A tunable shortwave active antenna

Abstract

The application discloses a tunable short-wave active antenna and belongs to the technical field of antennas. The application encapsulates a radiator and an active tuning assembly in an antenna cabin, and a radio frequency interface is directly connected with a short-wave radio station. The active tuning assembly comprises a detection assembly, a control assembly, a matching network assembly and a power supply assembly, and the antenna impedance is detected and the relay is controlled to switch the matching network element value. The active antenna is also provided with a heat-conducting insulation structural member which wraps the radiator root and is embedded in the shell of the active tuning assembly, so that the electrical insulation and heat conduction dual functions are realized. The application realizes the integration of the short-wave antenna radiation and tuning functions, has the characteristics of saving space, eliminating line loss, avoiding matching blind area, supporting high-power transceiving and intelligent heat management.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and more specifically, to a tunable shortwave active antenna. Background Technology

[0002] Shortwave wavelengths range from 10m to 150m. Due to strict physical size limitations, airborne shortwave antennas typically struggle to achieve wideband self-resonance. Under the constraint of small electrical design, the antenna's input impedance usually varies drastically with the operating frequency. In this case, directly connecting the antenna to the shortwave radio using a standard impedance coaxial cable will result in unacceptable mismatch losses. Furthermore, when transmitting high-power signals under high VSWR conditions, excessive reflected signal energy may damage the downstream power amplifier and shortwave radio.

[0003] However, airborne platforms impose strict limitations on antenna installation dimensions (typically no more than 5m in total length), causing shortwave antennas to exhibit typical electrically small antenna characteristics (maximum geometric dimensions much smaller than the wavelength) at the lower end of the operating frequency band (e.g., 2MHz~10MHz). Electrically small antennas have two significant characteristics in their input impedance: firstly, extremely low radiation resistance (typically on the order of milliohms to a few ohms); and secondly, impedance changes drastically with the operating frequency (exhibiting strong frequency sensitivity). When such antennas are directly connected to a shortwave radio using standard characteristic impedance (50Ω) copper coaxial cables, such as... Figure 2 As shown in (a), the following problems will occur due to severe impedance mismatch: most of the signal energy will be reflected back to the radio station, forming a standing wave, resulting in extremely low radiation efficiency; when the reflected signal energy is too large, it may burn out the final stage power amplifier of the radio station or cause a protective shutdown, which will seriously affect the reliability of communication.

[0004] To solve the above problems, existing technologies commonly employ a dedicated antenna tuner (referred to as "antenna tuner") connected in series between the antenna and the radio station, such as... Figure 2 As shown in (b), the antenna tuner contains a variable inductor and capacitor matching network. By manually or automatically adjusting the network parameters, the non-standard impedance at the antenna end is transformed to a standard 50Ω impedance, thereby eliminating standing waves and protecting the radio. This discrete "antenna + antenna tuner" architecture is mature in applications on land-based and shipborne platforms with ample space, but when transplanted to airborne platforms, the following inherent defects are exposed: (1) Space occupation problem: The sky tuner is usually an independent box-type device, which requires the valuable equipment compartment space in the flight platform and increases the difficulty of routing internal cables and pipes, which is contrary to the development trend of highly integrated and miniaturized airborne equipment.

[0005] (2) Difficulty in deep adaptation: The antenna tuner and the antenna are designed and manufactured by different manufacturers as independent components, and there is a lack of integrated optimization between the two. In actual engineering, the phenomenon of "false tuning" often occurs - although the antenna tuner adjusts the port VSWR to a low level, the signal energy is not effectively radiated, but is passively consumed by the heat generated by the internal resistors, magnetic cores and other components of the antenna tuner, resulting in a serious deterioration of the communication effect.

[0006] (3) Additional losses and matching dead zone: Additional RF cables and connectors are required between the antenna and the antenna tuner. These interconnect components introduce undesirable impedance changes and insertion losses, and may even create matching dead zones at certain frequencies (i.e., no matter how the antenna tuner is adjusted, a good match cannot be achieved), causing the actual performance of the antenna to deviate from the design specifications.

[0007] (4) Reliability risks: The airborne platform faces harsh environments such as strong vibration, wide temperature range (-55℃~+70℃), and low air pressure. The additional cables and connectors increase potential failure points, such as loose connectors, cable fatigue fracture, poor contact, etc., which may lead to communication failure.

[0008] On the other hand, there is also a type of "shortwave active antenna" in the existing technology, which usually integrates a broadband amplifier with high input impedance at the root of the radiator and uses active circuits to achieve impedance transformation and gain compensation. However, the amplifier in this type of active antenna is very prone to saturation, breakdown or burnout under high-power transmission signals, so it is only suitable for receiving applications and cannot meet the requirements of bidirectional communication (shared transmission and reception) on airborne platforms.

[0009] Therefore, this invention proposes a tunable shortwave active antenna. Summary of the Invention

[0010] The purpose of this invention is to provide a tunable shortwave active antenna. By integrating the radiator and tuning device into a single package within the antenna, an independent antenna feed unit with both radiation and tuning functions is formed. This eliminates the need for other external tuning equipment or devices, saving equipment compartment space. Furthermore, the "zero-cable" connection method achieves in-situ impedance matching, reducing matching dead zones, eliminating line losses, and minimizing potential failure points. To achieve the above objectives, the technical solution adopted by this invention is as follows: This application provides a tunable shortwave active antenna, comprising: The antenna includes a radiator for converting electromagnetic waves into electrical signals; an active tuning component whose radio frequency output port is electrically connected to the root of the radiator for tuning the antenna impedance; a backplate located behind the radiator for support and grounding; and an external interface mounted on the backplate, including at least a radio frequency interface and a control interface. The active tuning component and the radiator are encapsulated inside the antenna housing, and the radio frequency interface is used to connect to the radio frequency port of a shortwave radio.

[0011] Furthermore, the radiator adopts an inverted "L" shaped topology, with multiple periodically arranged coplanar rectangular meandering structures on its horizontal long arm to increase the electrical length; the period of the meandering structure is not less than 5 times the line width, and the total number of periods is not less than 3.

[0012] Furthermore, the plane containing the radiator is perpendicular to the plane of the back plate.

[0013] Furthermore, the active tuning component includes: a detection component for measuring antenna impedance; a matching network component including multiple capacitors, multiple inductors, and multiple relays, wherein the relays are used to control the connection state of the capacitors and inductors; a control component connected to the detection component and the matching network component respectively, for controlling the on / off state of the relays according to the antenna impedance measurement result of the detection component, thereby switching the component values ​​of the matching network component; and a power supply component for supplying power to the detection component and the control component.

[0014] Furthermore, it also includes a temperature sensor located at the heat source position inside the active tuning assembly. The control assembly is connected to the temperature sensor and configured to send power control commands to the shortwave radio via the control interface based on the monitored temperature.

[0015] Furthermore, it also includes a thermally conductive insulating structure that wraps around the root of the radiator and is embedded between the power supply vias of the metal casing of the active tuning assembly, for achieving electrical insulation between the radiator and the metal casing, and conducting the heat generated by the active tuning assembly to the radiator.

[0016] Furthermore, the thermally conductive and insulating structural component is a hexagonal boron nitride ceramic with a dielectric strength greater than 30 kV / mm and a thermal conductivity greater than 20 W / (m·K).

[0017] Furthermore, the tunable shortwave active antenna includes a tuning mode and an operating mode: in the tuning mode, impedance matching is performed at low power; after the matching conditions are met, it enters the operating mode, allowing high-power transmission.

[0018] Furthermore, the external interface also includes a power interface for connecting to an external DC power supply; the radio frequency interface is a standard 50Ω connector.

[0019] The beneficial effects of this invention are as follows: This invention provides a tunable shortwave active antenna architecture, which adopts an integrated design of radiation and tuning structure functions. Compared with the traditional "antenna + tuner" architecture, this invention does not require an additional antenna tuner, realizes "zero cable" connection, solves the problems of antenna tuner occupying internal space, avoids matching blind spots and additional line loss, eliminates potential fault points, and improves the reliability of the antenna feeder system.

[0020] This invention provides a tunable shortwave active antenna, which, unlike traditional untuned shortwave active antennas, has integrated transceiver functionality and can support bidirectional communication capabilities of shortwave communication systems.

[0021] This invention proposes a power supply interface device that combines electrical insulation and thermal conduction. By establishing a low thermal resistance conduction path between the tuning component and the radiator, and utilizing a larger area radiator for auxiliary heat dissipation, it provides electrical isolation to meet the antenna operating voltage, thus solving the dual requirements of high-voltage insulation and efficient heat conduction in high-power and demanding heat dissipation scenarios.

[0022] This invention proposes a dynamic thermal adaptive power derating strategy based on temperature information. By deploying temperature sensors at key heat source locations of the tuning component, the system can perceive temperature in real time at multiple points. By adopting a hierarchical gradient "temperature-power" management strategy, it achieves intelligent coordinated control of "heat" and "electricity", thus solving the pain point of communication interruption caused by traditional thermal protection.

[0023] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of the internal composition and connection relationship of a tunable shortwave active antenna according to the present invention; Figure 2 The diagrams show the external connections of the antennas; (a) shows the external connections of a tunable shortwave active antenna; and (b) shows the external connections of a traditional shortwave passive antenna. Figure 3 This is a schematic diagram of the construction of a tunable shortwave active antenna according to the present invention; Figure 4 Yes, yes Figure 3 Enlarged view of the circled area; Figure 5 This is a flowchart illustrating the operation of a tunable shortwave active antenna according to the present invention. Figure 6 This is a flowchart of the dynamic thermal adaptive power derating strategy for the shortwave active antenna. Figure 7 This is a flowchart of the dynamic thermal adaptive power recovery strategy for the shortwave active antenna. Figure 8 This is the measured voltage standing wave ratio (VSWR) result of a shortwave active antenna; In the diagram: 1—thermally conductive and insulating structural component, 2—backplate, 3—control interface, 4—power interface, 5—RF interface, 6—radiator, 7—active tuning component, 7-1—metal protective housing, 7-2—control component, 7-3—detection component, 7-4—power component, 7-5—matching network component. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] Example 1: This embodiment provides a tunable shortwave active antenna.

[0029] See Figure 3 and Figure 4 This embodiment provides a schematic diagram of the construction of a tunable shortwave active antenna. The main components of the antenna include a radiator 6, an active tuning assembly 7, a backplate 2, an external interface, and a thermally conductive and insulating structural component 1.

[0030] The backplate 2, located behind the radiator 6, is made of fiberglass and has a metallized surface. It serves for support, fixation, and grounding. This structure solves the problems of mechanical support and electrical reference ground for components inside the antenna compartment, while the metallized surface provides a stable radio frequency ground plane.

[0031] The external interfaces are located near one side of the antenna and are mounted on the backplate 2 with screws. They consist of a power interface 4, an RF interface 5, and a control interface 3. The RF interface 5 uses a standard 50Ω connector for connection to the RF port of the shortwave radio; the power interface 4 is used to connect to an external DC power supply; and the control interface 3 is used to transmit tuning control commands and power control commands. These external interfaces eliminate the need for additional cables and connectors between the antenna and the antenna tuner in traditional solutions, achieving a "zero-cable" connection. This helps eliminate unwanted impedance variations, reduce insertion loss, and lower potential failure points.

[0032] The active tuning component 7 is located inside the antenna compartment, on the inner side of the backplate 2, and is externally protected by a metal shell 7-1, which is fixed to the backplate 2 by screws. Integrating the active tuning component 7 inside the antenna compartment solves the problems of traditional antenna tuners occupying equipment compartment space and increasing the difficulty of cable routing, which is beneficial to saving valuable space inside the flight platform and improving system integration.

[0033] See Figure 4 The enlarged view shows that the active tuning component 7 includes a detection component 7-3, a control component 7-2, a matching network component 7-5, a power supply component 7-4, and a temperature sensor. In this embodiment, the connection relationships of the radiator 6, detection component 7-3, control component 7-2, matching network component 7-5, power supply component 7-4, and external interfaces are shown in the attached diagram. Figure 1 .

[0034] The detection component 7-3 is used to measure the antenna impedance. Its input is connected to the input port of the matching network component 7-5, and its output is connected to the control component 7-2.

[0035] Matching network component 7-5 includes multiple capacitors, multiple inductors, and multiple relays. The relays control the connection status of the capacitors and inductors to form L-type, T-type, or π-type matching networks. By switching different component combinations using relays, non-standard impedances are transformed to standard 50Ω impedances, which helps to minimize mismatch losses and protect the downstream power amplifier and shortwave radio.

[0036] The control component 7-2 is connected to the relays in the detection component 7-3 and the matching network component 7-5 respectively, and is used to control the on and off of the relays according to the antenna impedance measured by the detection component 7-3, so as to switch the component values ​​of the matching network component 7-5.

[0037] Power supply assembly 7-4 supplies power to detection assembly 7-3 and control assembly 7-2. A temperature sensor is located inside the active tuning assembly 7 at a heat source location (such as near a large inductor or relay). Control assembly 7-2 is connected to the temperature sensor and configured to send power control commands to the shortwave radio via control interface 3 based on the monitored temperature.

[0038] The thermally conductive and insulating structural component 1 is made of hexagonal boron nitride ceramic with a dielectric strength greater than 30 kV / mm and a thermal conductivity greater than 20 W / (m·K). This component tightly wraps around the root of the radiator 6 and is embedded between the feed vias of the metal casing of the active tuning assembly 7. It serves to achieve electrical insulation between the radiator 6 and the metal casing, and conducts the heat generated by the active tuning assembly 7 to the radiator 6, utilizing the larger area of ​​the radiator to assist in heat dissipation. The thermally conductive and insulating structural component 1 solves the problem of high-voltage breakdown or arcing between the root of the radiator and the metal casing during high-power transmission, and also solves the problem of heat accumulation and difficult heat dissipation inside the active tuning assembly.

[0039] This embodiment integrates the radiator 6 and the active tuning component 7 into a single package within the antenna compartment, forming an independent antenna feeder unit that combines radiation and tuning functions. This eliminates the need for an external antenna tuner, fundamentally solving the space constraints, cable losses, matching blind spots, and reliability issues inherent in traditional "antenna + tuner" solutions. Furthermore, the introduction of the thermally conductive insulating structure 1 resolves the conflict between high-voltage insulation and heat dissipation caused by integration, ensuring high-power transmission.

[0040] Example 2: See Figure 5 The operating procedure of a tunable shortwave active antenna is as follows: Step 1: When the shortwave radio switches frequencies or presses the tuning button, the shortwave radio sends a tuning command containing the operating frequency information to the active antenna through the control interface. Step 2: After receiving the tuning command containing frequency information, the control component 7-2 enters the tuning mode and sends an impedance detection command containing frequency information to the detection component 7-3. Step 3: After receiving the impedance detection command containing frequency information, the detection component 7-3 immediately starts the impedance detection program, measures the impedance value at the input port of the matching network component 7-5, and returns the detection result to the control component 7-2. Step 4: After receiving the impedance detection result, the control component 7-2 determines whether the circuit has met the matching requirements (e.g., voltage standing wave ratio < 1.5). If so, it skips directly to step 8. Otherwise, it calculates the network configuration parameters required to match the circuit to the standard impedance based on the impedance measurement result and feeds them back to the matching network component 7-5. Step 5: After receiving the network configuration information from the control component, the matching network component 7-5 adjusts the connected capacitor and inductor by controlling the on / off state of the relay, thereby changing the matching network scheme. Step 6: Test the impedance again using component 7-3; Step 7: Repeat steps 4 to 6. If the desired result is not achieved within the specified number of attempts, terminate the tuning mode, provide a tuning failure message, and prohibit entry into the working mode. Step 8: After the antenna meets the impedance matching requirements, the shortwave radio is allowed to transmit high-power signals. The antenna starts its working mode and realizes the transmission and reception of shortwave electromagnetic signals through the radiation structure.

[0041] In some preferred embodiments, see Figure 6 and Figure 7 The control component 7-2 is configured to execute a dynamic thermal adaptive power derating strategy, and the dynamic thermal adaptive power derating and recovery strategy is as follows: When the temperature is within a safe value (e.g., <85°C), the control component polls each temperature sensor and sends a full power command to the shortwave radio via the control interface. When the monitored temperature exceeds the first-level preset value (e.g., 85℃) but is less than the first-level preset value (e.g., 120℃), the antenna enters the warning derating mode and sends a power reduction request command to the shortwave radio, requesting the shortwave radio to reduce the transmission power to half power or other preset values. When the monitored temperature exceeds the first preset value (e.g., 120℃), the antenna enters the over-temperature protection mode and sends an over-temperature protection request command to the shortwave radio, requesting the shortwave radio to forcibly disconnect the transmission path. When the monitored temperature drops below the safe value, the antenna sends a full-power permission command to the shortwave radio, requesting the shortwave radio to restore its rated power.

[0042] See Figure 8 In this embodiment, the voltage standing wave ratio (VSWR) of the shortwave active antenna under continuous operation is measured in a frequency range of 2~29.9MHz. As shown in the figure, tunability is achieved across the entire frequency band, with VSWRs all less than 1.5, meeting the expected design effect and verifying the feasibility of the proposed scheme.

[0043] It should be noted that the specific manner in which each module performs its operation in the apparatus described in the above embodiments has been described in detail in the embodiments of the method, and will not be elaborated here.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0045] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A tunable shortwave active antenna, characterized in that, include: Radiator (6) is used to convert electromagnetic waves into electrical signals; An active tuning component (7) has its radio frequency output port electrically connected to the root of the radiator (6) for tuning the impedance of the antenna. The back plate (2), located behind the radiator (6), is used for support and grounding; The external interface is installed on the backplane (2) and includes at least a radio frequency interface (5) and a control interface (3). The active tuning component (7) and the radiator (6) are encapsulated inside the antenna compartment, and the radio frequency interface (5) is used to connect to the radio frequency port of the shortwave radio station.

2. The tunable shortwave active antenna according to claim 1, characterized in that, The radiator (6) adopts an inverted "L" shaped topology, and its horizontal long arm is provided with multiple periodically arranged coplanar rectangular meandering structures to increase the electric length; the period of the meandering structure is not less than 5 times the line width, and the total number of periods is not less than 3.

3. A tunable shortwave active antenna according to claim 2, characterized in that, The plane of the radiator (6) is perpendicular to the plane of the back plate (2).

4. A tunable shortwave active antenna according to claim 1, characterized in that, The active tuning component (7) includes: Detection component (7-3) is used to measure antenna impedance; Matching network component (7-5) includes multiple capacitors, multiple inductors and multiple relays, the relays being used to control the connection status of the capacitors and the inductors; The control component (7-2) is connected to the detection component (7-3) and the matching network component (7-5) respectively, and is used to control the on / off state of the relay based on the result of the antenna impedance measured by the detection component (7-3) to switch the component value of the matching network component (7-5); A power supply assembly (7-4) is provided for supplying power to the detection assembly (7-3) and the control assembly (7-2).

5. A tunable shortwave active antenna according to claim 4, characterized in that, It also includes a temperature sensor located at the heat source position inside the active tuning component (7), and the control component (7-2) is connected to the temperature sensor and configured to send a power control command to the shortwave radio through the control interface (3) based on the monitored temperature.

6. A tunable shortwave active antenna according to claim 1, characterized in that, It also includes a thermally conductive insulating structure (1), which wraps around the root of the radiator (6) and is embedded between the power supply vias of the metal casing of the active tuning assembly (7) to achieve electrical insulation between the radiator (6) and the metal casing and to conduct the heat generated by the active tuning assembly (7) to the radiator (6).

7. A tunable shortwave active antenna according to claim 6, characterized in that, The thermally conductive and insulating structural component (1) is a hexagonal boron nitride ceramic with a dielectric strength greater than 30kV / mm and a thermal conductivity greater than 20W / (m·K).

8. A tunable shortwave active antenna according to claim 5, characterized in that, The control component (7-2) is configured to execute a dynamic thermal adaptive power derating strategy, including: When the monitored temperature is below the first threshold, a full power command is sent to the shortwave radio via the control interface (3); When the monitored temperature is between the first threshold and the second threshold, a power reduction request command is sent to the shortwave radio. When the monitored temperature exceeds the second threshold, an over-temperature protection request command is sent to the shortwave radio.

9. A tunable shortwave active antenna according to claim 1, characterized in that, The tunable shortwave active antenna includes a tuning mode and an operating mode: in the tuning mode, impedance matching is performed at low power; after the matching conditions are met, it enters the operating mode, allowing high-power transmission.

10. A tunable shortwave active antenna according to claim 1, characterized in that, The external interface also includes a power interface (4) for connecting to an external DC power supply; the radio frequency interface (5) is a standard 50Ω connector.

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