Conformal antenna applied to high-temperature environment

Abstract

The invention discloses a conformal antenna applied to a high-temperature environment, and belongs to the technical field of antennas. The antenna comprises a high-temperature-resistant cable assembly, a circular ring structure, a resonance piece, a supporting block, a ceramic cover plate and a heat insulation coating, the high-temperature-resistant cable assembly is directly fixed to a cavity structure through threads on a connector of the high-temperature-resistant cable assembly, and a core on the connector is welded to the resonance piece. The fixing device is fixed to the tail of the aircraft through screw holes in the outer diameter. The heat insulation coating can insulate heat generated by the exhaust nozzle to a certain degree, and the heat is prevented from being directly transmitted to the cavity structure. The invention provides a high-temperature-resistant conformal antenna applicable to high-speed aircrafts.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a conformal antenna for use in high-temperature environments. Background Technology

[0002] With the rapid development of aerospace and defense weaponry technologies, high-speed flight vehicles such as hypersonic vehicles and tactical missiles pose unprecedented challenges to antenna systems. Generally, these high-speed flight vehicles are approximately cylindrical in shape. To enable communication with other aircraft or platforms behind them, the radiation pattern of the antennas on these vehicles must cover the area behind the aircraft. To avoid affecting the aerodynamic structure and ensure the reliability of rearward communication, rearward-radiating end-fire antennas conformally to the aircraft skin are typically chosen. Currently, antenna types that can achieve conformal design and whose radiation direction covers the tail of the aircraft mainly include: cavity slot antennas, microstrip patch antennas, and end-fire helical antennas. However, these antenna types all require appropriate adjustments to the aircraft fuselage or skin, which has a certain impact on the integrity design of the aircraft fuselage. Summary of the Invention

[0003] In view of this, the present invention provides a conformal antenna for use in high-temperature environments, which can be installed inside the tail section of an aircraft, with the radiation direction facing the tail. Structurally, it avoids the tail nozzle position inside the tail section. Through structural and process design, it avoids the impact of the 800°C high-temperature exhaust flame generated by the tail nozzle on the antenna performance.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A conformal antenna for use in high-temperature environments includes a high-temperature resistant cable assembly, a ring structure, a resonator, and a ceramic cover plate; The ring structure has an inner cavity of a ring segment; the inner cavity of the ring segment has stepped structures on both sides; the shape of the resonant plate is adapted to the inner cavity of the ring segment, the resonant plate is located in the inner cavity of the ring segment, and the two ends of the resonant plate rest on the corresponding stepped structures respectively. The ceramic cover plate covers the opening of the inner cavity of the annular segment, forming a sealed space, wherein the resonant plate divides the sealed space into two regions; the outer conductor of the high-temperature resistant cable assembly is connected to the annular structure, and the end of the inner conductor is located in the inner cavity of the annular segment and connected to the resonant plate.

[0005] Furthermore, the resonator is made of H62 type copper material and its surface is silver-plated.

[0006] Furthermore, it also includes support block A and support block B; Two support blocks A are provided, and the support blocks A are installed on the corresponding stepped structure by screws; the end of the resonant plate is clamped between the stepped structure and the support block A; Two support blocks B are provided, and support blocks B have an L-shaped structure. The vertical side plate of the L-shaped structure is installed on the side wall of the inner cavity of the annular segment by screws, and the horizontal side plate is provided with a sliding groove. A sliding pin is provided in the sliding groove. The sliding pin is perpendicular to the horizontal side plate and has the freedom to move along the sliding groove. The resonator is provided with positioning pin holes; the sliding pins and pin holes correspond one-to-one and fit together.

[0007] Furthermore, the resonant plate has positioning holes at both ends, and the stepped structure has positioning posts, with each positioning hole corresponding to a positioning post.

[0008] Furthermore, the two ends of the ceramic cover plate are pressed onto the corresponding support block A, and connected to the support block A by screws.

[0009] Furthermore, it also includes a heat-insulating coating, which is sprayed onto the inner surface of the annular structure.

[0010] Furthermore, the outer diameter of the resonant plate is smaller than the outer diameter of the inner cavity of the annular segment, while the inner diameter of the resonant plate is larger than the outer diameter of the inner cavity of the annular segment.

[0011] Furthermore, the annular segment cavity of the annular structure has cable mounting threaded holes for direct connection with cable assemblies; the annular segment cavity also has a ceramic cover plate support structure to ensure that the cover plate and the cavity surface remain on the same plane.

[0012] Furthermore, a 1.5mm thick heat-insulating coating is sprayed onto the inner side of the ring structure.

[0013] The beneficial effects of the above-mentioned technical solution adopted by the present invention are as follows: The conformal antenna of this invention can be integrated into the tail section of an aircraft carrier, with negligible impact on the aircraft's structural structure. By applying a heat-insulating coating to the portion in contact with the tail nozzle, selecting copper for the resonator, adding a ceramic radome, and designing suitable support blocks to prevent deformation of the resonator, the high-temperature environment near the aircraft's tail nozzle is ensured to not affect the antenna's performance. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the forward structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the rear structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the installation structure of the support blocks (support block A and support block B) of the present invention; Figure 4 This is a schematic diagram of the combined structure of the stepped structure and the resonant plate of the present invention.

[0015] Figure 5The voltage standing wave ratio (VSWR) is calculated by ANSOFT HFSS in an embodiment of the present invention.

[0016] Figure 6 The horizontal radiation pattern and its relative relationship with the antenna are calculated by ANSOFT HFSS in an embodiment of the present invention.

[0017] Figure 7 The radiation patterns at frequencies of 1.36 GHz, 1.385 GHz, and 1.41 GHz calculated by ANSOFT HFSS in this embodiment of the invention are shown.

[0018] In the diagram: 1. Circular structure, 2. Heat insulation coating, 3. Support block A, 4. Support block B, 5. Ceramic cover plate, 6. High temperature resistant cable assembly, 7. Resonant plate, 8. Sliding pin, 4-1. Vertical side plate, 4-2. Horizontal side plate, 9. Pin hole, 10. Positioning post, 11. Stepped structure. Detailed Implementation

[0019] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] This invention provides a conformal antenna for use in high-temperature environments. This antenna is designed to be integrated into the tail section of high-speed aircraft (such as hypersonic vehicles and tactical missiles), and can withstand the high temperature of the tail flame, which can reach up to 800°C, while maintaining stable electrical performance and structural integrity, to achieve rearward radiation communication.

[0021] See Figure 1 and Figure 2 The overall antenna structure of this embodiment mainly includes: a ring structure (as a cavity structure) 1, a heat insulation coating 2, a support block A 3, a support block B 4, a ceramic cover plate 5, a high-temperature resistant cable assembly 6, a resonant plate 7, a sliding pin 8, a pin hole 9, a positioning post 10, and a stepped structure 11.

[0022] 1. Circular ring structure (cavity structure) The circular ring structure 1 is the core mechanical carrier and part of the electromagnetic resonant cavity of this antenna. It is a ring-shaped metal structure, preferably made of aluminum alloy to reduce weight; copper can also be used in scenarios where weight is less critical or higher conductivity is required. This structure is conformally designed based on the actual contours of the aircraft's tail section and internal exhaust nozzle. Specifically, its outer diameter is slightly smaller than the aircraft's tail section inner diameter (e.g., 0.1 mm smaller), and its inner diameter is slightly larger than the exhaust nozzle outer diameter (e.g., 0.1 mm larger) to ensure smooth assembly and avoidance of the exhaust nozzle. Multiple screw holes are provided on the outer sidewall of the circular ring structure 1 for fixing the entire antenna assembly to the aircraft's tail section inner wall. The bottom of the circular ring structure 1 is designed to be flush with the aircraft's tail section inner wall, allowing it to also serve as the aircraft's bottom shield and reducing the impact on the original aerodynamic structure.

[0023] A circular annular cavity is machined into the annular structure 1, the cross-sectional shape of which is adapted to the resonator 7. Symmetrical stepped structures 11 are machined on the inner walls of both sides of the annular cavity. Positioning posts 10 for precise positioning are provided on the stepped structures 11. Furthermore, the cavity has pre-drilled cable mounting threaded holes for directly screwing in the connectors of the high-temperature resistant cable assembly 6; simultaneously, a ceramic cover plate support structure is provided at the edge of the cavity opening to ensure that the outer surface of the ceramic cover plate 5 remains on the same plane as the cavity surface after installation, maintaining the overall conformal characteristics.

[0024] 2. Resonator and its fixing The resonant element 7 is the core radiating element of the antenna, and its shape is an arc-shaped sheet structure that matches the inner cavity of the circular ring segment. The resonant element 7 is made of H62 type brass, a material with good mechanical strength and high-temperature resistance. To further improve conductivity and solderability, the surface of the resonant element 7 is silver-plated. Both ends of the resonant element 7 have positioning holes that mate with the positioning posts 10, and pin holes 9 for mate with the support block B4.

[0025] During installation, the resonant plate 7 is placed in the inner cavity of the annular segment of the annular structure 1, with its two ends resting on the stepped structures 11 on both sides, and is initially positioned by the cooperation of the positioning hole and the positioning post 10.

[0026] To securely fix the resonator in a high-temperature environment and prevent it from deforming or shifting, two support structures, support block A3 and support block B4, were used.

[0027] Installation and function of support block A: like Figure 3As shown, there are two support blocks A3, located at both ends of the resonant plate 7. Each support block A3 is fastened to the corresponding stepped structure 11 with screws, thereby tightly clamping the end of the resonant plate 7 between the stepped structure 11 and the support block A3. This fixing method, on the one hand, firmly installs the resonant plate 7 on the cavity, forming an air resonant cavity with a defined gap between the resonant plate 7 and the inner wall of the annular structure 1; on the other hand, through rigid clamping, it can effectively constrain the longitudinal deformation (i.e., along the depth direction of the cavity) that the resonant plate 7 may undergo at high temperatures.

[0028] Installation and function of support block B: See also Figure 3 Two support blocks B4 are also provided, with an L-shaped structure, consisting of a vertical side plate 4-1 and a horizontal side plate 4-2. The vertical side plate 4-1 is installed on the side wall of the inner cavity of the annular segment by screws. The horizontal side plate 4-2 has a long sliding groove. The sliding pin 8 is assembled in this sliding groove, and the axis of the sliding pin 8 is perpendicular to the horizontal side plate 4-2. The sliding pin 8 can have a certain degree of freedom of movement within the sliding groove. During installation, the end of the sliding pin 8 is inserted into the pre-set pin hole 9 on the resonant plate 7. The main function of the support block B4 is to restrict the radial displacement of the resonant plate 7 (i.e., the radial direction relative to the center of the annulus). Since the relative distance between the inner ring of the resonant plate 7 and the inner wall of the annular structure 1 is extremely sensitive to the antenna performance (such as the resonant frequency), the thermal expansion of the material may cause this distance to change under high temperature conditions. The cooperation between support block B4 and sliding pin 8 achieves radial fixation, while the sliding groove design allows for slight relative movement caused by thermal expansion, thus ensuring the stability of critical dimensions and ensuring that antenna performance is not affected by high temperature.

[0029] 3. Ceramic cover plate The ceramic cover plate 5 serves as the antenna's radiation window and protective cover, covering the opening of the inner cavity of the annular segment. Made of alumina ceramic material, it possesses excellent high-temperature insulation, thermal shock resistance, and ablation resistance, effectively preventing the high-temperature exhaust flame from directly ablating the internal structure. Both ends of the ceramic cover plate 5 are pressed onto corresponding support blocks A3 and fixed to them with screws. After installation, the ceramic cover plate 5 and the cavity of the annular structure 1 together form a sealed space. The resonator 7 is located within this sealed space, dividing it into two regions. The thickness of the ceramic cover plate 5 has an adjusting effect on the antenna's center frequency; in this embodiment, it is preferably 4mm, and during mass production, the thickness tolerance is controlled within ±0.1mm.

[0030] 4. High-temperature resistant cable assemblies The high-temperature resistant cable assembly 6 is used for signal input and output. Its outer conductor (shielding layer) is directly screwed into the cable mounting threaded hole on the annular structure 1 through the thread on the connector, achieving electrical connection and mechanical fixation with the annular structure 1. The end of the cable's inner conductor (core) passes through the through hole on the annular structure 1, extends into the inner cavity of the annular section, and is welded to the preset feed point on the resonator 7 to achieve signal excitation. The cable assembly as a whole adopts a high-temperature resistant design, with its inner conductor and shielding layer made of silver-plated copper, its insulation layer made of polytetrafluoroethylene, and its sheath made of high-temperature conductor and glass fiber material, ensuring reliable operation in environments above 200°C.

[0031] 5. Heat insulation coating To block the heat transferred from the tail nozzle, a heat-insulating coating 2 is sprayed onto the inner surface of the annular structure 1 (i.e., the side closest to the tail nozzle and subjected to the most severe heat), such as... Figure 1 As shown. This coating effectively reduces heat transfer to the cavity and internal structure. In this embodiment, the thickness of the heat insulation coating 2 is 1.5 mm, and tests have shown that it can reduce the temperature in this area by 60°C to 70°C, significantly protecting the internal components of the antenna.

[0032] A brief description of the working principle of an antenna; The basic radiation principle of this antenna is based on waveguide port radiation. For example... Figure 4 As shown, a ring-shaped matching structure (which can be considered a deformed waveguide or resonant cavity) is formed by the resonant plate 7, the inner wall of the ring structure 1, and the inner and outer conductors of the cable. The arc-shaped design of the resonant plate 7 makes the openings formed between its upper and lower edges and the inner and outer walls of the ring structure 1 equivalent to an arc-shaped waveguide opening. By precisely designing the dimensions of the resonant plate 7 (such as thickness, arc length, distance from the bottom surface of the cavity), its gap with the inner and outer walls of the cavity, and the cavity depth, the impedance matching of the antenna can be optimized, the operating bandwidth can be expanded, and the desired radiation modes can be excited.

[0033] In this embodiment, after parameter optimization (e.g., resonator 7 thickness 1mm, depth from cavity bottom surface 12mm), the antenna operates well in the L-band range of 1.36GHz to 1.41GHz. The simulated voltage standing wave ratio (VSWR) is less than 1.5 within this bandwidth (see the accompanying drawings in the specification). Figure 5 This indicates good port matching. Its radiation pattern is stable within the bandwidth, with the beam pointing towards the antenna normal (i.e., behind the tail of the aircraft), and the gain is greater than 2.5 dBi within a beamwidth of -30° to +30° (see the attached diagram in the manual). Figure 6 , Figure 7 This satisfies the requirements for backward communication coverage.

[0034] This invention comprehensively solves the problems of antenna integration, fixation, thermal protection, and performance stability in the extreme high-temperature environment of the aircraft's tail section by using a conformally designed ring structure, high-temperature resistant resonant plates and cables, a heat-insulating coating, an ablation-resistant ceramic cover plate, and a special support block fixing mechanism. By adjusting the resonant plate size, cavity structure, and ceramic cover plate parameters, the design concept of this invention can be extended to other operating frequency bands.

Claims

1. A conformal antenna for use in high-temperature environments, comprising a high-temperature resistant cable assembly, a circular ring structure, a resonant plate, and a ceramic cover plate; characterized in that, The ring structure has an inner cavity of a ring segment; the inner cavity of the ring segment has stepped structures on both sides; the shape of the resonant plate is adapted to the inner cavity of the ring segment, the resonant plate is located in the inner cavity of the ring segment, and the two ends of the resonant plate rest on the corresponding stepped structures respectively. The ceramic cover plate covers the opening of the inner cavity of the annular segment, forming a sealed space, wherein the resonant plate divides the sealed space into two regions; the outer conductor of the high-temperature resistant cable assembly is connected to the annular structure, and the end of the inner conductor is located in the inner cavity of the annular segment and connected to the resonant plate.

2. The conformal antenna for use in high-temperature environments according to claim 1, characterized in that, The resonator is made of H62 copper material and its surface is silver-plated.

3. A conformal antenna for use in high-temperature environments according to claim 1, characterized in that, It also includes support block A and support block B; Two support blocks A are provided, and the support blocks A are installed on the corresponding stepped structure by screws; the end of the resonant plate is clamped between the stepped structure and the support block A; Two support blocks B are provided, and support blocks B have an L-shaped structure. The vertical side plate of the L-shaped structure is installed on the side wall of the inner cavity of the annular segment by screws, and the horizontal side plate is provided with a sliding groove. A sliding pin is provided in the sliding groove. The sliding pin is perpendicular to the horizontal side plate and has the freedom to move along the sliding groove. The resonator is provided with positioning pin holes; the sliding pins and pin holes correspond one-to-one and fit together.

4. A conformal antenna for use in high-temperature environments according to claim 1, characterized in that, The resonant plate has positioning holes at both ends, and the stepped structure has positioning posts, with each positioning hole corresponding to a positioning post.

5. A conformal antenna for use in high-temperature environments according to claim 3, characterized in that, The two ends of the ceramic cover plate are pressed onto the corresponding support block A, and are connected to the support block A by screws.

6. A conformal antenna for use in high-temperature environments according to claim 3, characterized in that, It also includes a heat-insulating coating, which is sprayed onto the inner surface of the annular structure.

7. A conformal antenna for use in high-temperature environments according to claim 1, characterized in that, The outer diameter of the resonator is smaller than the outer diameter of the inner cavity of the annular segment, and the inner diameter of the resonator is larger than the outer diameter of the inner cavity of the annular segment.

8. A conformal antenna for use in high-temperature environments according to claim 1, characterized in that, The annular section of the ring structure has threaded holes for cable installation, which are used for direct connection with cable assemblies; the annular section also has a ceramic cover plate support structure to ensure that the cover plate and the surface of the cavity are on the same plane.

9. A conformal antenna for use in high-temperature environments according to claim 1, characterized in that, A 1.5mm thick heat-insulating coating is sprayed onto the inner side of the ring structure.

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