Patent Application
20240283134
The present disclosure relates to electronics, and more particularly, to an integrated additively manufactured modular aperture antenna and antenna array.
An aperture antenna is a type of antenna that emits electromagnetic (EM) waves through an aperture. The aperture is typically considered to include a portion of a surface of the antenna through which a majority of the EM waves are transmitted or received. Aperture antennas can be arranged in arrays to provide wideband and ultra-wideband (UWB) operations, such as in conjunction with radar and tracking systems, high data rate communication links, and multi-waveform, multi-function front end systems. The aperture antenna can be manufactured as a stand-alone component of a larger mechanical system, such as within an electronics package of a device.
Although the following detailed description will proceed with reference being made to illustrative examples, many alternatives, modifications, and variations thereof will be apparent in light of this disclosure.
In accordance with an example of the present disclosure, a device includes a frame and at least one printed circuit board attached to the frame. The frame includes an integrated aperture antenna array and an antenna feed in electrical communication with the at least one printed circuit board. The antenna feed is configured to receive a signal over a wide bandwidth. The integrated aperture antenna array further includes a first conductive dipole arm in planar alignment with a surface of the frame, and a second conductive dipole arm in planar alignment with the surface of the frame and adjacent to the first conductive dipole arm. A first feedline is in electrical communication with the first conductive dipole arm and the antenna feed. A second feedline is in electrical communication with the second conductive dipole arm and the surface of the frame. A shorting arm is in electrical communication with second conductive dipole arm and the frame.
As noted above, aperture antennas can be manufactured as stand-alone components of a larger mechanical system, such as within the electronics package of a device. Devices that utilize a spatial aperture antenna array can be assembled by attaching the antenna array sub-component to a frame of a larger electro-mechanical assembly. The frame provides both structural support and environmental protection to the electronic components. However, manufacturing the antenna array sub-component separately from other components, such as the frame and/or one or more sensors in the device, introduces additional complexity in the procurement, alignment, assembly, and operation of the antenna to the various system components.
By contrast, examples of the present disclosure include additively manufacturing an aperture antenna array directly into a device, such as an electronics package, frame, or housing, which improves the alignment of the antenna to a desired location within the device or system by removing the tolerances of the alignment features. Integrating the antenna with the device through additive manufacturing techniques reduces the number of separate parts and assembly steps. Furthermore, the disclosed techniques can utilize a superstrate of a circuit card assembly (CCA) frame as part of the antenna structure. The inclusion of a superstrate, which can take the form of a printed circuit board (PCB), aids in the antennas match by dielectrically loading the aperture. Directly integrating the aperture antenna array into the device can be achieved using two distinct technologies: Additive Manufacturing Modular Array (AMMA) Tightly Coupled Dipole Arrays (TCDA), and high resolution, metal additive manufacturing (e.g., less than or equal to one-third of the smallest structural feature and having an Ra less than or equal to 125 μin).
Referring to
Each unit cell 202 includes an antenna element 204, a ground plane 208 on a surface of the frame cap 108 or other portion of the frame 104, and at least one antenna feed 210 passing through the frame cap 108 or other portion of the frame 104. In some examples, an opening in the frame 104 through which the at least one antenna feed 210 passes through can be hermetically sealed to broaden the environmental applications of the device 100. The at least one antenna feed 210 is configured to receive a signal over a wide bandwidth. Each unit cell 202 further includes a shorting arm 212 for common mode rejection. The shorting arm 212 is electrically conductive and further provides structural support for the unit cell 202.
In some examples, the frame cap 108 includes one or more threaded holes 214 to preload the assembly. In some examples, the underside of the frame cap 108 incorporates soldering features 216 for soldering the at least one antenna feed 210 to the PCB 106. The spacing between the soldering features 216 can be varied to allow for surface-mount technology (SMT) components to reside on the array side of the mating PCB 106.
In some examples, the PCB 106 can be a dual sided board. For example, surface mounted technology (SMT) components that are smaller than the pitch (spacing) of the antenna feeds 210 of the aperture antenna array 102 can be placed on the same side of the board as the antenna feeds 210 by printing in recesses in the bottom of the frame cap 108, although it will be understood that the components that are larger than the pitch can also be placed on the same side of the board as the antenna feeds using other mounting techniques. This increases the potential SMT component count on components near or between the antenna feeds 210. In some examples, additive manufacturing can be used to route the antenna feed 210 through the ground plane (e.g., frame cap 108) to increase space for integrated components and or surface-mounted technology on the array side of the PCB 106. Some examples utilize additively manufactured structures as heat sinks for the integrated circuits on the PCB 106.
By way of further explanation,
respectively. An individual dipole antenna, such as dipole antenna 302a, radiates or receives a signal at a frequency f1. The dipole antennas 302a, 302b, 302c can be located or arrayed adjacent to each other to radiate or receive signals at frequencies f2, f3, etc., such as shown in
Antennas can be balanced or unbalanced and be of single polarization or dual polarization. Some existing TCDAs have wideband, single-ended (unbalanced) feeds. A single-ended feed antenna is considered unbalanced because the feed signal is not symmetrical about the point at which the feed meets the conductive element(s) of the antenna that radiate or absorb EM power. For example, in a dipole arrangement, one dipole arm is energized by the signal while the other dipole arm is shorted to a ground potential. By contrast, a balanced feed antenna has complementary signals 408 in the adjacent conductive elements, such as shown in
However, balanced and unbalanced antennas can suffer from distortions caused by common mode noise, power supply noise, or electromagnetic interference, each of which affects antenna performance. For example, a signal radiating from one or more of the dipole antennas 302a, 302b can excite a common mode resonance upon the balanced feed of the adjacent dipole antenna(s) 302a, 302b when scanning in the ground plane 404 over a wide or ultra-wideband frequency range. The common mode resonance radiating from the antenna can interfere with and alter the phase of the signal on the feed line (also referred to as signal coupling), creating an unbalanced current that degrades the signal strength and reduces antenna efficiency. Thus, antenna performance depends on various interdependent design features.
For instance, TCDAs create a so-called current sheet array (CSA) having a low-profile (e.g., ˜λHigh/2) by using many dipole ports in concert to approximate a flat current distribution across the array. Some CSAs achieve 4:1 bandwidth ratio by introducing capacitive coupling between antenna elements to counter the effect of ground pane inductance. The bandwidth of CSAs can be increased by introducing wideband balanced feeds integrated on a printed circuit board (PCB). Such designs employ baluns, which are devices that interface between unbalanced and balanced signals and are optimized among the various dipole elements. However, baluns are intrinsically lossy and can adversely affect isolation performance over the bandwidth of the antenna. Furthermore, single-ended feeds are not well suited for the close integration needed for DPAs. For example, some integrated transceivers can be differential to accompany the balanced transmission lines on the RF side of integrated transceiver chips. A full differential radio can have common mode currents at the aperture and in between the ports that feed the aperture. As noted above, these common mode currents can greatly reduce the impedance bandwidth.
TCDAs provide certain benefits in certain applications. However, there is typically a trade-off in features between different TCDA designs. For example, TCDAs have interdependent features that must be tuned for application-specific requirements. Thus, while one particular TCDA design may be highly suited for one application—for example, an expanded or extended bandwidth of the aperture—such a design may reduce, for example, platform scalability or compatibility of the TCDA with other DPA chains. Likewise, another TCDA design may be scalable and readily compatible with other DPA chains but may suffer from narrower bandwidth at the aperture.
In some examples, TCDAs include dipole antennas, which are inherently differential antennas with opposing phase signals. Wide bandwidth TCDAs enable the antenna to perform several functions (e.g., transmit and receive several signals across a wide range of frequencies, e.g., >500 MHz) at a single aperture. To achieve these functions efficiently, the antenna should be designed to reduce losses incurred by common mode resonances when the antenna is driven at the power levels associated with those functions. As noted above, a balun can be used to mitigate common mode resonance (such as in a sheet array); however, a balun changes the signal from balanced to single-ended (e.g., non-linear) and thus affects the ability of the antenna to perform as efficiently across a wide bandwidth.
Thus, there is a need for a TCDA antenna that is easily scalable and has a wide or ultra-wide bandwidth without incurring increased losses. Ultra-wideband operation is typically considered to include antenna arrays having a bandwidth ratio of 6:1 or greater, also referred to herein as a technology for transmitting information across a wide bandwidth. Examples of the present disclosure provide a TCDA that does not use a balun and/or a single-ended feed and permits differential (two balanced or complementary) signals to be fed into the antenna.
The unit cell 502 includes an antenna element 504, a ground plane 508, and at least one antenna feed 510. In some examples, the surface of the frame cap 108 or other portion of the frame 104 of
The unit cell 502 further includes a shorting arm 514 in electrical communication with the ground plane 508 and the first conductive dipole arm 504a (as shown in
In general, the modular antenna 500, including one or more unit cells 502 or portions thereof, is printed or otherwise fabricated using additive manufacturing techniques. It will be understood that any number of the unit cells 502 can be fabricated in the disclosed manner, for example, as component arrays (i.e., a single unit cell 502), blocks of sub-arrays (i.e., multiple adjacent unit cells 502), or complete arrays of the unit cells 502.
In operation, a signal, such as an analog RF signal, can propagate between the first conductive dipole arm 504a and the antenna feed 510 via the first feedline 504c. The signal can further propagate between the second conductive dipole arm 504b and the antenna feed 510 via the second feedline 504d.
In some examples, the unit cell 502, or an array of unit cells 502, is covered by a superstrate 116 or another overlay material, such as shown in
The modular antenna 500 and certain other structural or sacrificial components are constructed or fabricated by additively depositing or printing material to form the various structures of the antenna, such that the product is formed from a single piece of continuous material, also referred to as an integral element 520. The integral element 520 includes, for example, the antenna element 504 and the shorting arm 514. In some examples, the material is at least partially electrically conductive (e.g., it is all metal or at least partially metal). In some other examples, the material is at least partially non-conductive and at least partially plated with another conductive material (e.g., a metal plating). In some other examples, the material is dielectrically controlled.
Referring to
The unit cell 602 further includes a conductive wall (“H-wall”) 614 electrically coupled with the ground plane 608. The H-wall 614 has an end 614a adjacent to, and physically separate from, the second conductive dipole arm 604b of the antenna element 604. An axial length/of the H-wall 614 is orthogonal to the ground plane 608. In other words, the H-wall 614 extends orthogonally from the ground plane 608 toward the second conductive dipole arm 604b of the antenna element 604. The H-wall 614 does not physically contact the antenna element 604. Rather, the H-wall 614 disrupts the common mode resonances (e.g., the coupled signal between adjacent unit cells 602) that would otherwise cause feed line radiation/coupling and reduce antenna efficiency. The H-wall 614 electrically couples the ground plane to the dipole arm(s). As a result, the H-wall 614 enables efficient radiation from the first and second conductive dipole arms 604a, 604b without added losses such that a bandwidth ratio of the antenna aperture can reach or exceed 10:1 (e.g., between approximately 2-20 GHz) or greater for single-ended operation while using a single-ended feed and without a balun or other components for mitigating the common mode resonances.
In operation, a signal, such as an analog RF signal, can propagate to the first conductive dipole arm 304a from the single-ended antenna feed 610 via the first feedline 604c. The second conductive dipole arm 604b is grounded to the ground plane 608.
The following examples pertain to further examples, from which numerous permutations and configurations will be apparent.
Example 1 provides a device including a frame including a ground plane; and at least one printed circuit board attached to the frame, wherein the at least one printed circuit board includes an integrated aperture antenna array comprising an antenna feed in electrical communication with the at least one printed circuit board, the antenna feed configured to receive a signal over a wide bandwidth; a first conductive dipole arm in planar alignment with a surface of the frame; a second conductive dipole arm in planar alignment with the surface of the frame and adjacent to the first conductive dipole arm; a first feedline in electrical communication with the first conductive dipole arm and the antenna feed; a second feedline in electrical communication with the second conductive dipole arm and the surface of the frame; and at least one of a shorting arm and a conductive wall (“H-wall”), the shorting arm in electrical communication with second conductive dipole arm and the frame, the conductive wall (“H-wall”) in electrical communication with the ground plane and having an end adjacent to, and physically separate from, the second conductive dipole arm, an axial length of the H-wall being orthogonal to the ground plane.
Example 2 includes the subject matter of Example 1, further including one or more frame couplers and one or more assembly keys configured to attach the frame, the frame couplers, and the at least one printed circuit board together via one or more threaded holes in the frame.
Example 3 includes the subject matter of any one of Examples 1 and 2, wherein the frame comprises one or more soldering features for soldering the first feedline and the second feedline to the at least one printed circuit board.
Example 4 includes the subject matter of any one of Examples 1-3, wherein the at least one of the shorting arm and the H-wall is a structural support element between the ground plane and the second conductive dipole arm.
Example 5 includes the subject matter of any one of Examples 1-4, wherein the at least one of the shorting arm and the H-wall is electrically conductive.
Example 6 includes the subject matter of any one of Examples 1-5, further including an integral element additively manufactured into a single continuous piece of material, the integral element including the first conductive dipole arm, the second conductive dipole arm, the first feedline, the second feedline, and the at least one of the shorting arm and the H-wall.
Example 7 includes the subject matter of Example 6, wherein the integral element includes an electrically conductive material.
Example 8 includes the subject matter of Example 6, wherein the integral element includes a dielectrically controlled material.
Example 9 includes the subject matter of any one of Examples 1-8, wherein the frame includes at least one opening through which the antenna feed passes.
Example 10 includes the subject matter of Example 9, wherein the at least one opening of the frame is hermetically sealed.
Example 11 provides a device assembly method including constructing a frame including a ground plane, and at least one printed circuit board attached to the frame, additively manufacturing an integral element as a single continuous piece of material, the integral element including an antenna feed in electrical communication with the at least one printed circuit board, the antenna feed configured to receive a signal over a wide bandwidth; a first conductive dipole arm in planar alignment with a surface of the frame; a second conductive dipole arm in planar alignment with the surface of the frame and adjacent to the first conductive dipole arm; a first feedline in electrical communication with the first conductive dipole arm and the antenna feed; a second feedline in electrical communication with the second conductive dipole arm and the surface of the frame; and at least one of a shorting arm and a conductive wall (“H-wall”), the shorting arm in electrical communication with second conductive dipole arm and the frame, the conductive wall (“H-wall”) in electrical communication with the ground plane and having an end adjacent to, and physically separate from, the second conductive dipole arm, an axial length of the H-wall being orthogonal to the ground plane.
Example 12 includes the subject matter of Example 11, further including constructing one or more frame couplers and one or more assembly keys configured to attach the frame, the frame couplers, and the at least one printed circuit board together via one or more threaded holes in the frame.
Example 13 includes the subject matter of any one of Examples 11 and 12, further including constructing one or more soldering features on the frame for soldering the first feedline and the second feedline to the at least one printed circuit board.
Example 14 includes the subject matter of any one of Examples 11-13, wherein the at least one of the shorting arm and the H-wall is a structural support element between the ground plane and the second conductive dipole arm.
Example 15 includes the subject matter of any one of Examples 11-14, wherein the at least one of the shorting arm and the H-wall is electrically conductive.
Example 16 includes the subject matter of any one of Examples 11-15, wherein the integral element includes an electrically conductive material.
Example 17 includes the subject matter of any one of Examples 11-16, wherein the integral element includes a dielectrically controlled material.
Example 18 includes the subject matter of any one of Examples 11-17, wherein the frame includes at least one opening through which the antenna feed passes.
Example 19 includes the subject matter of Example 18, further including hermetically sealing the at least one opening of the frame.
Example 20 includes the subject matter of any one of Examples 11-19, further including constructing a superstrate over the integral element.
Example 21 includes the subject matter of any one of Examples 11-20, further including attaching or printing a surface mounted technology (SMT) component in a recess of the frame.
Example 22 includes the subject matter of any one of Examples 11-21, further including additively manufacturing a plurality of the integral elements adjacent to each other.
Numerous specific details have been set forth herein to provide a thorough understanding of the examples. It will be understood, however, that other examples may be practiced without these specific details, or otherwise with a different set of details. It will be further appreciated that the specific structural and functional details disclosed herein are representative of examples and are not necessarily intended to limit the scope of the present disclosure. In addition, 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 herein. Rather, the specific features and acts described herein are disclosed as example forms of implementing the claims. Furthermore, examples described herein may include other elements and components not specifically described, such as electrical connections, signal transmitters and receivers, processors, or other suitable components for operation of the modular antenna.
The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described (or portions thereof), and it is recognized that various modifications are possible within the scope of the claims. Accordingly, the claims are intended to cover all such equivalents. Various features, aspects, and examples have been described herein. The features, aspects, and examples are susceptible to combination with one another as well as to variation and modification, as will be appreciated in light of this disclosure. The present disclosure should, therefore, be considered to encompass such combinations, variations, and modifications. It is intended that the scope of the present disclosure be limited not by this detailed description, but rather by the claims appended hereto. Future filed applications claiming priority to this application may claim the disclosed subject matter in a different manner and may generally include any set of one or more elements as variously disclosed or otherwise demonstrated herein.
