Embodiments of the present disclosure generally relate to antenna assemblies, such as wideband electronically scanning antenna assemblies.
An antenna typically includes an array of conductors electrically connected to a receiver or a transmitter. The transmitter provides an electric current to terminals of the antenna, which in response radiates electromagnetic waves. Alternatively, as radio waves are received by the antenna, an electrical current is generated at the terminals, which in turn is applied to the receiver. Various types of known antennas are configured to transmit and receive radio waves with a reciprocal behavior.
In some aerospace applications, there is a need for antennas that are capable of being positioned on conformal or non-planar surfaces, such as wings and fuselages of aircraft. Small aircraft, such as unmanned aerial vehicles (UAVs) or drones, in particular, have surfaces with low radii of curvature. Such aircraft typically need light weight antennas with low aerodynamic drag and low visibility. Further, various surfaces of aircraft may be formed from conductive or carbon fiber materials, which are known to change the electrical behavior of antennas, such as monopole and dipole antennas and derivatives (for example, whip, blade, Yagi, and other such antennas).
Dish antennas are relatively large and may not be easily steerable. Certain dish antennas are coupled to gimbals, which allow for steering. However, dish antennas may be too large and bulky to be used with certain aircraft. For example, various dish antennas add substantial weight to aircraft, thereby reducing fuel efficiency. Further, the dish antennas may increase aerodynamic drag, due to their size and shape, which further reduces fuel efficiency and may also affect aircraft maneuverability.
As another example, certain antennas include relatively heavy and bulky slotted copper waveguide pipes, which form an aperture section of an electronically scanning antenna array system. Again though, the weight, size, and shape of such antennas may not be well-suited for aeronautical and aerospace applications, as such antennas may undesirably affect fuel efficiency and maneuverability. Further, the process of manufacturing such antennas is typically complex.
A need exists for a compact and lightweight antenna assembly. Further, a need exists for an electronically steerable antenna assembly that can be effectively used with vehicles without reducing fuel efficiency and/or maneuverability.
With those needs in mind, certain embodiments of the present disclosure provide an antenna assembly that includes a base including one or more feed transitions, a support panel (such as a non-metallic support panel) separated from the base, a patch (such as a metallic patch) secured to the support panel, and one or more T-shaped probes (such as metallic T-shaped probes) that couple the feed transition(s) to the patch. The T-shaped probe(s) are separated from the patch. In at least one embodiment, the T-shaped probe(s) are separated from the support panel by a feed gap.
In at least one embodiment, the base, the support panel, and/or the patch are formed from one or more portions of one or more circuit boards.
In at least one embodiment, outer perimeter walls are disposed between the base and the support panel. An internal cavity (such as an internal metallic cavity) is defined between the outer perimeter walls, the base, and the support panel. The T-shaped probe(s) are disposed within the internal cavity. The outer perimeter walls may be formed from one or more portions of one or more circuit boards.
In at least one embodiment, one or more inner cross walls (such as non-metallic inner cross walls) are within the internal cavity. The T-shaped probe(s) are supported by the inner cross wall(s).
For example, the feed transitions include a first feed transition and a second feed transition. The T-shaped probes include a first T-shaped probe, a second T-shaped probe, a third T-shaped probe, and a fourth T-shaped probe. The inner cross walls include a first inner cross wall, a second inner cross wall, a third inner cross wall, and a fourth inner cross wall. The first T-shaped probe is connected to the first feed transition and the first inner cross wall. The second T-shaped probe is connected to the first feed transition and the second inner cross wall. The third T-shaped probe is connected to the second feed transition and the third inner cross wall. The fourth T-shaped probe is connected to the second feed transition and the fourth inner cross wall. The first inner cross wall may be parallel to the second inner cross wall. The third inner cross wall may be parallel to the fourth inner cross wall. The first and second inner cross walls may be orthogonal to the third and fourth inner cross walls.
In at least one embodiment, the patch is a microstrip patch supported on an upper surface of the support panel.
In at least one embodiment, the antenna assembly also includes a frame defining an internal opening. The the frame is coupled to the support panel. The frame may be formed from one or more portions of one or more circuit boards.
In at least one embodiment, the antenna assembly also includes one or more feed lines coupled to the base and connected to the one or more feed transitions. One or more vias extend through the base proximate to the feed line(s).
In at least one embodiment, the T-shaped probes include a foot secured within one of the feed transitions(s), an extension body connected to the foot, and an expanded head connected to the extension body opposite from the foot.
Certain embodiments of the present disclosure provide a method of forming an antenna assembly. The method includes providing a base including one or more feed transitions; separating a support panel from the base; securing a patch to the support panel; and coupling one or more T-shaped probes to the feed transition(s) and the patch. Said coupling includes separating the T-shaped probe(s) from the patch.
The foregoing summary, as well as the following detailed description of certain embodiments, will be better understood when read in conjunction with the appended drawings. As used herein, an element or step recited in the singular and preceded by the word “a” or “an” should be understood as not necessarily excluding the plural of the elements or steps. Further, references to “one embodiment” are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional elements not having that property.
Certain embodiments of the present disclosure provide an antenna assembly, such as an electronically scanning antenna assembly. In at least one embodiment, the antenna assembly is formed of circuit board sections. A top section includes a layer of dielectric substrate that supports a patch, such as a microstrip patch, a square ring slot hybrid radiator, and a tuning square ring. A bottom section contains a metallic cavity formed by sidewalls. Cross walls support feed probes. A grounded dual layered dielectric substrate has an embedded stripline. The cavity suppresses backward radiation and reduces undesired mutual coupling with neighboring antenna elements. It has been found that such an antenna assembly exhibits improved radio frequency performance over bandwidth, has an ability to scan to at least sixty degrees from array broadside without onset of grating lobes, and provides dual linear polarizations and basis for circular polarizations.
Certain embodiments of the present disclosure provide an antenna assembly that is well suited for use with vehicles, such as aircraft. The antenna assembly allows for transmission and reception of radio frequency signals with an agile electronically scanning antenna array beam. In at least one embodiment, the antenna assembly has no moving parts. The antenna assembly can be used in radar and sensor systems, as well as other application including communications and electronic warfare.
Embodiments of the present disclosure provide a low-cost antenna assembly that is lightweight and has a low profile. In at least one embodiment, the antenna assembly is formed of lightweight and low-profile circuit board sections, which substantially reduce a weight and thickness of the antenna assembly, while at the same time maintaining desired performance.
Embodiments of the present disclosure provide an antenna assembly including one or more T-shaped probes that coupled a feed transition of a base to a patch secured to a support panel. The T-shaped probe(s) is/are disposed within an internal cavity of the antenna assembly. In at least one embodiment, a frame defining an internal opening is secured to the support panel, such as to below or over the support panel.
Outer perimeter walls 110 extend from the base 104. As an example, the outer perimeter walls 110 include lateral walls 110a and 110b connected to end walls 110c and 110d. As shown, the lateral walls 110a and 110b and the end walls 110c and 110d upwardly extend from the base 104, thereby forming an internal cavity 112 therebetween. In at least one embodiment, the outer perimeter walls 110 are orthogonal to the base 104. For example, the base 104 resides in one or more planes that are parallel to an X-Y plane (such as horizontal plane), while the perimeter walls 110 reside in one or more planes that are parallel to a Y-Z plane (such as a vertical plane).
As shown, the outer perimeter walls 110 are disposed between the base 104 and a support panel 120. The internal cavity 112 is defined between the outer perimeter walls 110, the base 104, and the support panel 120. As described herein, one or more T-shaped probes 130 are disposed within the internal cavity 112.
Open spaces within the internal cavity 112 (such as those not occupied by structures, such as a cross wall) can be filled with air or foam, for example. The internal cavity 112 suppresses backward radiation. Further, the internal cavity 112 reduces undesired mutual coupling with neighboring antenna assemblies 100 (shown in
In at least one embodiment, the outer perimeter walls 110 are formed of circuit boards, circuit board materials, and/or sections or portions of circuit boards. For example, the outer perimeter walls 110 are formed of non-etched circuit boards. As shown, the outer perimeter walls 110 provide a box-like perimeter extending from the base 104. Alternatively, the outer perimeter walls 110 may be sized and shaped differently than shown. For example, the outer perimeter walls 110 may be circular or otherwise arcuate, instead of flat, planar walls.
Inner cross walls 114 (such as first inner cross walls) extend from the base 104 within the internal cavity 112 between the lateral walls 110a and 110b. For example, two parallel inner cross walls 114 extend between the lateral walls 110a and 110b. The inner cross walls 114 reside in planes that are parallel to an X-Z plane. Like the outer perimeter walls 110, the inner cross walls 114 may be formed of circuit boards, circuit board materials, and/or sections or portions of circuit boards. Optionally, the antenna assembly 100 may include more or less inner cross walls 114 than shown. For example, the antenna assembly 100 may include three inner cross walls 114. As another example, the antenna assembly 100 may include only one inner cross wall 114.
Inner cross walls 116 (such as second inner cross walls) extend from the base 104 within the internal cavity 112 between the end walls 110c and 110d. For example, two parallel inner cross walls 116 extend between the end walls 110c and 110d. The inner cross walls 116 are orthogonal to the inner cross walls 114. The inner cross walls 116 reside in planes that are parallel to the Y-Z plane. The inner cross walls 116 may be formed of circuit boards, circuit board materials, and/or sections or portions of circuit boards. As shown, the inner cross walls 114 may intersect the inner cross walls 116 proximate to a central axis 118 of the antenna assembly 100. Optionally, the antenna assembly 100 may include more or less inner cross walls 116 than shown. For example, the antenna assembly 100 may include three inner cross walls 116. As another example, the antenna assembly 100 may include only one inner cross wall 116.
The support panel 120 (shown transparent) connects to upper edges of the outer perimeter walls 110 opposite from the base 104. The support panel 120 includes one or more dielectric substrates. In at least one embodiment, the support panel 120 is spaced apart from the base 104 by the outer perimeter walls 110, and is parallel to the base 104. For example, the support panel 120 resides in one or more planes that are parallel to the X-Y plane.
In at least one embodiment, the support panel 120 is a single dielectric layer. The support panel 120 supports a patch 122, such as a microstrip patch. For example, the patch 122 is supported on an upper surface of the support panel 120.
A frame 123 is coupled to the support panel 120. For example, the frame 123 extends below and around an outer perimeter of the support panel 120. The frame 123 may be formed of a metal. The frame 123 defines an internal opening 125 over the support panel 120. In at least one embodiment, the patch 122 is disposed within the internal opening 125. As shown, the frame 123 provides a ring, such as a square ring, defining the internal opening 125. In at least one embodiment, the frame 123 provides a cage that defines the internal opening 125 in which the patch 122 may be axially contained, such as within planes than are parallel to the X-Y plane. In at least one embodiment, the frame 123 may be formed of at least portions of a circuit board.
Optionally, the frame 123 can be disposed over the outer perimeter of the support panel 120. Also, optionally, a non-metallic environmental protective coating may be disposed over the antenna assembly 100.
The frame 123 provides a tuning mechanism for the patch/slot hybrid radiator formed by the patch 122 and the internal opening 125 (or ring slot). The patch 122 and internal opening 125 provide resonances that are configured to be close to each other in frequency, thereby allowing for an overall wide operating bandwidth.
Referring to
The feed lines 124 connect to feed transitions 128, such as feed transitions 128a and 128b. In at least one embodiment, the feed transitions 128 include solder joints that electrically connect to the feed lines 124, and then the electronics 102.
Probes 130 extend from the feed transitions 128 upwardly toward the patch 122. As described herein, in at least one embodiment, the probes 130 are T-shaped probes. The probes 130 are disposed within the internal cavity 112. In at least one embodiment, each probe 130 is supported on an inner cross wall 114 or an inner cross wall 116. As shown, the antenna assembly 100 includes a first probe 130a supported on an inner cross wall 114a, a second probe 130b supported on an inner cross wall 114b, a third probe 130c supported on an inner cross wall 116a, and a fourth probe 130d supported on an inner cross wall 116b. Optionally, the antenna assembly 100 may include more or less probes 130. For example, the antenna assembly 100 may include a single probe 130 supported on a single cross wall 114 or 116. As another example, the antenna assembly 100 may include one probe 130 supported on a cross wall 114, and another probe supported on a cross wall 116.
In at least one embodiment, the feed transitions 128 include the first feed transition 128a and the second feed transition 128b. The probes 130 (such as T-shaped probes 130) include a first T-shaped probe 130a, a second T-shaped probe 130b, a third T-shaped probe 130c, and a fourth T-shaped probe 130d. The cross walls 114, 116 include a first inner cross wall 114a, a second inner cross wall 114b, a third inner cross wall 116a, and a fourth inner cross wall 116b. The first T-shaped probe 130a is connected to the first feed transition 128a and the first inner cross wall 114a. The second T-shaped probe 130b is connected to the first feed transition 128a and the second inner cross wall 114b. The third T-shaped probe 130c is connected to the second feed transition 128b and the third inner cross wall 116a. The fourth T-shaped probe 130d is connected to the second feed transition 128b and the fourth inner cross wall 116b.
In at least one embodiment, the first inner cross wall 114a is parallel to the second inner cross wall 114b. The third inner cross wall 116a is parallel to the fourth inner cross wall 116b. The first and second inner cross walls 114a/114b are orthogonal (for example, perpendicular) to the third and fourth inner cross walls 116a/116b.
Each probe 130 includes a foot 132 secured within a feed transition 128. For example, the foot 132 can be soldered into the feed transition 128. The foot 132 may be or otherwise include a tab, for example. The foot 132 connects to an extension body 134, which, in turn, connects to an expanded head 136 (opposite from the foot 132), proximate to the support panel 120, thereby forming a T-shape.
The position, length, and shape of the probes 130 and feed transitions 128 are tunable for impedance matching and orthogonal polarization isolation. The frame 123 provides an additional mechanism for tuning of impedance matching and control of mutual coupling with neighboring antenna elements (such as neighboring antenna assemblies 100 within an antenna array 180, as shown in
The dual feed lines 124a and 124b, as shown in
Further, as noted, two probes 130 are coupled to each feed transition 128. By connecting two probes 130 to each feed transition, overall capacitance between the patch 122 and the expanded head 136 below is increased. The capacitance cancels the inductance caused by the feed probe 130 and thus improves antenna impedance matching. Alternatively, each feed transition 128 may connect to only one probe 130. For example, instead of two cross walls 114, a single cross wall 114a may support a single probe 130a that connects to the feed transition 128a.
The vias 126 are shorting vias that are positioned on sides of the feed lines 124a and 124b. The vias 126, as shorting vias, suppress undesirable parallel plate modes between two ground planes and isolate the feed line 124a from the feed line 124b, and vice versa, as well as provide a quasi-coaxial transition region. The antenna assembly 100 can include more or less vias 126 than shown, as desired.
The feed lines 124a and 124b are shown truncated in
In at least one embodiment, the horizontal dimensions (that is, with respect to the X-Y plane) may be chosen to meet desired scan angle requirements over a frequency band. In at least one embodiment, antenna assemblies 100 within an antenna array 180 (shown in
The base 104, the perimeter walls 110, the cross walls 114, and the cross walls 116 form a crate structure in an array setting. In at least one embodiment, the top section (including the support panel 120, the patch 122, and the frame 123) is fabricated separately from the bottom section (including the base 104, the perimeter walls 110, the cross walls 114, and the cross walls 116). The top and bottom sections may be bonded together during final assembly. Other methods of formation include using direct write technologies, bent/wrapped printed circuit boards, and flex circuit boards conformal to surfaces of structures, such as of vehicles.
The foot 132 of the probe 130 (such as the probe 130a, shown in
The expanded head 136 includes lateral extensions 138 that outwardly and laterally extend from the extension body 134. The extension body 134 has a longitudinal axis 140 that is perpendicular to a longitudinal axis 142 of the expanded head 136, thereby providing the probe 130 with a T shape.
The antenna assembly 100 has a thickness 111. As one example, the thickness 111 is approximately 0.2 wavelengths in free space at midband frequency.
The feed line 124 can be positioned over the base 104. Optionally, the feed line 124 can be embedded within the base 104.
As shown in
The feed line 124 can be a stripline. A width 173 of the feed line 124 may be selected to provide a 50, 75, 100, or the like Ohm characteristic impedance. The feed line 124 extends and connects to the feed transition 128 and may be soldered to the feed transition 128.
The expanded head 136 of the probe 130 is offset or otherwise separated from the support panel 120 by a feed gap 170. Alternatively, the expanded head 136 may connect to the second surface 162 of the support panel 120.
A thickness 127 for the support panel 120 is selected, as desired, and the size of the expanded head 136 and magnitude of the feed gap 170 is configured to provide sufficient capacitance to cancel inductance introduced by the feed probe 130. The T shape of the probe 130 provides balance between generating sufficient capacitance for impedance matching, while maintaining isolation with other orthogonal probes over an operating frequency band. The capacitive coupling between the probe 130 and the patch 122 eliminates, minimizes, or otherwise reduces a need to solder at the expanded head 136 during fabrication and/or formation of the antenna assembly 100.
As shown, the antenna assemblies 100 may form identical unit cells in the antenna array 180. A feed distribution network and supporting electronics such as amplifiers are not shown, for clarity. The configuration of the antenna array 180 shown in
Referring to
The aircraft 200 includes a propulsion system 210 that may include two engines 212, for example. Optionally, the propulsion system 210 may include more engines 212 than shown. The engines 212 are carried by wings 216 of the aircraft 200. In other embodiments, the engines 212 may be carried by a fuselage 218 and/or an empennage 220. The empennage 220 may also support horizontal stabilizers 222 and a vertical stabilizer 224. The wings 216, the horizontal stabilizers 222, and the vertical stabilizer 224 may each include one or more control surfaces.
Optionally, embodiments of the present disclosure may be used with respect to various other structures, such as other vehicles (including automobiles, watercraft, spacecraft, and the like), buildings, appliances, and the like.
In at least one example, the coupling (306) further includes separating the one or more T-shaped from the support panel by a feed gap.
In at least one example, the method also includes forming one or more of the base, the support panel, and the patch from one or more portions of one or more circuit boards.
In at least one example, the method also includes disposing outer perimeter walls between the base and the support panel; defining an internal cavity between the outer perimeter walls, the base, and the support panel; and disposing the one or more T-shaped probes within the internal cavity.
In at least one example, the method also includes providing one or more inner cross walls within the internal cavity; and supporting the one or more T-shaped probes by the one or more inner cross walls.
In at least one example, the method also includes coupling a frame defining an internal opening to the support panel.
As described herein, embodiments of the present disclosure provide antenna assemblies that may be formed from lightweight, low-profile portions of circuit boards (such as sections of circuit boards), in contrast to relatively heavy and bulky slotted copper waveguide pipes. Embodiments of the present disclosure provide low-profile and lightweight antenna assemblies. Further, embodiments of the present disclosure provide electronically steerable antenna assemblies that can be effectively used with vehicles without reducing fuel efficiency and/or maneuverability. Also, embodiments of the present disclosure provide antenna assemblies that may be efficiently and effectively manufactured, in contrast to complex antennas having slotted copper waveguide pipes, which are typically formed through complex manufacturing processes.
While various spatial and directional terms, such as top, bottom, lower, mid, lateral, horizontal, vertical, front and the like may be used to describe embodiments of the present disclosure, it is understood that such terms are merely used with respect to the orientations shown in the drawings. The orientations may be inverted, rotated, or otherwise changed, such that an upper portion is a lower portion, and vice versa, horizontal becomes vertical, and the like.
As used herein, a structure, limitation, or element that is “configured to” perform a task or operation is particularly structurally formed, constructed, or adapted in a manner corresponding to the task or operation. For purposes of clarity and the avoidance of doubt, an object that is merely capable of being modified to perform the task or operation is not “configured to” perform the task or operation as used herein.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the various embodiments of the disclosure without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various embodiments of the disclosure, the embodiments are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the various embodiments of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
This written description uses examples to disclose the various embodiments of the disclosure, including the best mode, and also to enable any person skilled in the art to practice the various embodiments of the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the various embodiments of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if the examples have structural elements that do not differ from the literal language of the claims, or if the examples include equivalent structural elements with insubstantial differences from the literal language of the claims.
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