Short wave antenna with common mode interference suppression function

Abstract

The application discloses a short-wave antenna with a common-mode interference suppression function and relates to the technical field of antennas. The short-wave antenna comprises a back plate, a radiation core, a choke component and a radio frequency interface. The radiation core adopts a long strip ring structure and a top backfolded feed. The choke component is integrated in the antenna and is installed close to a feed port. The choke component comprises an insulating framework which is sleeved on a magnetic core. A plurality of independent wire slots are arranged on the framework. Winding turns are respectively accommodated in the wire slots, and input ends and output ends are located in two wire slots which are farthest apart. An inner insulating layer and an outer heat conducting layer are sequentially wrapped outside the winding turns. An outer shell is in heat conduction connection with the back plate. Through multi-slot grading insulation and layered pouring sealing design, the short-wave antenna can suppress common-mode current, avoid distortion of a directional diagram, solve high-voltage insulation, low-pressure flashover, strong vibration impact and heat dissipation problems in an airborne environment, and realize high-reliability work of the antenna under full flight working conditions.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and more specifically, to a shortwave antenna with common-mode interference suppression function. Background Technology

[0002] Shortwave communication utilizes the reflection effect of the ionosphere to provide communication coverage over a range of thousands of kilometers. It is often used as the ultimate communication backup for maintaining contact with ground stations during long-range flights, polar routes, and other remote flight missions. The shortwave antenna is responsible for converting electrical signals into space electromagnetic waves. It is an essential front-end of the shortwave communication system and a crucial guarantee for achieving reliable communication across all areas of the aircraft.

[0003] Due to the long wavelength of shortwave frequencies, antenna radiation resistance is generally very low within extremely limited platform installation space, exhibiting high Q characteristics. It is difficult to achieve a wide-bandwidth resonance effect over a large octave range through antenna structural design alone. To address this, a dedicated external antenna tuner (hereinafter referred to as the antenna tuner) can be introduced as close as possible to the antenna end. This ensures compatibility between the antenna and the standard impedance systems of the power amplifier, transceiver, and RF cables, preventing signal reflection at the antenna feed point. The input of the antenna tuner is connected to the power amplifier via an RF cable, and the output typically uses an unbalanced dual-port or 50-ohm RF interface. When the output of the unbalanced antenna tuner is directly connected to the balanced antenna radiating core, common-mode current components are easily induced on the outer surface of the coaxial RF cable's shielding layer, and even on the metal casing of the antenna tuner and the radio. This common-mode current generates unintended parasitic radiation, ultimately forming a complex radiation system of "antenna + antenna tuner + RF cable + radio," causing the antenna's radiation pattern, gain, and impedance characteristics to deviate significantly from design values. The antenna then becomes a highly sensitive noise pickup, degrading communication performance. In this state, the antenna's radiation capability is strongly correlated with the length, direction, and bending state of the radio frequency cable, resulting in poor stability and uncontrollability of the radiation system.

[0004] Airborne platforms differ fundamentally from ground applications. The differences are: 1) Due to the extremely small size and high Q-value characteristics of the airborne shortwave antenna involved in this invention, the antenna and antenna tuner together form a high-Q series resonant circuit, which can generate extremely high voltage at the feed point, easily leading to arcing and breakdown; 2) Due to the special nature of the airborne environment, during platform flight, there are problems such as low air pressure (significantly reduced air dielectric strength), continuous vibration, impact, and stringent heat dissipation, making the operating conditions more complex. These differences present entirely new and unconventional technical requirements for the antenna's voltage withstand capability, heat dissipation, and vibration resistance design. Therefore, a shortwave antenna capable of common-mode current suppression and adaptable to the extreme airborne environment is needed. Summary of the Invention

[0005] The purpose of this invention is to provide a shortwave antenna with common-mode interference suppression, which can effectively suppress common-mode current interference generated when the unbalanced output interface of the antenna tuner is directly connected to the balanced radiating structure, thus solving problems such as radiation pattern distortion and performance instability caused by this. Simultaneously, for the extreme environment of high-Q resonance in airborne shortwave antennas, which involves high voltage, low air pressure, strong vibration, and stringent heat dissipation, a high-voltage resistant multi-slot graded insulation and layered potting heat dissipation and vibration-resistant integrated design scheme is proposed. This scheme solves the problems of high-voltage insulation, efficient heat dissipation, and vibration buffering while achieving good common-mode interference suppression, ensuring reliable operation of the antenna under all operating conditions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This application provides a shortwave antenna with common-mode interference suppression function, including: Backplate, used to provide support and fixation for internal antenna components; The radiating core, located inside the back plate, is used to receive and radiate shortwave electromagnetic waves. A choke assembly is integrated inside the backplate and installed close to the power supply port of the radiating core. The output end of the choke assembly is electrically connected to the radiating core, and the input end is connected to the radio frequency interface. It is used to suppress common-mode current interference and maintain the normal transmission of differential-mode signals. The radio frequency interface is mounted on the outside of the backplate and connected to the input terminal of the choke assembly.

[0007] The choke assembly includes a winding, a magnetic core, an insulating frame, an inner insulating layer, an outer thermally conductive layer, and a housing. The insulating frame is fitted onto the magnetic core and has multiple independent slots distributed circumferentially. The multi-turn coil of the winding is divided into multiple turn groups, each turn group being accommodated in one of the slots, with the input and output ends of the winding located in the two furthest slots, respectively. The inner insulating layer wraps around the outer surfaces of the insulating frame and the winding. The outer thermally conductive layer fills the space between the inner insulating layer and the housing. The housing is thermally connected to the backplate.

[0008] The working principle of the choke component is as follows: for the common-mode component, since the current direction in the winding is the same and the magnetic flux is superimposed, the choke component presents high impedance, thereby suppressing the common-mode current; for the differential-mode component, since the current direction in the winding is opposite and the magnetic flux cancels each other out, the choke component presents low impedance, thereby maintaining the normal transmission of the differential-mode signal.

[0009] Furthermore, the insulating skeleton is made of polyetherimide, and the insulating skeleton is also provided with a skirted spacer ring, which extends radially outward by 5-10 mm to extend the creepage distance and reduce the risk of surface flashover under low pressure.

[0010] Furthermore, the inner insulating layer is made of silicone gel with a dielectric constant < 3.0, a dielectric strength ≥ 18 kV / mm, and a thickness of 1–2 mm. The outer thermally conductive layer is made of silicone gel containing boron nitride filler with a thermal conductivity ≥ 2.0 W / (m·K) and a dielectric strength ≥ 15 kV / mm.

[0011] Furthermore, the outer shell is an aluminum alloy bracket, the bottom surface of which has an extended bonding surface. The extended bonding surface is tightly bonded to the inner surface of the back plate by thermally conductive silicone grease and fixed by screws.

[0012] Furthermore, the magnetic core is a NiZn ferrite ring with a Curie temperature > 300℃, a saturation magnetic flux density ≥ 400mT, and a specific loss coefficient ≤ 300× .

[0013] Furthermore, the winding is made of polyimide enameled copper wire, which is wound on the magnetic core in a double-wire parallel winding manner.

[0014] Furthermore, the radiating core is a long strip-shaped ring structure, with its ring plane perpendicular to the plane of the back plate, and it folds back at the geometric midpoint of the long side away from the back plate to the side near the back plate to form a top feed.

[0015] Furthermore, the wiring length between the input and output ends of the winding and the corresponding connection points does not exceed 30mm.

[0016] Furthermore, the back panel includes a rear back panel and two side back panels. The rear back panel is rectangular, and the two side back panels are respectively perpendicularly connected to both ends of the rear back panel and located on the same side of the rear back panel, forming an overall shape resembling a "...". The back panel is shaped like a "". The back panel is made of surface-metallized fiberglass.

[0017] The beneficial effects of this invention are as follows: This invention provides a shortwave antenna with common-mode interference suppression. The antenna integrates a choke component, eliminating the need for additional external choke devices or equipment. This effectively suppresses unwanted common-mode currents on the outer sheath of RF cables, antenna tuners, and the metal casing of radios, solving problems such as increased noise levels, poor system stability, uncontrollability, and testing difficulties that occur when feeding long cables. At the same time, it eliminates unexpected parasitic radiation interference and solves problems such as antenna radiation pattern distortion and performance degradation.

[0018] Meanwhile, a high-voltage resistant polyetherimide multi-slot insulating skeleton is nested on the magnetic core, distributing the number of winding turns into multiple independent slots, with the input and output terminals located in the two slots furthest apart. This achieves the avoidance of inter-turn breakdown caused by high potential difference between turns through solid forced insulation. At the same time, the creepage distance is extended by using skirt spacers, further reducing the risk of surface flashover at low pressure.

[0019] Pure organosilicon gel is wrapped around the insulating frame and winding surface as a buffer layer to absorb vibration shock while ensuring radio frequency performance. Organosilicon gel containing high thermal conductivity boron nitride filler is filled between the inner insulating layer and the aluminum alloy shell as an outer thermal conductive structure layer to create a low thermal resistance heat dissipation path. The aluminum alloy shell and the antenna metal backplate are integrated and bonded together, and the large metal backplate is used as the final heat sink to achieve a synergistic design of efficient heat dissipation and vibration buffering.

[0020] 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

[0021] 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.

[0022] Figure 1 This is a schematic diagram of a shortwave antenna with common-mode interference suppression function; Figure 2 This is a schematic diagram of the elongated annular radiator with top-folded back feeding; Figure 3 yes Figure 1 A magnified view of a portion of the image; Figure 4 This is a schematic diagram of the choke assembly as a whole; Figure 5 This is an exploded view of the choke assembly; Figure 6 This is a comparison of the measured normalized radiation patterns of the antenna of the present invention and the antenna of the traditional scheme; In the diagram: 1-Radiating core, 2-Choke assembly, 3-RF interface, 4-Backplane; 23-1 and 23-2 are the input feed lines of the choke assembly, 21-1 and 21-2 are the output feed lines; 2-1 is the winding; 2-2 is the magnetic core; 2-3 is the insulating frame; 2-4 is the inner insulating layer; 2-5 is the outer thermal conductive layer; 2-6 is the aluminum alloy bracket; 2-7 is the mounting hole; 2-3-1 is the insulating groove; 2-3-2 is the skirt spacer ring. Detailed Implementation 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.

[0023] 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.

[0024] Example 1: See Figure 1 This embodiment provides a shortwave antenna with common-mode interference suppression function.

[0025] The main components of the antenna include: radiating core 1, choke assembly 2, radio frequency interface 3, and backplate 4.

[0026] The back panel 4 provides overall support and fixation, and includes a rear back panel and two side back panels. The rear back panel is rectangular, and the two side back panels are perpendicularly connected to both ends of the rear back panel and located on the same side of the rear back panel, forming an overall shape resembling a "...". The backplate 4 is shaped like a "". The material of the backplate 4 is surface-metallized glass fiber, which combines high strength, lightweight, good heat dissipation performance and controllable electrical characteristics, and can meet the stringent weight requirements and mechanical environment of the flight platform. The metallized surface of the backplate 4 can also serve as an electrical grounding reference surface, which is beneficial to the electromagnetic compatibility design of the antenna system.

[0027] The RF interface 3 is mounted at the midpoint of the outer side of the backplate 4, and uses a standard 50Ω RF coaxial interface (such as N-type or TNC-type) for connection to the output of the antenna tuner via a coaxial cable. The inner core and outer shell of the RF interface 3 serve as the signal terminal and ground terminal, respectively, introducing unbalanced signals into the antenna.

[0028] The radiating core 1 is located inside the backplate 4 and is used to receive and radiate shortwave electromagnetic waves. The radiating core 1 is made of a high-conductivity metal material—a silver-plated copper sheet—to reduce high-frequency losses. Its specific structure is described in detail in the "Radiating Core" section below.

[0029] The choke assembly 2 is integrated inside the backplate 4, mounted close to the feed port of the radiating core 1. The output end of the choke assembly 2 is electrically connected to the two feed arms of the radiating core 1, and the input end is soldered to the inner core and outer shell of the RF interface 3, respectively. The function of the choke assembly 2 is to suppress common-mode current interference and maintain the normal transmission of differential-mode signals. By directly integrating the choke assembly 2 inside the antenna instead of an external device, this invention effectively solves the common-mode interference problem caused by the connection between the unbalanced antenna output and the balanced radiating core without adding an additional choke device, while avoiding the additional volume, weight, and insertion loss caused by an external choke device.

[0030] See Figure 2 The radiating core 1 is a long, ring-shaped structure, with its ring plane perpendicular to the plane of the backplate 4. The radiating core 1 is made of silver-plated copper sheet with a thickness of 0.5mm to 1mm. The width of the ring structure (i.e., the distance between the two long sides of the ring) is determined based on the lower limit frequency of the operating frequency band and the maximum operating installation size, and is typically <0.1mm. ( (This refers to the wavelength corresponding to the lowest operating frequency). In this embodiment, the width of the radiating core ring is approximately 300 mm.

[0031] The radiating core 1 is fed using a top-folded feeding method: at the geometric midpoint of the long side away from the backplate 4, the radiating core is folded back towards the backplate 4 to form a feed point. This feed point is located at the electrical and geometric midpoint of the radiating core 1, ensuring that the potential to ground is the same on both sides of the feed port, thus achieving balanced feeding. Compared with the traditional center-fed linear dipole, the top-folded annular structure of this invention can achieve a longer equivalent electrical length within a very small platform installation size, effectively improving the radiation resistance and reducing the Q value of the antenna, thereby reducing the matching pressure on the antenna tuner. At the same time, the folded structure places the feed point on the side of the antenna closer to the backplate, facilitating a compact connection with the choke assembly 2, shortening the wiring distance, and helping to suppress unnecessary parasitic parameters.

[0032] See Figure 3 The input dual-wire windings 23-1 and 23-2 of the choke assembly 2 pass through the vias into the aluminum alloy bracket and are then soldered to the inner core and outer shell of the RF interface 3, respectively. The output dual-wire windings 21-1 and 21-2 of the choke assembly 2 pass through the vias into the aluminum alloy bracket and are then soldered to two copper terminals, and then fixed to the two feed arms of the radiating core 1 by screws. The wiring length between the input and output ends of the windings and the corresponding connection points does not exceed 30mm.

[0033] See Figure 4 and Figure 5The choke assembly 2 includes, from the inside out, a magnetic core 2-2, a winding 2-1, an insulating frame 2-3, an inner insulating layer 2-4, an outer heat-conducting layer 2-5, and an aluminum alloy bracket 2-6.

[0034] The magnetic core 2-2 is made of toroidal NiZn ferrite material, with an outer diameter of 60mm, an inner diameter of 30mm, and a height of 20mm. NiZn ferrite has high resistivity, low eddy current loss, and good high-frequency characteristics, making it suitable for the shortwave band. Key electromagnetic parameters are as follows: Curie temperature > 300℃, ensuring no magnetic attenuation occurs under high-temperature airborne conditions; saturation magnetic flux density ≥ 400mT, ensuring the core will not saturate and fail during high-power transmission; specific loss coefficient ≤ 300× This results in minimal insertion loss of the choke assembly within the operating frequency band, without affecting antenna radiation efficiency. Those skilled in the art can adjust the core size and number of turns according to the actual operating frequency and power level, but the above parameter range represents a preferred option. By selecting a NiZn ferrite core with high Curie temperature, high saturation flux density, and low loss, the choke assembly 2 of this invention can maintain stable common-mode rejection performance under high-power airborne transmission and wide-temperature operating conditions, and will not fail due to core saturation or overheating.

[0035] Winding 2-1 uses polyimide enameled copper wire with a diameter of 2mm (including insulation). Polyimide has excellent high temperature resistance (long-term operating temperature > 200℃), high voltage resistance (breakdown voltage > 5kV), and chemical corrosion resistance, making it suitable for long-term use in harsh airborne environments. The winding method is double-wire parallel winding: two enameled copper wires of equal length are tightly bonded together and wound in the same direction, uniformly, and tightly onto the magnetic core 2-2. Double-wire parallel winding ensures that the magnetic flux generated by the differential mode current cancels each other out (the magnetic flux generated by the common mode current is superimposed), thereby achieving the electrical characteristics of high common-mode impedance and low differential-mode impedance. The number of turns is 9. The selection of the number of turns needs to achieve a balance between common-mode rejection ratio and insertion loss. In this embodiment, the 9 turns enable the choke assembly to achieve a common-mode impedance of over 1000Ω in the 2-30MHz frequency band, while the differential-mode insertion loss is less than 1dB. Among these, the double-wire parallel winding method has a simple structure, is easy to manufacture, and can achieve common-mode rejection over a wide frequency band. The polyimide insulation layer ensures high voltage resistance between windings and between windings and the magnetic core, adapting to the high voltage (up to several kilovolts) that may occur at the feed point of an airborne high-Q antenna.

[0036] The insulating frame 2-3 is made of high-voltage resistant polyetherimide and is tightly fitted onto the magnetic core 2-2. The insulating frame 2-3 is tightly fitted onto the magnetic core 2-2, and its function is to physically isolate and fix the coil turns of the winding 2-1.

[0037] The upper surface of the insulating frame 2-3 (i.e., the side facing the antenna radiation direction) has multiple independent slots 2-3-1 evenly distributed circumferentially. In this embodiment, there are 6 slots, and the depth and width of each slot are slightly larger than the outer diameter of the enameled copper wire (approximately 2.2 mm) to ensure that the coil can be firmly embedded without falling out. The total number of turns (9 turns) of the winding 2-1 is divided into multiple turn groups, each turn group containing 1 to 3 turns of coil, which are then respectively accommodated in each slot 2-3-1.

[0038] In this embodiment, the 9 turns are divided into 4 turns groups (e.g., turns group allocation: 2 turns, 2 turns, 2 turns, 3 turns), and placed in 4 slots respectively, with the remaining 2 slots reserved. The input and output ends of winding 2-1 are located in the two slots furthest apart to maximize the insulation distance between the input and output.

[0039] The insulating frame 2-3 is also provided with a skirted spacer ring 2-3-2, which extends radially outward from the outer edge of the insulating frame by 5-10 mm (5 mm in this embodiment). The function of the skirted spacer ring is to extend the creepage distance from the high-voltage end of the winding to the magnetic core or shell. In low-pressure environments (such as a flight platform at an altitude of 10,000 meters, with an air pressure of approximately 26 kPa, and the air dielectric strength decreasing to 25%-40% of that at sea level), the surface flashover voltage drops significantly, making surface discharge more likely. By providing the skirted spacer ring, the creepage distance between two adjacent turns is extended by an additional 10 mm, further reducing the risk of surface flashover.

[0040] This embodiment constructs a multi-slot hierarchical insulation structure using multiple independent slots 2-3-1. Compared to the traditional common-mode choke where multiple coils are tightly wound and isolated only by enameled wire insulation, this invention uses a solid insulating frame 2-3 to physically isolate each group of turns. Even if insulation breakdown occurs between one turn, it will not affect other groups of turns, greatly improving withstand voltage reliability. Simultaneously, the long-distance separation of the input and output terminals and the extended creepage distance design of the skirt spacer ring 2-3-2 are specifically optimized for airborne low-pressure environments, solving the problem of surface flashover that easily occurs in ordinary chokes at high altitudes. This design enables the antenna of this invention to operate safely and reliably throughout its entire flight envelope.

[0041] The inner insulation layer 2-4 is made of pure organic silicone gel with a dielectric constant < 3.0, dielectric strength ≥ 18kV / mm, and a thickness of 2mm. It is uniformly wrapped around the outer surface of the insulating frame 2-3 and the winding 2-1. This inner insulation layer absorbs high-frequency vibrations transmitted from outside the antenna, preventing core cracking, displacement, and winding loosening. On the other hand, it protects the winding transmission characteristics with its low dielectric constant and releases the stress generated by the thermal expansion of the material.

[0042] The outer thermal conductive layer 2-5 is made of silicone gel material containing boron nitride filler, with a thermal conductivity ≥2.0W / (m·K) and dielectric strength ≥15kV / mm, and is uniformly filled between the inner insulating layer 2-4 and the aluminum alloy bracket 2-6. This outer thermal conductive layer forms an efficient heat conduction path, transferring the heat generated by the magnetic core and windings to the aluminum alloy bracket, while absorbing some low-frequency vibrations and serving as an auxiliary buffer and high-voltage insulation.

[0043] The aluminum alloy brackets 2-6 are made of 6061-T6 steel, with an extended bonding surface on their bottom. After being coated with insulating and thermally conductive silicone grease, they are tightly bonded to the inner surface of the antenna metallized backplate 4 and secured with screws. The aluminum alloy brackets are integrally bonded to the backplate, utilizing the large metal backplate as the final heat sink to quickly conduct internal heat away, while also providing electromagnetic shielding and mechanical protection.

[0044] The electrical working principle of the choke component 2 is as follows: For the common-mode current component (i.e., the component with the same current direction on the two wires), the magnetic flux generated by the bi-wire winding in the magnetic core is superimposed, making the choke component present a high impedance (typical value > 1000Ω), thereby effectively suppressing the flow of common-mode current along the outer sheath or outer shell of the RF cable; For the differential-mode signal component (i.e., the signal component with the opposite current direction and equal magnitude on the two wires), the magnetic flux generated in the bi-wire is equal in magnitude and opposite in direction, canceling each other out in the magnetic core, and the choke component presents an extremely low impedance (typical value < 5Ω), so that the differential-mode signal can be transmitted to the radiating core without attenuation.

[0045] To achieve the best results from the above principle, this embodiment imposes strict constraints on the lead length of the winding. (See also...) Figure 3 The input terminals of winding 2-1, with double wires 23-1 and 23-2, pass through the vias of the aluminum alloy bracket 2-6 and are directly soldered to the inner core and outer shell of the RF interface 3, respectively. The length of the wire extension between the soldering point and the via is controlled within 30mm. Similarly, the output terminals of winding 2-1, with double wires 21-1 and 21-2, pass through the vias of the aluminum alloy bracket 2-6 and are soldered to two copper terminals, and then fixed to the two feed arms of the radiating core 1 by screws. The length of the wire extension between the feed point and the via is also controlled within 30mm.

[0046] The constraint of a wiring length not exceeding 30mm is crucial. Excessively long leads can create new sources of common-mode radiation because the lead itself is equivalent to an unbalanced transmission line, potentially exciting common-mode currents and weakening the choke's suppression effect. Simultaneously, excessively long leads can introduce undesirable series inductance and distributed capacitance, altering the choke's impedance characteristics in the shortwave band, potentially leading to impedance mismatch and gain reduction. The 30mm limit in this invention is a critical value derived through extensive simulation and experimental optimization, minimizing parasitic effects to an acceptable range while ensuring ease of installation.

[0047] See Figure 6 To verify the practical effectiveness of this invention, comparative tests were conducted in an open field environment. The test conditions were as follows: using the same transmitter (50W output power), antenna tuner, and the same RF cable (5m length, 50Ω impedance), a conventional shortwave antenna (without common-mode rejection) and the antenna of this invention were connected respectively, and the normalized radiation pattern was measured at a frequency of 24MHz. The test results showed that the radiation pattern of the conventional antenna exhibited significant distortion in the angular region of θ=90°~270°, with a maximum gain degradation exceeding 10dB, and the pattern was asymmetrical; while the radiation pattern of the antenna of this invention was smooth, with good symmetry, and highly consistent with the theoretical radiation pattern. This comparison fully demonstrates that the choke component of this invention effectively suppresses unwanted parasitic radiation caused by common-mode current, restoring the theoretical radiation characteristics of the antenna.

[0048] Furthermore, in combined tests simulating airborne environments including high voltage (peak voltage at the feed point simulated at 3000V), low air pressure (air pressure 26kPa, corresponding to an altitude of 10000 meters), vibration (5-500Hz frequency sweep, power spectral density 0.1g² / Hz), and high temperature (+70℃), the antenna of this invention continued to operate without breakdown, flashover, structural damage, or performance degradation, verifying its adaptability to airborne environments.

[0049] In summary, the shortwave antenna with common-mode interference suppression provided in this embodiment not only effectively suppresses common-mode interference, but also systematically solves the insulation, heat dissipation, and vibration resistance problems under extreme airborne operating conditions through a hierarchical and multi-functional structural design, demonstrating significant innovation and practical value.

[0050] 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.

[0051] 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.

[0052] 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 shortwave antenna with common-mode interference suppression function, characterized in that, include: Backplate (4) is used to provide support and fixation; The radiating core (1) is located inside the back plate (4) and is used to receive and radiate shortwave electromagnetic waves. The choke assembly (2) is integrated inside the back plate (4) and installed close to the power supply port of the radiating core (1). The output end of the choke assembly (2) is electrically connected to the radiating core (1), and the input end is connected to the radio frequency interface (3). It is used to suppress common-mode current interference and maintain the normal transmission of differential-mode signals. The radio frequency interface (3) is installed on the outside of the back plate (4) and connected to the input end of the choke assembly (2); The choke assembly includes a winding (2-1), a magnetic core (2-2), an insulating frame (2-3), an inner insulating layer (2-4), an outer heat-conducting layer (2-5), and a shell (2-6). The insulating frame (2-3) is sleeved on the magnetic core (2-2). Multiple independent wire slots (2-3-1) are distributed circumferentially on the insulating frame (2-3). The multi-turn coil of the winding (2-1) is divided into multiple turn groups, each turn group is accommodated in one wire slot (2-3-1), and the input end and output end of the winding (2-1) are located in the two wire slots (2-3-1) that are furthest apart. The inner insulation layer (2-4) wraps around the outer surface of the insulating frame (2-3) and the winding (2-1); The outer thermally conductive layer (2-5) is filled between the inner insulating layer (2-4) and the outer shell (2-6); The outer shell (2-6) is thermally connected to the back plate (4).

2. A shortwave antenna with common-mode interference suppression function according to claim 1, characterized in that, The insulating frame (2-3) is also provided with a skirted spacer ring (2-3-2), which extends radially outward by 5-10 mm.

3. A shortwave antenna with common-mode interference suppression function according to claim 2, characterized in that, The inner insulating layer (2-4) has a dielectric constant of <3.0, a dielectric strength of ≥18kV / mm, and a thickness of 1-2mm.

4. A shortwave antenna with common-mode interference suppression function according to claim 3, characterized in that, The thermal conductivity of the outer thermal conductive layer (2-5) is ≥2.0W / (m·K), and the dielectric strength is ≥15kV / mm.

5. A shortwave antenna with common-mode interference suppression function according to claim 1, characterized in that, The outer shell (2-6) is an aluminum alloy bracket. The bottom surface of the aluminum alloy bracket has an extended bonding surface. The extended bonding surface is tightly bonded to the inner surface of the back plate (4) by thermally conductive silicone grease and fixed by screws.

6. A shortwave antenna with common-mode interference suppression function according to claim 1, characterized in that, The magnetic core (2-2) is a NiZn ferrite ring with a Curie temperature > 300℃, a saturation magnetic flux density ≥ 400mT, and a specific loss coefficient ≤ 300× .

7. A shortwave antenna with common-mode interference suppression function according to claim 1, characterized in that, The winding (2-1) is made of polyimide enameled copper wire and is wound on the magnetic core (2-2) in a double-wire parallel winding manner.

8. A shortwave antenna with common-mode interference suppression function according to claim 1, characterized in that, The radiating core (1) is a long strip-shaped ring structure with its ring plane perpendicular to the plane of the back plate (4), and it folds back at the geometric midpoint of the long side away from the back plate (4) to the side near the back plate (4) to form a top feed.

9. A shortwave antenna with common-mode interference suppression function according to claim 8, characterized in that, The wiring length between the input and output ends of the winding and the corresponding connection point does not exceed 30mm.

10. A shortwave antenna with common-mode interference suppression function according to claim 9, characterized in that, The back panel (4) includes a rear back panel and two side back panels; the rear back panel is rectangular, and the two side back panels are respectively vertically connected to the two ends of the rear back panel and located on the same side of the rear back panel.

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