Multifunctional Expandable Antenna Array

Abstract

The modular radio frequency (RF) device includes N base units, each including a differentially segmented array (DSA) tile having a support substrate and a two-dimensional (2D) array of conductive tapered protrusions disposed on the support substrate. Neighboring pairs of the conductive tapered protrusions form RF pixels. The N DSA tiles are arranged to form RF apertures. The N base units are programmed to switch the RF apertures between a first operating mode and a second operating mode. In the first operating mode, the N base units are operated as at least two independent subsets, each subset operating as an RF transmitter or receiver independently of the other subsets. In the second operating mode, all N base units are coherently combined as a single phased array RF transmitter or receiver.

Description

[Technical Field]

[0001] This application claims the benefit of Provisional Application No. 63 / 394,462, filed August 2, 2022, which is incorporated herein by reference in its entirety.

[0002] The following relates to radio frequency (RF) aperture technology fields, gigahertz (GHz) RF technology fields, wideband RF technology fields, wideband GHz RF technology fields, and the like. Summary of the Invention [Means for solving the problem]

[0003] According to some non-limiting illustrative embodiments disclosed herein, a base unit includes a differentially segmented aperture (DSA) tile including a support substrate and a two-dimensional (2D) array of conductive tapered protrusions disposed on the support substrate, with the conductive tapered protrusions tapering in a direction extending away from the support substrate, wherein adjacent pairs of the conductive tapered protrusions form RF pixels, and at least one RF unit (RFU) having an RF connection with the DSA tile for transmitting and / or receiving RF signals via the RF pixels of the DSA tile. The at least one RFU of the base unit is programmed to operate the base unit in a plurality of different RF transmission and / or reception modes, including at least one independent mode in which the base unit operates as an RF transmitter or receiver independently from any other base unit, and at least one cooperative mode in which the base unit is coherently combined with at least one other base unit as a single phased-array RF transmitter or receiver.

[0004] According to certain non-limiting illustrative embodiments disclosed herein, a modular RF device includes N base units as described in the immediately preceding paragraph, where N is an integer greater than or equal to 2. The N DSA tiles of the N base units are arranged to form an RF aperture.

[0005] According to some non-limiting illustrative embodiments disclosed herein, a modular RF transmission and / or reception method is disclosed. N base units are provided, where N is an integer greater than or equal to 2. Each base unit includes a DSA tile including a support substrate and a 2D array of conductive tapered protrusions disposed on the support substrate, with the conductive tapered protrusions tapering in a direction extending away from the support substrate. Neighboring pairs of the conductive tapered protrusions form RF pixels. The N DSA tiles of the N base units are arranged to form an RF aperture. The RF aperture is switchable between a first operating mode and a second operating mode. In the first operating mode, the N base units are operated as at least two independent subsets, each subset operating as an RF transmitter or receiver independently of the other subsets. In the second operating mode, all N base units are coherently combined as a single phased-array RF transmitter or receiver.

[0006] In some embodiments of the method of the immediately preceding paragraph, each base unit of the N base units further includes at least one RFU having an RF connection with the DSA tiles of the base unit, and the RFU of the base unit is programmed to switch the RF aperture between the first and second operating modes. In some embodiments of the method of the immediately preceding paragraph, the N DSA tiles of the N base units are rearranged to change the shape of the RF aperture.

[0007] According to some non-limiting illustrative embodiments disclosed herein, a modular RF device includes N base units, where N is an integer greater than or equal to 2. Each base unit includes a DSA tile including a support substrate and a 2D array of conductive tapered protrusions disposed on the support substrate, with the conductive tapered protrusions tapering in a direction extending away from the support substrate. Neighboring pairs of the conductive tapered protrusions form RF pixels. The N DSA tiles of the N base units are arranged to form an RF aperture. The N base units are programmed to switch the RF aperture between a first operating mode and a second operating mode. In the first operating mode, the N base units are operated as at least two independent subsets, each subset operating as an RF transmitter or receiver independently of the other subsets. In the second operating mode, all N base units are coherently combined as a single phased-array RF transmitter or receiver. [Brief explanation of the drawings]

[0008] Any quantitative dimensions shown in the drawings are to be understood as non-limiting illustrative examples. Unless otherwise indicated, the drawings are not to scale, and if any aspect of a drawing is indicated as to scale, the scale shown is to be understood as a non-limiting illustrative example.

[0009] [Figure 1] FIG. 1 diagrammatically illustrates a base unit including a differential sectioned aperture (DSA) tile and at least one RF unit (RFU, illustratively two RFUs) having an RF connection with the DSA tile for transmitting and / or receiving RF signals via RF pixels of the DSA tile.

[0010] [Figure 2] FIG. 2 illustrates, in a schematic side cross-sectional view, one RF pixel of a DSA tile of the base unit of FIG.

[0011] [Figure 3] FIG. 3 diagrammatically illustrates (A) a base unit and (B) a modular RF device comprising N base units (illustratively six base units) arranged to form an RF aperture (illustratively a 2×3 tile aperture). DETAILED DESCRIPTION OF THE INVENTION

[0012] Detailed Description To transition RF communication systems to higher throughput and wider range for military, telecommunications, and other applications, the systems need to transmit more power. Throughput is a function of signal-to-noise ratio (SNR) and instantaneous bandwidth. As bandwidth increases, noise also increases. The way to increase the signal over this noise is power. Range is directly proportional to the square of the power. There are two ways to increase radiated power: the first is to generate a larger electric field through higher amplification at the expense of increased power, while the second is to increase the gain of the antenna to focus the electric field more narrowly. Embodiments disclosed herein provide a solution using a base unit with a tileable aperture array to create a scalable solution to the challenges of dynamically changing environments where, as a non-limiting illustrative example, the number of frequencies and signals, range, and throughput need to interact in a way that at one moment many signals in different bands interact and at other moments a single signal in one band over long distances needs to interact. The embodiments disclosed herein improve upon existing designs by optimizing for either many signals and many frequencies, or a smaller number of signals and frequencies for greater range / throughput. Each tile is a differentially segmented array (DSA) tile, a standalone digital / air interface (DAI) that may optionally have built-in filtering, amplification, and digitization. These DSA tiles can be used independently or collaboratively through synchronizing the phase of the DSA tiles to create much larger arrays. Such modularity gives users the ability to allocate their RF assets based on need and dynamically switch between operating on multiple bands with multiple signals at lower power and low directivity, and then quickly switching to high-power, highly directivity operation as desired. Each DSA tile is capable of operating over a wide bandwidth, providing bandwidth in the GHz or tens of GHz.By operating DSA tiles independently, a wide range of spectrum can be accessed. By operating DSA tiles cooperatively as smaller arrays or subarrays, large focused power can be delivered. If an RFU has four channels, it is feasible for the DSA tiles to operate simultaneously in four frequency bands. If an RFU has eight channels, eight bands are potentially accessible. In an example with four base units, each with a single RFU with four channels, operation can occur across 16 bands simultaneously, then progress to eight, four, two, or one band, increasing power and decreasing beamwidth each time. These are merely non-limiting illustrative operational examples. A channel includes a complete RF signal chain. At least one RFU should support at least two RF channels to enable coherent combining of DSA tiles. Each RF channel connects to one or more RF pixels. A minimum system would have four pixels connected to two channels. As a non-limiting illustrative example, each DSA tile may have 32 pixels, 16 channels, 1 RFU, or some other similar cascade.

[0013] In one non-limiting illustrative embodiment, each DSA tile is 10 inches by 10 inches in area with a thickness of approximately 4-6 inches and can be manufactured at low cost. This approach allows users to keep a small number of part numbers (e.g., interchangeable DSA tiles) in inventory and build modular RF devices of desired size and geometry by combining a select number of DSA tiles.

[0014] The disclosed approach, employing configurable and tileable DSA tiles, has numerous advantages over existing approaches such as omnidirectional antennas, directional passive antennas, or single-function phased arrays. Omnidirectional antennas provide near-full hemispherical coverage, but require extreme amounts of power to increase throughput or range—in some use cases, approximately 1 kW of RF power to supply the communications system, which would draw approximately 10 kW of power to generate. Directional passive antennas can improve antenna gain and significantly reduce its power, but involve physical pointing through either moving the platform on which the antenna is mounted (e.g., truck, plane, boat, unmanned aerial vehicle, or equivalent) or gimbaling the antenna. Moving the platform presents challenging operations, especially as gain becomes higher and, therefore, the antenna becomes more directional (narrower field of view). Gimbaling the antenna, while feasible, limits platform dynamics while occupying a large footprint and increasing signature. Phased array solutions are undesirably platform and function specific, increasing overall cost and reducing functional flexibility.

[0015] The modular RF device disclosed herein, built using DSA tiles, can be tiled to larger sizes as needed, providing high power (>70 dBm) and narrow beamwidths (above 2.4 GHz, 10° x 10° scanning volume), enabling an RF system that can convert its operating mode from a flat panel array to provide multiple signals of interest within a wide bandwidth (e.g., starting at 40 MHz in some non-limiting illustrative embodiments). Technical challenges such as signal loss, weight, size, and protrusion from the exterior to the interior are solved by the disclosed modular approach. Heat is generated external to the platform, eliminating the need to transfer heat from the interior to the exterior. The disclosed modular RF device provides a versatile steerable array composed of DSA tiles. These DSA tiles can be used independently or in conjunction with each other. A small number of tiles can be purchased and used initially, and then the modular RF device can be expanded in size and power by adding more DSA tiles. To interoperate with existing systems, RF data to and from the DSA tiles is, in some embodiments, streamed in digital I / Q format, eliminating cable losses and reducing protrusion size and weight. In some embodiments, each DSA tile uses an efficient, low-power amplifier, expected to achieve a ten-fold reduction in power requirements.

[0016] Below, several illustrative embodiments of suitable base units and modular RF devices constructed therefrom are described.

[0017] 1 , the base unit 8 includes a differentially partitioned array (DSA) tile 10 and at least one RF unit (RFU) 12 having an RF connection with the DSA tile 10. The RFU 12 may be an RF integrated circuit (RFIC) or an RF system-on-module (RFSOM), i.e., a board-level RF circuit that integrates RF system functionality onto a single board or module. An illustrative example includes two RFUs 12. RFU 12 may comprise, by way of non-limiting illustrative example only, an FPGA device such as a Xilinx FPGA available from Xilinx, Inc. (a subsidiary of Advanced Micro Devices (AMD) of Santa Clara, Calif., USA), other types of field programmable gate arrays (FPGAs) capable of operating at RF frequencies, an RF application-specific integrated circuit (ASIC) device, a three-dimensional (3D) RFIC (e.g., comprised of two or more stacked RFICs), or an RFSOM comprising at least one RF digital signal processing (DSP) IC, at least one random access memory (RAM) IC, and / or suitable integrated circuit (IC) components such as those mounted on a single printed circuit board (PCB).

[0018] With continued reference to Figure 1 and further reference to Figure 2, DSA tile 10 includes a support substrate 20 and a two-dimensional (2D) array of conductive tapered protrusions 22 disposed on the support substrate, as seen in the front view of DSA tile 10 shown in Figure 1. As seen in Figure 2, conductive tapered protrusions 22 extend in a direction d away from support substrate 20. TThe DSA tile 10 is tapered at a wavelength of 1000 nm, with adjacent pairs of conductive tapered protrusions 22 forming RF pixels (FIG. 2 diagrammatically illustrates one RF pixel using a schematic side cross-sectional view). Some DSA designs that may be suitable for use for the substrate 20 and conductive protrusions 22 of the DSA tile 10 are described as non-limiting illustrative examples in U.S. Publication No. 2020 / 0343929 A1, published October 29, 2020, to Welsh et al., which is incorporated herein by reference in its entirety. The DSA tile 10 advantageously has a wide bandwidth, e.g., a bandwidth of at least 2 GHz in some embodiments, or even greater, e.g., tens of GHz.

[0019] FIG. 2 further diagrammatically illustrates a non-limiting, illustrative example of suitable on-board electronics 24 of the DSA tile 10 (or, more specifically, illustrates a portion of the on-board electronics 24 for a single RF pixel shown in FIG. 2 ). In RF receive mode, the on-board electronics 24 is configured to heterodyne the RF signal received by the RF pixel to an intermediate frequency (IF). More generally, the heterodyne function can be performed before digitization in the analog domain or after digitization in the digital domain using a direct sampling receiver. The illustrative on-board electronics 24 includes a balun 30 that provides a single-ended output in response to differential RF signals input from the paired two lobes 22, an optional low-noise amplifier (LNA) 32 for boosting the RF signal, an RF mixer 34 for heterodyning the received RF signal to an IF frequency, and an optional anti-aliasing filter 36. In RF transmit mode, the on-board electronics 24 operates in reverse; i.e., in receive mode, the RF mixer 34 is operatively connected to heterodyne the RF signal received by the corresponding RF pixel with the LO / Sync signal to generate a received intermediate frequency (IF) signal, and in transmit mode, to heterodyne the received IF signal to generate an RF transmit signal that is coupled to the corresponding RF pixel. Conversely, the LO / Sync signal can be used to synchronize data converters (analog-to-digital, digital-to-analog) in direct sampling or zero-IF architectures to ensure phase synchronization across all channels. It should be understood that this is merely an illustrative example, and that other configurations of the on-board electronics 24 are alternatively contemplated. In some embodiments, the balun 30 is a chip balun suitably mounted on the backside of a substrate 38, on which a 2D array of conductive tapered protrusions 22 is mounted. Other design aspects described in U.S. Publication No. 2020 / 0343929 A1 to Welsh et al. may be suitably incorporated into DSA 10.

[0020] As further shown diagrammatically in FIG. 1 , the RFU 12 has an RF connection 40 with the DSA tile 10. The RF connection 40 can be a coaxial RF cable, a triaxial RF cable, or the like. In variant embodiments, direct card-to-card connectors can be used, traveling without cables between them from circuit card to circuit card, thereby reducing signal travel distance. An exemplary RF connection 40 includes an LO connection that delivers an LO / Sync signal from the RFU 12 to the DSA 10, and a transmit / receive line that, in receive mode, delivers an RF signal received by the DSA 10 (after processing by on-board electronics 24) to the RFU 12, and, in transmit mode, delivers an RF IF signal to be transmitted from the RFU 12 to the DSA 10 (which is heterodyned to the desired transmit RF frequency by mixer 34 prior to transmission via the RF pixel with the adjacent tapered protrusion 22). The RF connection 40, in some embodiments, is 10 meters or less (C in FIG. 2 ) to limit propagation delay. RF ) but longer RF connections are also envisioned if the resulting propagation delay is acceptable for a given application. Conversely, mixer 34 may be located on the same circuit card or even within RFU 12 itself. In this case, the LO / Sync signal is not forwarded into DSA tile 10 itself. In another variant, a direct sampling or zero / IF embodiment does not have any external mixers, and LO / Sync is brought directly into RFU 12.

[0021] 1 and 2 includes the following: RF signals collected by the RF pixels of the DSA tiles 10 (optionally frequency-shifted to an IF frequency and optionally analog-processed, e.g., including amplification by the LNA 32 and filtering by the anti-aliasing filter 36) are transmitted via RF connection 40 to the RFU 12, which is programmed or otherwise configured (e.g., by suitable design, such as an application-specific integrated circuit, i.e., ASIC, or a suitably programmed field-programmable gate array, i.e., FPGA, various combinations thereof, etc.) to receive RF signal data from the DSA tiles 10, digitize the RF signal data, generate digitized RF signal data, and transmit the digitized RF signal data to a computer or other RF data consuming device 11 via a wired and / or wireless Ethernet, WiFi, or other digital data link. Additionally or alternatively, the digitized RF signal data may be stored locally at the RFU 12. In this case, a trigger can communicate when to stream the stored data to the DSA tiles 10 or downstream computer 11. As a non-limiting illustrative example, RFU 12 may be, for example, an HTG-ZRF-16 RFU platform (available from HiTech Global, LLC, San Jose, CA, USA) whose RF input pins are connected to designated RF pixels of DSA 10 by RF connections 40. The use of custom-built RFUs is also contemplated.

[0022] The illustrative base unit 8 of FIG. 1 includes two RFUs 12. More generally, however, the number of RFUs in the base unit 8 can be one, or two (as shown), or as few as three, or as many as needed to receive, digitize, stream, and / or locally store received RF signal data for the number of channels processed. When multiple RFUs 12 are employed, each RFU 12 generally receives, digitizes, streams, and / or stores RF signal data from an assigned subset of the RF pixels of the DSA 10. When multiple RFUs 12 are employed in the base unit 8, they may be beneficially synchronized at any time and / or across multiple transmit and / or receive channels. To this end, as shown in FIG. 1, a synchronization signal source 42 is configured to output a local oscillator (LO) synchronization signal (or, in some other embodiments, a system reference clock that serves as the synchronization signal) configured to be received by the RFUs of the N base units. In the illustrative example, RFU 12 of base unit 8 has a local oscillator that generates an LO / Sync signal that is synchronized to the LO synchronization signal. In the case of a modular RF device constructed from multiple base units 8 (see FIG. 3 and related discussion), synchronization source 42 preferably provides a synchronization signal to synchronize the RFUs of the multiple base units 8 of the modular RF device, at least when the base units 8 are operating in a cooperative mode in which two or more base units 8 operate cooperatively to provide a combined phased-array RF transmitter or receiver. Synchronization signal source 42 can be variously embodied, for example, as an RF antenna that outputs the LO synchronization signal or as one or more of the base units that make up the modular RF device.In this latter case, for example, one of the base units 8 may act as a synchronization source 42 by having an RFU 12 programmed to generate a synchronization signal, which can then be distributed to the other RFUs 12 of the base units 8 that make up the modular RF device either over the air or by using its connected DSA tile 10 to emit LO synchronization using a wired RF connection (e.g., a coaxial cable connecting between the RFUs of the modular RF device).

[0023] In some embodiments, there are two synchronization signals. The first synchronization signal is a LO / Sync signal that synchronizes the analog-to-digital and / or digital-to-analog data converters and, optionally, the mixer 34 to maintain phase alignment. The second synchronization signal is a pulse-per-second (PPS) signal. The PPS signal is operable on the other side of the interface to synchronize digital data to and from the computer 11 to ensure sample alignment as the data travels out of the base unit 8. The PPS signal source may be implemented, for example, as a digital clock. The PPS signal provides synchronization for digital data transfer from the RFU to downstream digitized RF data consumers, such as the illustrative computer 11. The disclosed dual synchronization using LO / Sync and PPS facilitates cooperation between the DSA tiles 10. The PPS signal may be implemented in other ways. For example, an illustrative physical Ethernet or other wired data network 43 may be employed to communicate digital data between the RFU 12 and the computer or other RF data consuming device 11, and the shared Ethernet 43 may incorporate a PPS signal along with other information traversing the Ethernet 43. The PPS signal in such an embodiment may be implemented in accordance with the Precision Time Protocol (PTP) standard utilizing, for example, the IEEE 1588 Precision Time Protocol, the Internet Engineering Task Force (IETF) Network Time Protocol, the Synchronous Internet (SyncE) protocol, or the like.

[0024] 2 diagrammatically illustrates the case where heterodyning is used and a mixer 34 is located with the on-board electronics 24 of the DSA tile 10 to provide heterodyning of the RF signal received or transmitted via each RF pixel. A drawback of this approach is that there are cases involving a mixer 34 per RF pixel, and therefore a substantial duplication of the mixer electronics.

[0025] In one variant embodiment, mixer 34 may be located in (i.e., implemented by) RFU 12, rather than being implemented in on-board electronics 24 as shown in FIG. 2. In this variant, the synchronization signal is shared among RFUs 12 and serves as the LO input to the on-RFU mixers, which then distribute the mixers to each channel. Because mixing is performed in RFU 12 in this variant embodiment, there is advantageously no need to transmit an LO synchronization signal to DSA tile 10 or between pixels of that DSA tile 10, as shown in FIG. 1. In other words, in this variant embodiment, in addition to omitting the on-tile LO distribution wiring, the LO / Sync signal input shown in FIG. 1 from RFU 12 to DSA tile 10 can be omitted.

[0026] In another embodiment variant, the mixer 34 is omitted entirely, and direct sampling (without heterodyning) is employed instead. This approach is feasible if the bandwidth of the analog-to-digital converter (ADC, for receive mode) and / or digital-to-analog converter (DAC, for transmit mode) of the RFU 12 is high enough to simultaneously acquire the entire RF signal across the entire design base bandwidth. In this case, the synchronization source 42 is preferably a system reference clock used to synchronize the sampling of the ADCs and / or DACs so that they are all phase-aligned. In this embodiment variant, the system reference clock replaces the LO synchronization signal, and the system reference clock is routed to each RFU 12 (but not to the DSA tile 10 or distributed among its RF pixels).

[0027] RFU 12 is programmed or otherwise configured to provide flexible operation of DSA tile 10. RFU 12 of base unit 8 is programmed to operate base unit 8 in a number of different RF transmit and / or receive modes, including at least one independent mode in which base unit 8 operates as an RF transmitter or receiver independent of any other base unit of the modular RF device, and at least one cooperative mode in which base unit 8 coherently combines with at least one other base unit of the modular RF device as a single phased-array RF transmitter or receiver.

[0028] Referring to Figure 3, the use of multiple base units to form a modular RF device is illustrated. Figure 3 part (A) depicts another embodiment of a single base unit 8 similar to that shown in Figures 1 and 2, again including a 2D array of conductive tapered protrusions 22 disposed on a support substrate 20, the conductive tapered protrusions 22 tapering in a direction extending away from the support substrate 20 (as shown in Figure 2), and adjacent pairs of conductive tapered protrusions forming RF pixels (again as shown in Figure 2). Figure 3 part (A) shows only the DSA tiles 10 of the base unit 8, but it should be understood that the base unit 8 of Figure 3 may include at least one RFU 12 and associated RF connections 40, as shown in Figure 1, and that the backside of the DSA 10 may include on-board electronics 24, as shown in Figure 2. It should also be noted that mounting at least one RFU 12 on the backside of the DSA tile 10 and providing a compact base unit 8 is also contemplated. The base unit 8 of FIG. 3 part (A) further includes a heat sink 44, which is not included in FIG. 1 . The optional heat sink 44 facilitates higher power operation. In this case, the support substrate 20 may include a ground plate to provide thermal conduction from the tapered protrusions 22 to the heat sink 44. In this case, the on-board electronics 24 (and at least one RFU 12, if backside mounted) may optionally be disposed on a separate orthogonal circuit board oriented orthogonally to the support substrate 20 supporting the tapered protrusions 22, as described in U.S. Publication No. 2020 / 0343929 A1 to Welsh et al., published October 29, 2020 (incorporated herein by reference in its entirety).

[0029] Another feature of the DSA tile 10 of the base unit 8 shown in Figure 3 part (A) relates to the orientation of the tapered protrusions 22. As seen in the embodiment of Figure 3 part (A), the support substrate 20 is rectangular, and the conductive tapered protrusions 22 in this embodiment have square bases oriented at 45° relative to the rectangular support substrate 20. This arrangement has certain benefits when the DSA 10 is positioned with one edge parallel to the ground plane (common orientation), in which case the tapered protrusions 22 have their square bases oriented at 45° relative to the ground plane. This facilitates use of the base unit 8 of Figure 3 part (A) in multiple-input and multiple-output (MIMO) radios commonly used in terrestrial communications for communication protocols such as IEEE 802.11, HPSA+, WiMAX, 3GPP, ATSC, and the like, which often employ polarizations oriented at +45° and -45° relative to the ground plane.

[0030] Part (A) of Figure 3 also diagrammatically illustrates the LO synchronization signal received from the LO synchronization source 42 (see Figure 1), the power input, the digital RF signal data output via the line labeled "Digital I / Q" (assuming two polarizations are available, e.g., +45° and -45° polarizations for the tapered protrusion 22 whose square base is oriented at 45° as shown in part (A)), and the PPS I / Q sync signal line. As mentioned above, in some embodiments, the PPS I / Q sync signal line may be implemented via an exemplary physical Ethernet 43 using the Precision Time Protocol (PTP) standard. In addition to frequency flexibility, polarization flexibility is also provided by the disclosed embodiments. The DSA tile 10 provides orthogonal polarizations, e.g., (0°, 90°), (-45°, +45°). When these orthogonal polarizations are handled by at least two separate channels, the DSA tiles 10 can operate based on isolated polarizations specific to the DSA tile orientation or cooperate through phase shifts to generate arbitrary polarizations. For example, when two orthogonal polarizations are phase shifted by 90° and combined in the digital domain, circular polarization is obtained. By weighting the combination, diagonal polarization can be obtained. In one mode of operation, each base unit operates on an individual polarization, while the other base units can operate on different polarizations. They can then switch to cooperate on a single polarization. Such an approach can be useful when using individual base units to search for signals of unknown polarization and, when found, focus all base units on the detected polarization.

[0031] FIG. 3B illustrates multiple base units 8 of the embodiment shown in FIG. 3 to form a modular RF device 50. FIG. 3B shows an example in which six base units 8 are combined in a 3×2 grid to form a flat, planar RF aperture 52. More generally, N base units 8 can be arranged to form the RF aperture 52, where N is an integer greater than or equal to 2, and the N DSA tiles of the N base units are arranged to form the RF aperture. In the example of FIG. 3B, N=6. Advantageously, the N DSA tiles 10 of the N base units 8 can be rearranged as desired to change the shape of the RF aperture of the modular RF device 50. For example, the N=6 base units shown in FIG. 3B arranged in a 3×2 grid can be rearranged as a 2×3 grid, a 1×6 grid, or a 6×1 grid. Furthermore, base units can be removed or added and rearranged to design a desired size and shape for the tiled RF apertures 52. Also shown in Figure 3 part (B) is a power and digital data transfer bus 54 that connects to each of the N base units 8 to allow signals for RF transmission to be sent to the RF device 50 and to allow received RF signal data to be moved to or from the RF device 50. The bus 54 can generally be a wired bus, a wireless bus, or a combination thereof.

[0032] At least one RFU 12 of each base unit 8 of the modular RF device 50 is programmed to operate the base unit 8 in a plurality of different RF transmission and / or reception modes, including at least one independent mode in which the base unit 8 operates as an RF transmitter or receiver independent of any other base unit of the modular RF device 50, and at least one cooperative mode in which the base unit 8 is coherently combined with at least one other base unit of the modular RF device 50 as a single phased array RF transmitter or receiver. 3 part (B) to provide a maximum RF aperture size (e.g., six base units 8 coherently combine to generate constructive or destructive interference patterns to produce more power or better sensitivity in a desired direction or directions), or several subsets of the N base units can be coherently combined to provide an operable RF aperture for RF transmission and / or RF reception that is between the size of a single DSA tile and the size of the combined physical RF aperture 52. In another example, the RFU 12 is programmed to operate the N base units 8 as at least two independent subsets, each subset operating as an RF transmitter or receiver independently of the other subsets. When two or more base units 8 are operating cooperatively as a single phased array RF transmitter or receiver, the LO synchronization signal output by LO synchronization source 42 advantageously provides synchronization of the LO oscillators of all the RFUs of the cooperating base units.

[0033] 3 part (B) has N=6 DSA tiles arranged as a flat, planar RF aperture, however, it is also envisioned to arrange the tiles to provide a curved RF aperture (albeit the curvature is a faceted curvature due to its construction using flat DSA tiles).

[0034] The modular RF device 50 provides an RF aperture tightly coupled to supporting electronics that enables the import and export of RF data in digital format, creating a digital air interface (DAI). The system can be synchronized in its digital data delivery and its internal signal phase to operate in conjunction with other DAIs. Each base unit 8 can operate independently and provide phased array capability over a wide range of bandwidths. Multiple base units 8 can be co-located to create a larger aperture area and increase array gain and transmit power, as shown in Figure 3, part (B). When operating coherently, local oscillators are synchronized between base units 8 using an LO synchronization signal to create a phased array capability. Multiple co-located base units 8 can operate independently or in small groups, thereby increasing the number of simultaneous signals operated on. The operating mode can be dynamically changed via the data interface without requiring any physical changes to the base units 8 or their DSA tile 10 arrangement. A mode change can therefore occur within 20 milliseconds or less, and in some embodiments within 10 milliseconds or less, depending on factors such as the speed of the RFUs 12 and the propagation delay in the RF connection 40 (the latter can be reduced by keeping those RF connections short, e.g., 10 meters or less in some embodiments). Each base unit 8 can operate within one or more slices of instantaneous bandwidth (e.g., 100 MHz). If more than one base unit is available, one slice may be coordinated with other base units 8 while others are not.

[0035] Modular RF device 50 thus provides a base unit 8 with an ultra-wideband aperture array, supporting analog electronics 24 for amplification, filtering, and channel routing, and digital radio electronics that are implemented in the illustrative embodiment by RFU 12. Base unit 8 is self-contained, with power and I / Q inputs / outputs and thermal management (e.g., via heat sink 44 shown in FIG. 3 part (A)). DSA tiles 10 of base unit 8 may be square or rectangular (as shown), or may have another geometric shape such as hexagonal, depending on the engineering design considerations for the specific product variant.

[0036] To enable multiple base units 8 to be coherently combined, an LO synchronization signal is generated by an LO synchronization source 42, which may be a separate LO synchronization signal generator or may be generated internally by one of the RFUs and distributed to the other RFUs. The LO synchronization signal allows the phase of the signal to be synchronized across multiple base units 8, enabling operation as a phased-array RF transmitter for tasks such as beamsteering and direction-finding applications. For example, the modular RF device 50 of FIG. 3 part (B) is expected to be able to provide a beamwidth of 10° x 10° or less at 2.4 GHz or higher.

[0037] As discussed above, at least one RFU 12 in each base unit 8 of modular RF device 50 is programmed to operate base unit 8 in a plurality of different RF transmit and / or receive modes, including at least one independent mode in which base unit 8 operates as an RF transmitter or receiver independently of any other base unit of modular RF device 50, and at least one cooperative mode in which base unit 8 coherently combines with at least one other base unit of modular RF device 50 as a single phased-array RF transmitter or receiver. The LO / Sync signal synchronizes the analog-to-digital and / or digital-to-analog data converters and, optionally, the mixer 34 to maintain phase alignment, while the PPS signal is operative on the other side of the interface to synchronize digital data to / from computer 11 to ensure sample alignment as the data travels out of base unit 8. It should be understood that in some operating scenarios, coherent operation of multiple base units 8 may not be required. For example, for some MIMO applications, coherency may not be required, but time synchronization across the base unit 8 is still desired. In such embodiments, the LO / Sync signal may be omitted, while a PPS signal is included as described above to provide the desired time synchronization.

[0038] Preferred embodiments have been illustrated and described. Obvious modifications and alterations will occur to those skilled in the art upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A base unit, the base unit comprising: a differentially segmented aperture (DSA) tile including a support substrate and a two-dimensional (2D) array of conductive tapered protrusions disposed on the support substrate, with the conductive tapered protrusions tapering in a direction extending away from the support substrate, wherein adjacent pairs of the conductive tapered protrusions form RF pixels; at least one RF unit (RFU) having an RF connection with the DSA tile for transmitting and / or receiving RF signals via the RF pixels of the DSA tile; Equipped with The at least one RFU of the base unit is programmed to operate the base unit in a plurality of different RF transmission and / or reception modes, including at least one independent mode in which the base unit operates as an RF transmitter or receiver independent of any other base unit, and at least one cooperative mode in which the base unit coherently combines with at least one other base unit as a single phased array RF transmitter or receiver.

2. The base unit of claim 1 , wherein the support substrate is rectangular and the conductive tapered protrusion has a square base oriented at 45° to the rectangular support substrate.

3. 3. The base unit of claim 1, wherein the at least one RFU comprises an RF integrated circuit (RFIC) or an RF system-on-module (RFSOM) comprising one or more integrated circuits (ICs) disposed on a single printed circuit board (PCB).

4. 4. The base unit of claim 1, wherein the at least one RFU is connected to the DSA tile by an RF connection, and the at least one RFU is configured to digitize RF signals received from the DSA tile via the RF connection when the at least one RFU operates the base unit in a receive mode.

5. 5. The base unit of claim 1, wherein the at least one RFU is connected to the DSA tile by an RF connection, and the at least one RFU is configured to convert received digital signals into analog RF signals and transmit the analog RF signals to the DSA tile via the RF connection transmitted by the DSA tile when the at least one RFU operates the base unit in a transmit mode.

6. A base unit according to any preceding claim, wherein the DSA tile has a bandwidth of at least 2 GHz.

7. 7. The base unit of claim 1, wherein the plurality of different RF transmission and / or reception modes includes a mode in which the base unit operates as an RF transmitter or receiver for at least two different polarizations, and in the cooperative mode, signals of different base units operating at different polarizations are coherently combined using phase shifts.

8. 1. A modular radio frequency (RF) device, the modular RF device comprising:

2. N base units as recited in claim 1, wherein N is an integer greater than or equal to 2, and wherein the N DSA tiles of the N base units are arranged to form an RF aperture. A modular RF device comprising:

9. a local oscillator (LO) / sync signal source that outputs a synchronization signal configured to synchronize analog-to-digital and / or digital-to-analog converters of RFUs of the coherently combined base units; a pulse-per-second (PPS) signal source that outputs a PPS signal for synchronizing digital data transfer to and from the RFU of the coherently combined base unit; The modular RF device of claim 8 further comprising:

10. The synchronization signal source an RF antenna that outputs the LO synchronization signal or system reference clock; or One or more of the N base units outputting the LO synchronization signal or system reference clock.

10. The modular RF device of claim 9, comprising one of:

11. The modular RF device of any one of claims 8 to 10, wherein the N DSA tiles of the N base units are arranged to form the RF aperture as a flat, planar RF aperture.

12. 12. The modular RF device of any one of claims 8-11, wherein the RFUs of the N base units are programmed to operate the base units in a cooperative mode in which all N base units coherently combine as a single phased array RF transmitter or receiver with a beamwidth of 10° x 10° or less at a frequency of 2.4 GHz or higher.

13. 13. The modular RF device of any one of claims 8 to 12, wherein the RFUs of the N base units are programmed to operate the base units in a cooperative mode in which all N base units coherently combine as a single phased array RF transmitter that outputs an RF beam that is steerable based on control inputs to the RFUs.

14. 14. The modular RF device of claim 8, wherein the RFUs of the N base units are programmed to operate the base units in a cooperative mode in which signals of different base units operating at different polarizations are coherently combined using phase shifts.

14. 14. The modular RF device of any one of claims 8 to 13, wherein the RFUs of the N base units are programmed to switch between independent and cooperative modes in 20 milliseconds or less.

15. 1. A modular radio frequency (RF) transmission and / or reception method, said method comprising: providing N base units, N being an integer greater than or equal to 2, each base unit including a differentially sectioned aperture (DSA) tile including a support substrate and a two-dimensional (2D) array of conductive tapered protrusions disposed on the support substrate, with the conductive tapered protrusions tapering in a direction extending away from the support substrate, adjacent pairs of the conductive tapered protrusions forming RF pixels; arranging the N DSA tiles of the N base units to form an RF aperture; switching the RF aperture between a first mode of operation and a second mode of operation; In the first mode of operation, the N base units are operated as at least two independent subsets, each subset operating as an RF transmitter or receiver independently of the other subset; In the second mode of operation, all N base units are coherently combined as a single phased array RF transmitter or receiver; A method comprising:

16. 16. The modular RF transmission and / or reception method of claim 15, wherein each base unit of the N base units further includes at least one RF unit (RFU) having an RF connection with a DSA tile of the base unit, the RFU of the base unit being programmed to switch the RF aperture between the first and second operating modes.

17. 17. The modular RF transmission and / or reception method of claim 16, further comprising a synchronization signal source configured to generate local oscillator (LO) synchronization signals or system reference clocks for RFUs of the N base units to synchronize RF signals received by RF pixels of DSA tiles of the N base units.

18. 18. The modular RF transmission and / or reception method of claim 15, wherein arranging the N DSA tiles of the N base units to form the RF aperture comprises arranging the N DSA tiles of the N base units to form the RF aperture as a flat, planar RF aperture.

19. 19. The modular RF transmission and / or reception method of any one of claims 15 to 18, further comprising rearranging the N DSA tiles of the N base units to change the shape of the RF aperture.

20. 1. A modular radio frequency (RF) device, the modular RF device comprising: N base units, N being an integer greater than or equal to 2, each base unit comprising a differentially sectioned aperture (DSA) tile including a support substrate and a two-dimensional (2D) array of conductive tapered protrusions disposed on the support substrate, with the conductive tapered protrusions tapering in a direction extending away from the support substrate, adjacent pairs of the conductive tapered protrusions forming an RF pixel; the N DSA tiles of the N base units are arranged to form an RF aperture; The N base units include: operating as at least two independent subsets, each subset operating as an RF transmitter or receiver independently of the other subset; and / or Coherently combined and operating as a single phased array RF transmitter or receiver A modular RF device programmed to perform at least one of:

Images