A short-wave magnetic loop antenna system based on multi-modal collaborative reconstruction and a control method thereof

Abstract

The application belongs to the technical field of short-wave communication antennas, and relates to a short-wave magnetic loop antenna system based on multi-mode collaborative reconstruction and a control method thereof, which comprises a magnetic loop antenna radiator and an integrated antenna tuning module installed at the bottom of the magnetic loop antenna radiator, the integrated antenna tuning module comprises a reconstruction matching control unit and a reconstruction matching network unit, and the reconstruction matching control unit comprises a control unit, an impedance detection unit and a storage unit. During operation, the reconstruction matching control unit determines a target radiation mode according to communication requirements or a working frequency range, calls a corresponding path configuration scheme, controls the on-off of switches of an HF power network channel and an HF straight-through channel, and monitors and adjusts the impedance of each feed port in real time to complete the reconstruction matching of a radio frequency path. The application maintains the physical aperture and overall size of the antenna unchanged, realizes the synchronous switching of a radiation mode, impedance matching and frequency tuning through dynamic switching of a feed topology and a feed port, and achieves active reshaping of a radiation pattern.

Description

Technical Field

[0001] This invention belongs to the field of shortwave communication antenna technology, and relates to a shortwave magnetic loop antenna system and its control method based on multi-mode cooperative reconfiguration. It is particularly suitable for low-power shortwave communication scenarios that require dynamic optimization of radiation pattern according to communication distance under size constraints. Background Technology

[0002] Shortwave communication (operating frequency band 3MHz~30MHz), utilizing the ionospheric reflection propagation mechanism, enables long-distance communication beyond line of sight, making it one of the core technologies in emergency communication, military communication, and cross-regional communication systems. Magnetic loop antennas, as typical electrically small antennas, have a physical size much smaller than the operating wavelength, are compact in structure, and easy to integrate, making them promising for widespread application on space-constrained mobile platforms such as vehicles, airborne systems, and portable backpacks.

[0003] Existing technologies have conducted extensive research on shortwave magnetic loop antennas and reconfigurable antennas. For example, Chinese invention patent application number CN201710220049.1, published on June 23, 2017, discloses a reconfigurable shortwave loop antenna, which improves low-frequency matching efficiency by loading a bent conductive strip onto the antenna conductor surface and adjusting it with a switch to change the current distribution of the radiator. Another example is Chinese invention patent application number CN201910313245.2, published on August 2, 2019, which discloses an automatically tuned shortwave loop antenna and its tuning method, employing a hybrid tuning mode and controlling the electrical connection between the circuit, the radiating loop, and the coupling loop through a switch. Furthermore, Chinese utility model patent application number CN201920412961.1, published on December 24, 2019... The patent proposes a high-power shortwave antenna array mode reconfiguration switching unit, which switches the radio frequency channel between different antenna elements by switching, essentially selecting different physical antenna elements. Chinese utility model patent application number CN202520396403.6, published on March 3, 2026, discloses a pattern reconfigurable antenna that mechanically switches between dipole antennas and loop antennas via a rotation mechanism. Chinese invention patent application number CN202010085280.6, published on June 12, 2020, proposes a fractal reconfigurable vehicle-mounted shortwave antenna, which can construct different types of TE / TM electrically small antennas by switching between different shaped antenna bodies such as square, ring, and triangle. Although this solution involves TE / TM mode switching, its essence is to select among multiple physical antenna elements, similar to the technical approach of CN202520396403.6, both belonging to the "multi-element selection" physical switching scheme.

[0004] In summary, existing technologies have made some progress in the design and reconfiguration of magnetic ring antenna structures, but their research objectives mainly focus on the following three aspects: 1) Impedance matching and frequency tuning: By switching tuning elements such as capacitors and inductors or tuning paths, the antenna input impedance is matched with the 50Ω feed system. 2) Current distribution adjustment: By changing the current distribution on the radiating unit through the conduction band structure controlled by the loading switch, the operating frequency band can be widened or the gain at a specific frequency point can be increased. 3) Physical unit switching: Different antenna units can be selected by a switch, or physical replacement can be performed between different types of antennas by a mechanical mechanism.

[0005] However, the aforementioned existing technologies have the following inherent defects: 1) Limitations of the reconfiguration object: Most switching or reconfiguration processes essentially only serve impedance matching, frequency tuning, or physical unit replacement, and have never changed the fundamental radiation mechanism of the antenna, that is, the antenna always operates under a single radiation mode, and cannot achieve the essential reconfiguration of the radiation field distribution. 2) High structural complexity and high engineering difficulty: Existing technical solutions such as CN201710220049.1, CN202520396403.6 and CN202010085280.6 require the addition of multiple radiators or complex mechanical rotation mechanisms, resulting in complex overall structures, low reliability, and limited applications in magnetic loop antennas, lacking feasible engineering solutions.

[0006] On the other hand, traditional magnetic loop antennas are essentially magnetic dipole radiation systems, and their radiation pattern inherently exhibits a figure-eight distribution, with radiation null points or dips along the normal direction of the loop. This inherent radiation characteristic leads to: 1) Lack of elevation angle adjustment capability: It is impossible to dynamically optimize the radiation elevation angle according to the communication distance requirements, and it is difficult to take into account both high elevation angle blind zone communication (20km~100km) and low elevation angle short-range ground wave and medium-to-long-range sky wave communication; 2) Blind spots exist in azimuth coverage: the gain is significantly reduced at specific azimuth angles, resulting in communication blind spots and making it difficult to adapt to complex and ever-changing communication scenarios; 3) Limited environmental adaptability: The single radiation mode limits the antenna's anti-interference ability and multi-scenario adaptability in complex electromagnetic environments.

[0007] Furthermore, Chinese invention patent application number CN202111162902.1, published on August 9, 2024, discloses a tuning device with a loop antenna. It employs a dual-ring structure of an outer radiating ring and an inner resonant ring, with a tuning terminal within the base. Different rings are connected via high-pass / low-pass filters: in the low-frequency band, the inner resonant ring acts as a coupling ring, working in conjunction with the outer radiating ring to generate high-Q resonance; in the mid-to-high frequency band, only the outer radiating ring is connected, functioning as a full-ring antenna, while the inner resonant ring does not participate. Although this scheme adopts a dual-ring integrated layout structurally, its technical essence still belongs to the frequency band segmentation and coverage approach of "selecting different working rings / modes for different frequency bands." More importantly, regardless of whether dual-ring coordination is used in the low-frequency band or single-ring operation is used in the mid-to-high-frequency band, the feeding method is always the traditional symmetrical feeding mode, the antenna is always equivalent to a pure magnetic dipole (TE mode), and the radiation pattern is always a figure-eight shape or fountain shape with a high elevation angle. It is impossible to excite different radiation modes by changing the feeding method at the same operating frequency, let alone achieve active reshaping of the radiation pattern.

[0008] Therefore, how to break through the single radiation mode limitation of traditional magnetic loop antennas under the constraints of existing antenna size, and realize the active and on-demand reshaping of the radiation pattern through a simple and reliable structure to meet the differentiated requirements of radiation elevation angle for different communication distances, is a technical problem that urgently needs to be solved in this field.

[0009] Therefore, there is an urgent need to provide a shortwave magnetic loop antenna system and its control method based on multi-mode cooperative reconfiguration to solve the above problems. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and propose a shortwave magnetic loop antenna system and its control method based on multi-mode cooperative reconstruction.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention discloses a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration, comprising: A magnetic loop antenna radiator with several feed ports on it; An integrated antenna tuning module is directly installed at the bottom of the magnetic loop antenna radiator and electrically connected to each of the feed ports. The integrated antenna tuning module includes a reconfiguration matching control unit and a reconfiguration matching network unit. The reconfiguration matching control unit includes a control unit, an impedance detection unit, and a storage unit. The impedance detection unit is communicatively connected to the control unit. The control unit is communicatively connected to the storage unit and the reconfiguration matching network unit, respectively.

[0012] Furthermore, the magnetic ring antenna radiator includes an outer radiating ring and an inner coupling ring. The outer radiating ring is provided with a first feed port and a second feed port, and the inner coupling ring is provided with a third feed port and a fourth feed port.

[0013] Furthermore, the feed topology constructed by the reconstructed matching network unit includes the following four types: (a) Symmetrical multi-point feeding: Through multiple feeding ports, the current on the magnetic loop antenna radiator is symmetrically distributed, which excites pure TE mode radiation. (b) Asymmetric multi-point feeding: feeding through multiple feed ports with non-equal amplitude or non-in-phase current, so that the current on the magnetic loop antenna radiator is asymmetrically distributed, exciting TE / TM hybrid radiation mode; (c) Asymmetric dual-point feeding: Asymmetric feeding through two feeding ports concentrates the current in a preset arc segment of the magnetic loop antenna radiator, thereby exciting the TE / TM hybrid radiation mode. (d) Single-point feeding: The magnetic loop antenna radiator is equivalent to an open-circuit radiator, which excites TM mode radiation and achieves low radiation elevation angle enhancement.

[0014] Furthermore, the reconfigurable matching network unit includes an HF power network channel and an HF direct channel. Both the HF power network channel and the HF direct channel are equipped with a port selection switch group, a topology reconfiguration switch group, and several adjustable reactance elements. Each switch in the port selection switch group is connected to its corresponding feed port to switch the feed port combination. The topology reconfiguration switch group controls the connection and disconnection of each adjustable reactance element branch to switch the network topology and complete impedance matching.

[0015] Furthermore, the integrated antenna tuning module is electrically connected to each of the power supply ports via a socket; the mode switching time of the reconfigurable matching network unit is ≤10ms, and the frequency tuning time is ≤200ms.

[0016] Secondly, the present invention discloses a control method for a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration. The system used in this control method is the shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration as described in any one of the first aspects, and includes the following steps: Step 1: Target Mode Decision. The control unit determines the target radiation mode based on communication mode requirements or operating frequency range; Step 2: Topology and port policy mapping. The control unit retrieves the corresponding configuration scheme from the collaborative configuration policy library of the storage unit based on the target radiation mode and the current operating frequency; Step 3: Cooperative Execution and Mode Excitation. According to the configuration scheme, the control unit synchronously drives the switching devices in the reconfiguration matching network unit to synchronously and parallelly switch the feed topology and feed port combination within a single physical aperture. This changes the current distribution and effective current path on the magnetic loop antenna radiator 1, thereby introducing controllable TM mode components and exciting a hybrid radiation mode that combines TE and TM modes, achieving active reshaping of the radiation pattern. Step 4: Cooperative Matching and Closed-Loop Verification. While the control unit performs the target radiation mode switching operation, it synchronously adjusts the adjustable reactance components in the reconfiguration matching network unit according to the configuration scheme, so that the switching action and reactance tuning are performed in parallel, ensuring that the input impedance of the magnetic loop antenna radiator matches the standard impedance. After tuning, it checks whether the standing wave ratio (VSWR) of the impedance detection unit meets the set threshold. If the VSWR is less than the set threshold, the current matching state is locked and an RF transceiver ready signal is output. If the VSWR is greater than or equal to the set threshold, the matching parameters are adjusted or a backup strategy is triggered.

[0017] Further, in step 1, the target mode includes a high elevation angle omnidirectional mode, a medium-low elevation angle directional enhancement mode, and an omnidirectional equalization mode; specifically, the high elevation angle omnidirectional mode is a pure TE mode radiation mode; the medium-low elevation angle directional enhancement mode is a mixed radiation mode of TE mode and TM mode; and the omnidirectional equalization mode is a mixed radiation mode that simultaneously includes TE mode and TM mode components.

[0018] Furthermore, in step 2, the configuration scheme includes the operating frequency range, current path characteristics, and network topology type corresponding to each target radiation mode.

[0019] Furthermore, the network topology types include tunable networks, composite networks, inverted L-shaped networks, and π-shaped networks.

[0020] Furthermore, in step 4, the backup strategy is as follows: when the tuning time exceeds the preset time limit and the VSWR is still ≥ the set threshold, the control unit switches the radio frequency signal to the HF direct channel and bypasses all adjustable reactive components of the reconfiguration matching network unit to ensure basic communication capability.

[0021] Compared with the prior art, the present invention has the following beneficial effects: This invention aims to overcome the inherent limitation of traditional magnetic loop antennas, which only possess a single magnetic dipole radiation mode, while maintaining the antenna's physical aperture and overall dimensions. Through four feeding topologies (symmetric multi-point feeding, asymmetric multi-point feeding, asymmetric dual-point feeding, and single-point feeding) and dynamic switching of the feeding ports, it simultaneously achieves radiation mode reconstruction, impedance matching adjustment, and operating frequency tuning. By actively controlling the current distribution and effective radiation path length on the magnetic loop antenna radiator, it dynamically excites TE / TM hybrid radiation modes (transverse electric mode / transverse magnetic mode), altering the electromagnetic field composition of the magnetic loop antenna radiator. This allows for active reshaping of the antenna radiation pattern, especially the low-to-medium elevation angle radiation components, under a single physical aperture, simultaneously meeting the differentiated application needs of short-range ground wave communication, blind spot compensation communication, and long-range skywave communication.

[0022] The core of this invention lies in a multi-modal collaborative reconfiguration mechanism, which switches the feed topology corresponding to the matching network according to the differentiated coverage requirements of the communication distance, dynamically adjusts the current distribution state on the antenna, and thus excites different radiation modes (including pure TM mode, pure TE mode, and TE / TM hybrid radiation mode) on the same antenna as needed. The main advantages are: First, it breaks through the limitations of a single mode, achieving active reshaping of the radiation pattern. This is the most crucial and beneficial effect. Through the aforementioned multi-mode collaborative reconstruction mechanism, this invention, for the first time, enables on-demand dynamic control of the radiation pattern on a single magnetic loop antenna platform without altering the physical dimensions and aperture of the magnetic loop antenna radiator. The physical mechanism lies in the fact that a traditional symmetrically fed magnetic loop antenna is equivalent to a pure magnetic dipole, with a radiation mode of TE mode (transverse electric mode) and a far-field pattern exhibiting a figure-eight distribution. This invention, through asymmetrical feeding and current path reconstruction, introduces common-mode current components into the magnetic loop antenna, effectively superimposing electric dipole radiation (TM mode, transverse magnetic mode), causing the far-field vectors of the TE and TM modes to superimpose, thereby achieving horizontal broadening of the radiation pattern and enhanced gain at mid-to-low elevation angles. In the directional enhancement mode, the traditional figure-eight pattern is compressed and stretched horizontally, significantly improving the radiation components at mid-to-low elevation angles.

[0023] Second, the all-range communication capability is significantly improved. This invention features a cooperative control algorithm that realizes a complete cooperative process of mode decision-making → topology mapping → cooperative execution → closed-loop matching, simultaneously completing radiation mode reconstruction, impedance matching adjustment, and operating frequency tuning. Based on this algorithm, on-demand switching between high-elevation-angle omnidirectional modes and directional enhancement modes is achieved. A single antenna can handle short-range ground wave communication, blind-spot coverage communication, and medium-to-long-range skywave communication, achieving full-range coverage with a single antenna. Furthermore, under the same antenna size and operating frequency conditions, compared to traditional magnetic loop antennas, the low-elevation-angle gain in the 11MHz~20MHz band is improved by an average of approximately 4dB; the low-elevation-angle gain in the 20MHz~30MHz band is improved by an average of approximately 6dB.

[0024] Third, the integrated architecture of the magnetic loop antenna radiator and the integrated antenna tuning module reduces feeder loss and improves reconfiguration response speed. This invention employs an integrated antenna-feed architecture, which effectively reduces feeder transmission loss in traditional discrete designs, ensuring the system radiation efficiency of the high-Q magnetic loop antenna after multi-mode reconfiguration. Simultaneously, the reconfiguration matching network uses high-speed electronic switching devices, with a mode switching time of no more than 10ms and a frequency tuning time of no more than 200ms, meeting the application requirements of modern high-speed communication systems such as frequency hopping and adaptive communication.

[0025] In summary, this invention is not limited by the physical size of the antenna in any application scenario, and overcomes the inherent defect of traditional magnetic loop antennas that only have a single radiation mode. It can realize on-demand active reconstruction of the radiation pattern based on a simple and reliable structure, and can adapt to the different usage requirements of radiation elevation angle under different communication distances. Attached Figure Description

[0026] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall structure of the integrated shortwave magnetic ring antenna system provided in an embodiment of the present invention; Figure 2 This is a block diagram of the internal hardware structure of the integrated antenna control module provided in an embodiment of the present invention; Figure 3 A flowchart of the multimodal collaborative reconfiguration control method provided in an embodiment of the present invention; Figure 4 This is a typical radiation pattern of a traditional magnetic loop antenna, with a radiation null point in the direction of the normal to the loop. Figure 5 This is the radiation pattern of the present invention under the low elevation angle directional enhancement mode, stretched in the horizontal direction; Figure 6 This is a block diagram of the processing logic of the integrated shortwave magnetic ring antenna system of the present invention.

[0029] Wherein: 1 is the magnetic loop antenna radiator; 2 is the integrated antenna tuning module; 201 is the control unit; 202 is the impedance detection unit; 203 is the storage unit; and 204 is the reconfiguration matching network unit. Detailed Implementation

[0030] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0031] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0032] The correspondence between the "multimodal" physical nature and engineering effects of this invention is as follows: When a traditional magnetic loop antenna is fed with equal amplitude and phase, it is equivalent to a pure magnetic dipole. The radiation belongs to the TE mode (transverse electric mode), and the far-field radiation pattern is in the shape of an "8". This corresponds to high elevation angle radiation in engineering, but there is a radiation null point in the direction of the normal to the loop.

[0033] This invention introduces a common-mode current into the magnetic ring through asymmetric feeding and current path reconstruction, effectively superimposing the electric dipole radiation components (TM mode, transverse magnetic mode), thus superimposing the far-field vectors of the TE mode and the TM mode. Since the TM mode has a stronger radiation component in the horizontal direction, the superposition of the two modes results in a horizontally stretched radiation pattern and significantly enhanced gain at low and medium elevation angles, overcoming the limitations of traditional single-mode magnetic ring antennas. Furthermore, in the 25MHz~30MHz frequency band, when using single-point feeding, the ring is equivalent to an open-circuit radiator, no longer forming a closed magnetic ring current loop. Its radiation characteristics approach those of an electric dipole (TM mode), and the radiation pattern is compressed towards low elevation angles, thereby achieving a low elevation angle enhancement effect.

[0034] In a first aspect, the present invention discloses a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration, characterized in that it comprises: The magnetic loop antenna radiator 1 has several feed ports on it; An integrated antenna tuning module 2 is directly mounted on the bottom of the magnetic loop antenna radiator 1 and electrically connected to each of the feed ports. The integrated antenna tuning module 2 includes a reconfiguration matching control unit and a reconfiguration matching network unit 204. The reconfiguration matching control unit includes a control unit 201, an impedance detection unit 202, and a storage unit 203. The impedance detection unit 202 is communicatively connected to the control unit 201. The control unit 201 is communicatively connected to the storage unit 203 and the reconfiguration matching network unit 204, respectively.

[0035] Specifically, the reconfigurable operating frequency band of this invention covers 2MHz~30MHz, which has a relatively long wavelength. If a traditional external cable is used to connect the radiator and the antenna tuning module, the transmission loss caused by the long feeder will significantly reduce the radiation efficiency of the antenna system. Therefore, the integrated antenna and feeder provided by this invention is not only a physical integration of structure, but also a necessary condition to ensure that the multi-mode reconfigurable antenna has high radiation efficiency, enabling low-loss, high-reliability, and fast mode reconfiguration switching.

[0036] Specifically, the shape of the magnetic ring antenna radiator 1 can be any closed ring structure, including but not limited to circular, square or octagonal.

[0037] Specifically, the storage unit 203 is used to store a collaborative configuration strategy library, which pre-stores configuration schemes corresponding to different target radiation modes; the impedance detection unit 202 is used to monitor the standing wave ratio and impedance information of each feed port in real time and feed it back to the control unit 201.

[0038] Specifically, the control unit 201 is configured to: determine the target radiation mode according to the communication distance requirement or the operating frequency range, retrieve the corresponding configuration scheme from the collaborative configuration strategy library of the storage unit 203, and drive the reconfiguration matching network unit 204 to synchronously complete the feed topology switching and feed port combination selection within a single physical aperture, thereby changing the current distribution and effective current path on the magnetic loop antenna radiator 1 to excite different TE / TM hybrid radiation modes and realize active reshaping of the radiation pattern.

[0039] More specifically, the control unit 201 is preferably a microcontroller (MCU), a field-programmable gate array (FPGA), or a digital signal processor (DSP). The impedance detection unit 202 consists of a directional coupler and an amplitude / phase detector. Alternatively, the impedance detection unit can also use a detection bridge to achieve the impedance detection function. The storage unit 203 preferably uses an EEPROM chip to store a collaborative configuration strategy library of target radiation modes, operating frequencies, feed topologies, feed ports, and matching parameters.

[0040] Furthermore, the magnetic ring antenna radiator 1 includes an outer radiating ring and an inner coupling ring. The outer radiating ring is provided with a first feed port P1 and a second feed port P2, and the inner coupling ring is provided with a third feed port P3 and a fourth feed port P4.

[0041] Specifically, the number of the feed ports is preferably four, but can be set to three, five or more depending on the reconstruction accuracy requirements and the characteristics of the antenna itself.

[0042] Furthermore, the power supply topology constructed by the reconstructed matching network unit 204 includes the following four types: (a) Symmetrical multi-point feeding: Through multiple feeding ports, the current on the magnetic loop antenna radiator 1 is symmetrically distributed to excite pure TE mode radiation. (b) Asymmetric multi-point feeding: Through multiple feeding ports, non-equal amplitude or non-in-phase feeding is used to make the current on the magnetic loop antenna radiator 1 asymmetric, thereby exciting the TE / TM hybrid radiation mode. (c) Asymmetric dual-point feeding: Asymmetric feeding through two feeding ports concentrates the current in a preset arc segment of the magnetic loop antenna radiator 1, thereby exciting the TE / TM hybrid radiation mode. (d) Single-point feeding: fed through a single feeding port, the magnetic loop antenna radiator 1 is equivalent to an open-circuit radiator, which excites TM mode radiation and achieves low radiation elevation angle enhancement.

[0043] Furthermore, the reconfigurable matching network unit 204 includes an HF power network channel and an HF direct channel. Both the HF power network channel and the HF direct channel are equipped with a port selection switch group, a topology reconfiguration switch group, and several adjustable reactance elements. Each switch in the port selection switch group is connected to its corresponding feed port to switch the feed port combination. The topology reconfiguration switch group controls the connection and disconnection of each adjustable reactance element branch to switch the network topology and complete impedance matching.

[0044] Specifically, the adjustable reactance element includes an adjustable capacitor and an adjustable inductor.

[0045] Furthermore, the integrated antenna tuning module 2 is electrically connected to each of the power supply ports via a socket; the mode switching time of the reconfiguration matching network unit 204 is ≤10ms, and the frequency tuning time is ≤200ms.

[0046] Specifically, the integrated antenna tuning module 2 is installed below the geometric center of the magnetic ring antenna radiator 1.

[0047] Specifically, the reconfiguration matching network unit 204 employs high-speed electronic switching devices, including radio frequency relays or PIN diode arrays, which can achieve microsecond-level high-speed electronic reconfiguration.

[0048] Specifically, the switches, reconfiguration matching network unit 204, and magnetic loop antenna radiator 1 used in this invention can all be selected as devices with higher power capacity to adapt to the working requirements of high-power reconfigurable antennas.

[0049] Secondly, the present invention discloses a control method for a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration. The system used in this control method is the shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration as described in any one of the first aspects, and includes the following steps: Step 1: Target mode decision; The control unit 201 determines the target radiation mode according to communication mode requirements or operating frequency range; Step 2: Topology and port policy mapping; The control unit 201 retrieves the corresponding configuration scheme from the collaborative configuration policy library of the storage unit 203 according to the target radiation mode and the current operating frequency; Step 3: Cooperative execution and mode excitation; The control unit 201 synchronously drives the switching devices in the reconfiguration matching network unit 204 according to the configuration scheme, and synchronously and in parallel switches the feed topology and feed port combination within a single physical aperture to change the current distribution and effective current path on the magnetic loop antenna radiator 1, thereby introducing controllable TM mode components, exciting a hybrid radiation mode that combines TE mode and TM mode, and realizing active reshaping of the radiation pattern; Step 4: Cooperative matching and closed-loop verification; While the control unit 201 performs the target radiation mode switching operation, it synchronously adjusts the adjustable reactance element in the reconfiguration matching network unit 204 according to the configuration scheme, so that the switching action and reactance tuning are performed in parallel, and the input impedance of the magnetic loop antenna radiator 1 matches the standard impedance; After tuning, it is determined whether the impedance detection unit 202 verifies whether the standing wave ratio meets the set threshold. If the standing wave ratio is less than the set threshold, the current matching state is locked and an RF transceiver ready signal is output; if the standing wave ratio is greater than or equal to the set threshold, the matching parameters are adjusted or a backup strategy is triggered.

[0050] Specifically, in step 2, the standard impedance is 50Ω; the set threshold is 2.0.

[0051] Specifically, in step 4, the adjustment of the matching parameters is as follows: the control unit 201 adjusts the parameters of each of the adjustable reactance components in a step manner, and monitors the change of VSWR in real time to form a closed-loop iterative tuning until the VSWR meets the set threshold.

[0052] Further, in step 1, the target mode includes a high elevation angle omnidirectional mode, a medium-low elevation angle directional enhancement mode, and an omnidirectional equalization mode; the high elevation angle omnidirectional mode is a pure TE mode radiation mode; the medium-low elevation angle directional enhancement mode is a mixed radiation mode of TE mode and TM mode; the omnidirectional equalization mode is a mixed radiation mode that simultaneously includes TE mode and TM mode components.

[0053] Specifically, the radiation pattern of the high elevation angle omnidirectional mode is figure-eight shaped, which is suitable for blind zone communication; the radiation pattern of the medium and low elevation angle directional enhancement mode is stretched horizontally, which is suitable for short-range ground wave communication and long-range sky wave communication; the omnidirectional equalization mode is suitable for medium-range communication.

[0054] Specifically, in the mid-to-low elevation angle directional enhancement mode, the control unit 201 drives the reconfiguration matching network unit 204 to select an asymmetric dual-point feed or asymmetric multi-point feed topology. Through asymmetric feeding and current path reconstruction, a controllable TM mode component is introduced into the magnetic loop antenna radiator 1, so that the far-field vectors of the TE mode and the TM mode are superimposed, stretching the radiation pattern in the horizontal direction and enhancing the mid-to-low elevation angle gain.

[0055] Furthermore, in step 2, the configuration scheme includes the operating frequency range, current path characteristics, and network topology type corresponding to each target radiation mode.

[0056] Furthermore, the network topology types include tunable networks, composite networks, inverted L-shaped networks, and π-shaped networks.

[0057] Further, in step 4, the backup strategy is as follows: when the tuning time exceeds the preset time limit and the VSWR is still ≥ the set threshold, the control unit 201 switches the radio frequency signal to the HF direct channel and bypasses all adjustable reactance components of the reconfiguration matching network unit 204 to ensure basic communication capability.

[0058] Example 1 This embodiment describes a magnetic loop antenna system based on multi-mode cooperative reconfiguration for use in vehicles, airborne applications, and portable backpacks, with an operating frequency range of 2MHz to 30MHz.

[0059] Firstly, see [the following] Figure 1 As shown, this invention discloses a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration, comprising: Magnetic ring antenna radiator 1: The magnetic ring antenna radiator 1 includes a circular outer radiating ring with a diameter of 1.5 meters and a circular inner coupling ring with a diameter of 0.6 meters. Four feed ports (P1, P2, P3, P4) are distributed on the ring body, wherein P1 and P2 are located in the outer radiating ring, and P3 and P4 are located in the inner coupling ring. Integrated antenna tuning module 2: The integrated antenna tuning module 2 is fixed below the geometric center of the magnetic ring antenna radiator 1 and is directly connected to each feed port through a low-loss socket.

[0060] See Figure 2As shown, the integrated antenna adjustment module includes a reconfiguration matching control unit and a reconfiguration matching network unit 204. The reconfiguration matching control unit includes a control unit 201, an impedance detection unit 202, and a storage unit 203.

[0061] Specifically, the control unit is a microcontroller (MCU), the impedance detection unit 202 consists of a directional coupler and an amplitude / phase detector, and the storage unit 203 uses an EEPROM chip.

[0062] The core of the reconfigurable matching network unit 204 is a reconfigurable circuit board, including an HF power network channel and an HF pass-through channel. Each of the HF power network channel and the HF pass-through channel is equipped with a port selection switch group (K1~K4), a topology reconfiguration switch group (K5~K9), and several adjustable reactance components. Each switch in the port selection switch group (K1~K4) is connected to its corresponding feed port (P1~P4) to switch the feed port combination. The topology reconfiguration switch group controls the connection and disconnection of each adjustable reactance component branch to switch the network topology and complete impedance matching.

[0063] Specifically, both the gating switch group (K1~K4) and the topology reconfiguration switch group (K5~K9) use radio frequency relays; the first group of relays (K1, K2, K3, K4) are connected to the feed ports P1, P2, P3, and P4 respectively, and various feed topologies such as symmetrical multi-point feed, asymmetrical multi-point feed, asymmetrical dual-point feed, and single-point feed can be realized through different combinations of feed ports; the second group of relays (K5, K6, K7, K8, K9) is used to switch the matching network topology, and can select the adjustable capacity network, composite network, inverted L-type network or π-type network.

[0064] For details, see Figure 2 As shown, the HF power network channel includes multiple adjustable paths. Each adjustable path includes: an adjustable path composed of a sixth switch K6, a first adjustable inductor, a first adjustable capacitor, a third switch K3, a fourth switch K4, and an eighth switch K8; an adjustable path composed of a fifth switch K5, a first adjustable inductor, a first adjustable capacitor, a second adjustable inductor, a seventh switch K7, and a first switch K1; and an adjustable path composed of a fifth switch K5, a first adjustable inductor, a first adjustable capacitor, a second adjustable capacitor, a ninth switch K9, a first switch K1, and a second switch K2. All paths share a common RF input port as the signal input terminal.

[0065] Specifically, the HF direct channel includes a third feed port P3, a third switch K3, a balancing conversion unit, a fourth switch K4, and a fourth feed port P4 connected in series. A balancing conversion path is provided between the balancing conversion unit and the main path of the HF power network, and a sixth switch K6 is connected in series within the balancing conversion path. A second ground bypass branch is provided on the HF direct channel, and an eighth switch K8 is connected in series within the second ground bypass branch.

[0066] See Figure 6 As shown, in this embodiment, the control unit 201 collects the voltage standing wave ratio (VSWR) of each feed port in real time through the impedance detection unit 202 located at the feed port, and performs the following logical judgment: (1) When the standing wave ratio meets the target (i.e., VSWR < 2), the judgment result is "yes", indicating that the impedance matching is up to standard after the initial reconstruction matching; during the channel switching process, the control unit 201 executes the switch timing control logic of first disconnect and then make, that is, first turn off the switch of the current conducting channel, and then turn on the target channel switch to prevent the two paths from being simultaneously turned on and causing signal conflict caused by the simultaneous conduction of the radio frequency path; switch to the HF power network channel and enter the normal shortwave power transmission link; after the channel switching is completed, the tuning success status signal is sent back to the upper master control, and the process jumps to the end node.

[0067] (2) When the standing wave ratio does not meet the target (i.e., VSWR≥2), the judgment result is "No", indicating that the initial reconstruction matching effect is not up to standard. At this time, the second-level time-limited logic judgment is entered, and the cumulative tuning time is checked. The second-level time-limited logic judgment is configured with a tuning duration threshold, which is preferably 200ms. The timing self-control unit 201 starts when the first reconstruction matching operation is performed, and performs timeout protection judgment, as follows: (2.1) If the total pre-tuning time does not reach the upper limit of 200ms, the system performs fine-tuning of the matching network. The control unit 201 performs step-by-step fine-tuning by controlling the parameters of the first adjustable capacitor, the second adjustable capacitor, the first adjustable inductor and the second adjustable inductor of the matching network in the reconstructed matching network unit 204. During the fine-tuning process, the system determines whether the current mismatch is biased towards capacitive or inductive based on the phase of the reflection coefficient corresponding to the standing wave ratio, and flexibly adjusts the overall equivalent inductive reactance and capacitive reactance of the matching network to directionally cancel the impedance mismatch of the antenna port and realize directional fine-tuning. After the fine-tuning is completed, the system returns to the standing wave ratio detection and judgment step, re-acquires the standing wave ratio of the feed port voltage and performs the judgment, forming a closed-loop iterative tuning, and cyclically optimizes the impedance matching state until the standing wave ratio reaches the standard or the tuning timeout occurs.

[0068] (2.2) If the standing wave ratio still cannot meet the requirement of less than 2 after continuous iterative fine-tuning for 200ms, the adaptive matching is determined to be a failure. At this time, all adjustable reactance elements of the bypass reconfiguration matching network unit 204 are closed, only switches K1~K6 are closed to form an HF direct channel to ensure the basic communication capability of the equipment; at the same time, the tuning failure alarm status is sent back to the upper master control, and the process jumps to the end node.

[0069] Furthermore, regardless of whether the tuning result is successful or unsuccessful, after the corresponding status report is completed, all branches are uniformly merged into the "End" termination node. The matching and reconstruction process corresponding to the single communication mode is completed, and it waits for the next new communication mode requirement to trigger a new round of control logic.

[0070] More specifically, during the channel switching process, the control unit 201 first turns off the current conducting side switch and then turns on the target channel switch to avoid the simultaneous conduction of two sets of switches causing radio frequency path conflicts.

[0071] The first adjustable reactance branch achieves fast narrowband tuning by relying on the first adjustable capacitor; the second adjustable reactance branch expands the impedance adjustment range through multi-level LC composite reactance, adapting to wide-band and load impedance fluctuation scenarios; the control unit combines the real-time antenna impedance data collected by the impedance detection unit to adaptively select the single-branch or dual-branch working mode, and outputs control signals to adjust the on / off state of each switch, switching the feed port and network topology corresponding to different target modes in Matching Table 1.

[0072] Table 1 shows a typical configuration scheme for different target modes. This invention can achieve integrated, cooperative, and adaptive reconfiguration of radiation mode, operating frequency, and impedance matching with a single physical antenna aperture.

[0073] Table 1. A typical configuration scheme under different target modes. It should be noted that the configurations listed in Table 1 are only exemplary implementations; the complete configuration table pre-stored in the storage unit 203 can be used to pre-calibrate and optimize parameters based on the actual size of the magnetic ring antenna radiator 1, the on-site installation environment, and the target operating frequency band.

[0074] In addition, the frequency band intervals in Table 1 are only the basis for the design segmentation of this scheme. The division method may differ from the frequency band division of the measured data in the embodiment: the former is determined by the matching network hardware parameters and power supply topology configuration, while the latter is determined by the selection rules of the measured sampling points. The two belong to different design dimensions and there is no mandatory correspondence.

[0075] Specifically, the following are the communication distances for the target radiation modes: (1) High elevation angle omnidirectional mode: suitable for blind zone communication (20km~100km); (2) Medium and low elevation angle directional enhancement mode: suitable for short-range ground wave (about 0~20km) and long-range sky wave communication; (3) Omnidirectional equalization mode: suitable for medium-range communication.

[0076] Secondly, this invention provides a control method for a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration, and the system used in this control method is the shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration described in the first aspect. When a radio station needs to switch from dead-zone communication to short-range ground wave or long-range sky wave communication, see [link to relevant documentation]. Figure 3 As shown, the system performs the following steps: Step 1: The operator switches the radio mode from "blind zone" to "remote" or sets the communication frequency band. The MCU receives the mode change or frequency band instruction and determines that the target radiation mode is "low elevation angle directional enhancement mode".

[0077] Step 2: The MCU queries the collaborative configuration strategy library in the storage unit. For the "low elevation angle directional enhancement mode", a complete configuration scheme is retrieved: the power supply topology is asymmetric dual-point power supply; the selected ports are P1 and P2; the target current path is the arc segment concentrated between the two ports; and the matching topology is a π-type network.

[0078] Step 3: The MCU drives the relays to synchronously complete topology switching and port selection within 10ms: connecting P1 and P2, and disconnecting P3 and P4. This action changes the current distribution on the magnetic loop antenna radiator 1. Through asymmetric dual-point feeding and current path reconstruction, the original pure magnetic dipole current mode is broken, and a controllable TM mode component is introduced, which is equivalent to superimposed with the electric dipole radiation component, thereby exciting a hybrid radiation mode that combines TE and TM modes, achieving low elevation angle stretching of the radiation pattern.

[0079] Specifically, the asymmetric dual-point feeding (P1 / P2) concentrates the current on the outer radiation ring in the arc segment between the two ports, breaking the uniform circulation mode of the closed loop and introducing a controllable TM mode component, thereby realizing TE / TM hybrid radiation and low elevation angle stretching of the radiation pattern on the same outer radiation ring.

[0080] Step 4: Subsequently, the MCU synchronously controls the matching network relay to select the π-type network and adjusts the adjustable capacitor to complete impedance matching within 190ms, reducing the VSWR to below 2.0. Finally, the system sends a "ready" signal to the radio.

[0081] See Figure 4As shown, under the same test conditions, the radiation pattern of a traditional magnetic loop antenna at 20MHz is still figure-eight shaped, with a significant dip in the normal direction; while the radiation pattern of the magnetic loop antenna radiator 1 in this embodiment at 20MHz in the low elevation angle directional enhancement mode (see...) Figure 5 As shown, the main lobe is significantly stretched in the horizontal direction, and the gain at low elevation angles is significantly improved.

[0082] To further quantify the performance improvement effect of the present invention, under the same size and frequency conditions, the low elevation gain of this embodiment (low elevation angle enhancement mode) is compared with that of the traditional magnetic loop antenna, and the results are shown in Table 2.

[0083] Table 2. Comparison of low elevation angle gain (typical value range) The data in Table 2 are simulated values ​​under typical conditions. Specific values ​​may vary depending on factors such as antenna physical size, installation environment, and test site. The comparison benchmark is a traditional magnetic loop antenna of the same physical size and operating frequency. As shown in Table 2, after multi-mode cooperative reconfiguration, the antenna gain in the low elevation direction is significantly improved, with an average gain increase of approximately 4dB in the 11MHz~20MHz band and approximately 6dB in the 20MHz~30MHz band. Figure 4 , Figure 5 The changes in the radiation pattern shape are consistent with the observed changes—the radiation pattern is compressed and stretched horizontally, with a significant enhancement in the low and medium elevation radiation components.

[0084] In summary, this invention is not limited by the physical size of the antenna in any application scenario, and overcomes the inherent defect of traditional magnetic loop antennas that only have a single radiation mode. It can realize on-demand active reconstruction of the radiation pattern based on a simple and reliable structure, and can adapt to the different usage requirements of radiation elevation angle under different communication distances.

[0085] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0086] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration, characterized in that, include: A magnetic ring antenna radiator (1) is provided with several feed ports; An integrated antenna tuning module (2) is directly installed on the bottom of the magnetic loop antenna radiator (1) and electrically connected to each of the feed ports. The integrated antenna tuning module (2) includes a reconfiguration matching control unit and a reconfiguration matching network unit (204). The reconfiguration matching control unit includes a control unit (201), an impedance detection unit (202), and a storage unit (203). The impedance detection unit (202) is communicatively connected to the control unit (201). The control unit (201) is communicatively connected to the storage unit (203) and the reconfiguration matching network unit (204), respectively.

2. A shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration according to claim 1, characterized in that, The magnetic ring antenna radiator (1) includes an outer radiating ring and an inner coupling ring. The outer radiating ring is provided with a first feed port (P1) and a second feed port (P2). The inner coupling ring is provided with a third feed port (P3) and a fourth feed port (P4).

3. A shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration according to claim 1, characterized in that, The power supply topologies constructed by the reconstructed matching network unit (204) include the following four types: (a) Symmetrical multi-point feeding: Through multiple feeding ports, the current on the magnetic loop antenna radiator (1) is symmetrically distributed to excite pure TE mode radiation. (b) Asymmetric multi-point feeding: Through multiple feeding ports, non-equal amplitude or non-in-phase feeding is used to make the current on the magnetic loop antenna radiator (1) asymmetric, thereby exciting the TE / TM hybrid radiation mode. (c) Asymmetric dual-point feeding: Asymmetric feeding through two feeding ports concentrates the current in the preset arc segment of the magnetic loop antenna radiator (1) to excite the TE / TM hybrid radiation mode. (d) Single-point feeding: fed through a single feeding port, the magnetic ring antenna radiator (1) is equivalent to an open-circuit radiator, which excites TM mode radiation and achieves low radiation elevation angle enhancement.

4. A shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration according to claim 1, characterized in that, The reconfigurable matching network unit (204) includes an HF power network channel and an HF direct channel. Both the HF power network channel and the HF direct channel are equipped with a port selection switch group, a topology reconfiguration switch group, and several adjustable reactance elements. Each switch in the port selection switch group is connected to its corresponding feed port to switch the feed port combination. The topology reconfiguration switch group controls the connection and disconnection of each adjustable reactance element branch to switch the network topology and complete impedance matching.

5. A shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration according to claim 1, characterized in that, The integrated antenna tuning module (2) is electrically connected to each of the power supply ports via a socket; the mode switching time of the reconfiguration matching network unit (204) is ≤10ms and the frequency tuning time is ≤200ms.

6. A control method for a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration, characterized in that, The system used in this control method is the shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration as described in any one of claims 1 to 5, and includes the following steps: Step 1: Target mode decision; The control unit (201) determines the target radiation mode according to the communication mode requirements or the operating frequency range; Step 2: Topology and port policy mapping; The control unit (201) retrieves the corresponding configuration scheme from the collaborative configuration policy library of the storage unit (203) according to the target radiation mode and the current operating frequency; Step 3: Cooperative execution and mode excitation; The control unit (201) synchronously drives the switching devices in the reconfiguration matching network unit (204) according to the configuration scheme, and synchronously and in parallel switches the feed topology and feed port combination within a single physical aperture to change the current distribution and effective current path on the magnetic ring antenna radiator (1), thereby introducing controllable TM mode components, exciting a hybrid radiation mode that combines TE mode and TM mode, and realizing active reshaping of the radiation pattern; Step 4: Cooperative matching and closed-loop verification; while the control unit (201) performs the target radiation mode switching operation, it synchronously adjusts the adjustable reactance element in the reconfiguration matching network unit (204) according to the configuration scheme, so that the switching action and reactance tuning are performed in parallel, so that the input impedance of the magnetic loop antenna radiator (1) matches the standard impedance; after tuning, it is determined whether the impedance detection unit (202) verifies whether the standing wave ratio meets the set threshold. If the standing wave ratio is < set threshold, the current matching state is locked and the radio frequency transceiver ready signal is output; if the standing wave ratio is ≥ set threshold, the matching parameters are adjusted or the backup strategy is triggered.

7. The control method for a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration according to claim 6, characterized in that, In step 1, the target modes include a high elevation angle omnidirectional mode, a medium-low elevation angle directional enhancement mode, and an omnidirectional equalization mode; the high elevation angle omnidirectional mode is a pure TE mode radiation mode; the medium-low elevation angle directional enhancement mode is a mixed radiation mode of TE mode and TM mode; and the omnidirectional equalization mode is a mixed radiation mode that includes both TE mode and TM mode components.

8. The control method for a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration according to claim 6, characterized in that, In step 2, the configuration scheme includes the operating frequency range, current path characteristics and network topology type corresponding to each target radiation mode.

9. The control method for a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration according to claim 8, characterized in that, The network topology types include capacitive networks, composite networks, inverted L-shaped networks, and π-shaped networks.

10. The control method for a shortwave magnetic loop antenna system based on multi-mode cooperative reconfiguration according to claim 6, characterized in that, In step 4, the backup strategy is as follows: when the tuning time exceeds the preset time limit and the VSWR is still ≥ the set threshold, the control unit (201) switches the radio frequency signal to the HF direct channel and bypasses all adjustable reactance components of the reconfiguration matching network unit (204) to ensure basic communication capability.

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