber sleeve110and may be concentric to the absorber sleeve110. The inner sleeve112may provide structural support to the antenna assembly102and may at least partially enclose the insulator sleeve108and the absorber sleeve110and hold the insulator sleeve108and the absorber sleeve110in place relative to the fairing component104. The inner sleeve112may be fastened to the connection ring106. For instance, as is described in greater detail below, the inner sleeve112may include a plurality of tabs for connecting to the connection ring106via fasteners.

The plurality of cable assemblies114may be mechanically and electrically coupled to the fairing component104. Additionally, each of the plurality of cable assemblies114may include coaxial cable leading to an interior of the aerial vehicle100(e.g., to a controller of the aerial vehicle100). In some embodiments, the antenna assembly102may include at least eight, ten, twelve, or any number of cable assemblies114. Each of the above elements is described in greater detail below in regard toFIGS.6-16B.

FIG.6is a perspective view of the fairing component104according to one or more embodiments of the present disclosure.FIG.7is a side cross-sectional view of the fairing component104.FIG.8Ais an enlarged view of a portion of an antenna element of the fairing component104according to one or more embodiments of the present disclosure.FIG.8Bis another enlarged view of a portion of an antenna element of the fairing component104.FIG.9is a side view of the fairing component104with one or more elements (e.g., a termination pattern) removed to better show a coating of the fairing component104.FIG.10is another side view of the fairing component104showing a termination pattern of the fairing component104.

Referring toFIGS.6-10together, in one or more embodiments, the fairing component104may have a coating116(e.g., a conductive coating) formed on an inner surface of the fairing component104. Additionally, the fairing component104may include a plurality of antenna elements118a,118b,118c, etc. (e.g., planar antenna elements, planar waveguides, semi-coplanar waveguides, planar antenna arrays, etc.), formed in the coating116. Each of the antenna elements118a,118b,118cmay include two general sinusoidal slot lines117a,117b(e.g., absence of coating116lines) formed in the coating116. In particular, the two general sinusoidal slot lines117a,117bare defined by an absence of the coating116on the inner surface of the fairing component104and expose the material of the fairing component104. Each of the two general sinusoidal slot lines117a,117bmay form a transmission line (i.e., a first transmission line and a second transmission line) of the respective antenna element (e.g., antenna element118a). As is described in greater detail below, each of the antenna elements118a,118b,118cmay operate as a traveling wave type antenna.

In some embodiments, the fairing component104may form a dielectric body. For example, the fairing component104may include a ceramic matrix composite (CMC). For instance, in one or more embodiments, the fairing component104may include an aluminosilicate matrix (e.g., AS/N312, AS/N720, A/N720, AS/N650, AS/N610). In additional embodiments, the fairing component104may include any other type of CMC material suitable for aerospace applications, such as, for example C/C (e.g., carbon fibers reinforcing a carbon matrix), SiC/SiC, C/SiC and/or Oxide/Oxide CMC materials. In some embodiments, the fairing component104may have a thickness within a range of about 0.025 inch and about 0.075 inch. For example, the fairing component104may have a thickness of about 0.055 inch. Furthermore, while a specific thickness of the fairing component104is provided as an example herein, the present disclosure is not so limited, and the fairing component104may have any thickness facilitating an application of the fairing component104to achieve desired structural and/or electrical properties. For instance, the fairing component104may have a thickness greater than 0.075 inch, 0.10 inch, 0.20 inch, 0.5 inch, 1.0 inch, 5.0 inches, 10.0 inches, or any other thickness.

In one or more embodiments, the coating116may include a gold coating (e.g., a gold cermet). In other embodiments, the coating116may include silver, copper, annealed copper, aluminum, calcium, tungsten, zinc, nickel, iron, titanium, or any alloy thereof. In some embodiments, the coating116may be applied to the fairing component104. For example, the coating116may be printed onto the fairing component104. In some embodiments, the coating116may include a silk screen that is sprayed or printed onto the fairing component104. Furthermore, the coating116may be patterned via etching or patterning within a silk-screening process. The coating116may cover at least substantially an entirety of an inner surface of the fairing component104, and the coating116may wrap around the narrow end103of the fairing component104and across a portion of the outer surface of the fairing component104. As is described in greater detail below, the portion of the coating116that wraps around the fairing component104and across a portion of the outer surface of the fairing component104may provide a conductive shield near a launch portion of the antenna elements118a,118b,118c.

In some embodiments, the coating116may have a thickness within a range of about 0.0004 inch and about 0.0014 inch. For example, the coating116may have a thickness of about 0.0005 inch. Furthermore, while a specific thickness of the coating116is provided as an example herein, the present disclosure is not so limited, and the coating116may have any thickness facilitating an application of the coating116. For instance, the fairing component104may have a thickness of greater than 0.0014 inch, 0.002 inch, 0.003 inch, 0.005 inch, 0.01 inch, or any other thickness. Moreover, in one or more embodiments, the coating116may have a thickness that maintains a bulk conductivity of <mΩ/unit area.

Referring still toFIGS.6-10, the two general sinusoidal slot lines117a,117bof each antenna element118a,118b,118cmay be formed via laser etching processes. For example, the laser etching process may include an automated galvanometer driven laser etching process. In other embodiments, the coating116may be formed on the fairing component104via a silk-screening process such that the two general sinusoidal slot lines117a,117bof each antenna element118a,118b,118care predefined and formed during the silk-screening process. On other words, after forming the coating116of the fairing component104, there is no need to remove material to define the two general sinusoidal slot lines117a,117b. For example, a pattern of the coating116utilized to silk screen may define the two general sinusoidal slot lines117a,117b. To facilitate description of the antenna elements118a,118b,118c, a single antenna element may be referred to as an “antenna element118,” and the description of the single antenna element118applies to each of the antenna elements118a,118b,118cof the antenna assembly102.

As noted above, the antenna element118may include a first general sinusoidal slot line117a(referred to hereinafter as “first slot line117a”) and a second general sinusoidal slot line117b(referred to hereinafter as “second slot line117b”), which effectively form the two elements of the antenna element118. As is described herein, the antenna element118may form a duality (i.e., contrast) of a conventional wireline log-periodic antenna and may operate as a traveling wave type antenna.

Referring particularly toFIGS.7-8B, the antenna element118may be driven by a coaxial cable of a cable assembly114transmitting a driving frequency and coupled to a launch portion119of the antenna element118. As a result, the first and second slot lines117a,117bmay operate as transmission lines in a manner similar to slot antennas. For example, voltages may be created across the first and second slot lines117a,117band as a result, magnetic fields may be created across the first and second slot lines117a,117b.

The portion of the coating116formed on the outer surface of the fairing component104and depicted inFIG.8Bwith the dotted line forms a conductive shield141at (e.g., proximate) the launch portion119and isolates and suppresses higher order modes at the launch portion119(Region A) from radiating prior to initiating a desired (e.g., selected) co-planar propagating mode (Region B) along the first and second slot lines117a,117b. The conductive shield141of the coating116on the outer surface of the fairing component104is separated from the launch portion119by material of the fairing component104(e.g., a high-dielectric constant substrate (e.g., aluminosilicate matrix)). Additionally, the conductive shield141is transitioned away from a remainder of the antenna element118, which results in the material of the fairing component104(e.g., a high dielectric constant substrate) being on the exterior of the remainder of the antenna element118.

The first and second slot lines117a,117bmay be mirrored about an antenna center axis128extending through a reference origin, O. Having the first and second slot lines117a,117bbe mirrored about the antenna center axis128may effectively cancel the magnetic fields across the first and second slot lines117a,117bin the far field (e.g., the magnetic fields that are in a mirror direction (Region C; arrows131a,131b)). As a result, for a given slot line (e.g., first slot line117a), portions of the given slot line that extend in direction parallel to each other propagate as a transmission line and do not radiate (Region B; arrows133a,133b, and Region C; arrows135a,135b). Additionally, within Region C, a phase length around the first and second slot lines117a,117bis not long enough to create a delay around the cycle, and as a result, each cycle cancels in the far field.

Additionally, the antenna element118may be frequency independent due to its geometric shape defined by angles and self-scaling. Furthermore, within Region D of the antenna element118, the antenna element118may radiate and a phase of the instantaneous electric field along the first and second slot lines117a,117bin relationship to adjoining sections may be aligned in a transverse direction to the antenna center axis128, and the electric fields may add in phase in the direction of the propagation plane, as is represented by arrows137a,137bbeing in line. The foregoing occurs where a propagation length around sections of the first and second slot lines117a,117bincluding a first linear portion, an adjacent linear portion, and an arcuate portion extending between the linear portion and the adjacent linear portion, (referred to hereinafter as a “bobby pin portion”) approximate a half wavelength. Additionally, within the observation plane, the phase of the frequencies is where the fields add together. This is achieved due to the reversal of directions within the bobby pin portions and when the propagation delay matches a necessary phase such that all fields in an active direction add in phase.

Referring still toFIGS.7-8B, the transmission line propagation velocities exhibited by the first and second slot lines117a,117bare substantially different to free space propagation velocities exhibited by classical log-periodic antennas. Therefore, change of pitch (e.g., frequency of the sinusoidal shape) rates and expansion (e.g., amplitude changing) rates of the first and second slot lines117a,117bare selected to achieve desired element directivity and gain flatness across an operating band of the antenna element118. In some embodiments, the change of pitch rates and the expansion rates are at least partially dependent on the dielectric constant of the material of the fairing component104. For instance, as a dielectric constant of the material of the fairing component104increases, an expansion rate of the first and second slot lines117a,117bdecreases to achieve desired element directivity and gain flatness across an operating band of the antenna element118. In some embodiments, in a direction (depicted as arrows223,225) extending from the origin point O, the amplitudes of the first and second slot lines117a,117bincrease at the expansion rate, and the frequency decreases at the change of pitch rate. Moreover, the change of pitch rates and the expansion rates are at least partially dependent on a thickness of the material of the fairing component104. In some embodiments, a respective width of the first and second slot lines117a,117bincreases along the length of the first and second slot lines117a,117b. In other embodiments, a respective width of the first and second slot lines117a,117bmay remain substantially constant along the length of the first and second slot lines117a,117b.

In some embodiments, each of the antenna elements118a,118b,118cmay be forward facing (i.e., forward looking). In additional embodiments, the aerial vehicle100may include both forward facing and aft facing antenna elements. For instance, the aerial vehicle100may include pairs of antenna elements similar to those described in U.S. Pat. No. 7,583,233, the Goldberg et al., issued Sep. 1, 2009, the disclosure of which is incorporated in its entirety by reference herein.

Referring specifically toFIGS.8A and8B, near the origin point O (the point from which the first and second slot lines117a,117bextend and expand, and the point near which the first and second slot lines117a,117bapproximate each other) the first and second slot lines117a,117bof the antenna element118may transition from the oscillating general sinusoidal shape to two parallel linear lines130,132extending from the general sinusoidal shape and meeting at a general circular slot portion134. The two parallel lines130,132may define a connector contact region136there between. In some embodiments, the connector contact region136may have an elongated rectangle shape (e.g., between the two parallel linear lines130,132) with a rounded end defined within the circular slot portion134. The connector contact region136may extend past a center of the general circular slot portion134of the first and second slot lines117a,117b, and a tip138(i.e., the rounded end) (e.g., a “feed point”) of the connector contact region136may be isolated from a remainder of the coating116by the general circular slot portion134(i.e., the etched circular slot portion134). As is described in further detail below, a portion of the cable assembly114may be sized and shaped to contact the connector contact region136of the antenna element118. Moreover, the connector contact region136, the two parallel linear lines130,132of the first and second slot lines117a,117b, the circular slot portion134of the first and second slot lines117a,117b, and a region immediately surrounding the circular slot portion134of the first and second slot lines117a,117bmay define a launch portion119of the antenna element118. In some embodiments, each of the first and second slot lines117a,117bmay terminate in an elongated triangle slot portion (e.g., a fat dipole). In other embodiments, the first and second slot lines117a,117bmay be connected together at ends opposite the origin point O.

Referring specifically toFIGS.9and10, the coating116on the outer surface of the fairing component104may terminate in a general triangular-wave form shape. In other words, the boundary of the coating116on the outer surface of the fairing component104may define a general triangular-wave form shape. Additionally, as is referenced above, where the plurality of cable assemblies114are coupled to inner surface of the fairing component104(i.e., proximate the launch portions119of the antenna elements118a,118b,118c), the coating116on the outer surface may define (e.g., include) elongated triangle-shaped notches139formed in valleys of the triangular-wave form of the coating116. The triangle-shaped notches139may be aligned with the connector contact regions136of the antenna elements118a,118b,118c, and the triangle-shaped notches139may point toward the center of the general circular slot portion134of the first and second slot lines117a,117b. The triangle-shaped notches139may provide tapered ground transitions. The combination of the general circular slot portion134of the first and second slot lines117a,117b, the first and second slot lines, and the triangle-shaped notches139may also provide a transition from a micro-strip co-planar waveguide to a slot. Conventional micro-strip log-periodic antenna pattern structures tend to lose functional integrity (e.g., fall apart) around X-Band. The triangle-shaped notches139of the present disclosure enable the antenna element118to maintain functional integrity at at least 40 GHz.

Referring still toFIGS.6-10, in some embodiments, the antenna element118may include a single slot line that is an asymmetric log-periodic structure in place of the first and second slot lines117a,117b.

Additionally, the fairing component104may include a termination pattern121formed over and overlaying a portion of the boundary of the coating116. Additionally, the termination pattern121may have a first boundary123defined over the coating116and a second, opposite boundary125formed over the fairing component104beyond the coating116. In other words, the termination pattern121may span the boundary of the coating116. In some embodiments, the termination pattern121may include a plurality of segments127a,127b,127c, etc., in series and oriented around a circumference of the fairing component104. Each segment127of the termination pattern121may overlay portions of the coating116between adjacent triangle-shaped notches139of coating116. Additionally, the termination pattern121may not be formed over the triangle-shaped notches139of coating116. Each segment127of the termination pattern121may have a first boundary123formed over the coating116, and a second, opposite boundary125formed over the surface of the fairing component104.

In some embodiments, the termination pattern121may include a resistive metallic material that can yield a desired ohms/square inch of resistivity. For example, the termination pattern121may include an R-Card material. Furthermore, the termination pattern121may provide a field termination that performs pattern control for the antenna elements118a,118b,118c. Moreover, the termination pattern121may help to prevent bifurcation of transmission signals.

Referring still toFIGS.6-10, each of the antenna elements118a,118b,118cmay include a directional antenna. Additionally, as noted above, the antenna elements118a,118b,118cmay operate across a wide bandwidth. For instance, in one or more embodiments, the antenna elements118a,118b,118cmay operate at frequencies ranging from 10 MHz to at least 40 GHz. Additionally, as mentioned briefly above, the antenna elements118a,118b,118cmay be utilized to receive radio frequencies and may communicate received RF signals via the cable assemblies114to a control system of the aerial vehicle100. Moreover, in some embodiments, antenna elements118a,118b,118cmay be utilized to transmit communications from the control system to external or remote systems by emitting radio frequencies.

FIG.11Ais a perspective view of the connection ring106according to one or more embodiments of the present disclosure.FIG.11Bis an enlarged partial perspective view of a cable assembly receiving structure of the connection ring106according to one or more embodiments of the present disclosure.FIG.11Cis an enlarged partial perspective view of a tab receiving structure of the connection ring106according to one or more embodiments of the present disclosure.

Referring toFIGS.11A-11Ctogether, the connection ring106may have a general annular shape. The connection ring106may have an outer surface140for contacting the inner surface of the fairing component104and an opposite inner surface142. The connection ring106may further defined a plurality of cable assembly receiving structures144a,144b,144c, etc. (referred to hereinafter as “receiving structures”), for receiving connector structures of the cable assemblies (described below). Each of the receiving structures144a,144b,144cmay include a stepped-circular recess146, an aperture148, an alignment pin150, and opposing wing recesses152,154. The aperture148may extend completely through the connection ring106from a bottommost surface157of the stepped-circular recess146. The alignment pin150may extend upward axially from the bottommost surface157of the stepped-circular recess146and may abut a sidewall161of a bottommost step159of the stepped-circular recess146, and as is discussed in greater detail below, the alignment pin150may assist in properly aligning a respective cable assembly114when installing (e.g., fastening) a cable assembly114to the connection ring106. The opposing wing recesses152,154may be formed on opposing sides of the stepped-circular recess146and may be align along an annular axis of the connection ring106. Furthermore, the opposing wing recesses152,154may extend radially outward from the stepped-circular recess146. Each of opposing wing recesses152,154may include a respective fastener receiving aperture156,158, which may be threaded or otherwise sized and shaped to receive a fastener.

In one or more embodiments, the alignment pin150may be integrally formed with a portion of the connection ring106defining a respective receiving structure144a. In other embodiments, the alignment pin150may be separate and discrete from the portion of the connection ring106defining a respective receiving structure144a. For instance, the alignment pin150may have a respective recess into which the alignment pin150may be inserted and/or secured.

Referring still toFIGS.11A-11C, the connection ring106may further define a plurality of tab receiving structures160a,160b,160c, etc., for receiving tabs of the inner sleeve112. In some embodiments, each of the tab receiving structures160a,160b,160cmay have a general rounded rectangular shape; however, the present disclosure is not so limited, and the tab receiving structures160a,160b,160cmay have any geometric shape correlating to shapes of tabs of the inner sleeve112(described below). Additionally, each of the tab receiving structures160a,160b,160cmay have a respective fastener receiving aperture162, which may be threaded or otherwise sized and shaped to receive a fastener.

In some embodiments, the connection ring106may include a steel material. In one or more embodiments, the connection ring106may include stainless steel, brass, nickel, titanium, tungsten, or any alloy thereof. Furthermore, while specific examples of materials of the connection ring106are provided herein, the disclosure is not so limited, and the connection ring106may include any alloy that maintains structural integrity at the temperatures described herein and substantially meets the coefficient of thermal expansion of a material of the fairing component104.

FIG.12Ais a front view of the insulator sleeve108according to one or more embodiments of the present disclosure.FIG.12Bis a perspective view of a portion of the insulator sleeve108according to one or more embodiments of the present disclosure. As mentioned above, in some embodiments, the insulator sleeve108may have a truncated ogive shape (or other shape to match the fairing component104) and may have a shorter longitudinal length than the fairing component104. As a result, the insulator sleeve108may be disposable within the fairing component104, may abut against the connection ring106, and may fit completely within the fairing component104. Furthermore, a contour of an outer surface of the insulator sleeve108may at least substantially match a contour of the inner surface of the fairing component104.

In some embodiments, the insulator sleeve108may include multiple pieces that, when assembled, form a sleeve. For instance, in some embodiments, the insulator sleeve108may include eight pieces where each piece forms a 45° portion of the sleeve. Additionally, seams between pieces of the insulator sleeve108may be oriented between antenna elements118a,118b,118cof the fairing component104. For example, each piece may be centered about an antenna element118. In alternative embodiments, the insulator sleeve108may include a single piece sleeve, a two-piece sleeve, a four-piece sleeve, or any number of piece sleeve. In some embodiments, the insulator sleeve108may have a thickness within a range of about 0.25 inch and about 0.75 inch. For example, the insulator sleeve108may have a thickness of about 0.406 inch.

In one or more embodiments, the insulator sleeve108may include a dielectric foam. For example, in some embodiments, the insulator sleeve108may include a ceramic foam. As a non-limiting example, the insulator sleeve108may include AETB-12 ceramic tile insulation. In other embodiments, the insulator sleeve108may include one or more of toughened unipiece fibrous insulation tile, AIM-22 Tile, Fibrous Refractory Composite Insulation-12 Tile, or any other insulation layer. In some embodiments, the insulator sleeve108may include a low-density, rigid refractory structure composed of high-alpha polycrystalline alumina fibers and high-purity inorganic binders. For instance, the insulator sleeve108may include Alumina Type ZAL-12. While specific examples are provided herein, the insulator sleeve108may include any dielectric insulator (e.g., a low dielectric insulator). The insulator sleeve108may at least partially inhibit heat transfer from an exterior of the fairing component104to an interior of the antenna assembly102and the aerial vehicle100.

FIG.13Ais a perspective view of the absorber sleeve110according to one or more embodiments of the present disclosure.FIG.13Bis a side partial cross-sectional view of the absorber sleeve110according to one or more embodiments of the present disclosure.

Referring toFIGS.13A and13Btogether, in some embodiments, the absorber sleeve110may include a plurality of layers165a,165bof material. In some embodiments, the absorber sleeve110may include two layers with a first layer having a thickness forming about 60% (e.g., 60 mils) of an overall thickness of the absorber sleeve110and a second layer having a thickness forming about 40% (e.g., 40 mils) of the overall thickness of the absorber sleeve110. In additional embodiments, the absorber sleeve110may include three, four, five, or more layers. Additionally, in some embodiments, an innermost layer of absorber sleeve110may include at least one slot163(i.e., cutout) to receive a protrusion (e.g., jog) of the inner sleeve112(described below).

In some embodiments, the absorber sleeve110may have an overall thickness within a range of about 75 mils and about 125 mils. For example, the absorber sleeve110may have a thickness of about 100 mils. Furthermore, while a specific thickness of the absorber sleeve110is provided as an example herein, the present disclosure is not so limited, and the absorber sleeve110may have any thickness facilitating an application of the absorber sleeve110. For instance, the absorber sleeve110may have a thickness of greater than 100 mils, 200 mils, 0.5 inch, 1.0 inches, 5.0 inches, 10 inches, or any other thickness. In some embodiments, an overall thickness of the absorber sleeve may be at least partially dependent on the size and shape of the antenna element118. For instance, the absorber sleeve110may match the antenna element118to (e.g., provide the antenna element118with) a limited size cavity without shorting the antenna element118to the ground of the cavity (e.g., the inner sleeve112). For example, the absorber sleeve110may make the cavity larger from an electrical viewpoint. Furthermore, in one or more embodiments, each layer of the absorber sleeve110may include a plurality of pieces in a manner similar of the same as the insulator sleeve108and seams between adjacent pieces may lie between antenna elements of the plurality of antenna elements118a,118b,118c.

In one or more embodiments, the absorber sleeve110may include a high impedance laminate. For example, the absorber sleeve110may include a low loss, high resistivity ceramic filler, and a high-temperature polytetrafluoroethylene matrix, Teflon matrix, and/or thermoplastic matrix. For instance, the absorber sleeve110may include a MAGTREX™ high impedance laminate. The absorber sleeve110may serve to absorb extraneous or undesired fields in the cavity (e.g., absorb unwanted standing waves) within a particular range of radio frequencies. In particular, the absorber sleeve110may mitigate a cavity mode that would produce an effective short circuit across an active region of the antenna element118. In some embodiments, a cavity depth is one fourth wavelength making a reflected wave from the cavity at the antenna element118be in phase with a driving field. The limiting factor is that this condition cannot be achieved over multi-octave bandwidths requiring an absorber. Accordingly, the absorber sleeve110of the present disclosure provides an effectively high enough impedance at the antenna element118active region while not dissipating the energy in the transmission line (e.g., first and second slot lines117a,117b) and is capable of handling the relatively high temperatures described herein. Additionally, the absorber sleeve110may also at least partially inhibit heat transfer from an exterior of the fairing component104to an interior of the antenna assembly102and the aerial vehicle100. As is known in the art, an antenna assembly having an absorber sleeve comprising a high impedance laminate may enable an antenna element to have a smaller size by absorbing particular radio frequencies in comparison to antenna assembly not include such an absorber sleeve.

FIG.13Cis a perspective view of the absorber sleeve110according to one or more additional embodiments of the present disclosure.FIG.13Dis a side partial cross-sectional view of the absorber sleeve110according to one or more embodiments of the present disclosure.

In some embodiments, the absorber sleeve110may include multiple pieces that, when assembled, form a sleeve. For instance, in some embodiments, the absorber sleeve110may include eight pieces where each piece forms a 45° portion of the sleeve. Additionally, seams between pieces of the absorber sleeve110may be oriented between antenna elements118a,118b,118cof the fairing component104. For example, each piece may be centered about an antenna element118. In alternative embodiments, the absorber sleeve110may include a two-piece sleeve, a four-piece sleeve, or any number of piece sleeve.

Additionally, in one or more embodiments, an innermost layer of absorber sleeve110may not include the at least one slot163described above. Rather, the innermost layer of the absorber sleeve110may be at least substantially continuous.

FIG.14Ais a perspective view of the inner sleeve112according to one or more embodiments of the present disclosure.FIG.14Bis a partial perspective view of a tab of the inner sleeve112for connecting to the connection ring106according to one or more embodiments of the present disclosure.FIG.14Cis a partial perspective view of the jog of the inner sleeve112for aligning the inner sleeve112with the connection ring106.

Referring toFIGS.14A-14Ctogether, the inner sleeve112may include a plurality of tabs164a,164b,164c,164dextending generally axially from the inner sleeve112and at least one jog166formed in the inner sleeve112. In some embodiments, the plurality of tabs164a,164b,164c,164dmay be oriented to align with the plurality of tab receiving structures160a,160b,160cof the connection ring106(FIGS.11A-11C). Additionally, the plurality of tabs164a,164b,164c,164dmay be sized and shaped to be received into the plurality of tab receiving structures160a,160b,160cof the connection ring106(FIGS.11A-11C) and to be fastened to the connection ring106via one or more fasteners.

In some embodiments, the at least one jog166of the inner sleeve112may include a portion of the inner sleeve112where a wall of the inner sleeve112overlaps with itself, and a portion of the overlap protrudes (e.g., projects) radially inward to a center longitudinal axis of the inner sleeve112. In particular, the at least one jog166may include discontinuity167in the material of the inner sleeve112and two overlapping portions168,170of the wall of the inner sleeve112. In some embodiments, the two overlapping portions168,170may not be connected. In other words, within the limits of the flexibility of a material of the inner sleeve112, the two overlapping portions168,170may be free to move relative to one another. According, the inner sleeve112is compressible by increasing an amount of overlap between the two overlapping portions168,170, and as a result, the outer diameter of the inner sleeve112may be reduced when inserting the inner sleeve112into the absorber sleeve110. For example, the at least one jog166of the inner sleeve112may impart a spring function to the inner sleeve112. Additionally, the at least one jog166may be sized and shaped to be aligned with the cutout of the absorber sleeve110.

In some embodiments, the inner sleeve112may provide a controlled depth ground surface. The inner sleeve112may also provide structural support to the antenna assembly102and may hold the insulator sleeve108(FIG.12A) and the absorber sleeve110in place relative the fairing component104. In some embodiments, the inner sleeve112may include a metallic material. For instance, the inner sleeve112may include a stainless steel, a spring steel, titanium, etc. In some embodiments, the inner sleeve112may have a thickness within a range of about 0.005 inch and about 0.020 inch. For example, the inner sleeve112may have a thickness of about 0.011 inch. Furthermore, while a specific thickness of the inner sleeve112is provided as an example herein, the present disclosure is not so limited, and the inner sleeve112may have any thickness facilitating an application of the inner sleeve112. For instance, the inner sleeve112may have a thickness of greater than 0.011 inch, 0.02 inch, 0.05, 0.10 inch, 0.5 inch, 1.0 inch, 5.0 inches, or any other thickness. For example, the inner sleeve112may have any thickness meeting mechanical requirements of the antenna assembly102.

FIG.15Ais a perspective view of a cable assembly114of the antenna assembly102according to one or more embodiments of the present disclosure.FIG.15Bis an enlarged, partial cross-sectional view of the cable assembly114according to one or more embodiments of the present disclosure.FIG.15Cis a cross-sectional view of a cable assembly114mounted to the connection ring106.FIG.15Dis a perspective view of a cable assembly114operably coupled to an antenna element118according to one or more embodiments of the present disclosure.FIG.15Eis another cross-sectional view of the cable assembly114mounted to the connection ring106.FIG.15Fis a side view of the fairing component104depicting the conductive shield141, the termination pattern121, and the elongated triangle-shaped notches139. Some portions ofFIGS.15E and15Fhave been made transparent to better depict internal components.

Referring toFIGS.15A-15Dtogether, in some embodiments, the cable assembly114includes a front connector172, an aft connector174, and coaxial cable176extending between the front connector172and the aft connector174. The front connector172may include an outer contact178, an inner contact180, a retainer element182, a shim184, a first spring element188, a second spring element186, an upper insulator portion190, and a lower insulator portion192. The coaxial cable176may include an outer conductor194, an insulator sleeve196, and an inner conductor198. The aft connector174may be configured to span an outer wall of the aerial vehicle100and is described in greater detail below in regard toFIGS.16A and16B. In some embodiments, the cable assembly114may not include an aft connector but may include a second connector that spans the outer wall of the aerial vehicle100, and the second connecter may be connected anywhere as dictated by the design (e.g., convenient to the design) of the antenna assembly102and/or the aerial vehicle100.

In some embodiments, the outer contact178of the front connector172may be operably coupled of the outer conductor194of the coaxial cable176, and the inner contact180of the front connector172may be operably coupled of the inner conductor198of the coaxial cable176. In some embodiments, the outer contact178may have a general cylindrical shape and may define an inner chamber179. The inner contact180may be at least partially disposed within the inner chamber179(i.e., the outer contact178may house at least a portion of the inner contact180), and the inner contact180may have a cylinder shape (e.g., a shaft shape) and may be translatable axially within the inner chamber179of the outer contact178. Furthermore, in one or more embodiments, the outer contact178and the inner contact180may share a center longitudinal axis181. For instance, outer contact178and inner contact180may be generally concentric to each other. Additionally, the upper insulator portion190may be disposed around the inner contact180and between the inner contact180and the outer contact178of the front connector172. Likewise, the lower insulator portion192may be disposed around the inner conductor198of the coaxial cable176and between inner conductor198of the coaxial cable176and the outer contact178of the front connector172.

In one or more embodiments, the retainer element182may have a receiving aperture183through which the outer contact178and inner contact180may be inserted. Additionally, the retainer element182may be sized and shaped to be inserted into and fastened within a respective receiving structure of the plurality of receiving structures144a,144b,144cof the connection ring106. For instance, the retainer element182may have a circular center portion202and two opposing wing portions204,206. The circular center portion202of the retainer element182in conjunction with the outer contact178and the inner contact180may be sized and shaped to be inserted into stepped-circular recess146of a given receiving structure144a, and the two opposing wing portions204,206of the retainer element182may be sized and shaped to be inserted into the opposing wing recesses152,154of the given receiving structure144a. Furthermore, the retainer element182may be fastened to the connection ring106via fasteners208a,208bextending through apertures in the retainer element182aligned with the fastener receiving apertures156,158of the given receiving structure144a. In alternative embodiments, the plurality of receiving structures144a,144b,144cmay include a threaded aperture into which an outer threaded nut may be threaded, and which may retain a connector to the connection ring106.

Furthermore, as is depicted inFIGS.15C-15E, when the cable assembly114is fastened to connection ring106, the outer contact178may align with and contact a region (i.e., a first region of the launch portion119) of the fairing component104(and coating116) immediately surrounding the general circular slot portion134of the first and second slot lines117a,117b(i.e., the launch portion119of the antenna element118) through the aperture148of the connection ring106, and the inner contact180may align with and contact the connector contact region136(i.e., a second region of the launch portion119) of the antenna element118through the aperture148of the connection ring106.

In some embodiments, the outer contact178of the cable assembly114may include a partial annular protrusion210extending radially outward from a body of the outer contact178. Additionally, the shim184and the second spring element186may be disposed between the partial annular protrusion210of the outer contact178and the retainer element182. As a result, the outer contact178of the cable assembly114may be biased in an axial direction of the outer contact178relative to the retainer element182such that, when fastened to the connection ring106, the outer contact178is biased toward and is pushed against the fairing component104(e.g., the coating116formed on the fairing component104). In one or more embodiments, the second spring element186may include one or more spring washers (e.g., Belleville spring washers). In other embodiments, the second spring element186a plurality of compression springs (e.g., coil springs).

Additionally, in some embodiments, the first spring element188may be coupled to the inner contact180, and the first spring element188may be disposed between the inner contact180and the outer contact178of the cable assembly114. As a result, the inner contact180of the cable assembly114may be biased relative to the outer contact178of the cable assembly114, which is biased relative to the retainer element182, which is affixed to the connection ring106. Furthermore, as noted above, the outer contact178may define the inner chamber179along which the inner contact180and the upper insulator portion190may translate axially relative to the outer contact178. Because the inner contact180is biased relative to the outer contact178, and because the outer contact178is biased relative to a remainder of the antenna assembly102, when the cable assembly114is fastened to the connection ring106, the cable assembly114may at least substantially maintain contact between the inner contact180and the connector contact region136of the antenna element118.

In some embodiments, the first spring element188may include a compression spring. For example, the first spring element188may include coil spring. In other embodiments, the first spring element188may include volute spring or a collection a washer springs.

Biasing the inner contact180relative to the outer contact178and biasing the outer contact178relative to a remainder of the antenna assembly102may decrease a likelihood of the inner contact180and the outer contact178losing contact with the connector contact region136of the antenna element118and the fairing component104, respectively. Furthermore, biasing the inner contact180relative to the outer contact178and biasing the outer contact178relative to a remainder of the antenna assembly102may improve a contact between the inner contact180and the connector contact region136of the antenna element118relative to a rigid or unbiased contact. Additionally, biasing the inner contact180relative to the outer contact178and biasing the outer contact178relative to a remainder of the antenna assembly102may maintain contact between the inner contact180and the connector contact region136of the antenna element118during aerial operations. Moreover, biasing the inner contact180relative to the outer contact178and biasing the outer contact178relative to a remainder of the antenna assembly102may improve the contact between a flat surface of the longitudinal end of the inner contact180and a curved surface of the connector contact region136of the antenna element118, which is formed from the inner surface of the fairing component104.

Additionally, having a biased connection between the contacts of the cable assembly114and the antenna element118further facilitates the antenna assembly102to operate in relatively high temperatures. For example, a common solder connection would likely melt in temperatures above 600° F. even when using high temperature solder alloys. Likewise, a welded connection would ruin coating116(e.g., conductive coating) and would likely render the antenna element118inoperable. Therefore, the biased connection between the contacts of the cable assembly114and the antenna element118at least partially enables antenna assembly102to maintain structural and operational integrity in relatively high temperatures.

Referring still toFIGS.15A-15F, in some embodiments, the outer contact178may include a recess214formed in an upper portion of the outer contact178configured to contact the region of the fairing component104(and coating116) immediately surrounding the general circular slot portion134of the first and second slot lines117a,117b. The recess214may extend axially into the outer contact178. When the cable assembly114is fastened to the connection ring106, the recess214may align with the connector contact region136of the antenna element118, thus preventing the outer contact178from shorting on the connector contact region136of the antenna element118.

Additionally, the outer contact178may include a notch216formed in the partial annular protrusion210of the outer contact178. The notch216may be configured to align with (e.g., receive) the alignment pin150of the connection ring106. Put another way, the outer contact178may be keyed. The notch216of the outer contact178and alignment pin150of the connection ring106may assist in properly aligning the recess214of the outer contact178with the connector contact region136of the antenna element118, which as described above, will prevent the outer contact178from shorting on the connector contact region136of the antenna element118.

FIG.16Ais a side cross-sectional view of the antenna assembly102mounted to a portion of an aerial vehicle100.FIG.16Bis an enlarged cross-section view of the antenna assembly102mounted to the portion of the aerial vehicle100. Referring toFIGS.16A and16Btogether, in some embodiments, when the cable assembly114is mounted to the connection ring106, the aft connector174may span an exterior wall218of the aerial vehicle100. Furthermore, the aft connector174may provide an electromagnetic interference gasket that isolates the exterior of the aerial vehicle100from an interior of the aerial vehicle100. In some embodiments, the aft connector174may provide a threaded connection220for coupling the cable assembly114to a control system of the aerial vehicle100.

Referring toFIGS.1-16Btogether, the antenna assembly102of the present disclosure may provide advantages over conventional antenna assemblies. For example, because the antenna assembly102maintains structural and operational integrity at relatively high temperatures, the antenna assembly102increases operations that can be performed by vehicles and/or bodies (e.g., the aerial vehicle100) to which the antenna assembly102is attached and with which the antenna assembly102is utilized. For instance, the vehicles and/or bodies (e.g., the aerial vehicle100) can be subjected to environments having increased temperatures in comparison to conventional antenna assemblies. Furthermore, the antenna assembly102may maintain functionality of the antenna assembly102in high temperatures, and as a result, radio frequency communication with external components/controllers, even when subjected to unexpected high temperatures, is maintained. As a result, the antenna assembly102provides an increased reliability in comparison to conventional antenna assemblies. Moreover, the antenna assembly102increases a number of applications (e.g., uses) of the antenna assembly102in comparison to conventional antenna assemblies.

FIGS.17and18include plots showing an example S-parameter amplitude (in this case, the s22 parameter amplitude) plotted at times corresponding to before, during, and at an end of a temperature cycling of an antenna assembly according to one or more embodiments of the present disclosure obtained via testing done by the inventors.FIGS.17and18show that the performance of antenna assembly did not appreciably change during thermal ramping of the antenna assembly. For instance,FIGS.17and18show about 1 to 2 dB of change on average with larger fluctuations attributable to environmental changes and aerial vehicle movements during the text.

The embodiments of the disclosure described above and illustrated in the accompanying drawings do not limit the scope of the disclosure, which is encompassed by the scope of the appended claims and their legal equivalents. Any equivalent embodiments are within the scope of this disclosure. Indeed, various modifications of the disclosure, in addition to those shown and described herein, such as alternate useful combinations of the elements described, will become apparent to those skilled in the art from the description. Such modifications and embodiments also fall within the scope of the appended claims and equivalents.