An adaptive multi-element very low frequency phased array antenna system and its control method

Abstract

This application discloses an adaptive multi-element very low frequency (VLF) phased array antenna system and its control method. The system includes: antenna elements comprising a vertical radiator and a capacitor network mounted on top of the vertical radiator; a central signal processing and distribution unit containing the same number of parallel signal channels as the antenna elements, each signal channel integrating a signal conditioning device; a feed network whose input is connected to the central signal processing and distribution unit and whose output is connected to the vertical radiator, transmitting a radio frequency excitation signal; multiple feedback sensors disposed in the feed network monitoring the electrical state parameters of the signal flowing to the antenna elements; and a central control unit connected to the feedback sensors and the central signal processing and distribution unit, controlling the signal conditioning device to adjust the amplitude and phase of the excitation signal based on the electrical state parameters monitored by the feedback sensors. This invention enables VLF antennas to perform beamforming and directional communication, expanding the flexibility of the antenna system.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and more specifically, to an adaptive multi-element very low frequency phased array antenna system and its control method. Background Technology

[0002] Very Low Frequency (VLF, 3-30 kHz) communication plays an irreplaceable role in military communications, anti-submarine communications, global timing, and geophysical exploration due to its unique advantages of low propagation loss, high stability, and ability to penetrate seawater and strata. However, the extremely long wavelength in this frequency band means that the physical size of antenna elements in practical engineering is much smaller than the operating wavelength, forming typical "electrically small antennas." Their inherent low radiation resistance and relatively high loss resistance severely limit the antenna's radiation efficiency, which becomes the core challenge in the design and implementation of VLF antenna systems.

[0003] To improve efficiency, mainstream VLF antenna systems in current technology employ a top-loaded capacitor network composed of a large cable net, grounded through multiple vertical downleads. In this architecture, typically only one downlead serves as the main excitation unit, directly fed by the transmitter, while the remaining downleads act as parasitic units. Static phase tuning is achieved by connecting adjustable passive inductors (such as varistors) to their bases, aiming to couple with the main excitation unit and form an equivalent, larger current distribution region, thereby improving the antenna's radiation efficiency to some extent.

[0004] However, traditional solutions have several drawbacks. First, due to the lack of independent control over the excitation signals of each unit, the system cannot dynamically optimize based on real-time communication needs (such as changing beam direction) or environmental changes (such as changes in ground grid resistance with humidity), resulting in a essentially fixed radiation pattern and limited functionality. Second, in the physically demanding environment of very low frequency (VLF), relying on fixed passive components makes it difficult to accurately compensate for complex mutual coupling effects, causing the actual current distribution to deviate from the ideal state and limiting further efficiency improvements. Finally, the system's control is rigid, unable to intelligently reconfigure to maintain derating operation when some units fail, resulting in insufficient reliability and robustness. Summary of the Invention

[0005] To address at least one deficiency or improvement requirement in the prior art, this invention provides an adaptive multi-element very low frequency phased array antenna system and its control method. This system solves the problems in the prior art, such as the lack of independent control capability for the excitation signals of each element, the inability to dynamically optimize according to real-time communication requirements or environmental changes, the difficulty in accurately compensating for complex mutual coupling effects by relying on fixed passive components, and the resulting deviation of the actual current distribution from the ideal state, which limits the improvement of efficiency.

[0006] To achieve the above objectives, according to a first aspect of the present invention, an adaptive multi-element very low frequency phased array antenna system is provided, comprising:

[0007] It includes at least two antenna units, a central signal processing and distribution unit, a power supply network, multiple feedback sensors, and a central control unit.

[0008] Each antenna element includes a vertical radiator isolated from the ground by an insulator and a top-loaded capacitor network mounted on top of the vertical radiator.

[0009] The central signal processing and distribution unit contains multiple parallel signal channels, the same number as the antenna elements. Each signal channel integrates a signal conditioning device controlled by the central control unit.

[0010] The input of the feed network is connected to the output of the central signal processing and distribution unit, and its output is connected to the base of the vertical radiator of each antenna element to transmit radio frequency excitation signals.

[0011] Multiple feedback sensors are installed in the feed network to monitor the electrical status parameters of the signals flowing to each antenna element;

[0012] The central control unit communicates with the feedback sensor and the central signal processing and distribution unit. Based on the electrical status parameters monitored by the feedback sensor, it controls the signal conditioning device to dynamically adjust the amplitude and phase of the excitation signal fed to each antenna element through the power supply network.

[0013] In one possible implementation, each signal processing channel is also connected in series with an active impedance matching network, which is composed of variable reactance elements controlled by a central control unit.

[0014] The central control unit is also configured to calculate the real-time input impedance of each antenna unit based on the voltage and current data monitored by the feedback sensor, and to achieve dynamic matching between the active impedance matching network and the input impedance of the antenna unit by adjusting the parameters of the variable reactance element.

[0015] One possible implementation also includes a hierarchical grounding network system, which includes:

[0016] The main ground network, which is buried underground, covers the entire antenna array area, and there are multiple secondary ground networks corresponding to each antenna element. Each secondary ground network consists of a conductor network that is buried radially with the base of the vertical radiator of the corresponding antenna element as the center, and each secondary ground network is electrically connected to the main ground network through one or more current-limiting impedance points.

[0017] In one possible implementation, a ground current compensation network is also included, which includes controllable current paths connecting different secondary ground grids.

[0018] The controllable current path is controlled by the central control unit and is used to inject an adjustable compensation current into the grounding network system to counteract the interference circulating current generated between the secondary grounding networks of different antenna units due to electromagnetic coupling.

[0019] In one possible implementation, the top-loaded capacitor network is an umbrella-shaped cable net structure supported by multiple peripheral grounding support towers. The top-loaded capacitor networks of adjacent antenna elements partially overlap in space and are electrically isolated from each other by insulators.

[0020] In one possible implementation, the central control unit is also configured as follows:

[0021] By analyzing the data stream from the feedback sensors, the faulty antenna unit or signal channel can be identified.

[0022] After a fault is detected, the output amplitude of the faulty signal channel is reduced to a minimum through the amplitude control component to achieve electrical isolation.

[0023] Using other normally functioning antenna elements as the optimization target, calculate and set the excitation parameters of other normally functioning antenna elements.

[0024] According to a second aspect of the present invention, a control method is also provided for controlling an adaptive multi-element very low frequency phased array antenna system as described in any of the possible implementations above, comprising:

[0025] Based on real-time monitoring data from feedback sensors and preset system performance targets, control commands for each signal conditioning device are generated through optimization algorithms.

[0026] The real-time monitoring data includes at least the current amplitude and phase information of the feed point of each antenna element;

[0027] By controlling the signal conditioning device driven by the command, the amplitude and phase of the excitation signal fed to each antenna element are adjusted, and the mutual coupling effect between the antenna elements is dynamically compensated, so that the radiation characteristics reach the preset system performance target.

[0028] In one possible implementation, the optimization algorithm includes:

[0029] The real-time current amplitude and phase of the antenna element are used as feedback quantities;

[0030] The optimization objective is to maximize the total radiation resistance of the system or minimize the total power loss of the system.

[0031] By iteratively adjusting the amplitude control commands and phase control commands of each channel in the central signal processing and distribution unit, the feedback quantity is made closer to the optimization target.

[0032] One possible implementation also includes:

[0033] When a frequency switching command is received, the preset impedance matching parameters corresponding to the target frequency are called and loaded into the active impedance matching network.

[0034] Based on the expected beam pointing at the target frequency, the initial phase offset of each signal channel is calculated and loaded into the corresponding digital phase shifter, and closed-loop optimization based on real-time monitoring data is initiated.

[0035] One possible implementation also includes:

[0036] By comparing real-time monitoring data with historical operating data or preset thresholds, the specific antenna unit that has malfunctioned can be identified.

[0037] Generate control commands to reduce the signal amplitude of the channel leading to the faulty unit;

[0038] The remaining normal antenna elements are arranged into a new array, and the optimization algorithm is re-executed to assign appropriate excitation amplitude and phase to the remaining elements.

[0039] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0040] This invention provides an adaptive multi-element very low frequency (VLF) phased array antenna system. Through a central signal processing and distribution unit and multiple parallel signal channels (the same number as the antenna elements) within it, active feeding of each antenna element is achieved. The signal conditioning device integrated in each signal channel and controlled by the central control unit can independently adjust the amplitude and phase of the excitation signal fed to each antenna element. The excitation state of each element can be flexibly configured through control commands, thereby dynamically forming and scanning the radiated beam in the horizontal plane. This achieves beamforming and directional communication capabilities that were previously impossible in VLF antennas, expanding the flexibility of the antenna system. By using multiple feedback sensors installed in the feed network to monitor the electrical state parameters (such as current and voltage) of the signals flowing to each antenna element in real time, and the central control unit to control the aforementioned signal conditioning device to make dynamic adjustments based on this real-time data, a complete closed-loop feedback and control loop is formed. This loop can detect in real time the adverse effects of the strong mutual coupling effect caused by the extremely small spacing between elements on the current distribution, and immediately perform precise phase and amplitude compensation, forcing the current distribution of the entire array to always approach the ideal model with the highest radiation efficiency, which can significantly improve the overall radiation efficiency of the antenna. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is an overall structural diagram of an embodiment of the adaptive multi-element very low frequency phased array antenna system provided by the present invention.

[0043] Figure 2 A top view of an embodiment of the adaptive multi-element very low frequency phased array antenna system provided by the present invention;

[0044] Figure 3 A functional block diagram of an embodiment of the adaptive multi-element very low frequency phased array antenna system provided by the present invention;

[0045] Figure 4 A schematic diagram of an embodiment of a single antenna element and its base provided by the present invention;

[0046] Figure 5 This is a network schematic diagram of an embodiment of the hierarchical grounding grid system and ground current compensation network provided by the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0048] The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0049] This invention provides an adaptive multi-element very low frequency phased array antenna system and its control method, which are described below.

[0050] In one specific embodiment of the present invention, an adaptive multi-element very low frequency phased array antenna system is disclosed, comprising:

[0051] It includes at least two antenna units, a central signal processing and distribution unit, a power supply network, multiple feedback sensors, and a central control unit.

[0052] Each antenna element includes a vertical radiator isolated from the ground by an insulator and a top-loaded capacitor network mounted on top of the vertical radiator.

[0053] The central signal processing and distribution unit contains multiple parallel signal channels, the same number as the antenna elements. Each signal channel integrates a signal conditioning device controlled by the central control unit.

[0054] The input of the feed network is connected to the output of the central signal processing and distribution unit, and its output is connected to the base of the vertical radiator of each antenna element to transmit radio frequency excitation signals.

[0055] Multiple feedback sensors are installed in the feed network to monitor the electrical status parameters of the signals flowing to each antenna element;

[0056] The central control unit communicates with the feedback sensor and the central signal processing and distribution unit. Based on the electrical status parameters monitored by the feedback sensor, it controls the signal conditioning device to dynamically adjust the amplitude and phase of the excitation signal fed to each antenna element through the power supply network.

[0057] In the above embodiments, each antenna element is an independent electrically small antenna, the core of which consists of a vertical radiator (usually a tall tower structure) and a top-loaded capacitor network (a giant umbrella-shaped cable net). The vertical radiator is isolated from the ground by large insulators to ensure effective radiation of radio frequency energy; the top-loaded network effectively reduces the resonant frequency of the antenna through huge distributed capacitance, making it suitable for the VLF band. As a preferred embodiment, multiple antenna elements (at least two) can be geographically arranged according to a certain pattern (such as circular, triangular, or rectangular) to jointly form the physical basis of the antenna array.

[0058] The central signal processing and distribution unit is responsible for converting a single radio frequency (RF) signal from a main transmitter into multiple independently adjustable excitation signals. Internally, it contains multiple parallel signal channels corresponding to the number of antenna elements. Each channel is a complete signal conditioning link, integrating at least a digital phase shifter and a digital amplitude controller. The digital phase shifter receives instructions from the central control unit and performs continuous and precise phase shifting of the RF signal passing through that channel from 0° to 360°. The digital amplitude controller, typically implemented by a digitally controlled attenuator or a controllable gain amplifier, is used to precisely set the amplitude level of the channel's output signal. Additionally, an active impedance matching network, consisting of variable capacitors / inductors controlled by the central control unit, can be added to adjust the channel's output impedance in real time to match the fluctuating antenna input impedance due to environmental changes, ensuring efficient power transmission.

[0059] The power supply network consists of high-power, low-loss radio frequency cables or parallel feeders, which are responsible for transmitting the conditioned multi-channel excitation signals output by the central signal processing and distribution unit to the vertical radiator base of the corresponding antenna element with high fidelity.

[0060] On each output feed line of the feed network, a high-precision feedback sensor (such as a directional coupler or current / voltage probe) is installed close to the antenna feed point to monitor the key electrical state parameters of the signal flowing to each antenna element in real time and without damage, including but not limited to the amplitude and phase of the incident and reflected waves, as well as the equivalent impedance of the feed point.

[0061] The central control unit is a high-performance embedded computer or industrial control server that continuously receives real-time monitoring data from all feedback sensors via a high-speed data bus. Optimization algorithms (such as gradient descent and perturbation observation methods) run within the control unit, comparing and calculating real-time data against preset performance targets. Based on the algorithm's calculation results, the control unit generates digital control commands and sends them to the digital phase shifters and digital amplitude controllers of each channel within the central signal processing and distribution unit. The actuators then dynamically and independently adjust the phase and amplitude of their respective channel output signals according to the commands, enabling the system to respond in real-time to any factors that cause performance changes (such as antenna parameter drift caused by temperature and humidity changes, or strong mutual coupling effects between units), locking the antenna array's radiation state at the optimal or near-optimal operating point.

[0062] Compared with existing technologies, the adaptive multi-element very low frequency phased array antenna system provided in this embodiment achieves active feeding of each antenna element through a central signal processing and distribution unit and multiple parallel signal channels with the same number of antenna elements. The signal conditioning device integrated in each signal channel and controlled by the central control unit can independently adjust the amplitude and phase of the excitation signal fed to each antenna element. The excitation state of each element can be flexibly configured through control commands, thereby dynamically forming and scanning the radiation beam in the horizontal plane. This achieves beamforming and directional communication capabilities that were previously impossible in very low frequency antennas, expanding the tactical flexibility of the antenna system. By using multiple feedback sensors installed in the feed network to monitor the electrical state parameters (such as current and voltage) of the signals flowing to each antenna element in real time, and the central control unit to control the aforementioned signal conditioning device to make dynamic adjustments based on this real-time data, a complete closed-loop feedback and control loop is formed. This loop can detect in real time the adverse effects of the strong mutual coupling effect caused by the extremely small spacing between elements on the current distribution, and immediately perform precise phase and amplitude compensation, forcing the current distribution of the entire array to always approach the ideal model with the highest radiation efficiency, which can significantly improve the overall radiation efficiency of the antenna.

[0063] In some embodiments of the present invention, each signal processing channel is also connected in series with an active impedance matching network, which is composed of variable reactance elements controlled by a central control unit.

[0064] The central control unit is also configured to calculate the real-time input impedance of each antenna unit based on the voltage and current data monitored by the feedback sensor, and to achieve dynamic matching between the active impedance matching network and the input impedance of the antenna unit by adjusting the parameters of the variable reactance element.

[0065] In the above embodiments, in order to overcome the impedance mismatch problem caused by the sensitivity of very low frequency antennas to the environment, an active impedance matching network is connected in series in each signal processing channel. Its core structure is a reconfigurable π-type or T-type passive network. However, the key reactive components (such as capacitors or inductors) in the network are not fixed values ​​or manually adjusted. Instead, they adopt voltage-controlled or digitally controlled variable reactive components directly controlled by the central control unit, such as varactor diodes based on semiconductor technology or switched capacitor arrays based on microelectromechanical systems (MEMS). According to the received control signal, their equivalent capacitance or inductance value can be continuously or stepwise changed within the microsecond to millisecond range, providing the entire matching network with fast and accurate impedance transformation capability.

[0066] Using high-precision feedback sensors (such as directional couplers or voltage / current probes) positioned at the feed point, the system continuously monitors the voltage and current amplitudes of the RF signal flowing to each antenna element, as well as their relative phase, and transmits this raw data to the central control unit in real time. The central control unit runs dedicated impedance calculation firmware that calculates and updates the complex input impedance of each antenna element in real time based on the received voltage and current data. Subsequently, the control unit compares the calculated real-time impedance with the target matching impedance (usually purely resistive) preset by the system to maximize power transmission. Based on the built-in impedance matching model and optimization algorithm, it calculates the target reactance values ​​required for each variable reactance element in the network to achieve conjugate matching between the output impedance of the active impedance matching network and the antenna input impedance. The central control unit converts the calculated target reactance values ​​into control commands, driving the variable reactance elements in the channel to make corresponding changes, altering the impedance transformation characteristics of the matching network, thereby achieving real-time tracking and matching of the antenna input impedance.

[0067] Whether due to frequency switching or significant impedance drift caused by external environmental factors (such as temperature, humidity, and precipitation), the system can actively and accurately compensate for these changes through its fast closed-loop response, always keeping the system's voltage standing wave ratio at the lowest level. This greatly reduces power reflection loss between the transmitter's final stage and the antenna, not only directly improving the overall energy radiation efficiency of the system but also significantly widening the bandwidth that allows the antenna system to maintain efficient operation.

[0068] In some embodiments of the present invention, a hierarchical grounding grid system is also included, the hierarchical grounding grid system comprising:

[0069] The main ground network, which is buried underground, covers the entire antenna array area, and there are multiple secondary ground networks corresponding to each antenna element. Each secondary ground network consists of a conductor network that is buried radially with the base of the vertical radiator of the corresponding antenna element as the center, and each secondary ground network is electrically connected to the main ground network through one or more current-limiting impedance points.

[0070] In the above embodiments, in order to significantly reduce grounding network loss, the present invention adopts a hierarchical grounding network system, including a main grounding network covering the entire antenna array area, and a secondary grounding network independently set for each antenna element. The secondary grounding network is composed of a dense radial conductor network centered on the vertical radiator base of the corresponding antenna element, and is connected to the main grounding network through a current-limiting impedance point.

[0071] High-frequency isolation is achieved by using current-limiting impedance points, confining the main radio frequency ground current of each unit within its respective secondary ground network area, effectively reducing the grounding resistance of the unit itself. At the same time, by suppressing the coupling loop current formed between different units through the main ground network, the energy loss caused by ground current mutual coupling is reduced. Ground network management structurally reduces the total system loss resistance.

[0072] In some embodiments of the present invention, a ground current compensation network is also included, which includes controllable current paths connected between different secondary ground grids.

[0073] The controllable current path is controlled by the central control unit and is used to inject an adjustable compensation current into the grounding network system to counteract the interference circulating current generated between the secondary grounding networks of different antenna units due to electromagnetic coupling.

[0074] In the above embodiments, to fundamentally solve the ground current coupling problem, a ground current compensation network is introduced, comprising controllable current paths connecting different secondary ground grids. These paths are controlled by a central control unit. By monitoring the ground current characteristics of each unit in real time, the central control unit calculates the compensation current parameters to be injected and drives the controllable current paths to generate corresponding compensation currents. This accurately generates compensation currents with the same amplitude but opposite phase to the interference circulating current, thereby effectively neutralizing the electromagnetic coupling effect between different secondary ground grids. The compensation network works in conjunction with the hierarchical ground grid system to form a dual protection of passive isolation and active cancellation, improving the purity of the ground grid system.

[0075] In some embodiments of the present invention, the top-loaded capacitor network is an umbrella-shaped cable net structure supported by multiple peripheral grounding support towers. The top-loaded capacitor networks of adjacent antenna units partially overlap in space and are electrically isolated from each other by insulators.

[0076] In the above embodiment, an umbrella-shaped cable net suspended by an external grounding support tower is used as the top-loaded capacitor network. This structure allows the umbrella-shaped cable net structures of adjacent antenna elements to overlap appropriately in space to improve the electromagnetic field distribution. The umbrella-shaped cable net structures are electrically isolated from each other through insulators. While maintaining the electromagnetic coupling effect, the electrical independence of each unit is ensured. This not only improves the top loading efficiency but also provides a basis for the independent control of the phased array, achieving the best balance between structural efficiency and electrical performance.

[0077] In some embodiments of the present invention, the central control unit is further configured to:

[0078] By analyzing the data stream from the feedback sensors, the faulty antenna unit or signal channel can be identified.

[0079] After a fault is detected, the output amplitude of the faulty signal channel is reduced to a minimum through the amplitude control component to achieve electrical isolation.

[0080] Using other normally functioning antenna elements as the optimization target, calculate and set the excitation parameters of other normally functioning antenna elements.

[0081] In the above embodiments, the central control unit possesses intelligent fault detection and system self-healing capabilities. It continuously analyzes the data streams transmitted from various feedback sensors to monitor the operational status of the antenna units and signal channels in real time. When fault characteristics such as signal anomalies, impedance surges, or power transmission interruptions are detected, the control unit identifies the specific antenna unit or signal channel that has malfunctioned. After confirming the fault, the central control unit adjusts the digital amplitude controller of the faulty channel to reduce the RF output amplitude of that channel to a minimum, achieving electrical isolation of the faulty unit. This prevents the fault from escalating while ensuring the continuous operation of the rest of the system.

[0082] The central control unit uses the remaining normally functioning antenna elements as the optimization target, reconstructs the array model, and calculates the optimal combination of excitation parameters through optimization algorithms, including the excitation amplitude, phase, and impedance matching status of each normal element. This ensures that the system can maintain optimal radiation performance in degraded mode, giving the antenna system good fault tolerance. Even if some elements fail, it can still maintain basic functions through parameter reconfiguration.

[0083] According to a second aspect of the present invention, a control method for controlling an adaptive multi-element very low frequency phased array antenna system as described in any of the above embodiments is also provided, comprising:

[0084] Based on real-time monitoring data from feedback sensors and preset system performance targets, control commands for each signal conditioning device are generated through optimization algorithms.

[0085] The real-time monitoring data includes at least the current amplitude and phase information of the feed point of each antenna element;

[0086] By controlling the signal conditioning device driven by the command, the amplitude and phase of the excitation signal fed to each antenna element are adjusted, and the mutual coupling effect between the antenna elements is dynamically compensated, so that the radiation characteristics reach the preset system performance target.

[0087] In the above embodiments, the core of the control method lies in constructing a dynamic adaptive control system. A feedback sensor network deployed at the feed points of each antenna element continuously collects multi-dimensional real-time monitoring data, including current amplitude, phase, and impedance characteristics, forming the basis for system state awareness. The central control unit simultaneously receives preset system performance targets, which can be flexibly set according to actual application requirements, including but not limited to specific radiation patterns, maximum radiation efficiency, optimal bandwidth characteristics, or specific beam pointing requirements.

[0088] Based on the comparative analysis of real-time monitoring data and preset performance targets, the central control unit runs optimization algorithms (such as gradient descent method, disturbance observation method, etc.). This algorithm comprehensively considers the electromagnetic coupling effect between each antenna unit, changes in environmental parameters and the current working state of the system. It generates the optimal control instruction set for each signal channel through iterative calculation, and specifies the required phase offset, amplitude weight and impedance matching parameters for each channel, forming a complete control strategy.

[0089] During the command execution phase, the generated control commands are sent in real time to various signal conditioning devices in the central signal processing and distribution unit. The digital phase shifter precisely adjusts the phase characteristics of the radio frequency signal according to the commands, the digital amplitude controller sets the amplitude level of the signal as needed, and the active impedance matching network dynamically optimizes the impedance matching state. These conditioning devices work together to achieve independent and precise control of the excitation signal for each antenna element.

[0090] In some embodiments of the present invention, the optimization algorithm includes:

[0091] The real-time current amplitude and phase of the antenna element are used as feedback quantities;

[0092] The optimization objective is to maximize the total radiation resistance of the system or minimize the total power loss of the system.

[0093] By iteratively adjusting the amplitude control commands and phase control commands of each channel in the central signal processing and distribution unit, the feedback quantity is made closer to the optimization target.

[0094] In the above embodiments, the optimization objectives of the algorithm have clear physical meaning, mainly including two optional optimization directions: one is to maximize the total radiation resistance of the system by optimizing the current distribution of each element to enhance the effective radiation capability of the antenna; the other is to minimize the total power loss of the system by adjusting the excitation parameters to reduce ohmic loss and ground network loss. Both objectives essentially aim to improve the overall efficiency of the antenna system, and can be flexibly selected and switched according to actual application requirements.

[0095] During the optimization process, the algorithm employs an iterative adjustment strategy. It continuously fine-tunes the amplitude and phase control commands of each channel in the central signal processing and distribution unit, observing the changing trends of the system response. Specifically, the algorithm applies small perturbations to the control parameters near the current operating point according to a specific optimization strategy (such as gradient descent or perturbation observation). By analyzing the corresponding changes in the feedback quantity, it determines the optimal adjustment direction to achieve the optimization objective.

[0096] Each iterative adjustment is based on feedback data from the previous measurement, forming a closed loop of measurement-decision-adjustment-verification. Through continuous optimization, the system can gradually drive feedback quantities such as current amplitude and phase towards the predetermined optimization target, achieving precise control of radiation characteristics. Real-time parameter adjustments effectively compensate for electromagnetic coupling effects between units, ensuring that the system maintains optimal radiation performance under various operating conditions.

[0097] In some embodiments of the present invention, it further includes:

[0098] When a frequency switching command is received, the preset impedance matching parameters corresponding to the target frequency are called and loaded into the active impedance matching network.

[0099] Based on the expected beam pointing at the target frequency, the initial phase offset of each signal channel is calculated and loaded into the corresponding digital phase shifter, and closed-loop optimization based on real-time monitoring data is initiated.

[0100] In the above embodiments, the present invention also includes a complete frequency adaptive control mechanism to ensure that the system can quickly switch between different operating frequencies and maintain optimal performance. When the central control unit receives a frequency switching command, the system starts a preset parameter calling program, retrieves and calls preset impedance matching parameters corresponding to the target frequency from the storage unit. These preset parameters are optimal values ​​obtained based on prior analysis of the antenna impedance characteristics at each frequency point, and are then quickly loaded into the active impedance matching network of each channel to achieve the initial configuration of the variable reactance element.

[0101] Meanwhile, based on the expected beam pointing requirements at the target frequency, the system calculates the initial phase offset required for each signal channel using a built-in beamforming algorithm. This offset is then loaded into the corresponding digital phase shifters via the control bus to complete the initial beam pointing calibration. By combining preset parameters with real-time optimization, the system effectively avoids performance oscillations during frequency switching and shortens the system stabilization time.

[0102] After initial parameter configuration, a closed-loop optimization process based on real-time monitoring data is initiated. Operating parameters at the new frequency are continuously collected, and the optimization algorithm is adjusted according to the actual current amplitude and phase information, gradually eliminating residual mismatch and pointing errors. The entire frequency switching process achieves a smooth transition from preset configuration to closed-loop optimization, ensuring both switching speed and final operating accuracy, enabling the system to maintain adaptability and stability throughout multi-frequency band operation.

[0103] In some embodiments of the present invention, it further includes:

[0104] By comparing real-time monitoring data with historical operating data or preset thresholds, the specific antenna unit that has malfunctioned can be identified.

[0105] Generate control commands to reduce the signal amplitude of the channel leading to the faulty unit;

[0106] The remaining normal antenna elements are arranged into a new array, and the optimization algorithm is re-executed to assign appropriate excitation amplitude and phase to the remaining elements.

[0107] In the above embodiments, the system accurately identifies specific antenna elements that have malfunctioned by continuously comparing real-time monitoring data with normal operating modes in the historical operating database, or by comparing them with preset abnormal threshold ranges. When an abnormal drop in current amplitude, a sudden change in phase, or a continuous deviation of impedance characteristics from the normal range is detected in a certain element, the system immediately marks that element as faulty.

[0108] After a fault is confirmed, the central control unit generates a specific control command. By adjusting the digital amplitude controller of the faulty channel, the amplitude of the radio frequency signal leading to the faulty unit is reduced to the lowest level, thereby achieving electrical isolation of the faulty channel. This not only prevents the spread of the fault's impact but also ensures the continued stable operation of the rest of the system.

[0109] The control unit removes the isolated faulty elements from the effective array and reconstructs the optimized model using the remaining normally functioning antenna elements. Based on the new array configuration, the system re-executes the optimization algorithm, calculating and assigning the optimal excitation amplitude and phase combination to each normal element. This fully considers the layout changes and mutual coupling effects of the remaining elements, and through parameter re-optimization, the system can maintain the best radiation characteristics even in degraded mode, ensuring that the loss of beam pointing accuracy and radiation efficiency is minimized.

[0110] The entire fault handling process achieves fully automated intelligent response, completing the entire process from fault identification to system reconstruction without human intervention, thereby enhancing the system's survivability and mission reliability in complex environments.

[0111] Specifically, this invention also provides a three-element adaptive VLF phased array system; please refer to [link / reference]. Figure 1 , Figure 2 , Figure 1 This is an overall structural diagram of an embodiment of the adaptive multi-element very low frequency phased array antenna system provided by the present invention. Figure 2 This is a top view of an embodiment of the adaptive multi-element very low frequency (VLF) phased array antenna system provided by the present invention. This embodiment describes an adaptive VLF phased array system consisting of three antenna elements 2. The three antenna elements 2 are arranged in an equilateral triangle, with the transmitter room / control center 7 at its center.

[0112] The structure of each antenna element 2 includes:

[0113] 1. A vertical radiator 21, typically a steel pipe or steel frame structure, whose base is insulated from the ground by a large insulator.

[0114] 2. A large top-loaded capacitor network 22, in the form of a hexagonal umbrella, covers a wide area. This network is constructed of conductors and is suspended and supported by multiple (e.g., six) peripheral grounding support towers 23. The top-loaded networks of the three antenna elements may partially overlap in the edge regions, but are electrically isolated by insulators to reduce unwanted direct coupling.

[0115] The core of this invention lies in its control system. Please refer to [link / reference]. Figure 3 , Figure 3 This is a functional block diagram of an embodiment of the adaptive multi-element very low frequency phased array antenna system provided by the present invention. The very low frequency radio frequency signal from the main transmitter first enters the central signal processing and distribution unit 3.

[0116] 1. The signal is split into three paths by an RF power divider 31 and sent to three parallel signal processing channels respectively.

[0117] 2. In each channel, the signal passes through sequentially:

[0118] Digital phase shifter 32: Controlled by the central control unit 5, it can make precise and rapid adjustments to the signal phase from 0 to 360°.

[0119] Digital amplitude controller 33: Controlled by the central control unit 5, used to precisely adjust the amplitude of the channel signal.

[0120] Active impedance matching network 34: This is an adjustable LC network whose component values ​​(such as variable capacitors and variable inductors) are controlled by the central control unit 5 to achieve real-time matching of the input impedance of the antenna unit.

[0121] 3. The processed three signals are fed to the base of the vertical radiator 21 of the three antenna elements 2 respectively through the feeding network 4.

[0122] 4. At the feed point of each vertical radiator 21, a feedback sensor 41, typically a current / voltage transformer, is installed. It can losslessly couple out a small portion of the signal and measure the current and voltage at that point, thereby calculating the antenna impedance and signal phase.

[0123] 5. These measurement data are sent back to the central control unit 5. This is a high-performance processor (CPU) that runs the core control algorithm of this invention. Based on these real-time feedback data, the central control unit 5 compares them with preset performance targets, calculates the required adjustments to the phase, amplitude, and impedance matching of each channel, and issues corresponding control commands to devices 32, 33, and 34, forming a complete, high-speed closed-loop control.

[0124] Please see Figure 4 , Figure 4 This is a schematic diagram of an embodiment of a single antenna element and its base provided by the present invention. The base structure of each vertical radiator 21 is complex. It is mounted on a large insulator to isolate it from the ground. In addition to the feed line connected from the feed network 4, a large tuning coil 8 (typically a varistor) is connected in series at the base for coarse adjustment of the antenna's reactance component. The active impedance matching network 34 is responsible for fine, dynamic matching based on this.

[0125] Please see Figure 5 , Figure 5 This is a network diagram of an embodiment of the hierarchical ground network system and ground current compensation network provided by the present invention. Ground network loss is the biggest bottleneck to the efficiency of very low frequency antennas. The present invention uses a hierarchical ground network system for optimization.

[0126] Main ground network 61: Composed of radial or grid-like copper strips buried underground, covering the entire antenna array area, providing a unified, low-resistance radio frequency ground for the entire system.

[0127] Secondary grounding grid 62: A separate, higher-density radial grounding grid is set up around each vertical radiator 21. It directly carries the main grounding current of the radiator unit and is connected to the main grounding grid 61 through a limited number of connection points. This design can effectively reduce the ground resistance near each unit.

[0128] Ground current compensation network 63: This is another innovation of the present invention. Due to the strong coupling between units, the grounding current of one unit will affect other units through the ground. The ground current compensation network 63 is an active or passive network controlled by the central control unit 5. It is connected between different secondary ground networks 62 and can actively change the current distribution of the ground network system. For example, it can force the ground current coupling between units to zero or achieve a certain optimal distribution, thereby further reducing the total ground loss.

[0129] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0130] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0131] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some service interface; the indirect coupling or communication connection between devices or units may be electrical or other forms.

[0132] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0133] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0134] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0135] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, which may include: a flash drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc.

[0136] The foregoing description is merely an exemplary embodiment of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Those skilled in the art will readily conceive of embodiments of this disclosure upon considering the specification and practicing the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described herein. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

[0137] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0138] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An adaptive multi-element very low frequency phased array antenna system, characterized in that, include: It includes at least two antenna units, a central signal processing and distribution unit, a power supply network, multiple feedback sensors, and a central control unit. Each of the antenna elements includes a vertical radiator isolated from the ground by an insulator and a top-loaded capacitor network mounted on top of the vertical radiator. The central signal processing and distribution unit contains multiple parallel signal channels, the same number as the antenna units, and each signal channel integrates a signal conditioning device controlled by the central control unit. The input terminal of the feed network is connected to the output terminal of the central signal processing and distribution unit, and its output terminal is connected to the base of the vertical radiator of each antenna element for transmitting radio frequency excitation signals. The plurality of feedback sensors are disposed in the power supply network and are used to monitor the electrical status parameters of the signals flowing to each antenna element; The central control unit is communicatively connected to the feedback sensor and the central signal processing and distribution unit. Based on the electrical state parameters monitored by the feedback sensor, it controls the signal conditioning device to dynamically adjust the amplitude and phase of the excitation signal fed to each antenna element through the feed network. Each of the signal channels is also connected in series with an active impedance matching network, which is composed of variable reactance elements controlled by the central control unit. The central control unit is also configured to: calculate the real-time input impedance of each antenna unit based on the voltage and current data monitored by the feedback sensor, and dynamically match the input impedance of the active impedance matching network with that of the antenna unit by adjusting the parameters of the variable reactance element. In the parallel signal channel, the signal passes sequentially through a digital phase shifter, a digital amplitude controller, and an active impedance matching network. The digital phase shifter performs phase adjustment, the digital amplitude controller performs amplitude adjustment, and the active impedance matching network performs impedance adjustment.

2. The adaptive multi-element very low frequency phased array antenna system according to claim 1, characterized in that, It also includes a hierarchical grounding network system, which comprises: The system includes a main ground network buried underground, covering the entire antenna array area, and multiple secondary ground networks corresponding to each antenna element. Each secondary ground network consists of a conductor network that is radially buried with the base of the vertical radiator of the corresponding antenna element as the center, and each secondary ground network is electrically connected to the main ground network through one or more current-limiting impedance points.

3. The adaptive multi-element very low frequency phased array antenna system according to claim 2, characterized in that, It also includes a ground current compensation network, which includes controllable current paths connected between different secondary ground grids; The controllable current path is controlled by the central control unit and is used to inject an adjustable compensation current into the grounding network system to counteract the interference circulation current generated between the secondary grounding networks of different antenna units due to electromagnetic coupling.

4. The adaptive multi-element very low frequency phased array antenna system according to claim 1, characterized in that, The top-loaded capacitor network is an umbrella-shaped cable net structure supported by multiple peripheral grounding support towers. The top-loaded capacitor networks of adjacent antenna units partially overlap in space and are electrically isolated from each other by insulators.

5. The adaptive multi-element very low frequency phased array antenna system according to claim 1, characterized in that, The central control unit is also configured to: By analyzing the data stream from the feedback sensor, the faulty antenna unit or signal channel can be identified. After a fault is detected, the output amplitude of the faulty signal channel is reduced to a minimum through the amplitude control component to achieve electrical isolation. Using other normally functioning antenna elements as the optimization target, calculate and set the excitation parameters of other normally functioning antenna elements.

6. A control method for controlling an adaptive multi-element very low frequency phased array antenna system as described in any one of claims 1 to 5, characterized in that, include: Based on real-time monitoring data from the feedback sensors and preset system performance targets, control commands for each of the signal conditioning devices are generated through an optimization algorithm. The real-time monitoring data includes at least the current amplitude and phase information of the feed point of each antenna element; The control command drives the signal conditioning device to adjust the amplitude and phase of the excitation signal fed to each antenna element, dynamically compensating for the mutual coupling effect between antenna elements, so that the radiation characteristics reach the preset system performance target.

7. The control method for the adaptive multi-element very low frequency phased array antenna system according to claim 6, characterized in that, The optimization algorithm includes: The real-time current amplitude and phase of the antenna element are used as feedback quantities; The optimization objective is to maximize the total radiation resistance of the system or minimize the total power loss of the system. By iteratively adjusting the amplitude control commands and phase control commands of each channel in the central signal processing and distribution unit, the feedback quantity is made to approach the optimization target.

8. The control method for the adaptive multi-element very low frequency phased array antenna system according to claim 6, characterized in that, Also includes: When a frequency switching command is received, the preset impedance matching parameters corresponding to the target frequency are called and loaded into the active impedance matching network. Based on the expected beam pointing at the target frequency, the initial phase offset of each signal channel is calculated and loaded into the corresponding digital phase shifter, and closed-loop optimization based on the real-time monitoring data is initiated.

9. The control method for the adaptive multi-element very low frequency phased array antenna system according to claim 6, characterized in that, Also includes: By comparing the real-time monitoring data with historical operating data or preset thresholds, the specific antenna unit that has malfunctioned can be identified. Generate control commands to reduce the signal amplitude of the channel leading to the specific antenna element that has malfunctioned; The remaining normal antenna elements are arranged into a new array, and the optimization algorithm is re-executed to assign appropriate excitation amplitude and phase to the remaining elements.

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