Missile telemetry antenna array based on feed phase difference and screw coupling

Abstract

A missile telemetry antenna array based on feed phase difference and screw coupling, comprising: inverted F antenna, missile cabin, rectifier block, RF cable and transmitter; a plurality of inverted F antennas are evenly distributed around the central axis of the missile cabin, and the inverted F antennas are fixedly installed on the outer wall of the missile cabin; the inverted F antennas are connected with the transmitter through the RF cable; a rectifier block is arranged above the head of each inverted F antenna; the rectifier block is fixedly installed on the outer wall of the missile cabin; and the rectifier block is used for flow guiding, so that no stagnation point of aerodynamic heating appears on the inverted F antenna. The present application optimizes the gain depression of the axis direction of the missile body, realizes the protection of the aerodynamic heating and force of the antenna by installing the rectifier block in front of the antenna, generates electromagnetic resonance and induced current through the installation screw of the rectifier block, realizes the secondary radiation of electromagnetic waves and the reflection guiding effect.

Description

Technical Field

[0001] This invention designs a projectile telemetry antenna array based on feed phase difference and screw coupling to achieve rear coverage of telemetry signals during projectile flight, thereby ensuring the stability and reliability of the telemetry link and ensuring reliable reception of telemetry data. Background Technology

[0002] Telemetry is a technology that measures the parameters of an object over a long distance. It is crucial in the design and testing of missiles and rockets. The role of the telemetry transmitting antenna is to convert high-frequency current into electromagnetic waves and radiate them in a specified direction. It is one of the key components of the missile and rocket telemetry system.

[0003] During missile and rocket test flights, the radiation pattern of the telemetry transmitting antenna is crucial for receiving telemetry data. Typical missile and rocket telemetry antennas are implemented using microstrip antennas. Loop microstrip antennas are usually installed inside the nose cone or embedded in the fuselage wall. Installing them inside the nose cone occupies payload space and requires a transparent nose cone, increasing the complexity and cost of nose cone manufacturing and design. Embedding microstrip antennas in the fuselage wall weakens the rocket's structural strength and increases manufacturing complexity. Furthermore, because the microstrip antenna's polarization is horizontal relative to the rocket surface, the horizontally polarized wave attenuates rapidly along the direction of the metal projectile surface, resulting in an irreparable gain dip at the rear of the missile's axis. This dip places higher demands on the number and location of telemetry data receiving stations, increasing the cost and complexity of telemetry data reception during launch missions. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a projectile telemetry antenna array that, based on screw electromagnetic coupling and feed phase difference, realizes the directional optimization and adjustment of the antenna pattern, improves the reliability of telemetry data acquisition, and reduces the site deployment requirements and costs.

[0005] The technical solution of this invention is:

[0006] A projectile telemetry antenna array based on feed phase difference and screw coupling includes: an inverted-F antenna, a projectile housing, a rectifier block, an RF cable, and a transmitter;

[0007] Multiple inverted-F antennas are evenly distributed around the central axis of the missile cabin, and the inverted-F antennas are fixedly installed on the outer wall of the missile cabin; the inverted-F antennas are connected to the transmitter through radio frequency cables;

[0008] Each inverted F antenna has a rectifier block installed above its head; the rectifier block is fixedly installed on the outer wall of the missile cabin; the rectifier block is used to guide the airflow so that there are no aerodynamic heating stagnation points on the inverted F antenna.

[0009] Preferably, the length difference of different RF cables meets the feed phase difference requirement of the corresponding inverted-F antenna.

[0010] Preferably, the number of inverted-F antennas is determined by the results of radiation pattern simulation.

[0011] Preferably, the installation location, structure, and materials of the rectifier block are determined based on aerodynamic heat protection requirements and radiation pattern simulation results.

[0012] Preferably, the rectifier block is a semi-conical structure, the axis of the semi-conical structure is parallel to the axis of the missile body, and the apex of the semi-conical structure faces the head of the missile body;

[0013] Parts of the structure are removed from both sides of the semi-conical structure to form two oblique cutting planes.

[0014] Preferably, the rectifier block is made of epoxy glass cloth laminate material.

[0015] Preferably, the inverted-F antenna includes: a radiator, a base plate, and a feed connector;

[0016] The base plate is used to fix the radiator and the power supply connector, and to fix the radiator to the outer wall of the missile cabin;

[0017] One end of the power connector is connected to the radio frequency cable, and the inner core of the other end is connected to the radiator.

[0018] Preferably, the head of the radiator is machined with a ramp surface, which faces the head of the missile hull.

[0019] Preferably, the axes of different power supply connectors are coplanar, and the plane containing the axes is perpendicular to the axis of the missile body.

[0020] Preferably, the rectifier block is fixedly installed on the outer wall of the missile cabin by fixing screws. The fixing screws serve as a guiding unit, coupling out induced current, which serves as a guiding or reflecting vibrator to realize the control of the antenna radiation pattern.

[0021] The advantages of this invention compared to the prior art are as follows:

[0022] 1) This invention employs an inverted-F antenna design, which features a simple structure, low cost, and a small mounting surface, eliminating the need for windows or conformal design on the hull, thus reducing installation requirements. The inverted-F antenna generates an electric field perpendicular to the rocket body surface, which can be mitigated by adjusting the feed phase difference to eliminate axial concavity in the radiation pattern.

[0023] 2) The present invention can greatly increase the temperature resistance of the antenna system through the design of the current guide block. The design of the current guide block fixing screw can flexibly adjust the pattern before and after. The effect of the current guide block dielectric material makes the wavelength of electromagnetic waves in the current guide block shorter, reducing the length required for the screw resonance.

[0024] 3) This invention achieves the power supply phase difference through the cable length difference, reducing the design complexity of the power divider. Attached Figure Description

[0025] Figure 1 This is a structural diagram of the telemetry antenna array for the projectile-launched rocket of the present invention.

[0026] Figure 2(a) shows the radiation pattern of the meridional antenna when the azimuth angle is 0 degrees.

[0027] Figure 2(b) shows the radiation pattern of the meridional antenna when the azimuth angle is 90 degrees. Detailed Implementation

[0028] This design employs multiple inverted-F antennas 1, evenly distributed across the rocket body surface. The feed phase difference between each inverted-F antenna 1 is adjusted via radio frequency cables of varying lengths connecting them to the transmitter, optimizing the gain dip along the rocket's axis. A rectifier block is installed in front of the antennas to provide aerodynamic, thermal, and mechanical protection. Electromagnetic resonance and induced current are generated through the rectifier block's mounting screws, achieving secondary radiation and reflection of electromagnetic waves. This optimizes the antenna's front-to-back radiation ratio and enhances rear gain. It is primarily suitable for the reliable reception of telemetry data during rocket launch and flight.

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 As shown, the present invention comprises an inverted-F antenna 1, a missile housing 2, a rectifier block 3, fixing screws 4, an RF cable 5, and a transmitter 6. Multiple inverted-F antennas 1 are evenly distributed circumferentially about the central axis of the missile housing, and are fixedly mounted on the outer wall of the missile housing 2. The inverted-F antennas 1 are connected to the transmitter 6 via the RF cable 5. A rectifier block 3 is provided above the head of each inverted-F antenna 1. The rectifier block 3 is fixedly mounted on the outer wall of the missile housing 2. The rectifier block 3 is used for airflow guidance, preventing aerodynamic heating stagnation points from appearing on the inverted-F antennas 1.

[0031] The length difference of different RF cables 5 meets the feed phase difference requirement of the corresponding inverted-F antenna 1. The number of inverted-F antennas 1 is determined by the radiation pattern simulation results. The installation position, structure, and materials of the rectifier block 3 are determined based on aerodynamic heat protection requirements and radiation pattern simulation results.

[0032] The rectifier block 3 has a semi-conical structure, with its axis parallel to the axis of the missile body 2. The apex of the semi-conical structure faces the head of the missile body 2. Parts of the structure are removed from both sides of the semi-conical structure to form two oblique cutting planes. The material of the rectifier block 3 is epoxy fiberglass laminate.

[0033] The inverted-F antenna 1 includes a radiator 11, a base plate 12, and a feed connector 13. The base plate 12 is used to fix the radiator 11 and the feed connector 13, and to fix the radiator 11 to the outer wall of the missile cabin 2. One end of the feed connector 13 is connected to the radio frequency cable 5, and the inner core of the other end is connected to the radiator 11. The head of the radiator 11 is machined with a ramp surface, which faces the head of the missile cabin 2.

[0034] The axes of the different power supply connectors 13 are coplanar, and the plane containing the axes is perpendicular to the axis of the missile body 2.

[0035] Example

[0036] The system consists of two inverted-F antennas 1, two RF cables, an antenna heat shield, and heat shield mounting screws. The center frequency is 2250.5MHz. In this embodiment, the two feed connectors 13 are symmetrical about the central axis of the missile body, and their axes are coaxial. The origin of the coordinate system is located at the intersection of the axis of the missile body 2 and the axis of the feed connectors 13. The Z-axis points towards the head of the missile, and the Y-axis is orthogonal to the X and Z axes, forming a right-handed rectangular coordinate system. The missile body has a diameter of 300mm. The number of telemetry antennas is determined based on the body dimensions. In this example, there are two inverted-F antennas 1. Each inverted-F antenna 1 consists of a radiator 11, a base plate 12, and feed connectors 13. The base plate 12 is used to fix the radiator 11 and the feed connectors 13, and to fix the antenna to the surface of the missile body 2. One end of the feed connector 13 is connected to the RF cable 5, and the inner core of the other end is connected to the radiator 11. The dimensions and structure of the inverted-F antenna 1 are optimized through antenna simulation calculations, mainly considering the impedance matching of the antenna.

[0037] The two inverted F antennas 1 are mirror-symmetrically installed on both sides of the missile body 2, with the head slope facing the head of the missile and the tail opening facing the tail of the missile. The connector of the inverted-F antenna 1 extends into the interior of the missile cabin 2 through a hole on the missile cabin 2. Based on aerodynamic heat protection requirements and radiation pattern simulation results, a semi-conical rectifier block 3 is arranged in front of the two inverted-F antennas 1. In this example, the rectifier block is a semi-conical shape with two oblique planes, a semi-conical height of 40mm, and a base radius of 25mm. It is made of epoxy glass cloth laminate material with a dielectric constant of 4.3 and a loss tangent of 0.019, exhibiting wave transmission performance. A mounting hole is located 9mm from the bottom surface of the rectifier block. The rectifier block 3 is fixed to the missile cabin 2 using an M4 fixing screw 4 through the mounting hole. The installation position and height of the fixing screw 4 above the surface of the missile cabin 2 must meet the simulation calculation requirements. In this example, the axis distance between the fixing screw 4 and the antenna feed connector 13 is 44mm, and the screw length is 14mm (3+11mm). Two RF cables of different lengths are used to connect the two RF output interfaces of transmitter 6 to the RF interfaces of the two inverted F antennas 1. The length difference of the two RF cables needs to meet the feed phase difference requirement of the two inverted F antennas 1. In this example, the feed phase difference requirement is 180 degrees. For a coaxial cable with a dielectric constant of 2.1, at a center frequency of 2.3 GHz, its phase velocity is approximately 14.32 mm / rad, corresponding to a 180-degree phase. After simulation calculation (using the connector model) correction, the length difference of the two RF cables is approximately 45 mm.

[0038] The projectile telemetry antenna array based on screw electromagnetic coupling and feed phase difference of the present invention was simulated in full-wave using ANSYS HFSS electromagnetic simulation software. At the same time, as a comparison, the antenna array with the rectifier block and screw removed and the feed phase difference eliminated was simulated in full-wave. The far-field radiation patterns of the projectile telemetry antenna array based on screw electromagnetic coupling and feed phase difference of the present invention and the antenna array used for comparison are shown in Figure 2.

[0039] As shown in Figure 2(a), at an operating frequency of 2.3 GHz, the solid line represents the gain of the antenna array in the azimuth plane (Phi = 0°) as a function of elevation angle. Theta = 0° represents the direction of the projectile's head, and Theta = 180° represents the direction of the projectile's tail. At the projectile's tail, the minimum gain is -6.7 dBi, the maximum gain is 7.3 dBi, and the angle range with a gain greater than -8 dBi is 180°. The dashed line represents the gain of the antenna array in the azimuth plane (Phi = 0°) as a function of elevation angle, without a rectifier block and screws, and without the feed phase difference. At the projectile's tail, the minimum gain is -27.9 dBi, the maximum gain is 4.5 dBi, and the angle range with a gain greater than -8 dBi is 176°.

[0040] As shown in Figure 2(b), at an operating frequency of 2.3 GHz, the solid line represents the gain of the antenna array in the azimuth plane (Phi = 90°) as a function of elevation angle. Theta = 0° represents the direction of the projectile's head, and Theta = 180° represents the direction of the projectile's tail. At the projectile's tail, the minimum gain is 1.6 dBi, the maximum gain is 6.4 dBi, and the angle range with a gain greater than -8 dBi is 180°. The dashed line represents the gain of the antenna array in the azimuth plane (Phi = 90°) as a function of elevation angle, without a rectifier block and screws, and without the feed phase difference. At the projectile's tail, the minimum gain is -27.9 dBi, the maximum gain is -4.5 dBi, and the angle range with a gain greater than -8 dBi is 90°.

[0041] Evenly distributed on the rocket body surface, the feed phase difference between each inverted-F antenna 1 is adjusted via radio frequency cables of varying lengths connecting each antenna to the transmitter, optimizing the gain dip along the rocket body axis. A rectifier block installed in front of the antenna provides aerodynamic, thermal, and mechanical protection. Electromagnetic resonance and induced current are generated through the rectifier block's mounting screws, achieving secondary radiation and reflection of electromagnetic waves, thus optimizing the antenna's front-to-back radiation ratio and enhancing rear gain. This system is primarily suitable for the reliable reception of telemetry data during rocket launch and flight.

[0042] The technical problem solved by this invention is to design a missile telemetry antenna array to achieve good coverage of the tail of the antenna pattern.

[0043] The device operates as follows: the telemetry transmitter splits the telemetry signal carrying data information into two equal-amplitude, in-phase telemetry radio frequency signals through a power divider. These signals are fed back 180 degrees in reverse through radio frequency cables with a length difference of half an equivalent wavelength. The two reverse-fed signals are then output to two inverted-F antennas 1. The heat-insulating, wave-transparent conical block in front of the inverted-F antenna 1 is used for current guiding, preventing aerodynamic heating stagnation points on the antenna and greatly reducing the temperature on the antenna. The fixing screw 4 of the rectifier block 3 serves as a guiding unit, coupling out induced current as a guiding or reflecting vibrator to control the antenna radiation pattern.

[0044] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make possible variations and modifications to the technical solutions of the present invention using the disclosed methods and techniques without departing from the spirit and scope of the invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall fall within the protection scope of the present invention. Where there is no conflict, the embodiments of this application and the technical features thereof can be combined with each other.

[0045] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A missile telemetry antenna array based on feed phase difference and screw coupling, characterized in that, The application relates to a multiple inverted-F antenna system for a missile or rocket. The multiple inverted-F antennas (1) are evenly distributed around the central axis of the missile or rocket cabin body (2) and are fixedly installed on the outer wall of the missile or rocket cabin body (2); the inverted-F antennas (1) are connected with the transmitter (6) through the radio frequency cables (5); The head of each inverted-F antenna (1) is provided with a fairing (3) which is fixedly installed on the outer wall of the missile or rocket cabin body (2); the fairing (3) is used for guiding flow so that no aerodynamic heating stagnation point appears on the inverted-F antenna (1); The length difference of the different radio frequency cables (5) meets the feeding phase difference requirement of the corresponding inverted-F antennas (1); The fairing (3) is fixedly installed on the outer wall of the missile or rocket cabin body (2) through the fixing screw (4); the fixing screw (4) is used as a directional unit, couples out induced current and is used as a directional or reflecting vibrator to realize the control of the antenna radiation pattern; the axial distance between the fixing screw (4) and the antenna feeding connector (13) is 44mm; The head of the radiator (11) is provided with a slope surface which faces the head of the missile or rocket cabin body (2); The inverted-F antenna (1) comprises a radiator (11), a bottom plate (12) and a feeding connector (13); The bottom plate (12) is used for fixing the radiator (11) and the feeding connector (13) and fixing the radiator (11) on the outer wall of the missile or rocket cabin body (2); One end of the feeding connector (13) is connected with the radio frequency cable (5) and the other end is connected with the radiator (11); The axial lines of the different feeding connectors (13) are coplanar and the plane where the axial lines are located is perpendicular to the axial line of the missile or rocket cabin body (2). The number of the inverted-F antennas (1) is determined according to the radiation pattern simulation result.

2. The missile telemetry antenna array based on the phase difference of feed and screw coupling according to claim 1, characterized in that, The installation position, structure and material of the fairing (3) are determined according to the aerodynamic heatproof requirement and the radiation pattern simulation result.

3. The missile telemetry antenna array based on the phase difference of feed and screw coupling according to claim 1, characterized in that, The fairing (3) is a half-cone structure, the axial line of the half-cone structure is parallel to the axial line of the missile or rocket cabin body (2) and the top angle of the half-cone structure faces the head of the missile or rocket cabin body (2); 4. The missile telemetry antenna array based on the phase difference of feed and screw coupling according to claim 3, characterized in that, The two sides of the half-cone structure are respectively provided with a part of structure removed to form two oblique planes. The material of the fairing (3) is an epoxy glass cloth laminate material.

5. The missile telemetry antenna array based on the phase difference of feed and screw coupling according to claim 3, characterized in that, ​

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