High-isolation annular groove patch radiator for phased-array antenna

Abstract

The invention relates to a high-isolation annular groove patch radiator for a phased-array antenna. The antenna element comprises a metal square ring patch and a metal square ring groove and is used for transmitting or receiving radio frequency (RF) signals. The antenna element uses dielectric layers separated by a low dielectric foam layer on which a square ring patch is located. The antenna elements may be arranged in an antenna array that is tunable to collectively generate or receive RF signals to and from onboard and moving vehicles using flexible electronically scanned antenna array beams without moving parts. The antenna array includes a top for communicating RF signals; a bottom for generating a desired RF signal; and a foam layer between the top and the bottom for separating the annular patch from the annular groove. The high isolation between the top and bottom allows the antenna elements to be used for higher gain and high power arrays without producing adverse feedback issues.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 251,582, filed on October 1, 2021, entitled "LOW COST ELECTRONICALLY SCANNING ANTENNA ARRAY ARCHITECTURE" and U.S. Patent Application Serial No. 17 / 588,172, filed on January 28, 2022, entitled "LOW COST ELECTRONICALLY SCANNING ANTENNA ARRAY ARCHITECTURE", the entire contents of both applications are incorporated herein by reference in their entirety. Technical Field

[0003] Examples generally relate to phased - array antennas ("PPA") for providing reception and transmission of radio - frequency (RF) signals. More specifically, these examples relate to low - cost PPAs that provide high isolation between an antenna feed structure and an RF distribution layer. Background Art

[0004] A phased - array antenna ("PAA") is a type of antenna that includes a plurality of sub - antennas (commonly referred to as antenna elements, array elements, or radiating elements that make up the array), where the relative amplitudes and phases of the respective signals fed into the array elements can be varied in such a way that the effect on the overall radiation pattern of the PAA is enhanced in a desired direction and suppressed in an undesired direction. In other words, beams can be generated that can be pointed or steered in different directions. Pointing the beam of a transmitting or receiving PAA is achieved by controlling the amplitude and phase of the transmit or receive signals from each antenna element in the PAA.

[0005] Individual radiated signals are combined to form constructive and destructive interference patterns produced by the PAA, resulting in one or more antenna beams. Then, one or more beams can be quickly pointed in azimuth and elevation using the PAA.

[0006] However, some existing solutions provide relatively low isolation between the antenna elements or the antenna feed structure and the radio - frequency (RF) distribution elements or distribution layer. As the size of the antenna array (e.g., the number of elements) and power increase, these configurations may encounter feedback problems. Therefore, there is a need for a PPA that provides high isolation between the antenna feed structure and the RF distribution layer. Summary of the Invention

[0007] The disclosed examples are described in detail below with reference to the accompanying drawings listed below. The following overview is provided to illustrate the examples or implementations disclosed herein. However, this does not mean that all examples are limited to any specific configuration or operating sequence.

[0008] The disclosed examples and implementations relate to antenna elements that can be positioned together to form an antenna array (or PAA). The disclosed antenna elements use multiple stacked dielectric layers, with at least two separated by a low-dielectric foam layer. The horizontal top dielectric layer supports a microstrip square ring patch radiator and also serves as an environmental shield against corrosion. The square ring patch cutout holes lower the resonant frequency of the patch and allow for a smaller outer diameter, which is desirable for reduced mutual coupling and avoiding overemphasis on broadside antenna gain.

[0009] The disclosed antenna elements can be arranged together in an antenna array that is tunable to jointly generate or receive RF signals. In particular, the antenna array serves as a 256-element transmit / receive half-duplex antenna that operates either in a transmit or receive mode at any given time, but not both simultaneously. The antenna array includes a radiator block, a transmit / receive (T / R) amplifier block, a beamformer block, and a distribution network block.

[0010] Other disclosed examples and implementations relate to a unit cell antenna system for a periodic antenna array that includes a top for communicating radio frequency (RF) signals, the top including a dielectric layer and a ring patch, where the ring patch is supported by the dielectric layer and the ring patch has a central cutout hole to lower the resonant frequency of the ring patch; a bottom for generating a desired radio frequency (RF) signal, the bottom including multiple dielectric layers; an annular slot supported by one of the multiple dielectric layers; a conductive fence substantially surrounding the annular slot; two feed lines, where the feed lines are 90 degrees out of phase; and a foam layer disposed between the top and the bottom that separates the ring patch from the annular slot.

[0011] Still other disclosed examples and implementations relate to a method of providing a unit cell antenna for a periodic antenna array, the method including providing a top for communicating radio frequency (RF) signals, the top including a dielectric layer and a ring patch, where the ring patch is supported by the dielectric layer and the ring patch has a central cutout hole to lower the resonant frequency of the ring patch; providing a bottom for generating a desired radio frequency (RF) signal, the bottom including multiple dielectric layers; an annular slot supported by one of the multiple dielectric layers; a conductive fence substantially surrounding the annular slot; two feed lines, where the feed lines are 90 degrees out of phase; and providing a foam layer disposed between the top and the bottom that separates the ring patch from the annular slot.

[0012] Other further disclosed examples and implementations relate to a method of manufacturing a unit cell antenna system for a periodic antenna array, the method including forming a top to communicate radio frequency (RF) signals, the top including a dielectric layer and a loop patch, wherein the loop patch is supported by the dielectric layer, the loop patch having a central cutout hole to reduce the resonant frequency of the loop patch; forming a bottom to generate a desired radio frequency (RF) signal, the bottom including a plurality of dielectric layers; an annular slot supported by one of the plurality of dielectric layers; a conductive fence substantially surrounding the annular slot; two feed lines, wherein the feed lines are 90 degrees out of phase; and forming a foam layer disposed between the top and the bottom, the foam layer separating the loop patch from the annular slot.

[0013] From the following drawings, specification, and claims, other technical features will be apparent to those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] To more fully understand the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

[0015] Figure 1 A perspective view of an annular unit having a conductive fence is shown in accordance with some disclosed implementations;

[0016] Figure 2 A cross-sectional side view of an annular unit having a conductive fence is shown in accordance with some disclosed implementations;

[0017] Figure 3 A top view of an antenna array composed of a plurality of annular units is shown in accordance with some disclosed implementations;

[0018] Figure 4 A perspective view of an annular unit having a circular through-hole fence is shown in accordance with some disclosed implementations;

[0019] Figure 5A and 5B Perspective and top views of an annular unit having a T-shaped junction delay feed line are shown respectively in accordance with some disclosed implementations;

[0020] Figure 6A and 6B Perspective and top views of an annular unit having a 90-degree hybrid coupler are shown respectively in accordance with some disclosed implementations;

[0021] Figure 7 A block diagram of an antenna system for an antenna array composed of the annular units disclosed in the present disclosure is shown;

[0022] Figure 8 A perspective view of an aircraft having one or more array antennas composed of the annular units disclosed in the present disclosure is shown;

[0023] Figure 9 Shows an antenna integrated printed wiring board (AIPWB) for an antenna array constructed from a number of annular elements according to some disclosed implementations;

[0024] Figure 10 Shows another AIPWB for an antenna array constructed from a number of annular elements according to some disclosed implementations;

[0025] Figure 11 Shows a schematic diagram of a sixteen-annular-element sub-array using a type of beamformer and front-end integrated circuit (IC) according to some disclosed implementations;

[0026] Figure 12 Shows layer 1 of the interface of the MMIC for the sixteen-annular-element sub-array antenna 1100; and

[0027] Figure 13 Shows a block diagram of a transmit / receive antenna array for line-of-sight applications according to some disclosed implementations.

[0028] Figure 14 Shows a perspective view of an annular element having a conductive fence that includes a number of additional adhesive layers according to some disclosed implementations;

[0029] Figure 15 Shows a cross-sectional side view of an annular element having a conductive fence that includes a number of additional adhesive layers according to some disclosed implementations;

[0030] Figure 16 Shows a top view of an antenna array composed of a number of annular elements according to some disclosed implementations;

[0031] Figure 17 Shows a perspective view of an annular element having a circular via fence that includes a number of additional adhesive layers according to some disclosed implementations;

[0032] Figure 18A And 18B Show a perspective view and a top view, respectively, of an annular element having a T-junction delay feeder according to some disclosed implementations;

[0033] Figure 19A And 19B Show a perspective view and a top view, respectively, of an annular element having a 90-degree hybrid coupler according to some disclosed implementations;

[0034] Figure 20 Shows an example of an antenna array composed of a number of annular elements according to some disclosed implementations;

[0035] Figure 21 A block diagram showing an example of an antenna system composed of the loop units disclosed in the present disclosure;

[0036] Figure 22 An antenna integrated printed wiring board (AIPWB) for an antenna array according to some disclosed embodiments, the antenna array being constructed from a plurality of loop units;

[0037] Figure 23 A partial view showing an example of an antenna array composed of the disclosed loop units;

[0038] Figure 24 A method of providing a unit cell antenna for a periodic antenna array according to some disclosed embodiments; and

[0039] Figure 25 A method of manufacturing a unit cell antenna system for a periodic antenna array according to some disclosed embodiments.

[0040] Corresponding reference numerals indicate corresponding parts throughout the drawings. Detailed Description of Specific Embodiments

[0041] Various examples will be described in detail with reference to the drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. References to specific examples and embodiments throughout the present disclosure are provided for illustrative purposes only and do not imply a limitation of all embodiments unless otherwise indicated.

[0042] A phased array antenna (PAA) includes a plurality of transmitters and is used for beamforming in high-frequency RF applications such as radar, 5G, or numerous other applications. The number of transmitters in a PAA can range from a few to thousands. The purpose of using a PAA is to control the direction of the transmit beam by taking advantage of constructive interference between two or more radiating signals. This is known in the antenna art as "beamforming".

[0043] More specifically, a PAA achieves beamforming by adjusting the phase difference between the drive signals sent to each transmitter in the array. This allows control of the radiation directivity pattern and its orientation towards a target without any physical movement of the antenna. This means that beamforming in a specific direction is an interference effect between quasi-omnidirectional transmitters (such as dipole antennas).

[0044] The disclosed implementations and examples provide a low-cost Ku-band electronically scanned antenna array architecture that integrates one or more low-complexity apertures, coupled hybrid patch radiators, and commercial monolithic microwave integrated circuits (MMICs) with a low-cost multilayer printed circuit board design called an antenna integrated printed wiring assembly (AIPWA). More specifically, a loop antenna element (referred to herein as a "ring cell") is described that provides an ultra-low-cost unit cell antenna element for an electronically scanned array with a unique feed structure. The loop element has a circuit board-like portion and a low-dielectric spacer, such as a foam or a core structure. The top of the antenna element includes a layer of dielectric substrate to support the microstrip loop patch radiator. The bottom has a layer of dielectric substrate to support the loop slot and the dual feed lines. The disclosed antenna element provides high-quality antenna performance, as well as dual linear polarization and circular polarization, over a wide frequency bandwidth and a 1D scan range of up to + / - 45 degrees.

[0045] The ring cell includes a unique feed structure for a PAA or other electronically scanned array. The ring cell consists of a circuit board-based portion and a foam spacer. The top has a layer of dielectric substrate to support the microstrip loop patch radiator. The bottom has two layers of dielectric substrate to support the loop slot, the dual feed lines, and the metal fence. The disclosed ring cell provides high-quality antenna performance over a wide frequency bandwidth and a large scan volume. The ring cell also provides dual linear polarization or circular polarization. The disclosed ring cell does not use mechanically moving parts, which eliminates most of the complexity and failure points of traditional antenna cells.

[0046] The disclosed ring cell can be arranged in an array antenna (e.g., a PAA) that includes multiple ring cells that collectively serve as an electronically scanned antenna array beam. The array antenna using the disclosed ring cell can be used in a variety of practical applications. For example, airplanes, motor vehicles, various military systems, Internet of Things (IoT) devices, and any device that uses RF signaling can be equipped with an array antenna using the disclosed ring cell. The disclosed ring cell and antenna array provide an electronically scanned antenna system that significantly reduces the integration cost of both due to the low-profile design and the use of affordable off-the-shelf materials.

[0047] Traditionally, ceramic chip carrier modules have been used to connect MMICs and AIPWBs. Such ceramic packages are relatively expensive and require costly labor to assemble. Moreover, the ceramic packages also use large and complex waveguide radiators, which add lamination steps and additional layers to the AIPWB. The waveguide radiators require expensive and complex wide-angle impedance matching (WAIM) structures as the interface between the antenna array and free space. Unfortunately, this does not meet the cost-per-element target of many line-of-sight communication customers.

[0048] The disclosed implementations and examples use a low-complexity aperture-coupled patch radiator, low-cost commercial-off-the-shelf surface-mounted MMICs, and a low-cost multi-layer printed circuit board stack-up. The low-complexity aperture-coupled patch radiator reduces the number of AIPWB layers by 50% and eliminates the WAIM component without sacrificing the antenna RF performance within + / -45-degree elevation scan. Using low-cost commercial-off-the-shelf MMICs with surface-mount integration reduces the cost per element of the antenna array by more than three times. The low-cost and reduced-complexity multi-layer printed circuit board stack-up reduces the manufacturing cost and opens the manufacturing path for a more diverse supplier base.

[0049] The disclosed loop element can transmit or receive RF signals to or from vehicles and aircraft using a flexible electronically scanned antenna array beam without mechanical moving parts. The antenna elements can be assembled into an antenna array that can be used in many applications, such as but not limited to, for radar, sensors, or other applications. The antenna elements provide a high-performance, lightweight, low-profile, and ultra-low-cost solution to meet challenging and evolving mission requirements. Additionally, the disclosed antenna elements are used to fabricate integrated and structurally integrated antennas, particularly in composite sandwich panels, due to the minimal use of vias and connections.

[0050] Figure 1 A perspective view of a loop element 100 with a conductive fence 102 ("loop fence" 102) is shown in accordance with some disclosed implementations. The loop element 100 includes a plurality of circuit board-based parts. In addition to the conductive fence 102, the loop element 100 further includes a loop patch 104, two feed lines 106 and 108, a loop slot 110, a top dielectric layer 112, a top adhesive layer 114, a foam layer 116, an upper inner adhesive layer 118, an inner metal layer 120, an intermediate dielectric layer 122, and a bottom dielectric layer 122. In some implementations, the foam layer 116 includes a foam layer that separates the loop patch 104 from the loop slot 110 and is thus referred to herein as the "foam layer" 116. In some examples, the various dielectric layers 112, 122, and 126 are printed circuit boards (PCBs). Additionally, the loop patch 104 can be formed, etched, or adhered to the foam layer 114 to hold the loop patch 104 in place.

[0051] The conductive fence 102 includes one or more metal (or otherwise conductive) walls. Figure 4 The alternative design shown in replaces the metal walls with a circular via pattern.

[0052] More specifically, the horizontal top of the loop unit 100 includes a top dielectric layer 112, which supports the loop patch 104 below and also serves as an environmental shield against corrosion. The loop patch 104 includes cutout holes that lower the resonant frequency of the patch and allow for a smaller outer diameter, which is desirable for mutual coupling reduction and avoiding overemphasis on broadside antenna gain.

[0053] The bottom of the loop unit 100 includes two layers of dielectric substrates, an intermediate dielectric layer 122 and a bottom dielectric layer 126, which together support the loop slot 110, the dual feed lines 106 and 108, and the thin conductive fence 102. The feed lines 106 and 108 provide power supply to excite the orthogonal resonant modes in the loop slot 110, which in turn excite the orthogonal resonant modes in the loop patch 104 above for RF signaling. When transmitting an RF signal, the feed lines provide power supply (voltage and current) to generate an electrical resonance in the loop 110, and then generate the desired RF signal in the loop patch 104. When receiving an RF signal, the feed lines receive the power supply induced in the loop 110 by the loop patch 104 that receives the RF signal.

[0054] The loop slot 110 and the loop patch 104 work together to provide a wider impedance bandwidth than either one alone can provide. Thus, the loop unit 100 is designed to operate as a hybrid radiator that works in both transmit and receive modes. Optionally, the loop unit 100 can operate in only transmit or only receive mode.

[0055] The conductive fence 102 separates the loop slot 110 from the RF distribution network and reduces the unwanted mutual coupling with other loop slots 110 in adjacent loop units 100 that are part of an array antenna (e.g., PAA). The diameter and depth of the conductive fence 102 are set such that the loop slot 110 resonates at or near the desired operating frequency band. In some embodiments, the openings 128 and 130 around the conductive fence 102 allow the feed lines 106 and 108 to enter the interior without being electrically shorted.

[0056] The loop patch 104 and the conductive fence 102 are metallic or otherwise conductive. Power is supplied to the loop unit 100 through the feed lines 106 and 108, causing the conductive fence 102 and the loop patch 104 to operate as radiating elements for generating a specific RF signal. In terms of shape, the conductive fence 102 has a larger diameter than the loop slot 110. This allows the loop slot 110 to be positioned horizontally within the conductive fence 102. However, as Figure 2 visible, at least in some embodiments, the loop slot 110 is vertically positioned above the conductive fence 102.

[0057] The twin feed lines 106 and 108 excite the orthogonal dual linear polarization required for some applications. For other applications, dual or single circular polarization may be required. Optionally, some embodiments include a feed structure using a T-junction divider / combiner (for transmission / reception respectively) and a 90-degree delay line for right-hand circular polarization, which is shown in Figure 5A and 5B . This integrated coplanar feed provides an economical way to achieve optimal polarization performance in the far field. Left-hand circular polarization can also be achieved by moving the L-shaped input line portion from its current position to the other side of the V-junction. For improved circular polarization performance during scanning, other embodiments use a different feed structure that uses a 90-degree hybrid coupler, as shown in Figure 6A and 6B .

[0058] The shown annular unit 100 disclosed herein is shaped in a hexagonal pattern. However, other shapes are also fully contemplated. For example, the annular unit 100 can be circular, rectangular, square, etc. Among these non-hexagonal shaped annular units 100, some embodiments still use the circular ring patch 104, the annular slot 110, and the conductive fence 102.

[0059] Figure 2 A cross-sectional side view of the annular unit 100 with the conductive fence 102 is shown according to some disclosed embodiments. As depicted, the ring patch 104 is located above the top adhesive layer 114 and below the dielectric layer 112. The foam layer 116 separates the top adhesive layer 114 from the annular slot 110. Specifically, the foam layer 116 is located between the top adhesive layer 114 and the upper inner adhesive layer 118. The annular slot 110 is located within the inner metal layer 120. The conductive fence 102 spans the intermediate dielectric layer 122, the lower adhesive layer 124, and the bottom dielectric layer 126.

[0060] The disclosed example shows the feed lines 106 and 108 vertically positioned in the upper half of the conductive fence 102. The dashed line 202 shows the vertical middle of the conductive fence 102. It can be seen that the feed lines 106 and 108 are located in the upper half 204, rather than the lower half 206.

[0061] Figure 3 A top view of an antenna array 300 composed of multiple annular units 100a-d is shown according to some disclosed embodiments. This illustration shows that the feed lines 106a-d and 108a-d of various annular units 100a-d are rotated 90 degrees therein. In other words, the feed lines 106a and 108a are rotated 90 degrees from the positions of the feed lines 106b and 108b. This positioning suppresses the unwanted cross-polarization signal level in the far field.

[0062] In Figure 4 - 6BAn alternative design that does not use the conductive fence 102 is shown. Instead of the conductive fence, these alternative implementations use a collection of vias to form a circular fence.

[0063] Along these lines, Figure 4 A perspective view of an annular unit 400 with a circular via fence 402 according to some disclosed implementations is shown. The annular unit 400 includes a loop patch 404, two feed lines 406 and 408, an annular slot 410, a top dielectric layer 412, a top adhesive layer 414, a foam layer 416, an upper inner adhesive layer 418, an inner metal layer 420, an intermediate dielectric layer 422, and a bottom dielectric layer 422. These various components are positioned in the same manner as the annular unit 100 discussed previously. However, instead of the conductive fence 102, the annular unit 400 includes electrical vias 402a-n, which are positioned in a circular pattern around the annular slot 410 and together form a via fence with multiple openings 430 - 436 (although only four openings are labeled).

[0064] Similar to the annular unit 100, the horizontal top of the annular unit 400 includes a top dielectric layer 412, which supports the loop patch 404 below and also serves as an environmental shield against corrosion. The loop patch 404 includes cutout holes that lower the resonant frequency of the patch and allow for a smaller outer diameter, which is desirable for mutual coupling reduction and avoiding overemphasis on broadside antenna gain.

[0065] The bottom of the annular unit 400 includes two dielectric substrates, an intermediate dielectric layer 422 and a bottom dielectric layer 426, which together support the annular slot 410, the dual feed lines 406 and 408, and the via fence formed by the electrical vias 402a-n. The feed lines 406 and 408 excite orthogonal resonant modes in the annular slot 410, which in turn excite orthogonal resonant modes in the loop patch 404 above. The annular slot 410 and the loop patch 404 work together to provide a wider impedance bandwidth than either one alone can provide. Thus, the annular unit 400 is designed to operate as a hybrid radiator that works in both transmit and receive modes. Optionally, the annular unit 400 can operate in only transmit or only receive mode.

[0066] The loop patch 404 and the electrical vias 402a-n are metallic or otherwise conductive. Power is supplied to the annular unit 400 through the feed lines 406 and 408, causing the electrical vias 402a-n and the loop patch 404 to operate as radiating elements for generating a specific RF signal. In terms of shape, the via fence has a larger diameter than the annular slot 410. This allows the annular slot 410 to be positioned horizontally within the conductive fence 402.

[0067] The via fences created by the vias 402a-n also isolate the annular slots 410 from the power distribution network and reduce unwanted mutual coupling with other annular slots 410 in adjacent annular cells 400 that are part of an array antenna (e.g., PAA). The diameter and depth of the via fences are set such that the annular slots 410 resonate at or near the desired operating frequency band. In some implementations, the openings around the conductive via fences 402 allow the feed lines 406 and 408 to enter the interior without being electrically shorted.

[0068] The feed lines 406 and 408 are vertically positioned in the upper half of the vias 402a-n.

[0069] Figure 5A and 5B Perspective and top views of an annular cell 400 with a T-junction delay feed line 500 are shown, respectively, in accordance with some disclosed implementations. The T-junction delay feed line 500 includes two feed lines (a shorter feed line 502 and a longer L-shaped feed line 504) extending from a single input / output (I / O) line 506. The feed line 504 is longer than the feed line 502 and is used for circular polarization formation in the RF signals transmitted or received through the annular cell 400. These separate feed lines 504 and 506 are positioned at 90 degrees to each other. Although an annular cell 400 design with vias 402a-n is shown, the T-junction delay feed line 500 can be used in an annular cell 100 with a conductive fence 102.

[0070] The depicted T-junction delay feed line 500 provides right-handed circular polarization, which provides optimal polarization in the far field. Left-handed circular polarization can also be achieved by moving the longer L-shaped feed line 504 from the shown position to the other side of the V-junction.

[0071] The depicted T-junction delay feed line 500 can also be used in the annular cell 100 instead of the depicted annular cell 400. The annular cell 400 is shown only as Figure 5A - 5B an example of an annular cell with a T-junction delay feed line 500.

[0072] Figure 6A and 6BPerspective and top views of a loop unit 400 with a 90-degree hybrid coupler 600 according to some disclosed implementations are shown, respectively. The hybrid coupler 600 includes two feed lines 602 and 604 and an elliptical (or circular) path line 906. In some implementations, the feed lines 604 and 606 are positioned at 90 degrees to each other. The hybrid coupler 600 includes two terminal ends 608 and 610. The end 608 serves as an input or output for a voltage source, depending on whether the loop unit is transmitting or receiving an RF signal. The end 610 is connected to a via 612 that spans the bottom dielectric layer 426 and is electrically coupled to a resistor 614. In operation, such a hybrid coupler 600 provides improved circular polarization performance.

[0073] The depicted hybrid coupler 600 can also be used in a loop unit 100 instead of the depicted loop unit 400. The loop unit 400 is shown only as Figure 6A - 6B an example of a loop unit having a hybrid coupler 600.

[0074] Figure 7 A block diagram of an antenna system 700 for an antenna array 702 formed of loop units 100a-n disclosed in the present disclosure is shown. In this example, the antenna system 700 includes a power supply 704, a controller 706, and an antenna array 702. In this example, the antenna array 702 is a phased array antenna (“PAA”) including a plurality of loop units 102a-n, and the loop units 100a-n operate as transmitting and / or receiving modules. The loop units 100a-n include corresponding radiating elements that, combined, are capable of transmitting and / or receiving RF signals. For example, the loop units 100a-n can be configured to operate in the K-band frequency range (e.g., for the NATO K-band, approximately 20 GHz to 40 GHz, and for the IEEE K-band, approximately 18 GHz to 26.5 GHz).

[0075] The power supply 704 is a device, component, and / or module that supplies power to the controller 706 in the antenna system 700. The controller 706 is a device, component, and / or module that controls the operation of the antenna array 702. The controller 706 can be a processor, microprocessor, microcontroller, digital signal processor (“DSP”), or other type of device that can be programmed with hardware and / or software. The controller 706 controls the feed power supplied to the antenna array 702, including but not limited to calibrating the specific polarization, voltage, frequency, etc. of the feed. For clarity, only one line is shown between the controller 706 and the antenna array 702, but in reality, several electrical connections and power lines can connect the controller 706 to the antenna array 702.

[0076] In some implementations, the controller 706 supplies a specific feed to each of the loop elements 100a-n to generate a large number of RF signals that combine constructively or destructively to form a desired cumulative RF signal for transmission.

[0077] The RF signals emitted from each of the loop elements 100a-n in the array antenna 702 can be in-phase to constructively generate strong radiation, or out-of-phase to destructively generate a specific RF signal. The direction can be controlled by setting the phase shift between the signals sent to different loop elements 100a-n. The phase shift can be controlled by the controller 706 by placing a slight time delay between the signals sent to consecutive loop elements 100a-n in the array.

[0078] The antenna system 700 is described as communicating signals with each other, where signal communication refers to any type of communication and / or connection between circuits, components, modules, and / or devices that allows the circuits, components, modules, and / or devices to transfer and / or receive signals and / or information from another circuit, component, module, and / or device. The communication and / or connection can be along any signal path between circuits, components, modules, and / or devices that allows signals and / or information to be transferred from one to another and includes wireless or wired signal paths. The signal path can be physical, such as, for example, wires, electromagnetic waveguides, cables, attached and / or electromagnetically or mechanically coupled terminals, semiconducting or dielectric materials or devices, or other similar physical connections or couplings. Additionally, the signal path can be non-physical, such as free space (in the case of electromagnetic propagation) or an information path through digital components, where communication information is transferred from one circuit, component, module, and / or device to another in different digital formats without the need for a direct electromagnetic connection.

[0079] The antenna system 700 provides a means of transmitting (or receiving) RF signals to (or from) an airborne / mobile vehicle using a flexible electronically scanned antenna array beam without the need for mechanically moving parts. The antenna system 700 can be used in communication systems and other applications, including but not limited to radar / sensors, electronic warfare, military applications, mobile communications, etc. The antenna system 700 provides a high-performance, lightweight, low-profile, and cost-effective solution to meet challenging and evolving mission requirements.

[0080] Figure 8A perspective view of an aircraft having an antenna array 702 in accordance with various implementations of the present disclosure is shown. The aircraft 800 includes wings 802 and 804 attached to a fuselage 806. The aircraft 800 also includes engines 808 attached to wing 802 and engines 810 attached to wing 804. The fuselage 806 has a tail 812, which has a horizontal stabilizer 814, a horizontal stabilizer 816, and a vertical stabilizer 818 attached to the tail 812 of the fuselage 806. In some instances, the fuselage 806 has a composite skin 820.

[0081] In some instances, the previously discussed antenna system 700, which includes the disclosed loop elements 100 in the antenna array 702 or just the loop elements 100 alone, can be included on or within the aircraft 800. This is shown in Figure 8 dashed boxes. The antenna system 700 can be located inside or outside the aircraft 700.

[0082] The illustration of the aircraft 800 is not meant to imply physical or architectural limitations on the manner in which the illustrative configurations can be implemented. For example, while the aircraft 800 is a commercial aircraft, the aircraft 800 can be a military aircraft, a tiltrotor, a helicopter, an unmanned aerial vehicle, or any other suitable aircraft. Other vehicles are also possible, such as, for example but not limited to, cars, motorcycles, buses, boats, trains, etc.

[0083] Traditionally, ceramic chip carrier modules have been used to connect MMICs and AIPWBs. Such ceramic packages are relatively expensive and require costly labor to assemble. Moreover, the ceramic packages also use large and complex waveguide radiators, which add a lamination step and an additional layer to the AIPWB. The waveguide radiator requires an expensive and complex wide-angle impedance matching (WAIM) structure as an interface between the antenna array and free space. Unfortunately, this does not meet the cost-per-element targets of many line-of-sight communication customers.

[0084] The disclosed implementations and examples use low-complexity aperture-coupled patch radiators, low-cost commercial off-the-shelf surface-mounted MMICs, and low-cost multi-layer printed circuit board stacks. The low-complexity aperture-coupled patch radiators reduce the number of AIPWB layers by 50% and eliminate the WAIM components without sacrificing the antenna RF performance within + / -45-degree elevation scanning. Using low-cost commercial off-the-shelf MMICs with surface-mount integration reduces the cost per element of the antenna array by more than three times. The low-cost and reduced-complexity multi-layer printed circuit board stacks reduce the manufacturing cost and open the manufacturing path to a more diverse supplier base.

[0085] The disclosed loop units can transmit or receive RF signals to and from vehicles and aircraft using a flexible electronically scanned antenna array beam without mechanical moving parts. The antenna elements can be assembled into an antenna array that can be used in many applications such as, but not limited to, radar, sensors, or other applications. The antenna elements provide a high-performance, lightweight, low-profile, and ultra-low-cost solution to meet challenging and evolving mission requirements. In addition, the disclosed antenna elements are used to fabricate integrated and structurally integrated antennas, particularly in composite sandwich panels, due to the minimal use of vias and connections.

[0086] Figure 9 An AIPWB 900 for an antenna array 702 constructed from a number of loop units 100 in accordance with some disclosed implementations is shown. The AIPWB 900 includes nine vias (1 - 9) and various laminates (1, 2, 3), one of which is split into two separate sub-laminates (1A and 1B). Sub-laminate 1A includes layers 1 through 6 and uses a single drill step to provide control and power routing for the MMIC and RF interconnects on layer 1. Sub-laminate 1B covers layers 7 through 9 and is an RF asymmetric stripline that provides RF distribution across the antenna array 702 to a four (or other multiple) element beamforming MMIC and a feed structure to the aperture-coupled patch. Sub-laminate 1B has a drill step for an RF suppression via for isolation between the radiating structure and the RF distribution network. Laminate 2 can be implemented with a via from layer 1 to layer 9 that goes coast-to-coast as Figure 9 shown, or the electrical bonding of sub-laminates 1A and 1B can be accomplished by the Figure 10 Ormet paste process shown in. Laminate 3 connects the entire PCB structure to a foam spacer (such as foam layer 116) and an electrically insulating radiating patch on layer 10.

[0087] Figure 10Another AIPWB 1000 for an antenna array 702 constructed from a number of annular units 100 is shown in accordance with some disclosed implementations. The AIPWB 1000 is an aperture-coupled patch antenna array element that does not require vertical interconnections between radiation layers while still suppressing surface modes across the array and limiting mutual coupling. Compared to traditional line-of-sight (LOS) radiator designs, the AIPWB 1000 significantly reduces PCB complexity. The new aperture-coupled patch antenna array element supports a grating lobe free scan volume of + / - 45 degrees in elevation at all azimuth angles, without any scan blind spots. Using the AIPWB 1000, the antenna array 702 can be pushed to scan beyond 45 degrees; however, when operating in these scan regions, a steeper gain roll-off is expected.

[0088] In some implementations, the antenna array 702 uses a mature and fully functional commercial off-the-shelf half-duplex phased array chipset. In some instances, this chipset operates in the 8 - 16 GHz range. In some implementations, the chipset consists of two land grid array (LGA) MMICs: a four-element SiGe beamformer and an RF front-end IC consisting of a low-noise amplifier (LNA) and a single-pole double-throw (SPDT) switch.

[0089] Figure 11 A schematic diagram of a conventional sixteen-annular unit subarray antenna 1100 using one type of beamformer and front-end integrated circuit IC is shown in accordance with some implementations. A four-element beamformer is shown, but any beamformer can be used. The sixteen-annular unit subarray antenna 1100 has multiple antenna arrays 702, which have various annular units 100 / 400. A single four-wire serial peripheral interface (SPI) bus controls the 16-element subarray. In some implementations, these sixteen-annular unit subarray antennas 1100 are tiled together in a PCB panel to produce any 16n-element array, where n is an integer greater than 1. The sixteen-annular unit subarray antenna 1100 is MMIC-agnostic and can be easily changed to accommodate different commercial off-the-shelf MMIC chipsets.

[0090] Figure 13FIG. 0 shows a block diagram of a transmit / receive antenna array 1300 for LOS applications according to some disclosed implementations. In some implementations, the antenna array 1300 functions as a 256-element transmit / receive half-duplex antenna that operates in transmit or receive mode for half the time. Specifically, the antenna array 1300 includes a radiator block 1301, a transmit / receiver (TR) amplifier block 1302, a beamformer block 1304, and a distribution network block 1306. The radiator block 1301 includes a bilinear polarization patch antenna having two vertically placed antenna elements (a horizontal element 1308 and a vertical element 1310). The T / R amplifier block 1302 includes a power amplifier 1312, a front-end switch 1314, and a low-noise amplifier 1316. The beamformer block 1304 includes a driver amplifier 1318, seven-bit equivalent (or other) phase shifters 1320 and 1328, variable operational amplifiers (op amps) 1322 and 1326, a back-end switch 1324, and a low-noise amplifier 1328. The beamformer block 1304 can take the form of a dual, quad, or other multi-element beamformer. The distribution block 1306 includes a splitter 1330 and an RF port 1332 that is used to receive an RF input for transmission or to direct a received RF input that has been received.

[0091] The front-end switch 1314 and the back-end switch 1324 are controlled to selectively configure the antenna array 1300 in transmit or receive mode. The depicted example shows the antenna array 1300 in transmit mode. Optionally, both the front-end switch 1314 and the back-end switch 1324 can be switched to their other throws for receive mode.

[0092] When operating in transmit mode, the RF input 1332 is received by the splitter 1330 and split into 64 different ways. The 64-way split signal is passed through the back-end switch 1324 to the op amp 1322, the phase shifter 1320, and the power amplifier 1312, and then provided to the transmitter block 1301 through the front-end switch 1314, where the RF signal is transmitted.

[0093] When operating in receive mode, the RF input is received at the radiator block 1301. The received RF signal is passed through the front-end switch 1314 to the low-noise amplifiers 1316 and 1328, the phase shifter 1328, and the power amplifier 1326. The amplified RF signal is then provided through the back-end switch 1320, through the splitter 1330, and out the RF port 1332.

[0094] While the above disclosed embodiments provide many advantages, there is still an opportunity to improve the signal isolation between the antenna element or antenna feed structure and the radio frequency (RF) distribution element or distribution layer to avoid feedback problems. This may be especially true when the size (e.g., number of elements) and power of the antenna array increase. Accordingly, there is a need for a PPA that provides high isolation between the antenna feed structure and the RF distribution layer. High isolation can be achieved by embedding a symmetric stripline RF distribution layer within the asymmetric stripline of the antenna feed structure. Thus, the high isolation between the antenna feed structure and the RF distribution layer allows the antenna element to be used in higher gain and high power arrays.

[0095] Figure 14 A perspective view of a loop unit 1400 having a conductive fence 1402 (“loop fence” 1402) in accordance with some disclosed embodiments is shown. Similar to loop unit 100, loop unit 1400 includes a plurality of circuit board-based portions. In addition to conductive fence 1402, loop unit 1400 further includes a loop patch 1404, two feed lines 1406 and 1408, a loop slot 1410, a top dielectric layer 1412, a top adhesive layer 1414, a foam layer 1416, an upper inner adhesive layer 1418, an inner metal layer 1420, an intermediate dielectric layer 1422, and a bottom dielectric layer 1426. Different from loop unit 100, in at least some embodiments, loop unit 1400 includes a plurality of additional layers (e.g., “lower” dielectric and adhesive layers). For example, some embodiments may include a top lower adhesive 1442, a top lower dielectric layer 1444, a bottom lower adhesive layer 1446, and a bottom lower dielectric layer 1448. In some embodiments, foam layer 116 includes a foam layer that separates loop patch 1404 from loop slot 1410 and is thus referred to herein as “foam layer” 1416. Foam layer 1416 provides a spacer between loop slot 1410 and loop patch 1404 and is selected to have a low dielectric constant close to air to maximize the scan impedance bandwidth and suppress unwanted dielectric modes. In some instances, the various dielectric layers 1412, 1422, 1426, 1444, and 1448 are printed circuit boards (PCBs). Additionally, loop patch 1404 may be formed, etched, or adhered to foam layer 1416 via top adhesive layer 1414 to hold loop patch 1404 in place. As Figure 15 more particularly shown, an additional plurality of dielectric layers, including for example top lower dielectric layers 1444, 1548 and bottom lower dielectric layers 1444, 1548, provide high isolation between the antenna feed structure and the RF distribution layer.

[0096] Conductive fence 1402 includes one or more metal (or otherwise conductive) walls. Figure 17 The alternative design shown in replaces the metal wall with a circular via pattern.

[0097] More specifically, the horizontal top of the loop unit 1400 includes a top dielectric layer 1412 that supports the loop patch 1404 below and also serves as an environmental shield against corrosion. The loop patch 1404 includes cutout holes that lower the resonant frequency of the patch and allow for a smaller outer diameter, which is desirable for reduced mutual coupling and avoiding overemphasis on broadside antenna gain.

[0098] The bottom of the loop unit 1400 includes a multi-layer dielectric substrate that includes an intermediate dielectric layer 1422, a bottom dielectric layer 1425, a top sub-dielectric layer 1444, and a bottom sub-dielectric layer 1448 that jointly support the loop slot 1410, the dual feed lines 1406 and 1408, and the thin conductive fence 1402. A plurality of thin adhesive layers 1424, 1442, and 1446 are sandwiched between and bond together the plurality of dielectric layers. The feed lines 1406 and 1408 provide power supply that excites orthogonal resonant modes in the loop slot 1410, which in turn excites orthogonal resonance modes in the loop patch 1404 described above for RF signaling. When transmitting an RF signal, the feed lines supply power (voltage and current) to generate an electrical resonance in the loop 1410, and then generate the desired RF signal in the loop patch 1404. When receiving an RF signal, the feed lines receive the power supply induced in the loop 1410 by the loop patch 1404 that receives the RF signal.

[0099] The loop slot 1410 and the loop patch 1404 work together to provide a wider impedance bandwidth than either can provide alone. Thus, the loop unit 1400 is designed to operate as a hybrid radiator that works in both transmit and receive modes. Optionally, the loop unit 1400 can operate in only transmit or only receive mode.

[0100] The conductive fence 1402 separates the loop slot 1410 from the RF distribution network and reduces unwanted mutual coupling with other loop slots 1410 in adjacent loop units 1400 that are part of an array antenna (such as a PAA). The diameter and depth of the conductive fence 1402 are set such that the loop slot 1410 resonates at or near the desired operating frequency band. In some embodiments, the openings 1428 and 1430 around the conductive fence 1402 allow the feed lines 1406 and 1408 to enter the interior without being electrically shorted.

[0101] The loop patch 1404 and the conductive fence 1402 are metallic or otherwise conductive. Power is supplied to the loop unit 1400 through the feed lines 1406 and 1408, causing the conductive fence 1402 and the loop patch 1404 to operate as radiating elements for generating a specific RF signal. In terms of shape, the conductive fence 1402 has a larger diameter than the loop slot 1410. This allows the loop slot 1410 to be positioned horizontally within the conductive fence 1402. However, as Figure 15As can be seen, at least in some embodiments, the annular grooves 1410, 1510 are vertically positioned above the conductive fences 1402, 1502.

[0102] The dual feed lines 1406, 1506 and 1408, 1508 excite the orthogonal dual linear polarization required for some applications. For other applications, dual or single circular polarization may be required. Optionally, some embodiments include a feed structure using a T-junction divider / combiner (transmit / receive respectively) and a 90-degree delay line for right-handed circular polarization, as shown in Figure 18A and 18B . This integrated coplanar feed provides an economical way to achieve optimal polarization performance in the far field. Left-handed circular polarization can also be achieved by moving the L-shaped input line portion from its current position to the other side of the V-junction. For improved circular polarization performance during scanning, other embodiments use different feed structures using 90-degree hybrid couplers, as shown in Figure 19A and 19B .

[0103] The shown annular unit 1400 disclosed herein is shaped in a hexagonal pattern. However, other shapes are also fully contemplated. For example, the annular unit 1400 can be circular, rectangular, square, etc. Among these non-hexagonal shaped annular units 1400, some embodiments still use the circular ring patch 1404, the annular groove 1410, and the conductive fence 1402.

[0104] Figure 15 A cross-sectional side view of the annular unit 1500 (structurally identical to the annular unit 1400) with a conductive fence 1502 is shown according to some disclosed embodiments. As depicted, the annular unit includes a top and a bottom. The top includes a top dielectric layer 1512, a ring patch 1504, a top adhesive layer 1514, a foam layer 1516, and a lower adhesive layer 1518. The bottom includes an annular groove 1510, an upper inner metal layer 1520, an intermediate dielectric layer 1522, an upper adhesive layer 1524, a bottom dielectric layer 15.26, an upper lower adhesive layer 1542, a top lower dielectric layer 1544, and a bottom lower dielectric layer 1548. The ring patch 1504 is located above the top adhesive layer 1514 and below the dielectric layer 1512. The foam layer 1516 separates the top adhesive layer 1514 from the annular groove 1510. Specifically, the foam layer 1516 is located between the top adhesive layer 1514 and the upper inner adhesive layer 1518. The annular groove 1510 is located within the inner metal layer 1520. The conductive fence 1502 is located within the bottom of the annular unit 1500 and spans the intermediate dielectric layer 1522, the upper adhesive layer 1524, the bottom dielectric layer 15.26, the upper lower adhesive layer 1542, the top lower dielectric layer 1544, and the bottom lower dielectric layer 1548.

[0105] The bottom of the annular unit 1500 also includes an asymmetric stripline 1503 and a symmetric stripline 1505. The disclosed example shows that the feed lines 1506 and 1508 are located within the symmetric stripline 1503 of the conductive fence 1502, and the RF distribution line 1507 is located within the symmetric stripline 1505. In at least some embodiments, the symmetric stripline 1503 is embedded within the asymmetric stripline. Embedding the symmetric stripline 1505 including the RR distribution line 1507 within the symmetric stripline 103 provides high isolation for the antenna feed and distribution network. In at least some embodiments, embedding the symmetric stripline 1505 including the RF distribution line 1507 (i.e., the RF distribution layer or the RF distribution network) within the asymmetric stripline 1503 (i.e., the antenna feed structure) can increase the isolation by up to 30 dB without adding any additional physical thickness to the PCB. Due to the physical separation of the antenna feed and distribution network in the z direction, and adding a ground layer between the structures to prevent coupling, the isolation is improved. Therefore, the high isolation between the antenna feed structure and the RF distribution layer allows the antenna elements to be used in higher gain and high power arrays. For example, the following Figure 20 and 23 show unit cells 2000, 2300 including a symmetric stripline having an RF distribution line embedded within an asymmetric stripline.

[0106] Figure 16 A top view of an antenna array 1600 composed of a plurality of annular units 1600a-d according to some disclosed embodiments is shown. In at least some embodiments, the antenna array 1600 includes annular units 1600a-d, which are structurally the same as the annular units 1400 and 1500. The figure shows an example in which the feed lines 1600a-d and 1608a-d of various annular units are rotated 90 degrees. In other words, the feed lines 1606a and 1608a are rotated 90 degrees from the positions of the feed lines 1606b and 1608b. This positioning suppresses the unwanted cross-polarization signal level in the far field.

[0107] Figure 17 - 19B An alternative design without using the conductive fences 1402, 1502 is shown in. Instead of the conductive fences 1402, 1502 as shown in Figure 14 - 15 these alternative embodiments use a set of vias to form a circular fence.

[0108] Along these lines, Figure 17A perspective view of an annular unit 1700 with a circular through-hole fence 1702 according to some disclosed embodiments is shown. The annular unit 1700 includes a loop patch 1704, two feed lines 1706 and 1708, an annular slot 1710, a top dielectric layer 1712, a top adhesive layer 1714, a foam layer 1716, an upper inner adhesive layer 1718, an inner metal layer 1720, an intermediate dielectric layer 1722, a bottom dielectric layer 1726, a top sub-dielectric layer 1744, and a bottom sub-dielectric layer 1448. As with the annular units 1400, 1500, a plurality of thin adhesive layers (not shown here) are sandwiched between and bond together the plurality of dielectric layers. These different components are positioned in the same manner as previously discussed with respect to the annular units 1400, 1500. However, instead of the conductive fence 1402, the annular unit 1700 includes electrical through-holes 1702a-n, which are positioned in a circular pattern around the annular slot 1710 and together form a through-hole fence with a plurality of openings 1730 - 1736 (although only four openings are labeled).

[0109] Similar to the annular units 1400, 1500, the horizontal top of the annular unit 1700 includes a top dielectric layer 1712, which supports the loop patch 1704 below and also serves as an environmental shield against corrosion. The loop patch 1704 includes cutout holes that lower the resonant frequency of the patch and allow for a smaller outer diameter, which is desirable for mutual coupling reduction and avoiding overemphasis on broadside antenna gain.

[0110] The bottom of the annular unit 1700 includes a multi-layer dielectric substrate that includes an intermediate dielectric layer 1722, a bottom dielectric layer 1726, a top sub-dielectric layer 1744, and a bottom sub-dielectric layer 1748, which together support the annular slot 1710, the dual feed lines 1406 and 1408, and the through-hole fence formed by the conductive through-holes 1702a-n. A plurality of thin adhesive layers (not shown here) are sandwiched between and bond together the plurality of dielectric layers. The feed lines 1706 and 1708 provide power supply to excite the orthogonal resonant modes in the annular slot 1710, which in turn excite the orthogonal resonant modes in the above-mentioned loop patch 1704 for RF signaling. When transmitting an RF signal, the feed lines supply power (voltage and current) to generate an electrical resonance in the loop 1710, and then generate the desired RF signal in the loop patch 1704. When receiving an RF signal, the feed lines receive the power supply induced in the loop 1710 by the loop patch 1704 that receives the RF signal.

[0111] The loop patch 1704 and the vias 1702a-n are metallic or otherwise conductive. Power is supplied to the loop unit 1700 via feed lines 1706 and 1708 such that the vias 1702a-n and the loop patch 1704 operate as radiating elements for generating a specific RF signal. In terms of shape, the via fence has a larger diameter than the loop slot 1710. This allows the loop slot 1710 to be positioned horizontally within the conductive fence 1702.

[0112] The via fence created by the vias 1702a-n also separates the loop slot 1710 from the power distribution network and reduces unwanted mutual coupling with other loop slots 1710 in adjacent loop units 1700 that are part of an array antenna (e.g., a PAA). The diameter and depth of the via fence are set such that the loop slot 1710 resonates at or near the desired operating frequency band. In some implementations, the openings around the conductive via fence 1702 allow the feed lines 1706 and 1708 to enter internally without being electrically shorted. The feed lines 1706 and 1708 are vertically positioned in the upper half of the vias 1702a-n. Except for the features associated with the conductive fence 1702 described above, the loop unit 1700 is substantially the same in structure and operation as the loop units 1400, 1500.

[0113] Figure 18A and 18B Perspective and top views of loop units 1400, 1500 with a T-junction delay feed line 1801 are shown respectively in accordance with some disclosed implementations. The T-junction delay feed line 1801 includes two feed lines (a shorter feed line 1802 and a longer L-shaped feed line 1804) extending from a single input / output (I / O) line 1806. The feed line 1804 is longer than the feed line 1802 and is used for circular polarization formation in the RF signals transmitted or received through the loop unit 1800. These separate feed lines 1804 and 1806 are positioned at 90 degrees to each other. Although a loop unit 1800 with vias (such as vias 1702a-n) is shown, the T-junction delay feed line 1801 can be used in loop units 1400, 1500 having conductive fences 1402, 1502.

[0114] The depicted T-junction delay feed line 1801 provides right-handed circular polarization, which supplies optimal polarization in the far field. Left-handed circular polarization can also be achieved by moving the longer L-shaped feed line 1804 from the shown position to the other side of the V-junction.

[0115] The depicted T-junction delay feed line 1801 can also be used in loop units 1400, 1500 instead of the depicted loop unit 1700. The loop unit 1800 is shown only in Figure 18A - 18B as an example of a loop unit having a T-junction delay feed line 1801.

[0116] Figure 19A and 19B FIGS. 19B and Figure 19A respectively show a perspective view and a top view of a loop unit 1900 having a 90-degree hybrid coupler 1901 according to some disclosed embodiments. The hybrid coupler 1901 includes two feed lines 1902 and 1904 and an oval (or circular) path line 1906. In some embodiments, the feed lines 1906 are positioned at 90 degrees to each other. The hybrid coupler 1901 includes two terminal ends 1908 and 1910. The end 1908 serves as the input or output of a voltage source, depending on whether the loop unit is transmitting or receiving an RF signal. The end 1910 is connected to a via 1912 that spans the bottom dielectric layer 1926 and is electrically coupled to a resistor 1914. In operation, such a hybrid coupler 1901 provides improved circular polarization performance.

[0117] The depicted hybrid coupler 1900 can also be used in the loop unit 1800 instead of the depicted loop unit 1900. The loop unit 1900 is shown only as an example of a loop unit having a hybrid coupler 1901 in Figure 19A - 19B FIG. Figure 19A - 19B .

[0118] Figure 20 FIG. Figure 20 shows an example of an antenna array according to some disclosed embodiments. The antenna array 2000 depicts an example of a symmetric stripline 2005 as discussed above with respect to Figure 15 FIG. Figure 15 . In at least some embodiments, the symmetric stripline 2005 includes an embedded asymmetric stripline that has an RF power distribution line within the symmetric stripline.

[0119] In at least some embodiments, the disclosed loop units can be configured into an array to operate with an aircraft 800 in a manner similar to that of the loop units 100 disclosed above with respect to Figure 8 FIG. Figure 8 .

[0120] Figure 21 FIG. Figure 21 shows a block diagram of an example of an antenna system 2100 for an antenna array 2102 formed by the loop units 1600a-n disclosed in the present disclosure. In this example, the antenna system 2100 includes a power supply 1704, a controller 1706, and an antenna array 2102. In this example, the antenna array 2102 is a phased array antenna (“PAA”) including a plurality of loop units 1600a-n that operate as transmit and / or receive modules. The loop units 1600a-n include respective radiating elements that, in combination, are capable of transmitting and / or receiving RF signals. For example, the loop units 100a-n can be configured to operate in the K-band frequency range (e.g., for the NATO K-band, approximately 20 GHz to 40 GHz, and for the IEEE K-band, approximately 18 GHz to 26.5 GHz).

[0121] Power supply 2104 is a device, component, and / or module that supplies power to controller 2106 in antenna system 2100. Controller 2106 is a device, component, and / or module that controls the operation of antenna array 2102. Controller 2106 can be a processor, microprocessor, microcontroller, digital signal processor (“DSP”), or other type of device that can be programmed with hardware and / or software. Controller 2106 controls the feed power supplied to antenna array 2102, including but not limited to calibrating the specific polarization, voltage, frequency, etc. of the feed. For clarity, only one line is shown between controller 2106 and antenna array 2102, but in reality, several electrical connections and power lines can connect controller 2106 to antenna array 2102.

[0122] In some implementations, controller 2106 supplies a specific feed to each of the loop units 1600a-n to generate a large number of RF signals, which are combined constructively or destructively to form a desired cumulative RF signal for transmission.

[0123] The RF signals emitted from each of the loop units 1600a-n in array antenna 2102 can be in-phase to generate strong radiation constructively, or out-of-phase to generate a specific RF signal destructively. The direction can be controlled by setting the phase shift between the signals sent to different loop units 1600a-n. The phase shift can be controlled by controller 2106 by placing a slight time delay between the signals sent to consecutive loop units 1600a-n in the array.

[0124] Antenna system 2100 is described as communicating signals with each other, where signal communication refers to any type of communication and / or connection between circuits, components, modules, and / or devices that allows circuits, components, modules, and / or devices to transfer and / or receive signals and / or information from another circuit, component, module, and / or device. The communication and / or connection can be along any signal path between circuits, components, modules, and / or devices that allows signals and / or information to be transferred from one to another and includes wireless or wired signal paths. The signal path can be physical, such as, for example, wires, electromagnetic waveguides, cables, attached and / or electromagnetically or mechanically coupled terminals, semiconductive or dielectric materials or devices, or other similar physical connections or couplings. Additionally, the signal path can be non-physical, such as free space (in the case of electromagnetic propagation) or an information path through digital components, where communication information is transferred from one circuit, component, module, and / or device to another in different digital formats without the need for a direct electromagnetic connection.

[0125] The antenna system 2100 provides a means for transmitting (or receiving) RF signals to (or from) an airborne / mobile vehicle using a flexible electronically scanned antenna array beam without mechanical moving parts. The antenna system 2100 can be used in communication systems and other applications, including but not limited to radar / sensors, electronic warfare, military applications, mobile communications, etc. The antenna system 2100 provides a high-performance, lightweight, low-profile, and cost-effective solution to meet challenging and evolving mission requirements.

[0126] Figure 22 Shown is an AIPWB 2200 for an antenna array 2102 constructed from a number of annular units 1600a-n according to some disclosed implementations. The AIPWB 2200 includes nine vias (1-9) and various laminates (1, 2, 3), one of which is split into two separate sub-laminates (1A and 1B). Sub-laminate 1A includes layers 1 to 6 and provides control and power routing for the MMIC and RF interconnects on layer 1 using a single drilling step. Sub-laminate 1B covers layers 7 to 11 and is an RF asymmetric stripline that provides RF distribution across the antenna array 2102 to a four (or other multiple) element beamforming MMIC and a feed structure to the aperture-coupled patch. Sub-laminate 1B has one drilling step for RF suppression vias for isolation between the radiating structure and the RF distribution network. Laminate 2 can be implemented with vias from layer 1 to layer 11 from edge to edge as Figure 22 shown, or the electrical bonding of sub-laminates 1A and 1B can be accomplished by Figure 10 the Ormet paste process shown in. Laminate 3 connects the entire PCB structure to foam spacers (such as foam layers 1416, 1516) and an electrically insulating radiating patch on layer 12.

[0127] Figure 23 Shown is a partial view of an antenna array 2300 constructed from the annular units 1600a-n disclosed in the present disclosure. Depicted are elements from layers 8 to 10, which include a layer 8 distribution network 2302, a layer 9 GND 2304 removed around the antenna feed to maintain an asymmetric stripline with GND on layers 7 and 11, and a layer 10 antenna feed 2306.

[0128] In at least some implementations, according to some implementations, the disclosed annular units can use a beamformer and a front-end integrated circuit (IC) in a conventional sixteen-annular array sub-array antenna configuration, as disclosed above with respect to Figure 11 that.

[0129] Figure 24Illustrates a method of providing a unit cell antenna for a periodic antenna array according to at least some of the disclosed implementations. In at least some instances, method 2400 can be used to provide a unit cell (e.g., loop cells 1400, 1500) as discussed above with respect to Figure 14 - 23 Method 2400 includes, at 2410, providing a top (e.g., the top in Figure 15 ) to communicate radio frequency (RF) signals. In at least some instances, the top will include a dielectric layer (e.g., dielectric layers 1412, 1512) and a loop patch (e.g., loop patches 1404, 1504). The loop patch will be supported by the dielectric layer, and the loop patch will have a central cutout hole to reduce the resonant frequency of the loop patch. Method 2400 includes, at 2420, providing a bottom (e.g., the bottom in Figure 15 ) to generate a desired radio frequency (RF) signal. In at least some instances, the bottom will include a plurality of dielectric layers (e.g., dielectric layers 1422, 1426, 1448; 1522, 1526, 1548), a loop slot (e.g., loop slots 1410, 1510), a conductive fence (e.g., a loop fence or conductive fence 1402, 1502), and two feed lines (e.g., feed lines 1406, 1408; 1506, 1508). In at least some instances, the loop slot will be supported by one of the plurality of dielectric layers. The conductive fence will substantially surround the loop slot. The two feed lines will have a 90-degree phase difference. Method 2400 includes, at 2430, providing a foam layer (e.g., foam layers 1416, 1516) to be disposed between the top and the bottom. In at least some instances, the foam layer will separate the loop patch from the loop slot. The method 2400 and configuration outlined herein provide high isolation between the top and the bottom and allow the antenna element to be used in arrays with higher gain and higher power without creating adverse feedback problems.

[0130] Figure 25 Illustrates a method of manufacturing a unit cell antenna system for a periodic antenna array according to at least some of the disclosed implementations. In at least some instances, manufacturing method 2500 can be used to manufacture, fabricate, and / or assemble a unit cell antenna system (e.g., loop cells 1400, 1500) for a periodic antenna array (e.g., antenna array 1600) as discussed above with respect to Figure 14 - 23 As disclosed herein, the steps, actions, operations, procedures, and / or processes of manufacturing and / or assembling a unit cell antenna system will be substantially consistent with those known to a person of ordinary skill in the art of manufacturing, fabricating, and / or assembling. At 2510, manufacturing method 2500 includes forming a top (e.g., Figure 15at the top) with a communication radio frequency (RF) signal. In at least some instances, the top will be formed to include a dielectric layer (e.g., dielectric layers 1412, 1512) and a loop patch (e.g., loop patches 1404, 1504). The loop patch will be formed to be supported by the dielectric layer, and the loop patch will be formed to have a central cutout hole to reduce the resonant frequency of the loop patch. At 2520, manufacturing method 2500 includes forming a bottom (e.g., Figure 15 the bottom in) to generate a desired radio frequency (RF) signal. In at least some instances, the bottom will be formed to include multiple dielectric layers (e.g., dielectric layers 1422, 1426, 1448; 1522, 1526, 1548), an annular groove (e.g., annular grooves 1410, 1510), a conductive fence (e.g., an annular fence or conductive fences 1402, 1502), and two feed lines (e.g., feed lines 1406, 1408; 1506, 1508). In at least some instances, the annular groove will be formed to be supported by one of the multiple dielectric layers. The conductive fence will be formed to substantially surround the annular groove. The two feed lines will be formed to have a 90-degree phase difference. At 2530, manufacturing method 2500 includes forming a foam layer (e.g., foam layers 1416, 1516) disposed between the top and the bottom. In at least some instances, the foam layer is formed to separate the loop patch from the annular groove. The method 2500 and configuration outlined herein provide high isolation between the top and the bottom and allow the antenna element to be used in higher-gain and high-power arrays without adverse feedback problems.

[0131] Additional notes and examples:

[0132] Example 1 includes a unit cell antenna system for a periodic antenna array, the system including a top for communicating a radio frequency (RF) signal, the top including a dielectric layer and a loop patch, wherein the loop patch is supported by the dielectric layer and the loop patch has a central cutout hole to reduce the resonant frequency of the loop patch; a bottom for generating a desired radio frequency (RF) signal, the bottom including multiple dielectric layers; an annular groove supported by one of the multiple dielectric layers; a conductive fence substantially surrounding the annular groove; two feed lines, wherein the feed lines have a 90-degree phase difference; and a foam layer disposed between the top and the bottom, the foam layer separating the loop patch from the annular groove.

[0133] Example 2 includes the system of Example 1, wherein the bottom further includes an embedded symmetric strip line RF distribution layer within an asymmetric strip line of the bottom, and wherein the embedded symmetric strip line RF distribution layer will provide high signal isolation due to the physical separation of the top and the bottom.

[0134] Example 3 includes the system described in Example 1, wherein, when in the transmitting mode, the feeder line couples energy into the annular slot, and the annular slot generates a desired RF signal in the loop patch.

[0135] Example 4 includes the system described in Example 1, wherein, when in the receiving mode, the loop patch generates an electrical resonance in the annular slot, and the annular slot couples energy into the feeder line.

[0136] Example 5 includes the system described in Example 1, wherein the conductive fence is used to separate the annular slot from the RF power distribution network and reduce the unwanted mutual coupling with other annular slots in adjacent annular units that are part of an array antenna.

[0137] Example 6 includes the system described in Example 5, wherein the conductive fence includes one or more metal walls.

[0138] Example 7 includes the system described in Example 5, wherein the conductive fence includes a circular via hole pattern.

[0139] Example 8 includes the system described in Example 1, wherein the feeder line includes a T-junction delay for feeding the power.

[0140] Example 9 includes the system described in Example 1, wherein the feeder line includes a hybrid coupler for feeding the power.

[0141] Example 10 includes a method for providing a unit cell antenna for a periodic antenna array, the method including providing a top for communicating radio frequency (RF) signals, the top including a dielectric layer and a loop patch, wherein the loop patch is supported by the dielectric layer, and the loop patch has a central cutout hole to reduce the resonance frequency of the loop patch; providing a bottom for generating a desired radio frequency (RF) signal, the bottom including a plurality of dielectric layers; an annular slot supported by one of the plurality of dielectric layers; a conductive fence substantially surrounding the annular slot; two feeder lines, wherein the feeder lines have a 90-degree phase difference; and providing a foam layer disposed between the top and the bottom, the foam layer separating the loop patch from the annular slot.

[0142] Example 11 includes the method described in Example 10, wherein the bottom further includes an embedded symmetric strip line RF distribution layer in an asymmetric strip line of the bottom, and due to the physical separation between the top and the bottom, the embedded symmetric strip line RF distribution layer provides high signal isolation.

[0143] Example 12 includes the method described in Example 10, wherein, when in the transmitting mode, the feeder line couples energy into the annular slot, and the annular slot generates a desired RF signal in the loop patch.

[0144] Example 13 includes the method described in Example 10, wherein when in the receiving mode, the loop patch will generate an electrical resonance in the annular slot, and the annular slot will couple energy to the feeder line.

[0145] Example 14 includes the method described in Example 10, wherein the conductive fence is used to separate the annular slot from the RF distribution network and reduce the unwanted mutual coupling with other annular slots in adjacent annular units that are part of an array antenna.

[0146] Example 15 includes the method described in Example 14, wherein the conductive fence includes one or more metal walls.

[0147] Example 16 includes the method described in Example 14, wherein the conductive fence includes a circular pattern of electrical vias.

[0148] Example 17 includes the method described in Example 10, wherein the loop patch is located below the dielectric layer and above the foam layer.

[0149] Example 18 includes the method described in Example 10, wherein the feeder line includes a T-junction delay for feeding the power.

[0150] Example 19 includes a method of manufacturing a unit cell antenna system for a periodic antenna array, the method including forming a top for communicating radio frequency (RF) signals, the top including a dielectric layer and a loop patch, wherein the loop patch is supported by the dielectric layer and the loop patch has a central cutout hole to reduce the resonant frequency of the loop patch; forming a bottom for generating a desired radio frequency (RF) signal, the bottom including a plurality of dielectric layers; an annular slot supported by one of the plurality of dielectric layers; a conductive fence substantially surrounding the annular slot; two feeder lines, wherein the feeder lines are 90 degrees out of phase; and forming a foam layer disposed between the top and the bottom, the foam layer separating the loop patch from the annular slot.

[0151] Example 20 includes the method described in Example 19, wherein the bottom further includes an embedded symmetric stripline RF distribution layer within an asymmetric stripline of the bottom, and the embedded symmetric stripline RF distribution layer will provide high signal isolation due to the physical separation of the top and the bottom.

[0152] Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the above specific features and acts are disclosed as example forms of implementing the claims.

[0153] It will be understood that the above benefits and advantages may pertain to one embodiment or may pertain to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or have any or all of the stated benefits and advantages. It will further be understood that reference to "an" item means one or more of those items.

[0154] As used in this disclosure, the term "comprising" means including the features or acts that follow, without excluding the presence of one or more additional features or acts.

[0155] In some instances, the operations shown in the figures may be implemented as software instructions encoded on a computer-readable medium, in hardware programmed or designed to perform the operations, or both. For example, aspects of the present disclosure may be implemented as an ASIC, an SoC, or other circuitry including a plurality of interconnected conductive elements.

[0156] Unless otherwise stated, the order in which the operations in the examples of the present disclosure are executed or carried out is not essential. That is, unless otherwise stated, the operations may be executed in any order, and the examples of the present disclosure may include more or fewer operations than those disclosed herein. For example, it is contemplated that a particular operation may be executed or carried out before, concurrently with, or after another operation within the scope of aspects of the present disclosure.

[0157] When introducing elements of aspects of the present disclosure or examples thereof, the articles "a", "an", "the", and "said" are intended to mean that there is one or more of the elements. The terms "comprising", "including", and "having" are intended to be inclusive and mean that there may be other elements in addition to the listed elements. The term "exemplary" is intended to mean "an example". The phrase "one or more of the following: A, B, and C" means "at least one of A and / or at least one of B and / or at least one of C".

[0158] Aspects of the present disclosure have been described in detail. It is apparent that modifications and variations can be made without departing from the scope of the aspects of the present disclosure as defined in the appended claims. Since various changes can be made to the above structures, products, and methods without departing from the scope of the aspects of the present disclosure, all of the content included in the above description and shown in the drawings should be construed as illustrative and not restrictive.

[0159] It should be understood that the above description is illustrative and not restrictive. By way of illustration, the above embodiments (and / or aspects thereof) may be used in combination with each other. Additionally, many modifications may be made to adapt a particular situation or material to the teachings of the various embodiments of the present disclosure without departing from its scope. Although the dimensions and types of the materials described herein are intended to define the parameters of the various embodiments of the present disclosure, the embodiments are in no way restrictive and are exemplary embodiments. After reading the above description, many other embodiments will be apparent to those of ordinary skill in the art. Accordingly, the scope of the various embodiments of the present disclosure should be determined with reference to the appended claims and the full scope of equivalents to which such claims are entitled. In the appended claims, the terms "comprising" and "wherein" are used as the plain English equivalents of the respective terms "including" and "in which". Additionally, the limitations of the appended claims are not written in means-plus-function form and are not intended to be construed under 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase "means for" followed by a statement of function without further structure.

[0160] The written description uses examples to disclose the various embodiments of the present disclosure, including the best mode, and also enables any ordinary person skilled in the art to practice the various embodiments of the present disclosure, including manufacturing and using any device or system and performing any incorporated method. The patent scope of the various embodiments of the present disclosure is defined by the claims and includes other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

[0161] Although the present disclosure has been described with reference to various embodiments, various changes and modifications can be made without departing from the scope of the present disclosure.

Claims

1. A unit cell antenna system (1400, 1500) for a periodic antenna array (1600), the system comprising: A top portion, for communicating a radio frequency (RF) signal, the top portion comprising: Dielectric layers (1412, 1512), and a ring patch (1404, 1504), wherein the ring patch is supported by the dielectric layer, the ring patch having a central cutout hole to reduce a resonant frequency of the ring patch; A bottom portion, for generating a desired radio frequency (RF) signal, the bottom portion comprising: A plurality of dielectric layers (1422, 1426, 1444, 1448; 1522, 1526, 1544, 1548); an annular groove (1410, 1510) supported by one of the plurality of dielectric layers; a conductive fence (1402, 1502) substantially surrounding the annular groove; two feed lines (1406, 1408; 1506, 1508), wherein the feed lines are 90 degrees out of phase; and A foam layer (1416, 1516) is disposed between the top and bottom portions, the foam layer separating the ring patch from the annular groove.

2. The system of claim 1, wherein the bottom portion further comprises an embedded symmetrical stripline RF distribution layer (1507) within the asymmetrical stripline (1505) of the bottom portion, wherein the embedded symmetrical stripline RF distribution layer will provide high signal isolation due to the physical separation of the top and bottom portions.

3. The system according to claim 1, wherein: When in transmit mode, the feed lines (1406, 1408; 1506, 1508) couple energy into the annular slots (1410, 1510), wherein the annular slots generate a desired RF signal in the ring patch.

4. The system according to claim 1, wherein: When in receive mode, the ring patch (1404, 1504) will generate an electrical resonance in the annular slot, wherein the annular slot couples energy to the feed line.

5. The system of claim 1, wherein the conductive fence (1402, 1502) is used to isolate the annular slot (1410, 1510) from an RF power distribution network and reduce unwanted mutual coupling with other annular slots in adjacent annular units (1600a-d) that are part of an array antenna (1600).

6. The system of claim 5, wherein the conductive fence (1402, 1502) comprises one or more metal walls.

7. The system of claim 5, wherein the conductive fence (1402, 1502) comprises a circular electrical via pattern (1702a-n).

8. The system of claim 1, wherein the feed line (1802, 1804) comprises a T-junction delay (1801) for supplying feed power.

9. The system according to claim 1, wherein the feeder line (1902, 1904) comprises a hybrid coupler (1901) for supplying feed power.

10. A method (2400) of providing a unit cell antenna (1400, 1500) for a periodic antenna array (1600), the method comprising: providing (2410) a top portion to communicate a radio frequency (RF) signal, the top portion comprising: Dielectric layers (1412, 1512), and a ring patch (1404, 1504), wherein the ring patch is supported by the dielectric layer, the ring patch having a central cutout hole to reduce a resonant frequency of the ring patch; Providing (2420) a base portion to generate a desired radio frequency (RF) signal, the base portion comprising: A plurality of dielectric layers (1422, 1426, 1444, 1448; 1522, 1526, 1544, 1548); an annular groove (1410, 1510) supported by one of the plurality of dielectric layers; a conductive fence (1402, 1502) substantially surrounding the annular groove; two feed lines (1406, 1408; 1506, 1508), wherein the feed lines are 90 degrees out of phase; and A foam layer (1416, 1516) is provided (2430) disposed between the top and bottom portions, the foam layer separating the ring patch from the annular groove.

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