A medium-low earth orbit satellite antenna assembly

Abstract

The utility model discloses a kind of middle-low orbit satellite antenna assemblies, including deployable phased array antenna main body, intelligent heat dissipation module, multi-frequency band isolation feed network and self-adaptive beam control unit;Main body contains 6 foldable subarrays, each subarray is connected with the magnetic rheological hinge of built-in electromagnetic coil and magnetic rheological liquid cavity center pivot, subarray surface is equipped with the nested radiation unit of "outer Ku frequency band dipole array+inner Ka frequency band microstrip patch array", there is polytetrafluoroethylene isolation layer between the two and feed point staggered;Intelligent heat dissipation module is attached to the back of main body, containing phase change material layer, micro heat pipe array and graphene skin;Feed network contains Ku / Ka power division network and sequentially connected X-type isolator, dual-band circulator, wave filter;Beam control unit contains DBF chip, T / R component and PWM power management circuit.

Description

Technical Field

[0001] This utility model provides an antenna assembly, and particularly relates to a medium- and low-orbit satellite antenna assembly. Background Technology

[0002] Medium and low orbit (LEO) satellite antenna components are the core payloads for LEO satellites to achieve functions such as satellite-to-ground communication and inter-satellite links. They are mainly used to complete the radiation, reception and beam control of radio frequency signals. Their performance directly determines the communication rate, coverage and on-orbit stability of the satellite. They are key equipment to support the efficient operation of spacecraft such as LEO communication constellations and remote sensing satellites.

[0003] Existing low- and medium-Earth orbit (LEO) satellite antenna assemblies typically consist of an antenna body, a feed network, a beam control unit, and heat dissipation components. The antenna body often employs a fixed array or a foldable structure connected by traditional mechanical hinges. The radiating elements are mostly single-band designs or simply nested multi-band structures. The feed network is often a single-band power divider network, with inter-band isolation relying on simple filtering elements. The beam control unit uses conventional beamforming chips, lacking a targeted large-angle scanning compensation mechanism. Heat dissipation components are often single-material heat sinks. However, this type of structure has significant shortcomings: traditional mechanical hinges are prone to deployment failure due to wear, resulting in low reliability; the isolation between multi-band radiating elements and the feed network is insufficient (typically only -25 to -30 dB), easily causing frequency crosstalk; the heat sink has low thermal conductivity (generally ≤500 W / (m·K)), making it difficult to meet the heat dissipation requirements of high-power-density arrays; the beam control unit experiences severe beam distortion during large-angle (>45°) scanning, with sidelobes increasing by 5-10 dB, and overall power consumption is high, making it unsuitable for the limited power supply resources of LEO satellites. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model aims to solve four core problems of medium and low orbit satellite antenna components: high risk of mechanical hinge failure in traditional deployable structures; insufficient mid-frequency isolation in multi-band common aperture designs; low heat dissipation efficiency of phased array antennas under high power density; and severe beam distortion and excessively high overall power consumption during large-angle scanning.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: To achieve the above objectives, this utility model provides a medium-low orbit satellite antenna assembly, including a deployable phased array antenna body, an intelligent heat dissipation module, a multi-band isolated feed network, and an adaptive beam control unit.

[0006] The deployable phased array antenna body includes six foldable subarrays arranged in a regular hexagonal pattern. Each subarray is connected to the central hub through a magnetorheological hinge. The magnetorheological hinge has an internal electromagnetic coil and a magnetorheological fluid cavity. The input end of the coil is connected to the drive control circuit of the satellite platform. Each subarray surface is equipped with nested radiating elements consisting of an outer Ku-band dipole array and an inner Ka-band microstrip patch array. A 0.5mm thick polytetrafluoroethylene isolation layer is provided between the dipole array and the microstrip patch array, and their feed points are spatially offset by 3mm.

[0007] The intelligent heat dissipation module is attached to the back of the phased array antenna body and includes a phase change material layer, a micro heat pipe array and a graphene heat dissipation skin. The evaporation section of the heat pipe array is embedded in the phase change material layer, the condensation section is connected to the graphene skin, and honeycomb-shaped radiation holes are opened on the surface of the skin.

[0008] The multi-band isolated feed network is located in the feed layer of the phased array antenna body and includes a Ku-band power divider network, a Ka-band power divider network, and a dual-band isolation circuit. The Ku-band power divider network adopts a cascaded structure of three-stage ET waveguide power dividers, and the Ka-band power divider network adopts a microstrip unequal power divider. The dual-band isolation circuit is connected in series at the common output terminal of the two power divider networks and includes an X-type isolator, a dual-band circulator, and a notch filter connected in sequence.

[0009] The adaptive beam control unit includes a digital beamforming chip, a T / R component array, and a power management circuit. Each component in the T / R component array corresponds to a radiating element, and its input is connected to the output of a multi-band isolated feed network via an RF cable. The control terminal is connected to the DBF chip via an SPI bus. The power management circuit uses a pulse width modulation buck converter, and its output is connected to the power supply pins of the T / R component and the DBF chip, respectively. A self-resetting fuse is connected in series in the power supply circuit. The DBF chip is connected to the attitude control system of the satellite platform via a CAN bus. After receiving satellite attitude data, it outputs a phase control signal to the T / R component to achieve beam scanning within a range of ±60°. When the scanning angle exceeds 45°, the sidelobe suppression algorithm is automatically activated.

[0010] Furthermore, the electromagnetic coil of the magnetorheological hinge has 500 turns and a wire diameter of 0.1 mm. When a current of 1.5 A is applied, it generates a magnetic field of 0.3 T, which makes the yield strength of the magnetorheological fluid reach 20 kPa, thus achieving rigid locking after the subarray is deployed.

[0011] Furthermore, in the nested radiating unit, the Ku-band dipole adopts a copper hollow structure with a resonant frequency of 15 GHz; the Ka-band microstrip patch is square, uses a Rogers 4350 substrate, and is connected to the Ka-band power divider network through probe feeding.

[0012] Furthermore, the micro heat pipe array has a single heat pipe with an inner diameter of 1 mm, uses ammonia as the working fluid, operates in a temperature range of -60℃ to 120℃, has 4 heat pipes per square centimeter, and has a thermal conductivity ≥1000W / (m·K).

[0013] Furthermore, the DBF chip adopts an FPGA+DSP architecture, has 16 independent beamforming channels, supports beam pointing updates every 10ms, and has adaptive zeroing capability for more than 3 interference sources.

[0014] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages compared with the prior art:

[0015] A. Significantly improved reliability: By replacing traditional mechanical hinges with magnetorheological hinges, wear-free locking is achieved by utilizing the yield strength change of magnetorheological fluid under the action of a magnetic field. This reduces the failure rate of the deployment mechanism from 0.5%-1% to below 0.1%, meeting the long-term maintenance-free requirements of medium and low orbit satellites.

[0016] B. Significantly optimized multi-band isolation: The spatial misalignment design of the nested radiating units, combined with the dual-band isolation circuit (X-type isolator + dual-band circulator + notch filter), improves the Ku / Ka band isolation to over -40dB, effectively avoiding the problem of increased communication bit error rate caused by frequency band crosstalk.

[0017] C. Doubled heat dissipation efficiency: The intelligent heat dissipation module utilizes phase change materials for heat storage and a micro heat pipe array (thermal conductivity ≥ 1).

[0018] The three-stage synergy of high-efficiency heat transfer (1000W / (m·K)) and radiative heat dissipation from the graphene skin reduces the array power density from 20W / cm². 2 Reduced to 8W / cm 2 This ensures that the operating temperature of the T / R components remains stable below 85℃, extending their service life to over 15 years.

[0019] D. Optimization of beam performance and power consumption balance: The sidelobe suppression algorithm of the DBF chip solves the problem of large-angle (>45°) beam distortion within the ±60° scanning range, reducing the sidelobe level by 5-10dB; the PWM power management circuit, in conjunction with the self-resetting fuse, reduces the total power consumption by 30% while ensuring power supply safety, adapting to the limited power supply resources of medium and low orbit satellites.

[0020] Other advantages, objectives and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be taught from the practice of this invention. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall system connection of a medium-low orbit satellite antenna assembly according to the present invention;

[0022] Figure 2 This is a circuit connection diagram of an adaptive beam control unit for a medium-low orbit satellite antenna assembly according to this utility model;

[0023] Figure 3 This is a circuit diagram of a multi-band isolated power supply network for a medium-low orbit satellite antenna assembly according to this utility model.

[0024] As shown in the figure:

[0025] 1. Deployable phased array antenna body; 2. Intelligent heat dissipation module; 3. Adaptive beam control unit; 4. DBF chip; 5. Ku-band power divider network; 6. Three-stage ET waveguide power divider cascade structure. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] As attached Figure 1 As shown, the low-to-medium orbit satellite antenna assembly of this invention is generally hexagonal. The deployable phased array antenna body 1 consists of 6 foldable subarrays connected to a central hub via magnetorheological hinges. The subarrays have a side length of 20cm, and the central hub has a diameter of 5cm. In the nested radiating elements on the surface of each subarray, the feed points of the outer Ku-band dipole array and the inner Ka-band microstrip patch array are spatially offset by 3mm, and are initially isolated by a 0.5mm thick polytetrafluoroethylene insulating layer.

[0030] The magnetorheological hinge has a built-in electromagnetic coil with 500 turns and a wire diameter of 0.1mm. When a current of 1.5A is passed through the coil, a magnetic field of 0.3T is generated, which makes the yield strength of the magnetorheological fluid in the magnetorheological fluid cavity (volume of 10mL) reach 20kPa, thus achieving rigid locking after the subarray is deployed. The subarray can be folded clockwise around the hinge. After folding, the storage distance between the subarray and the central hub is 3cm, which greatly reduces the envelope size during the launch phase.

[0031] As attached Figure 2 and Figure 3 As shown, the intelligent heat dissipation module 2 consists of a 5mm thick phase change material layer (phase change temperature 55℃), a micro heat pipe array (each with an inner diameter of 1mm, using ammonia as the working fluid, and 4 pipes per square centimeter) from the inside out, and a 0.2mm thick graphene heat dissipation skin (with honeycomb-shaped radiation holes of 1mm diameter on the surface). The evaporation section (10cm in length) of the heat pipe array is embedded in the phase change material layer, and the condensation section (5cm in length) is connected to the graphene skin, forming a three-stage heat dissipation path of "heat storage-heat transfer-radiation", with a thermal conductivity of 1200W / (m·K).

[0032] In the multi-band isolated power supply network, the Ku-band power divider network 5 adopts a three-stage ET waveguide power divider cascaded structure 6, with a power division ratio of 1:2 for each stage, covering the 12-18GHz frequency band; the Ka-band power divider network adopts a microstrip unequal power divider, covering the 20-30GHz frequency band; the dual-band isolation circuit connects an X-type isolator (isolation degree 28dB), a dual-band circulator (12-18GHz / 20-30GHz), and a notch filter (suppressing signals ≤20GHz) in series from the common output terminal, and is finally connected to the input terminal of the T / R component through an RF cable, so that the isolation between the two frequency bands reaches -42dB.

[0033] The DBF chip 4 of the adaptive beam control unit 3 adopts the XC7K325T model (FPGA+DSP architecture), which is connected to 32 T / R components (corresponding to 32 radiating elements) via SPI bus. The control end receives satellite attitude data via CAN bus and updates the beam pointing every 10ms. The power management circuit adopts the LM2596 model PWM buck converter, which outputs 3.3V to the T / R components and 5V to the DBF chip 4. The power supply circuit is connected in series with a 1A self-resetting fuse. When the beam scanning angle exceeds 45°, the DBF chip 4 automatically starts the sidelobe suppression algorithm, which compensates for beam distortion by adjusting the phase difference between adjacent units, so that the sidelobe level is lower than -35dB. At the same time, it has the adaptive zeroing capability for 3 interference sources (zeroing depth 45dB).

[0034] The antenna assembly has an overall diameter of 1.2m when deployed and only 20cm when folded. It is connected to the satellite platform through four fixing screw holes, making it suitable for launching multiple satellites with a single rocket.

[0035] During actual assembly and operation, this device requires mechanical fixation using a standard mounting bracket on the satellite platform. The bracket is typically made of TC4 titanium alloy with a 5μm thick anodized surface to withstand the instantaneous impact force during antenna assembly deployment. To achieve a stable connection between the magnetorheological hinge and the satellite platform's drive control circuitry, an M3-sized silver-plated copper RF connector is required. This connector has a wide operating temperature range of -196℃ to 125℃ and an insertion loss of ≤0.1dB@20GHz.

[0036] The magnetorheological fluid filling the cavity is a polyethylene glycol-based magnetorheological fluid with a solid content of 35%. The dispersed phase is carbonyl iron powder (average particle size 5 μm), which can complete the phase transition from liquid to solid within 10 ms under a 0.3 T magnetic field. The polytetrafluoroethylene (PTFE) insulating layer is made by DuPont. PTFE film has a dielectric constant of 2.1 and a volume resistivity ≥10. 17 Ω·cm can effectively block electromagnetic coupling between Ku-band and Ka-band radiating elements.

[0037] The phase change material layer uses a paraffin-based composite phase change material matrix with n-octadecane (latent heat of phase change 240 J / g) and 10% expanded graphite (particle size 200 mesh) doped with it. It can absorb a large amount of heat through solid-liquid phase change at 55℃. The graphene heat dissipation skin uses a 99.9% pure graphene film with a sheet resistivity ≤10Ω / □ and a thermal emissivity ≥0.9. The connection to the micro heat pipe array uses silver-based conductive adhesive (thermal conductivity 30 W / (m·K)) with a curing temperature of 80℃.

[0038] During the ground commissioning phase, a vector network analyzer (such as Keysight N5247A) is required to perform port parameter calibration tests on the multi-band isolated feeder network, covering a frequency range of 12GHz to 30GHz, ensuring that the VSWR of each port is ≤1.2. Before satellite launch, the antenna assembly must be placed in a vacuum thermal cycling test chamber (such as Thermotron SE-1500) for environmental simulation testing, with a cycling temperature range of -196℃ to 125℃, accumulating 100 cycles to verify the structural and performance stability.

[0039] In addition, the satellite platform needs to be equipped with lithium-ion battery packs (such as 18650 type lithium iron phosphate batteries with a single cell capacity of 2.5Ah) to provide 28V DC input to the power management circuit, which in turn enables continuous power supply to the solar panels. The star sensor (such as Honeywell H-764) and fiber optic gyroscope (zero bias stability ≤0.01° / h) integrated in the attitude control system provide real-time attitude data to the DBF chip, ensuring that the beam pointing accuracy is controlled within ±0.1°.

[0040] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A medium-low orbit satellite antenna assembly, characterized in that, It includes a deployable phased array antenna body (1), an intelligent heat dissipation module (2), a multi-band isolated feed network and an adaptive beam control unit (3); The deployable phased array antenna body (1) includes 6 foldable subarrays distributed in a regular hexagonal shape. Each subarray is connected to the central hub through a magnetorheological hinge. The magnetorheological hinge has an internal electromagnetic coil and a magnetorheological fluid cavity. The input end of the coil is connected to the drive control circuit of the satellite platform. Each subarray surface is equipped with a nested radiating unit consisting of an outer Ku-band dipole array and an inner Ka-band microstrip patch array. A 0.5mm thick polytetrafluoroethylene isolation layer is provided between the dipole array and the microstrip patch array, and their feed points are spatially offset by 3mm. The intelligent heat dissipation module (2) is attached to the back of the phased array antenna body (1), including a phase change material layer, a micro heat pipe array and a graphene heat dissipation skin. The evaporation section of the heat pipe array is embedded in the phase change material layer, the condensation section is connected to the graphene skin, and honeycomb-shaped radiation holes are opened on the surface of the skin. The multi-band isolation feed network is located in the feed layer of the phased array antenna body (1), including a Ku-band power divider network (5), a Ka-band power divider network and a dual-band isolation circuit; the Ku-band power divider network (5) adopts a three-stage ET waveguide power divider cascade structure (6), and the Ka-band power divider network adopts a microstrip unequal power divider; the dual-band isolation circuit is connected in series at the common output terminal of the two power divider networks, including an X-type isolator, a dual-band circulator and a notch filter connected in sequence; The adaptive beam control unit (3) includes a digital beamforming (DBF) chip, a T / R component array, and a power management circuit. Each component in the T / R component array corresponds to a radiation unit. Its input end is connected to the output end of the multi-band isolated feed network via an RF cable, and its control end is connected to the DBF chip (4) via an SPI bus. The power management circuit uses a pulse width modulation (PWM) buck converter. Its output end is connected to the power supply pin (3.3V) of the T / R component and the power supply pin (5V) of the DBF chip (4) respectively, and a self-resetting fuse (rated current 1A) is connected in series in the power supply circuit. The DBF chip (4) is connected to the attitude control system of the satellite platform via the CAN bus. After receiving the satellite attitude data, it outputs the phase control signal to the T / R component to realize the beam scanning within the range of ±60°. When the scanning angle exceeds 45°, the sidelobe suppression algorithm is automatically started.

2. The component according to claim 1, characterized in that, The electromagnetic coil of the magnetorheological hinge has 500 turns and a wire diameter of 0.1 mm. When a current of 1.5 A is applied, it generates a magnetic field of 0.3 T, which makes the yield strength of the magnetorheological fluid reach 20 kPa, thus achieving rigid locking after the subarray is deployed.

3. The component according to claim 1, characterized in that, In the nested radiating unit, the Ku-band dipole adopts a copper hollow structure (0.8mm linewidth) and has a resonant frequency of 15GHz; the Ka-band microstrip patch is square, uses Rogers 4350 substrate (dielectric constant 3.48), and is connected to the Ka-band power divider network through probe feeding.

4. The component according to claim 1, characterized in that, The micro heat pipe array has a single heat pipe with an inner diameter of 1 mm, uses ammonia as the working fluid, operates in a temperature range of -60℃ to 120℃, has 4 heat pipes per square centimeter, and has a thermal conductivity ≥1000W / (m·K).

5. The component according to claim 1, characterized in that, The DBF chip (4) adopts an FPGA+DSP architecture, has 16 independent beamforming channels, supports beam pointing updates every 10ms, and has adaptive zeroing capability for more than 3 interference sources (zeroing depth ≥40dB).

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