Antenna array calibration device and method

Abstract

Described herein is an apparatus and method for an antenna array calibration device and method, comprising: a radio frequency / optical (RF / optical) data center having at least one optical input / output, N single mode fibers (SMFs), where N is a positive integer, each having a proximal end and a distal end connected to at least one optical input / output of the RF / optical data center, N optical / RF parabolic antennas, each having an optical input / output connected to the distal end of the at least one SMF input / output, N coaxial transmission lines, each having a proximal end and a distal end connected to one of the RF inputs / outputs of the N optical / RF parabolic antennas, and the N parabolic antennas, each connected to the distal end of one of the N coaxial transmission lines.

Description

[Background technology]

[0001] Deep space radar requires large arrays of parabolic antennas spanning distances of over 1 km. These parabolic antennas must be synchronized to a common clock and maintained in constant radio frequency (RF) phase alignment. Phase alignment of array elements spanning such distances cannot be achieved using conventional coaxial cabling methods due to the high cable losses.

[0002] Traditional methods for distributing a common clock signal focus solely on stabilizing the single-mode fiber (SMF) between each satellite dish and the data center, using analog feedback to correct for fiber phase variations. However, this approach does not account for the entire end-to-end optical and RF path at the remote element location. This approach only considers RF phase variations at the external SMF interface. Summary of the Invention

[0003] In accordance with concepts described herein, exemplary antenna array calibration devices and methods utilize linear RF-over-fiber components to deliver signals such as a common clock and RF test signals over SMF, where phase alignment is achieved by facilitating short-open-load (SOL) RF calibration of the remote boundary conditions (RBC) at each parabolic antenna from a common measurement instrument and RF source located at the data center.

[0004] In accordance with the concepts described herein, an exemplary antenna array calibration device and method applies the RBC calibration method to a fiber-RF distribution network to calibrate radar array elements distributed over long distances (e.g., ∼1.5 km).

[0005] In accordance with the concepts described herein, an exemplary antenna array calibration device and method provides linear RF-over-fiber components in a data center, with each parabolic antenna providing a bidirectional path connection over one SMF.

[0006] In accordance with the concepts described herein, an exemplary antenna array calibration device and method provides SOL path characteristics measured at each parabolic antenna using a common digital receiver / exciter (DREX) located at the data center.

[0007] In accordance with the concepts described herein, the exemplary antenna array calibration device and method provides SOL calibration performed as frequently as necessary to correct for phase changes in the fiber and / or RF paths / components due to time, temperature, and / or physical movement of the coaxial and / or parabolic antenna array components.

[0008] In accordance with the concepts described herein, an exemplary antenna array calibration device and method uses linear electrical / optical and optical / electrical components and optical wavelength division multiplexing (WDM) technology to provide a bidirectional RF calibration signal from a data center that is distributed over N SMFs to a remote array of N parabolic antennas.

[0009] In accordance with the concepts described herein, an exemplary antenna array calibration device and method provides an RBC at each parabolic antenna, where system software periodically measures and corrects for phase changes across the RF to optical to RF path. [Brief explanation of the drawings]

[0010] The methods and processes for making and using the disclosed embodiments may be understood by reference to the accompanying drawing figures. It should be understood that the components and structures shown in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the concepts described herein. Like reference characters designate corresponding parts throughout the different views. Moreover, embodiments are illustrated in the drawings by way of example, and not by way of limitation.

[0011] [Figure 1] 1 is a diagram of an exemplary embodiment of an antenna array calibration device. [Figure 2] 2 is a diagram of an example embodiment of the RF / optical data center of FIG. 1. [Figure 3] FIG. 3 is a diagram of an example embodiment of the RF measurement system of FIG. 2. [Figure 4] 3 is a diagram of an example embodiment of the bidirectional RF / optical system of FIG. 2. [Figure 5] 2 is a diagram of an exemplary embodiment of the optical / RF parabolic antenna calibrator of FIG. 1; [Figure 6] 2 is a diagram of an exemplary embodiment of the alternative optical / RF parabolic antenna calibrator of FIG. 1. [Figure 7] FIG. 6 is a diagram of an example embodiment of the bidirectional optical / RF system of FIG. 5. [Figure 8] 2 is a diagram of an example embodiment of an alternative RF / optical data center of FIG. 1. [Figure 9] 2 is a diagram of an exemplary embodiment of the alternative optical / RF parabolic antenna calibrator of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure provides exemplary antenna array calibration devices and methods.

[0013] An exemplary embodiment of the present disclosure relates to the problem of calibration and alignment of radar array elements distributed over a large area (e.g., 1 km, 2 km, etc.). In an exemplary embodiment, an apparatus and method initially aligns and maintains alignment of an array of parabolic antenna elements distributed over a large area (e.g., greater than 1.5 km) with small degrees of phase (e.g., much less than 10 degrees). The device and method compensates for errors in the antenna array, including RF connections and components within the system. Calibration is software controlled and can be integrated into a real-time radar scheduler to compensate for parabolic antenna beam position movement, stability effects over time, and temperature.

[0014] In an exemplary embodiment, a linear RF-over-fiber optical component delivers a common clock and RF test signal over a single SMF. Phase alignment is achieved by facilitating RBC SOL RF calibration at each dish from a common measurement instrument and RF source at the data center. The RF-over-fiber interface uses a linear wavelength division multiplexer and optical transceiver to transmit the DREX clock and bidirectional RF calibration signal over a single SMF. The RF-over-fiber interface provides a virtual coaxial transmission line between the common measurement instrument at the data center and each remote dish array. Each dish array may include an RBC SOL calibration component to accurately characterize and align the phase at each dish by compensating for phase changes in the end-to-end RF and optical paths. RBC calibration may be software-controlled and integrated into scheduling to compensate for time, temperature, and dish movement on the fly.

[0015] In an exemplary embodiment, analog fiber stabilization may be utilized, but is not required. RF-over-fiber components may include sampling clocks and components to compensate for fiber-only phase variations, as well as bidirectional RF calibration signals and dish DREX clocks. In an exemplary embodiment, a 23-dish array may be distributed over 1.5 km from the data center.

[0016] When performing calibration of array elements distributed over an area greater than 1.5 km, the use of coaxial transmission lines alone is prohibited due to insufficient signal-to-noise ratios caused by high cable losses. The present invention can be utilized to align the phase of radar systems with elements distributed over large areas where the use of coaxial transmission lines alone is prohibited.

[0017] In an exemplary embodiment, bidirectional RF measurements allow for characterization and compensation of phase changes, fiber, and RF components between the data center and the parabolic antenna array. System phase calibration can be performed as needed to ensure accurate alignment of the antenna array elements, such as whenever the parabolic antenna is moved to a new beam position.

[0018] The present disclosure provides a low-complexity, low-cost solution for maintaining phase alignment between antenna array elements distributed over long distances.

[0019] 1 is a diagram of an example embodiment of an antenna array calibration device 100. In the example embodiment, the antenna array calibration device 100 comprises an RF / optical data center 101, N SMFs 103, at least one optical / RF parabolic antenna calibration device 105, and at least one parabolic antenna, where N is a positive integer. In the example embodiment, there may be an SMF 103 for each parabolic antenna array used in the antenna array calibration device 100. Furthermore, each parabolic antenna array may include multiple receive parabolic antennas 107 or multiple transmit parabolic antennas 109.

[0020] The RF / optical data center 101 has a bidirectional input / output connected to each of N SMFs 103. Each SMF 103 is connected to at least one optical / RF dish calibration device 105. Each optical / RF dish calibration device 105 has a bidirectional input / output connected to a receiving dish 107 or a transmitting dish 109.

[0021] 2 is a diagram of an example embodiment of the RF / optical data center 101 of FIG. 1. In the example embodiment, the RF / optical data center 101 includes an RF measurement system 201, a 1-to-N RF switch 203, and N bidirectional RF / optical systems 205, where N is a positive integer. In the antenna array calibration device 100, there is a bidirectional RF / optical system 205 for each parabolic antenna array. As mentioned above, each parabolic antenna array may have one or more receive parabolic antennas 107 or one or more transmit parabolic antennas 109.

[0022] RF measurement system 201 has a bidirectional input / output connected to 1:N RF switch 203 via a coaxial transmission line. 1:N RF switch 203 has a first bidirectional input / output connected to RF measurement system 201 via a coaxial transmission line, and N bidirectional inputs / outputs connected to the N coaxial transmission lines, respectively. Each bidirectional RF / optical system 205 has a first bidirectional input / output connected to 1:N RF switch 203 via a coaxial transmission line, and a bidirectional input / output connected to an SMF.

[0023] Figure 3 is a diagram of an example embodiment of the RF measurement system 201 of Figure 2. In the example embodiment, the RF measurement system 201 includes a calibration DREX assembly 301 and a dual coupler 303. The forward path from the dual coupler provides a reference signal that is directly proportional to the EX output of the calibration DREX assembly 301. The reverse path from the dual coupler carries a return signal from a SOL standard located in a parabolic antenna array that is selected by the 1:N RF switch 203 shown in Figure 2.

[0024] The calibration DREX assembly 301 has an output EX connected via a coaxial transmission line to a first input of a dual coupler 303, a first input RX1 connected via a coaxial transmission line to the first output of the dual coupler 303 to receive a forward signal, and a second input RX2 connected via a coaxial transmission line to the second output of the dual coupler 303 to receive a reverse signal. The bidirectional input / output of the dual coupler 303 is the coaxial transmission line output of the RF measurement system 201.

[0025] Figure 4 is a diagram of an example embodiment of one of the N bidirectional RF / optical systems 205 of Figure 2. In the example embodiment, each of the bidirectional RF / optical systems 205 comprises a broadband coupler (combiner) 401, a fiber optic transceiver 403, and a wavelength division multiplexer (WDM) 405.

[0026] Broadband coupler 401 has a first bidirectional input / output connected to the input / output coaxial transmission line of bidirectional RF / optical system 205, an input connected to the coaxial transmission line, and an output connected to the coaxial transmission line. Optical fiber transceiver 403 has a first output connected to the input of broadband coupler 401 via the coaxial transmission line, a first input connected to the output of broadband coupler 401 via the coaxial transmission line, a second input connected to the SMF, and a second output connected to the SMF. WDM 405 has a first output connected to the second input of optical fiber transceiver 403 via the SMF, a first input connected to the second output of optical fiber transceiver 403 via the SMF, and a second bidirectional input / output connected to the SMF, which is the bidirectional input / output of bidirectional RF / optical system 205.

[0027] Figure 5 is a diagram of an example embodiment of the optical / RF dish calibrator of Figure 1. In the example embodiment, the optical / RF dish calibrator 105 includes a bidirectional optical / RF system 501 and a remote boundary condition short-open-load (RBC SOL) test fixture 503.

[0028] The bidirectional optical / RF system 501 includes a bidirectional input / output SMF and a bidirectional input / output coaxial transmission line, where the SMF is the optical fiber bidirectional input / output of the optical / RF parabolic antenna calibrator 105. The RBC SOL test equipment 503 includes a bidirectional input / output connected to the bidirectional coaxial input / output of the bidirectional optical / RF system 501, and a second bidirectional input / output coaxial transmission line, where the second bidirectional input / output line is the coaxial bidirectional input / output of the optical / RF parabolic antenna calibrator 105 to / from each parabolic antenna array.

[0029] Figure 6 is a diagram of an example embodiment of the alternative optical / RF dish calibrator 105 of Figure 1. In the example embodiment, the optical / RF dish calibrator 105 includes a bidirectional optical / RF system 601 and an RBC SOL clock, temperature sensor, and motion sensor test fixture 603 that facilitates calibration and alignment of the end-to-end RF-to-optical-to-RF path between each dish and a common data center.

[0030] The bidirectional optical / RF system 601 includes a bidirectional input / output SMF and a bidirectional input / output coaxial transmission line, where the SMF is the optical fiber bidirectional input / output of the optical / RF parabolic antenna calibrator 105. The RBC SOL clock, temperature sensor, and operation sensor tester 603 includes a bidirectional input / output connected to the bidirectional coaxial input / output of the bidirectional optical / RF system 601 and a bidirectional input / output coaxial transmission line, where the bidirectional input / output line is the coaxial bidirectional input / output of the optical / RF parabolic antenna calibrator 105. In an exemplary embodiment, the optical / RF dish calibrator 105 can recalibrate on the fly in response to user-definable time changes (e.g., a user-settable time (e.g., a specific minute, hour, day, etc.), after a user-definable number of time units (e.g., after a specific number of seconds, minutes, hours, days, etc.), temperature (e.g., a specific temperature, after a specific number of degree changes, etc.), and movement (e.g., a specific location, after a specific number of minutes of inch, inch, foot change, etc.). The RBC SOL calibration may be initiated and controlled by software. The frequency of operation may be periodic at set intervals or initiated based on known changes or movement of the dish.

[0031] Figure 7 is a diagram of an example embodiment of the bidirectional optical / RF system 501 of Figure 5. In the example embodiment, the bidirectional optical / RF system 501 includes a WDM 701, a fiber optic transceiver 703, and a broadband coupler 705. Figure 7 illustrates optical to RF conversion, while Figure 4 illustrates RF to optical conversion.

[0032] WDM 701 has a first bidirectional input / output connected to an SMF, which is a bidirectional input / output of bidirectional optical / RF system 501, an input connected to a first output of optical fiber transceiver 703 via SMF, and an output connected to the first input of optical fiber transceiver 703 via SMF. Optical fiber transceiver 703 has a first output connected to the input of WDM 701 via SMF, a first input connected to the output of WDM 701 via SMF, a second output connected to a coaxial transmission line, and a second input connected to the coaxial transmission line. Broadband coupler 705 has an input connected to the second output of optical fiber transceiver 703 via a coaxial transmission line, an output connected to the second input of optical fiber transceiver 703 via a coaxial transmission line, and a bidirectional input / output connected to the input / output coaxial transmission line of bidirectional RF / optical system 501.

[0033] Figure 8 is a diagram of an example embodiment of the RF / optical data center 101 of Figure 1. In the example embodiment, the RF / optical data center 101 includes a low phase noise source 801, a calibration manager controller 803, a calibration DREX 805, a dual coupler 807, a 1-to-N RF switch 809, M first 1-to-P splitters 811, M second 1-to-P splitters 813, N RF multiplexer assemblies 815, and N phase-stabilizing cards 817, where N, M, and P are positive integers.

[0034] The low phase noise source 801 has an input configured to receive a 10 MHz signal, a first output configured to provide a 550 MHz signal, a second output configured to provide a 550 MHz signal, a third output configured to provide a 550 MHz signal, and a fourth output configured to provide a 1 GHz signal. The calibration manager controller 803 has a first input configured to receive a one pulse per second signal, a second input configured to receive an Inter-Range Instrumentation Group (IRIG) time code format B (IRIG B) signal, a first bidirectional input / output configured to receive a 10 Gigabit Ethernet (GbE) signal, a second bidirectional input / output configured to receive a 1 GbE signal, a third input connected to the first 550 MHz output of the low phase noise source 801, and an output configured to provide a resource period (RP) RP synchronization signal (RP sync).

[0035] The calibration DREX 805 comprises a first bidirectional input / output configured to receive a 1 GbE signal, a first input configured to receive a 1 pulse per second signal, a second input configured to receive a 10 MHz signal, a third input connected to the RP sync output of the calibration manager controller 803, a fourth input connected to the second 550 MHz output of the low phase noise source 801, a second bidirectional input / output configured to receive calibration DREX data, a third output, a sixth input configured to receive a forward signal, and a seventh input configured to receive a reverse signal. The dual coupler 807 comprises a first input / output connected to the third output of the calibration DREX assembly 805, a first output connected to the sixth input of the calibration DREX assembly 805 and configured to provide a forward signal, a second output connected to the seventh input of the calibration DREX assembly 805 and configured to provide a reverse signal, and a second bidirectional input / output.

[0036] The 1:N RF switch 809 has a first bidirectional input / output configured to receive a 1 GbE signal, a first input / output connected to the output of the dual coupler 807, and a second bidirectional input / output configured to provide an RF calibration signal.

[0037] The M (e.g., 4) first 1-to-P (e.g., 6) splitters 811 comprise input buses for receiving M 550 MHz signals and output buses configured to provide N (e.g., 23) 550 MHz signals. The M (e.g., 4) second 1-to-P (e.g., 6) splitters 813 comprise input buses for receiving M 550 MHz signals and output buses configured to provide N (e.g., 23) 550 MHz signals.

[0038] The N RF multiplexer assemblies 815 comprise a first bidirectional input / output connected to the second bidirectional input / output of the 1-to-N RF switch 809 and configured to receive an RF calibration signal, a first input bus connected to the output bus of the first M 1-to-P dividers 811, a second input bus connected to the output bus of the second M 1-to-P dividers 813, and a bidirectional input / output bus configured to provide N input / output signals, where the bidirectional input / output bus comprises SMF. The N phase-stabilizing cards 817 comprise a first bidirectional input / output bus connected to the bidirectional input / output buses of the N RF multiplexer assemblies 815 and a second bidirectional input / output bus configured to provide N signals, where the first bidirectional input / output bus and the second bidirectional input / output bus each comprise SMF, and the second bidirectional input / output bus comprises N bidirectional inputs / outputs of the RF / optical data center 101. The N phase-stabilizing cards 817 are part of an SMF-only analog phase correction. The exemplary embodiments can correct for phase changes throughout the RF to optical to RF chain independent of fiber stabilization, such as the lack of analog fiber stabilization.

[0039] Figure 9 is a diagram of an example embodiment of the optical / RF parabolic antenna calibrator 105 of Figure 1. In the example embodiment, the optical / RF parabolic antenna calibrator 105 comprises an RF / optical multiplexer assembly 901, a termination (TERM) device 903 (e.g., a 50 ohm termination), a short test device 905, an open test device 907, a load test device 909, a K-to-1 switch 911, a 1-to-L (e.g., 2) splitter 913, a parabolic antenna DREX assembly 915, a low noise amplifier (LNA) assembly 917, a transmit assembly 918, a first circulator 919, a second circulator 921, a first coupler 923, a second coupler 925, and a polarizer 927, where K (e.g., 8) and L (e.g., 2) are positive integers.

[0040] RF / optical multiplexer assembly 901 comprises a bidirectional optical input / output configured to connect to RF / optical data center 101, a bidirectional RF input / output configured to provide an RF calibration signal (e.g., an RF test signal), a first RF output configured to provide a 550 MHz signal, and a second RF output configured to provide a 1 GHz signal. TERM device 903 comprises an RF input connected to the second RF output of RF / optical multiplexer assembly 901.

[0041] The short test device 905 has an RF input and output. The open test device 907 has an RF input and output. The load test device 909 has an RF input and output. The short test device 905, the open test device 907, and the load test device 909 constitute a calibration standard. The K-to-1 switch 911 comprises a first bidirectional RF input / output connected to the bidirectional RF input / output of the RF / optical multiplexer assembly 901, a second bidirectional RF input / output connected to the RF input / output of the short test device 905, a third bidirectional RF input / output connected to the RF input / output of the open test device 907, a fourth bidirectional RF input / output connected to the RF input / output of the load test device 909, a first RF output configured to provide a calibration monitor signal (Cal Monitor), a second RF output configured to provide a calibration injected right-hand circular polarization (RHCP) signal (Cal Inject RHCP), a third RF output configured to provide a calibration injected left-hand circular polarization (LHCP) signal (Cal Inject LHCP), a first RF input (TX TWT 1 Monitor) configured to monitor the RF output of the first coupler 923, and a second RF input (TX TWT 2 Monitor) configured to monitor the RF output of the second coupler 925. The first and second RF inputs are used to monitor and maintain calibration of the transmit RF signal. In the case of a receive-only parabolic antenna, the first and second RF inputs are not required.

[0042] The 1-to-L splitter 913 has an RF input connected to the first RF output of the RF / optical multiplexer assembly 901 and an RF output (e.g., a 550 MHz signal). The parabolic antenna DREX assembly 915 has a first RF input configured to receive a one pulse per second signal, a second RF input configured to receive a 10 MHz signal, a third RF input configured to receive an RP synchronization signal, a fourth RF input connected to the RF output of the 1-to-L splitter 913, a fifth RF input (RX4) connected to the first RF output of the K-to-1 switch 911, a first RF output connected to the sixth RF input (RX3) and configured to provide a third external reference signal (EX3), a seventh RF input, an eighth RF input, a second RF output configured to provide a second external reference signal (EX2), and a third RF output configured to provide the first external reference signal (EX1).

[0043] The LNA assembly 917 has a first RF output connected to the seventh RF input of the parabolic antenna DREX assembly 915 and configured to provide the RX2 LHCP signal, a second RF output connected to the eighth RF input of the parabolic antenna DREX assembly 915 and configured to provide the RX1 RHCP signal, a first RF input connected to the second output of the K-to-1 switch 911 and configured to receive the calibration injection RHCP signal, a second RF input connected to the third output of the K-to-1 switch 911 and configured to receive the calibration injection LHCP signal, a third RF input, and a fourth RF input. The transmit assembly 918 has a first RF input connected to the third RF output of the parabolic antenna DREX assembly 915 and configured to receive EX1, a second RF input connected to the second RF output of the parabolic antenna DREX assembly 915 and configured to receive EX2, a first RF output configured to transmit TX TWT1, and a second RF output configured to transmit TX TWT2. A first bidirectional RF input / output of the LNA assembly 917 monitors a receive signal from the parabolic antenna (via a first coupler 923 and a first circulator 919), and a second bidirectional RF input / output of the LNA assembly 917 monitors a second receive signal from the parabolic antenna (via a second coupler 925 and a second circulator 921). The first circulator 923 and the second circulator 925 are also connected to a transmit signal to provide transmit functionality for the transmit and receive parabolic antennas.

[0044] The first circulator 919 is connected to the first RF output of the transmit assembly 918 and has an RF input configured to receive TX TWT1, an RF output connected to the fourth RF input of the LNA assembly 917, and a bidirectional RF input / output. The second circulator 921 is connected to the second RF output of the transmit assembly 918 and has an RF input configured to receive TX TWT2, an RF output connected to the third RF input of the LNA assembly 917, and a bidirectional RF input / output.

[0045] The first coupler 923 has a first bidirectional RF input / output connected to the bidirectional RF input / output of the first circulator 919, a second bidirectional RF input / output, and an RF output connected to the first RF input of the K-to-1 switch 911 and configured to receive the TX TWT1 monitor signal. The second coupler 925 has a first bidirectional RF input / output connected to the bidirectional RF input / output of the second circulator 921, a second bidirectional RF input / output, and an RF output connected to the second RF input of the K-to-1 switch 911 and configured to receive the TX TWT2 monitor signal. The polarizer 927 has a first bidirectional RF input / output connected to the second bidirectional RF input / output of the first coupler, a second bidirectional RF input / output connected to the second bidirectional RF input / output of the second coupler, and a third bidirectional RF input / output including the bidirectional RF input / output of the optical / RF parabolic antenna calibrator 105.

[0046] While illustrative embodiments of the present disclosure have been described, it will be apparent to those skilled in the art that other embodiments incorporating these concepts may also be used. The embodiments contained herein should not be limited to the disclosed embodiments, but rather should be limited only by the spirit and scope of the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.

[0047] Elements of different embodiments described herein can be combined to form other embodiments not specifically described above. Various elements described in the context of a single embodiment may be provided separately or in any suitable subcombination. Other embodiments not specifically described herein are also within the scope of the following claims.

[0048] Various embodiments of the concepts, systems, devices, structures, and techniques for which protection is sought are described herein with reference to the associated drawings. As noted above, in embodiments, the concepts and features described herein may be embodied in a digital multi-beam beamforming system. Alternative embodiments may be contemplated without departing from the scope of the concepts, systems, devices, structures, and techniques described herein.

[0049] It should be noted that in the above description and drawings, various connections and relationships (e.g., above, below, adjacent, etc.) are described between elements. These connections and / or relationships may be direct or indirect unless otherwise specified, and the described concepts, systems, devices, structures, and techniques are not intended to be limiting in this regard. Thus, coupling of entities can refer to direct or indirect coupling, and relationship between entities may be direct or indirect relationship.

[0050] As an example of an indirect positional relationship, reference in this description to forming layer "A" on layer "B" includes the situation where one or more intermediate layers (e.g., layer "C") are between layer "A" and layer "B," so long as the relevant properties and functions of layer "A" and layer "B" are not substantially altered by the intermediate layer(s). The following definitions and abbreviations shall be used in interpreting the claims and the specification. As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, mixture, process, method, article, or device that includes a list of elements is not necessarily limited to only those elements and may include other elements not expressly listed or other elements inherent to such composition, mixture, process, method, article, or device.

[0051] Additionally, the term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The terms "one or more" and "one or more" are understood to include any integer number greater than or equal to one, i.e., 1, 2, 3, 4, etc. The term "plurality" is understood to include any integer number greater than or equal to two, i.e., 2, 3, 4, 5, etc. The term "connected" can include indirect and direct "connections."

[0052] References in the specification to "one embodiment," "an embodiment," "an exemplary embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but that all embodiments may include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with one embodiment, it is believed to be within the knowledge of one of ordinary skill in the art to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly stated.

[0053] For purposes of this description, the terms "above," "below," "right," "left," "vertical," "horizontal," "top," "bottom" (to name a few) and their derivatives refer to the structures and methods described, as well as the orientation of the drawings. The terms "overlying," "atop," "on top," "positioned on," or "positioned atop" mean that a first element, such as a first structure, is above a second element, such as a second structure, and intervening elements, such as interfacial structures, may be present between the first and second elements. The term "direct contact" means that a first element, such as a first structure, and a second element, such as a second structure, are connected without intervening elements. Such terms may also be referred to as directional or positional terms.

[0054] The use of ordinal numbers such as "first," "second," "third," etc. in the claims to modify claim elements does not, in itself, imply any priority, precedence, or ordering of one claim element relative to other claim elements, or the chronological order in which method actions are performed, but is merely used as a label to distinguish one claim element with a particular name from another element with the same name (other than the use of the ordinal number) to distinguish between claim elements.

[0055] The terms "approximately" and "about" may be used in some embodiments to mean within ±20% of a target value, in some embodiments within ±10% of a target value, in some embodiments within ±5% of a target value, and even in some embodiments within ±2% of a target value. The terms "approximately" and "about" may include the target value. The term "substantially equal" may be used to refer to values ​​that are in some embodiments within ±20% of each other, in some embodiments within ±10% of each other, in some embodiments within ±5% of each other, and even in some embodiments within ±2% of each other.

[0056] The term "substantially" may be used in some embodiments to refer to values ​​within ±20%, in some embodiments within ±10%, in some embodiments within ±5%, and even in some embodiments within ±2% of a comparison measurement. For example, a first direction that is "substantially" perpendicular to a second direction may in some embodiments refer to a first direction that is within ±20% of a 90° angle with the second direction, in some embodiments within ±10% of a 90° angle with the second direction, in some embodiments within ±5% of a 90° angle with the second direction, and even in some embodiments within ±2% of a 90° angle with the second direction.

[0057] It is to be understood that the disclosed subject matter is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings, as the disclosed subject matter is capable of other embodiments and of being practiced and carried out in various ways.

[0058] It is also to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. Thus, those skilled in the art will appreciate that the conception underlying the present disclosure may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out some of the purposes of the disclosed subject matter. Accordingly, the claims should be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the disclosed subject matter.

[0059] While the disclosed subject matter has been described and illustrated in the foregoing exemplary embodiments, it should be understood that the disclosure is made by way of example only, and that numerous changes may be made in the details of the implementation of the disclosed subject matter without departing from the spirit and scope of the disclosed subject matter.

Claims

1. A radio frequency / optical (RF / optical) data center having at least one optical input / output, N single-mode fibers (SMFs), each having a proximal end and a distal end connected to the at least one optical input / output of the RF / optical data center, where N is a positive integer, N optical / RF parabolic antenna calibrators, each having an optical input / output and an RF input / output, where the optical input / output is connected to the distal end of one of the N SMFs, N coaxial transmission lines, each having a proximal end and a distal end, where the proximal end is connected to the RF input / output of one of the N optical / RF parabolic antenna calibrators, N parabolic antennas, each connected to the distal end of one of the N coaxial transmission lines, comprising: The N optical / RF parabolic antenna calibrators are configured to receive an RF test signal from the RF / optical data center via the N SMFs and perform a test for RF calibration using the RF test signal. The RF / optical data center has an RF measurement system having an RF input / output, a first coaxial transmission line having a proximal end and a distal end, where the proximal end is connected to the RF input / output of the RF measurement system, a 1-to-N RF switch having a first RF input / output connected to the distal end of the first coaxial transmission line and N RF input / outputs, and N bidirectional RF / optical systems, each having an RF input / output and an optical input / output, where the RF input / output is connected to one of the N RF input / outputs of the 1-to-N RF switch. An antenna array calibration device.

2. The RF measurement system has a calibration digital receiver / exciter (DREX) assembly having an RF output, a first RF input configured to receive a reverse direction signal, and a second RF input configured to receive a forward direction signal, and a dual coupler having a first RF input / output connected to the RF output of the calibration DREX assembly, a first RF output connected to the first RF input of the calibration DREX assembly, a second RF output connected to the second RF input of the calibration DREX assembly, and a second RF input / output. The antenna array calibration device according to Claim 1.

3. Each of the N bidirectional RF / optical systems has a broadband coupler having an RF input / output, an RF input, and an RF output. An optical fiber transceiver having an RF output connected to the RF input of the broadband combiner, an RF input connected to the RF output of the broadband combiner, an optical input, and an optical output; A wavelength division multiplexer (WDM) having an optical output connected to the optical input of the optical fiber transceiver, an optical input connected to the optical output of the optical fiber transceiver, and an optical input / output; The antenna array calibration device according to claim 1, comprising:

4. Each of the N optical / RF parabolic antenna calibrators A bidirectional optical / RF system having an optical input / output and an RF input / output; A short-circuit / open-circuit / load test device for remote boundary conditions having a first RF input / output and a second RF input / output The antenna array calibration device according to claim 1, comprising:

5. The short-circuit / open-circuit / load test device for remote boundary conditions further includes A clock; A temperature sensor; An operation sensor The antenna array calibration device according to claim 4, comprising:

6. The bidirectional optical / RF system A wavelength division multiplexer (WDM) having an optical input / output, an optical input, and an optical output; An optical fiber transceiver having an optical output connected to the optical input of the WDM, an optical input connected to the optical output of the WDM, an RF input, and an RF output; A broadband combiner having an RF output connected to the RF input of the optical fiber transceiver, an RF input connected to the RF output of the optical fiber transceiver, and an RF input / output The antenna array calibration device according to claim 4, comprising:

7. The antenna array calibration device according to claim 1, wherein the N parabolic antennas include at least one receiving antenna array and / or at least one transmitting antenna array.

8. A radio frequency / optical (RF / optical) data center having at least one optical input / output; N single-mode fibers (SMFs) each having a proximal end and a distal end connected to the at least one optical input / output of the RF / optical data center, where N is a positive integer; N optical / RF parabolic antenna calibrators each having an optical input / output and an RF input / output connected to the distal end of one of the N SMFs; N coaxial transmission lines each having a proximal end and a distal end connected to the RF input / output of one of the N optical / RF parabolic antenna calibrators; N parabolic antennas respectively connected to the distal ends of one of the N coaxial transmission lines and comprising the N optical / RF parabolic antenna calibrators are configured to receive an RF test signal from the RF / optical data center via the N SMFs and perform a test for RF calibration using the RF test signal the RF / optical data center includes a low-phase-noise source having a 10 MHz input, a 550 MHz output, a 1 GHz output, a first M output buses, and a second M output buses (M is a positive integer) a calibration manager controller having a 1 pulse per second (1 PPS) input, an IRIG (Inter-Range Instrumentation Group) time code format B (IRIGB) input, a 10 MHz input, a 10 gigabit Ethernet (registered trademark) (GbE) input, a 1 GbE input, a 550 MHz input connected to the 550 MHz output of the low-phase-noise source, and a resource period (RP) synchronization (RP sync) output a calibration digital receiver / exciter (DREX) assembly having a 1 GbE input, a 1 PPS input, a 10 MHz input, a first input connected to the RP synchronization output of the calibration manager controller, a second input connected to the 550 MHz output of the low-phase-noise source, a calibration DREX data input / output, an output, a third input, and a fourth input a dual coupler having a first input / output connected to the output of the calibration DREX assembly, a first output connected to the third input of the calibration DREX assembly, a second output connected to the fourth input of the calibration DREX assembly, and a second input / output a 1-to-N RF switch having a 1 GbE input, an input / output, and N input / output buses M first 1-to-P distributors having M input buses respectively connected to the first M output buses of the low-phase-noise source and N output buses (M and P are positive integers) M second 1-to-P distributors having M input buses respectively connected to the second M output buses of the low-phase-noise source and N output buses N RF multiplexer assemblies each having N input / output buses connected to the N input / output buses of the 1:N RF switch, first N input buses connected to the N output buses of the M first 1:P dividers, respectively, second N input buses connected to the N output buses of the M second 1:P dividers, respectively, and N optical input / output buses; N phase-stable cards each having a first N number of optical input / output buses and a second N number of optical input / output buses respectively connected to the N number of optical input / output buses of the N number of RF multiplexer assemblies; 1. An antenna array calibration device comprising:

9. A radio frequency / optical (RF / optical) data center having at least one optical input / output; N single mode fibers (SMFs), each having a proximal end connected to the at least one optical input / output of the RF / optical data center and a distal end, where N is a positive integer; and N optical / RF parabolic antenna calibrators, each having an optical input / output and an RF input / output connected to the distal end of one of the N SMFs; N coaxial transmission lines, each having a proximal end connected to the RF input / output of one of the N optical / RF parabolic antenna calibrators, and a distal end; N parabolic antennas, each connected to the distal end of one of the N coaxial transmission lines; Equipped with the N optical / RF parabolic antenna calibrators are configured to receive RF test signals from the RF / optical data center via the N SMFs and perform tests for RF calibration using the RF test signals; Each of the optical / RF parabolic antenna calibrators comprises: an optical / RF multiplexer assembly having an optical input / output, a first RF output, a second RF output, and an RF input / output; a 1-to-L splitter having an RF input connected to the first RF output of the optical / RF multiplexer assembly and L RF outputs, where L is a positive integer; a termination (TERM) device having an RF input connected to the second RF output of the optical / RF multiplexer assembly; a K-to-1 switch having an RF input / output, a first RF input / output, a second RF input / output, a third RF input / output, a fourth RF input / output, a first RF output, a second RF output, a third RF output, a first RF input, and a second RF input connected to the RF input / output of the optical / RF multiplexer assembly, where K is a positive integer; a short circuit tester having an RF input / output connected to the second RF input / output of the K-to-1 switch; an open test device having an RF input / output connected to the third RF input / output of the K-to-1 switch; a load tester having an RF input / output connected to the fourth RF input / output of the K-to-1 switch; a parabolic antenna digital receiver / exciter (DREX) assembly having a one pulse per second (1 PPS) input, a 10 MHz input, a resource period (RP) synchronization (sync) input, a first RF input connected to the RF output of the 1-to-L splitter, a second RF input, a third RF input, a first RF output, a fourth RF input connected to the first RF output, a fifth RF input connected to the first RF output of the K-to-1 switch, a second RF output configured to provide a first excitation signal, and a third RF output configured to provide a second excitation signal; a low noise amplifier (LNA) assembly having a first RF output connected to the second RF input of the parabolic antenna DREX assembly, a second RF output connected to the third RF input of the parabolic antenna DREX assembly, a first RF input connected to the second RF output of the K-to-1 switch, a second RF input connected to the third RF output of the K-to-1 switch, a third RF input, and a fourth RF input; a transmitter assembly having a first RF input connected to the third RF output of the parabolic antenna DREX assembly, a second RF input connected to the second RF output of the parabolic antenna DREX assembly, a first RF output, and a second RF output; a first circulator having a first RF input connected to the first RF output of the transmit assembly, an RF output connected to the fourth RF input of the LNA assembly, and an RF input and output; a second circulator having a first RF input connected to the second RF output of the transmit assembly, an RF output connected to the third RF input of the LNA assembly, and an RF input and output; a first coupler having a first RF input / output connected to the RF input / output of the first circulator and a second RF input / output; a second coupler having a first RF input / output connected to the RF input / output of the second circulator and a second RF input / output; a polarizer having a first RF input / output connected to the second RF input / output of the first circulator, a second RF input / output connected to the second RF input / output of the second circulator, and a third RF input / output including the RF output of the optical / RF parabolic antenna calibrator; 1. An antenna array calibration device comprising:

10. transmitting N optical signals through a radio frequency / optical (RF / optical) data center having at least one optical input / output, where N is a positive integer; receiving the N optical signals via N single mode fibers (SMFs), each having a proximal end connected to the at least one optical input / output and a distal end connected to the at least one optical input / output of the RF / optical data center, by N optical / RF dish antenna calibrators, each having an optical input / output and an RF input / output connected to the distal end of one of the N SMFs; receiving N RF signals via N coaxial transmission lines, each having a proximal end connected to the RF input / output of one of the N optical / RF parabolic antenna calibrators and a distal end, by N parabolic antennas, each connected to the distal end of one of the N coaxial transmission lines; Including, the N optical / RF parabolic antenna calibrators perform tests for RF calibration using the N optical signals as RF test signals; the RF / optical data center; an RF measurement system having an RF input and output; a first coaxial transmission line having a proximal end connected to the RF input / output of the RF measurement system and a distal end; a first RF input / output connected to the distal end of the first coaxial transmission line; and a 1:N RF switch having N RF inputs / outputs; N bidirectional RF / optical systems, each having an RF input / output connected to one of the N RF inputs / outputs of the 1:N RF switch, and an optical input / output; 1. An antenna array calibration method comprising:

11. the RF measurement system comprising: a calibrated digital receiver / exciter (DREX) assembly having an RF output, a first RF input configured to receive a reverse signal, and a second RF input configured to receive a forward signal; a dual coupler having a first RF input / output connected to the RF output of the calibration DREX assembly, a first RF output connected to the first RF input of the calibration DREX assembly, a second RF output connected to the second RF input of the calibration DREX assembly, and a second RF input / output; The method of claim 10, comprising:

12. each of the N bidirectional RF / optical systems a broadband combiner having an RF input / output, an RF input, and an RF output; a fiber optic transceiver having an RF output connected to the RF input of the wideband combiner, an RF input connected to the RF output of the wideband combiner, an optical input, and an optical output; a wavelength division multiplexer (WDM) having an optical output connected to the optical input of the fiber optic transceiver, an optical input connected to the optical output of the fiber optic transceiver, and an optical input and output; The method of claim 10, comprising:

13. Each of the N optical / RF parabolic antenna calibrators a bidirectional optical / RF system having an optical input / output and an RF input / output; a remote boundary condition short-open-load test device having a first RF input / output and a second RF input / output; The method of claim 10, comprising:

14. The remote boundary condition short circuit, open circuit, and load test device further comprises: Clock and A temperature sensor; Motion sensor and The method of claim 13 comprising:

15. the bidirectional optical / RF system comprises: a wavelength division multiplexer (WDM) having an optical input / output, an optical input, and an optical output; a fiber optic transceiver having an optical output connected to the optical input of the WDM, an optical input connected to the optical output of the WDM, an RF input, and an RF output; a broadband combiner having an RF output connected to the RF input of the fiber optic transceiver, an RF input connected to the RF output of the fiber optic transceiver, and an RF input and output; The method of claim 13 comprising:

16. The method of claim 10 , wherein the N parabolic antennas include at least one receive antenna array and / or at least one transmit antenna array.

17. A method for transmitting N optical signals by a radio frequency / optical (RF / optical) data center having at least one optical input / output, where N is a positive integer; receiving the N optical signals via N single mode fibers (SMFs), each having a proximal end connected to the at least one optical input / output and a distal end connected to the at least one optical input / output of the RF / optical data center, by N optical / RF dish antenna calibrators, each having an optical input / output and an RF input / output connected to the distal end of one of the N SMFs; receiving N RF signals via N coaxial transmission lines, each having a proximal end connected to the RF input / output of one of the N optical / RF parabolic antenna calibrators and a distal end, by N parabolic antennas, each connected to the distal end of one of the N coaxial transmission lines; Including, the N optical / RF parabolic antenna calibrators perform tests for RF calibration using the N optical signals as RF test signals; the RF / optical data center; a low phase noise source having a 10 MHz input, a 550 MHz output, a 1 GHz output, a first M number of output buses, and a second M number of output buses, where M is a positive integer; a calibration manager controller having a one pulse per second (PPS) input, an Inter-Range Instrumentation Group (IRIG) time code format B (IRIGB) input, a 10 MHz input, a 10 Gigabit Ethernet (GbE) input, a 1 GbE input, a 550 MHz input connected to the 550 MHz output of the low phase noise source, and a resource period (RP) synchronization (RP Sync) output; a calibration digital receiver / exciter (DREX) assembly having a 1 GbE input, a 1 PPS input, a 10 MHz input, a first input connected to the RP sync output of the calibration manager controller, a second input connected to the 550 MHz output of the low phase noise source, a calibration DREX data input / output, an output, a third input, and a fourth input; a dual coupler having a first input / output connected to the output of the calibration DREX assembly, a first output connected to the third input of the calibration DREX assembly, a second output connected to the fourth input of the calibration DREX assembly, and a second input / output; a 1:N RF switch having 1GbE input, input, output, and N input / output buses; M first 1-to-P dividers each having M input buses and N output buses (M and P are positive integers) connected to the first M output buses of the low phase noise source, respectively; M second 1-to-P dividers each having M input buses and N output buses respectively connected to the second M output buses of the low phase noise source; N RF multiplexer assemblies each having N input / output buses connected to the N input / output buses of the 1:N RF switch, first N input buses connected to the N output buses of the M first 1:P dividers, respectively, second N input buses connected to the N output buses of the M second 1:P dividers, respectively, and N optical input / output buses; N phase-stable cards each having a first N number of optical input / output buses and a second N number of optical input / output buses respectively connected to the N number of optical input / output buses of the N number of RF multiplexer assemblies; A method comprising:

18. A method for transmitting N optical signals by a radio frequency / optical (RF / optical) data center having at least one optical input / output, where N is a positive integer; receiving the N optical signals via N single mode fibers (SMFs), each having a proximal end connected to the at least one optical input / output and a distal end connected to the at least one optical input / output of the RF / optical data center, by N optical / RF dish antenna calibrators, each having an optical input / output and an RF input / output connected to the distal end of one of the N SMFs; receiving N RF signals via N coaxial transmission lines, each having a proximal end connected to the RF input / output of one of the N optical / RF parabolic antenna calibrators and a distal end, by N parabolic antennas, each connected to the distal end of one of the N coaxial transmission lines; Including, the N optical / RF parabolic antenna calibrators perform tests for RF calibration using the N optical signals as RF test signals; Each of the optical / RF parabolic antenna calibrators comprises: an optical / RF multiplexer assembly having an optical input / output, a first RF output, a second RF output, and an RF input / output; a 1-to-L splitter having an RF input connected to the first RF output of the optical / RF multiplexer assembly, and L RF outputs, where L is a positive integer; a termination (TERM) device having an RF input connected to the second RF output of the optical / RF multiplexer assembly; a K-to-1 switch having an RF input / output, a first RF input / output, a second RF input / output, a third RF input / output, a fourth RF input / output, a first RF output, a second RF output, a third RF output, a first RF input, and a second RF input connected to the RF input / output of the optical / RF multiplexer assembly, where K is a positive integer; a short circuit tester having an RF input / output connected to the second RF input / output of the K-to-1 switch; an open test device having an RF input / output connected to the third RF input / output of the K-to-1 switch; a load tester having an RF input / output connected to the fourth RF input / output of the K-to-1 switch; a parabolic antenna digital receiver / exciter (DREX) assembly having a one pulse per second (1 PPS) input, a 10 MHz input, a resource period (RP) synchronization (sync) input, a first RF input connected to the RF output of the 1-to-L splitter, a second RF input, a third RF input, a first RF output, a fourth RF input connected to the first RF output, and a fifth RF input connected to the first RF output of the K-to-1 switch, a second RF output configured to provide a first excitation signal, and a third RF output configured to provide a second excitation signal; a low noise amplifier (LNA) assembly having a first RF output connected to the second RF input of the parabolic antenna DREX assembly, a second RF output connected to the third RF input of the parabolic antenna DREX assembly, a first RF input connected to the second RF output of the K-to-1 switch, a second RF input connected to the third RF output of the K-to-1 switch, a third RF input, and a fourth RF input; a transmitter assembly having a first RF input connected to the third RF output of the parabolic antenna DREX assembly, a second RF input connected to the second RF output of the parabolic antenna DREX assembly, a first RF output, and a second RF output; a first circulator having a first RF input connected to the first RF output of the transmit assembly, an RF output connected to the fourth RF input of the LNA assembly, and an RF input and output; a second circulator having a first RF input connected to the second RF output of the transmit assembly, an RF output connected to the third RF input of the LNA assembly, and an RF input and output; a first coupler having a first RF input / output connected to the RF input / output of the first circulator and a second RF input / output; a second coupler having a first RF input / output connected to the RF input / output of the second circulator, and a second RF input / output; a polarizer having a first RF input / output connected to the second RF input / output of the first circulator, a second RF input / output connected to the second RF input / output of the second circulator, and a third RF input / output including the RF output of the optical / RF parabolic antenna calibrator; A method comprising:

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