Satellite load system of Internet of Things

Abstract

The invention discloses an internet of things satellite load system, which belongs to the technical field of communication, and comprises an X-band transceiving antenna, a transponder and a UHF (Ultra High Frequency) band antenna unit, the first transponder comprises a first signal conditioning unit, a first switch matrix, a forward link unit, a second switch matrix and a first radio frequency front end unit which are connected in sequence; and the second transponder comprises a second radio frequency front end unit, a third switch matrix, a reverse link unit, a fourth switch matrix and a second signal conditioning unit which are connected in sequence. According to the system, an X-band multi-band signal input mode is adopted, and signal coverage of different frequencies in a rotation range of 0-360 degrees of a main radiating surface under a full-open state of a UHF-band antenna unit is realized by utilizing forward link frequency conversion and a first radio frequency front-end unit; similarly, the UHF band antenna unit receives multi-band (narrowband) signals in a full-open state, X-band feed antenna multi-band signal emission is realized by using reverse link frequency conversion and the second radio frequency front-end unit, and the antenna system has a dual-band fusion function.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication technology, and in particular to an Internet of Things satellite payload system. Background Art

[0002] Satellite communication is a communication technology that uses space satellites as relays to send and receive data from ground stations. With the development of satellite communication technology and the construction of low-orbit satellite constellations, the Internet of Things has broken free from the constraints of ground base stations and geographical restrictions to form a new industry - satellite Internet of Things, which is widely used in smart cities, smart agriculture, environmental monitoring and other fields.

[0003] UHF band signals have strong penetration and diffraction capabilities, making them suitable for use in cities and complex terrains. Secondly, this band is suitable for low-power applications, supports large-scale equipment deployment, and has high spectrum resource utilization efficiency. Therefore, the UHF band is widely used in global communications, with high equipment compatibility and standardization, strong anti-interference ability, and can ensure the stability and reliability of communications.

[0004] X-band signals have higher frequencies and shorter wavelengths, and their signal resolution is much higher than that of low-frequency signals. At the same time, X-band signals have a certain ability to penetrate clouds, vegetation, etc., and can penetrate these obstacles to a certain extent for target detection and data transmission. More importantly, X-band signals have a higher frequency and relatively strong anti-interference ability, and can maintain good stability and reliability in complex electromagnetic environments.

[0005] At present, when using UHF band antennas for satellite communications, high-gain antennas are required. Ordinary wide-beam antenna units have low gain near 58°. If you want to further improve the antenna gain, you need to use a multi-unit array and control the beam pointing to achieve high gain at a specified angle, but this will lead to a complex structure and high cost. At the same time, the size of the UHF band antenna is large. If a phased array solution is adopted, the size of the payload system will increase sharply and it will be difficult to implement. In addition, X-band signals also have some limitations in practical applications. For example, their high frequency characteristics cause relatively large signal attenuation in the atmosphere, which requires higher precision for the transmitting and receiving equipment, and the cost increases accordingly. In order to realize the coordinated application of UHF band and X-band by the satellite payload system, an antenna system with dual-band fusion function needs to be proposed. The key technical challenge of this system is to establish a cross-band data conversion mechanism, so how to realize the data conversion processing between UHF band and X-band is a technical problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems of the prior art and provide an Internet of Things satellite payload system.

[0007] The object of the present invention is achieved through the following technical solutions: An Internet of Things satellite payload system, the system includes a forward communication subsystem and a reverse communication subsystem. The forward communication subsystem includes an X-band receiving antenna, a first transponder, and a UHF-band antenna unit connected in sequence. The reverse communication subsystem includes a UHF-band antenna unit, a second transponder, and an X-band transmitting antenna connected in sequence. The UHF-band antenna unit includes a plurality of UHF-band antennas;

[0008] The first transponder includes a first signal conditioning unit, a first switch matrix, a forward link unit, a second switch matrix, and a first radio frequency front-end unit connected in sequence. During forward communication, the X-band receiving antenna receives a plurality of X-band signals, and the first transponder is used to perform signal conditioning, frequency conversion processing, and radio frequency front-end processing on the plurality of X-band signals to obtain a plurality of UHF-band signals. Each UHF-band antenna radiates the UHF-band signals outward to achieve omnidirectional signal coverage in the full-open state of the UHF-band antennas;

[0009] The second transponder includes a second radio frequency front-end unit, a third switch matrix, a reverse link unit, a fourth switch matrix, and a second signal conditioning unit connected in sequence. During reverse communication, each UHF-band antenna receives a plurality of UHF-band signals, and the second transponder is used to perform radio frequency front-end processing, frequency conversion processing, and signal conditioning on the plurality of UHF-band signals to obtain a plurality of X-band signals. The X-band transmitting antenna radiates the plurality of X-band signals outward to achieve omnidirectional signal coverage in the full-open state of the UHF-band antennas.

[0010] In one example, the first radio frequency front-end unit includes a first power divider network, a first power amplifier unit, a receive blocking filter unit, a second power amplifier unit, and a duplexer unit connected in sequence; the second radio frequency front-end unit includes a duplexer unit, a third power amplifier unit, a transmit blocking filter unit, a fourth power amplifier unit, and a second power divider network connected in sequence.

[0011] In one example, the first signal conditioning unit includes a first filter, a first low-noise amplifier, a first fixed attenuator, and a second low-noise amplifier connected in sequence; the second signal conditioning unit includes a third low-noise amplifier, a second fixed attenuator, a fourth low-noise amplifier, and a second filter connected in sequence.

[0012] In one example, the UHF-band antenna includes a tubular dielectric, on which a metal strip line and a feeding network are attached, and the metal strip line and the feeding network form a right-handed circularly polarized antenna.

[0013] In one example, the metal strip line includes a first metal sub-strip line, a second metal sub-strip line, and a third metal sub-strip line. The length of the first metal sub-strip line is 0.25λ and its width is gradually changing. The length of the second metal sub-strip line is from 0.01λ to 0.04λ, and the length of the third metal sub-strip line is from 0.22λ to 0.24λ;

[0014] The angle between the first metal sub-strip line and the horizontal plane is 35° - 42°. The center line of the first metal sub-strip line is parallel to the center line of the third metal sub-strip line. The first metal sub-strip line is connected to the third metal sub-strip line via the second metal sub-strip line.

[0015] In one example, the X-band receiving antenna and the X-band transmitting antenna have the same structure, and both include a dielectric plate, on which metal patches are attached, and shielding blocks are provided at the edges of the dielectric plate.

[0016] In one example, the X-band receiving antenna, the X-band transmitting antenna, the first repeater, the second repeater, and the UHF-band antenna unit are all arranged on a metal support frame, and the installation inclination angle of the metal support frame is less than 90°; the X-band receiving antenna and the X-band transmitting antenna are parallel to the horizontal plane, the first repeater and the second repeater are arranged inside the metal support, and the metal support frame includes multiple inclined surfaces, and UHF-band antennas are arranged on each inclined surface.

[0017] In one example, a metal plate is provided on the hypotenuse of the inclined surface.

[0018] It should be further noted that the technical features corresponding to the above examples can be combined or replaced with each other to form a new technical solution.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. In one example, the satellite payload system adopts an X-band multi-band (narrowband) signal input mode, and uses forward link frequency conversion and the first radio frequency front-end unit to realize data conversion processing between the X-band and the UHF-band, so as to realize signal coverage of different frequencies in the 0° - 360° rotation range of the main radiation surface in the fully open state of the UHF-band antenna unit; similarly, in the fully open state of the UHF-band antenna unit, multi-band (narrowband) signals are received, and data conversion processing between the UHF-band and the X-band is realized by using reverse link frequency conversion and the second radio frequency front-end unit, so as to realize multi-band signal transmission of the X-band feeding antenna, which is an antenna system with dual-band fusion function. In this transceiver mode, in the fully open state of the UHF-band antenna unit, signal coverage of different frequencies in the 0° - 360° rotation range of the main radiation beam can be realized, with simple structure, low cost, and high reliability.

[0021] Meanwhile, the satellite payload system of the present invention adopts the method of mutual conversion between UHF band and X band signals, making full use of the advantages of the UHF band in Internet of Things communication and the advantages of the X band in data transmission, and ensuring the reliability of system data acquisition and transmission.

[0022] 2. In an example, the power distribution network in the RF front-end unit is used for signal distribution, the power amplifier unit is used for signal amplification, the filter is used to suppress interference signals, and the duplexer is used for signal transceiver isolation, cooperating with each other to support the coverage of different frequency signals within the range of 0° to 360° rotation direction of the main radiation beam in the fully open state of the UHF band antenna unit.

[0023] 3. In an example, the metal strip line and the feeding network of the UHF band antenna form a right-handed circularly polarized antenna, which can effectively reduce the influence of multipath effect and atmospheric refraction on the signal, reduce signal fading, and improve communication quality; at the same time, the circularly polarized antenna propagates more uniformly in space, can achieve wide coverage, and has lower requirements for the polarization direction of the receiving antenna, reducing signal loss caused by polarization mismatch.

[0024] 4. In an example, through the cooperation of the first metal sub-strip line and the third metal sub-strip line (the center lines of the two are parallel), the antenna bandwidth can be expanded, enabling a single UHF band antenna unit to operate in the frequency band of 300 MHz to 330 MHz.

[0025] 5. In an example, the X-band transceiver antenna has a simple and reliable structure and can meet the requirements of a narrowband circularly polarized antenna; at the same time, the X-band transceiver antenna can meet the antenna index coverage requirements of greater than 0 dB within the range of ±55° during the satellite flight scanning process, realizing normal satellite communication.

[0026] 6. In an example, the satellite payload system is integrated on a metal support frame, and this layout can take into account the effective working areas of the X-band transceiver antenna, two transponders, and the UHF band antenna unit, and reduce the mutual influence, ensuring the reliability of the system operation.

[0027] 7. In an example, by arranging a metal plate, the electromagnetic wave radiated by the antenna can be reflected, making the energy originally radiated backward reflected forward, thereby concentrating the energy in a specified direction and further increasing the gain of the antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The following further elaborates on the specific implementation manners of the present invention in conjunction with the drawings. The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The same reference numerals are used in these drawings to represent the same or similar parts. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application.

[0029] Figure 1 System framework diagram provided for an example of the present invention;

[0030] Figure 2 System framework diagram provided for a preferred example of the present invention;

[0031] Figure 3 Principle framework diagram of forward communication of the system provided for an example of the present invention;

[0032] Figure 4 Principle framework diagram of reverse communication of the system provided for an example of the present invention;

[0033] Figure 5 Top view of the system layout provided for an example of the present invention;

[0034] Figure 6 Side view of the system layout provided for an example of the present invention;

[0035] Figure 7 Schematic diagram of the placement of the metal plate provided for an example of the present invention;

[0036] Figure 8 Gain pattern of the UHF-band antenna without a metal plate when exciting one subarray provided for an example of the present invention;

[0037] Figure 9 Gain pattern of the UHF-band antenna with a metal plate when exciting one subarray provided for an example of the present invention;

[0038] Figure 10 Schematic diagram of the structure of the UHF-band antenna provided for an example of the present invention;

[0039] Figure 11 Schematic diagram of the structure of the metal strip line provided for an example of the present invention;

[0040] Figure 12 Performance parameter diagram of a single UHF-band antenna provided for an example of the present invention;

[0041] Figure 13 shows the pattern of the UHF-band antenna when exciting different subarrays provided for an example of the present invention;

[0042] Figure 14 Pattern obtained by superimposing the patterns of the UHF-band antenna when exciting all subarrays provided for an example of the present invention;

[0043] Figure 15 2D pattern on different cross-sections when exciting one subarray of the UHF-band antenna provided for an example of the present invention;

[0044] Figure 16 Schematic diagram of the structure of the feeding antenna provided for an example of the present invention;

[0045] Figure 17 The radiation pattern of the X-band transmitting antenna provided for an example of the present invention;

[0046] Figure 18 The axial ratio performance graph of the X-band transmitting antenna provided for an example of the present invention;

[0047] Figure 19 The graph of the relationship between the standing wave ratio and frequency of the X-band transmitting antenna provided for an example of the present invention;

[0048] Figure 20 The radiation pattern of the X-band receiving antenna provided for an example of the present invention;

[0049] Figure 21 The axial ratio performance graph of the X-band receiving antenna provided for an example of the present invention;

[0050] Figure 22 The graph of the relationship between the standing wave ratio and frequency of the X-band receiving antenna provided for an example of the present invention.

[0051] In the figure: 1 - metal support frame; 4 - UHF-band antenna; 41 - feeding network; 42 - metal strip line; 421 - first metal sub-strip line; 422 - second metal sub-strip line; 423 - third metal sub-strip line; 43 - tubular dielectric; 5 - X-band transmitting antenna; 51 - metal patch; 52 - dielectric plate; 53 - shielding block; 6 - X-band receiving antenna; 7 - hollowed-out area; 11 - metal plate; 111 - first side; 112 - second side; 113 - third side; 114 - fourth side; 115 - fifth side. Detailed implementation manners

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0053] In the description of the present invention, it should be noted that the directions or position relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are the directions or position relationships based on the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. In addition, the use of ordinal numbers (for example, "first and second", "first to fourth", etc.) is to distinguish objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0054] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0056] In one example, an Internet of Things satellite payload system, as Figure 1 shown, the system includes an X-band antenna, a UHF-band antenna, and a transponder. The X-band antenna is connected to the UHF-band antenna through the transponder. Specifically, the system includes a forward communication subsystem and a reverse communication subsystem. The forward communication subsystem includes an X-band receiving antenna, a first transponder, and a UHF-band antenna unit connected in sequence. The reverse communication subsystem includes a UHF-band antenna unit, a second transponder, and an X-band transmitting antenna connected in sequence. The UHF-band antenna unit includes a plurality of UHF-band antennas.

[0057] Specifically, the first transponder includes a first signal conditioning unit, a first switch matrix, a forward link unit, a second switch matrix, and a first radio frequency front-end unit connected in sequence. Among them, the first signal conditioning unit is used to condition the signal, including one or more of filtering, amplification, and attenuation processing, that is, the first signal conditioning unit includes one or more of a filter, an attenuator, and an amplifier. The first switch matrix and the second switch matrix are used for signal selection processing. Preferably, the first switch matrix can also perform power distribution processing on the signal. The forward link unit includes a plurality of forward links and is used to perform down-conversion processing on the signal. The first radio frequency front-end unit is used to perform radio frequency front-end processing, including one or more of signal distribution, signal amplification, filtering, and transceiver isolation processing, that is, the first radio frequency front-end unit includes one or more of a power distribution network, a power amplifier unit, a filtering unit, and an isolator. During forward communication (operating state 1), the X-band receiving antenna receives N X-band signals, and then the first signal conditioning unit conditions the multiple X-band signals, the first switch matrix performs signal selection, the forward link unit performs frequency conversion processing on the signal to obtain frequency signals Ud1 to UdN, and then the first radio frequency front-end unit performs radio frequency front-end processing to obtain N UHF-band signals. Each UHF-band antenna radiates the UHF-band signal outward to achieve omnidirectional signal coverage in the full-open state of the UHF-band antenna.

[0058] Specifically, the second repeater includes a second RF front-end unit, a third switch matrix, a reverse link unit, a fourth switch matrix, and a second signal conditioning unit connected in sequence. Among them, the second signal conditioning unit is used to condition the signal, including one or more of filtering, amplification, and attenuation processing, that is, the second signal conditioning unit includes one or more of a filter, an attenuator, and an amplifier. The third switch matrix and the fourth switch matrix are used for signal selection processing. Preferably, the fourth switch matrix can also perform power distribution processing on the signal. The reverse link unit includes multiple reverse links and is used for up-converting the signal. The second RF front-end unit is used for RF front-end processing, including one or more of signal distribution, signal amplification, filtering, and transceiver isolation processing, that is, the second RF front-end unit includes one or more of a power distribution network, a power amplifier unit, a filtering unit, and an isolator. During reverse communication (operating state two), each UHF band antenna receives N UHF band signals. The second RF front-end unit performs RF front-end processing on the signals, and the reverse link unit performs frequency conversion processing to obtain N X-band signals. The fourth switch matrix performs power distribution processing on the N X-band signals, and then the second signal conditioning unit conditions the N X-band signals. After that, the N X-band signals are radiated outward through the X-band transmitting antenna, realizing omnidirectional signal coverage in the full-open state of the UHF band antenna.

[0059] Preferably, as Figure 2 shown, the system further includes a control network and a power supply network. The control network is connected to the first repeater and the second repeater, thereby realizing signal distribution, power management control, frequency conversion processing control, polarization control, beam control, etc.; the power supply network is used to provide operating voltage for the devices in each unit of the system.

[0060] In one example, the first RF front-end unit includes a first power distribution network, a first power amplifier unit, a receive blocking filter unit, a second power amplifier unit, and a duplexer unit connected in sequence; the second RF front-end unit includes a duplexer unit, a third power amplifier unit, a transmit blocking filter unit, a fourth power amplifier unit, and a second power distribution network connected in sequence. Among them, the power distribution network is used for signal power distribution, the power amplifier unit is used for signal amplification, the filter is used to suppress interference signals, and the duplexer is used for signal transceiver isolation, cooperating with each other to support the coverage of different frequency signals in the main radiation beam within the 0° to 360° rotation range in the full-open state of the UHF band antenna unit.

[0061] In one example, the first signal conditioning unit includes a first filter, a first low-noise amplifier, a first fixed attenuator, and a second low-noise amplifier connected in sequence; the second signal conditioning unit includes a third low-noise amplifier, a second fixed attenuator, a fourth low-noise amplifier, and a second filter connected in sequence. By filtering, low-noise amplifying, attenuating, etc. the signal to condition the signal, it is beneficial for front-end processing or outward radiation of the signal.

[0062] Combining the above three examples, a preferred repeater of the present invention is obtained. At this time, the forward communication subsystem includes an X-band receiving antenna, a first filter, a first low-noise amplifier, a first fixed attenuator, a second low-noise amplifier, a first switch matrix, a forward link unit, a second switch matrix, a first power splitter network, a first power amplifier unit, a receive blocking filter unit, a second power amplifier unit, and a duplexer unit connected in sequence; the reverse communication subsystem includes a duplexer unit, a third power amplifier unit, a transmit blocking filter unit, a fourth power amplifier unit, a second power splitter network, a third switch matrix, a reverse link unit, a fourth switch matrix, a third low-noise amplifier, a second fixed attenuator, a fourth low-noise amplifier, and a second filter connected in sequence.

[0063] Now, taking the example of transmitting and receiving 9 signals, the UHF band antenna unit includes 9 UHF band antennas. The UHF band antennas are connected through a feeding network, and the antenna is connected to a duplexer to share the antenna in the transmit and receive modes. Correspondingly, in the forward communication subsystem, the first switch matrix includes 9 switches (1a, 2a... 9a), the forward link unit includes 9 forward links, the second switch matrix includes 9 switches (1c, 2c... 9c), the first power splitter network includes a 1-to-2 power splitter, and each port of the power splitter maintains a certain isolation degree. The first power amplifier unit includes 9 first power amplifiers, the receive blocking filter unit includes 9 receive blocking filters, the second power amplifier unit includes 9 second power amplifiers, and the duplexer unit includes 9 duplexers. In the reverse communication subsystem, the duplexer unit includes 9 duplexers, the third power amplifier unit includes 9 third power amplifiers, the transmit blocking filter unit includes 9 transmit blocking filters, the fourth power amplifier unit includes 9 fourth power amplifiers, the second power splitter network includes 9 1-to-2 power splitters, and each port of the power splitter maintains a certain isolation degree. The third switch matrix includes 9 switches (1d, 2d... 9d), the reverse link unit includes 9 reverse links, and the fourth switch matrix includes 9 switches (1b, 2b... 9b).

[0064] Preferably, the first switch matrix includes a multi-way third power splitter network, specifically a 1-to-9 power splitter network (splitter). The number of power split branches (splitters) of this power splitter network can be adjusted and matched according to the number of UHF band antennas, and each port of the power splitter maintains a certain isolation degree. At this time, each UHF band antenna contains two frequency signals. Preferably, the fourth switch matrix includes a multi-way fourth power splitter network, specifically a 1-to-9 power splitter network. At this time, the end X-band feeding antenna contains 9 band signals.

[0065] At this time, the principle framework diagram of the forward communication subsystem for forward communication is as Figure 3 shown, taking Figure 3Taking the blue and red lines as an example, the blue line corresponds to the transmission line of a single signal Ud2 after 9 signal splits, and the red line corresponds to the transmission lines of other signals. At this time, the X-band feeding antenna receives 9 frequency band (narrowband) signals Gu1 to Gu9. After passing through the first filter, the first low-noise amplifier, the first fixed attenuator, the second low-noise amplifier, and the first switch matrix, it enters forward links 1 to 9 and is frequency-converted into frequency signals Ud1 to Ud9. Then, after passing through the second switch matrix, the first power distribution network, the first power amplifier unit, the receive blocking filter unit, and the second power amplifier unit, it reaches the duplexer and flows to the two UHF-band antenna terminals, realizing signal electromagnetic conversion and outward propagation. At this time, the single UHF-band antenna at the end (such as antenna 2) contains two frequency signals, Ud1 and Ud2, and the links of the remaining UHF-band antennas (antennas 1 to 9 except antenna 2) are similar. Therefore, when the forward communication subsystem conducts forward communication, it can achieve signal coverage (different frequencies) with a specified off-axis angle state of 0° to 360° rotation in the full-open state of the UHF-band antenna unit after frequency conversion of a total of 9 frequency band signals, Gu1 to Gu9.

[0066] At this time, the schematic diagram of the principle of the reverse communication subsystem for reverse communication is as shown in Figure 4 shown, taking Figure 4 the blue and green lines as an example. The blue line corresponds to the transmission line for combining 9 signals into one signal Gd1, and the green line corresponds to the transmission lines of other signals. Each UHF-band antenna unit (antennas 1 to 9) receives 9 frequency band signals (Uu1 to Uu9) of the Internet of Things. After passing through the duplexer, the third power amplifier, the transmit blocking filter, the fourth power amplifier, the second power distribution network, and the third switch matrix, it enters reverse links 1 to 9 and is frequency-converted into frequency signals Gd1 to Gd9. Then, after passing through the fourth switch matrix, the third low-noise amplifier, the second fixed attenuator, the fourth low-noise amplifier, and the second filter, the signal is forwarded through the X-band feeding antenna. At this time, the X-band transmitting antenna at the end contains a total of 9 frequency band signals, Gd1 to Gd9. Therefore, when the reverse communication subsystem conducts reverse communication, it can achieve the reception of a total of 9 frequency band signals, Uu1 to Uu9, from the full-open state of the UHF-band antenna unit, frequency conversion, and then the transmission output of a total of 9 frequency band signals, Gd1 to Gd9, from the X-band feeding antenna. In the same situation, it also achieves signal coverage with a specified off-axis angle of 0° to 360° rotation in the full-open state of the UHF-band antenna.

[0067] In one example, such as Figure 5As shown, the X-band receiving antenna 6, the X-band transmitting antenna 5, the first transponder, the second transponder, and multiple UHF-band antennas 4 (UHF-band antenna units) are all arranged on the metal support frame 1. The installation tilt angle of the metal support frame is less than 90°, and the preferred tilt angle is 50°. Specifically, the X-band transmitting antenna and the X-band receiving antenna are respectively placed at the upper and lower ends of the top of the platform of the metal support frame 1, and the placement angle is parallel to the horizontal plane. The first transponder and the second transponder are arranged inside the metal support. The number of UHF-band antenna units is an integer N, which is installed on an inclined plane with an inclination angle θ (0° < θ < 90°). By adjusting the inclination angle θ, the pointing direction of the maximum gain beam of the combined radiation pattern can be adjusted, and the remaining parameters are adjusted according to the actual scenario. The interval angle of the UHF-band antennas is 360 / N, and the number of inclined planes is adaptively adjusted according to the number of UHF-band antennas. In this example, the metal support frame includes multiple inclined planes, and this example preferably has 9 inclined planes. Each inclined plane is provided with a UHF-band antenna, and two adjacent UHF-band antennas form a sub-array, with a total of 9 sub-arrays. Further, as Figure 5 shown, the metal support frame is in the shape of a nine-sided prism. At this time, the length L1 of the installation base is 1445 mm; further, as Figure 5 shown, the center of the metal support frame is a hollow area 7, preferably a circular hollow area, for placing a CCD camera. The layout of this satellite payload system takes into account the effective working areas of the UHF-band antenna units, the X-band receiving antenna, the X-band transmitting antenna, the two transponders, and the camera layout, and at the same time reduces the mutual influence among them, especially the influence between the UHF-band antenna units and between the UHF-band antennas and the camera.

[0068] In one example, as Figure 5 - Figure 6 shown, a metal plate 11 is provided on the common inclined edge of adjacent inclined planes. It should be noted that the number of metal plates is adaptively adjusted according to the number of inclined planes. In this example, 9 metal plates are preferably provided, and the length L2 of the metal support frame including the metal plates is 1581 mm, and the height H1 is 380 mm.

[0069] Optionally, as Figure 7As shown, the metal plate 11 successively includes a first side 111, a second side 112, a third side 113, a fourth side 114, and a fifth side 115 that are successively connected end to end. Specifically, the fifth side is parallel to and has the same length as the hypotenuse of the inclined plane, with an inclination angle less than 90°, preferably 50°. Further, the first side is perpendicular to the fifth side, the second side is arranged at an acute angle with the fifth side, the third side is parallel to the fifth side, and the fourth side is arranged at an acute angle with the fifth side. Furthermore, the height of the metal plate, that is, the distance between the third side and the fifth side, is 0.1λ to 0.2λ, which is used to adjust the coupling degree between UHF-band antennas, thereby adjusting the synthetic beam pattern direction of the UHF band. In this example, the height h between the third side and the fifth side is 140 mm, and the lengths of the other sides can be optimized and adjusted according to the actual situation. By arranging the metal plate in this example, the antenna gain can be improved. As Figure 8 shown, before adding the metal plate, the maximum gain of the synthetic pattern of the UHF-band antenna unit is 7.4 dBi, and after adding the metal plate, the synthetic gain is 8.3 dBi. As Figure 9 shown, the maximum gain is increased by 0.9 dBi, that is, adding the metal plate can improve the beam directivity and the pattern gain of the antenna at a specified angle.

[0070] In one example, as Figure 10 shown, the UHF-band antenna 4 includes a tubular dielectric 43, on which a metal strip line 42 and a feeding network 41 are attached. The metal strip line 42 and the feeding network 41 form a right-handed circularly polarized antenna, operating in the UHF band. In this example, 4 metal strip lines are attached to the tubular dielectric of the UHF-band antenna, and a one-to-four feeding network is correspondingly provided at the bottom of the tubular dielectric. Among them, the thickness of the tubular dielectric is 0.5 mm to 3 mm, the phase difference between the ports of the one-to-four feeding network is 90°, and the four ports are 0°, 90°, 180°, and 270° respectively. Among them, the diameter D1 of the tubular dielectric is 220 mm, and the height H2 is 153 mm. The developed view of the structure of the metal strip line 42 is as Figure 11As shown, the metal strip line 42 includes a first metal strip line 421, a second metal strip line 422, and a third metal strip line 423 that are connected in sequence. The length of the first metal sub-strip line is 0.25λ and the width is gradually changed. The length of the second metal sub-strip line is 0.01λ - 0.04λ, and the length of the third metal sub-strip line is 0.22λ - 0.24λ. Among them, the angle between the center line of the first metal strip line and the horizontal plane is 35° - 42°. The center line of the first metal strip line 421 is parallel to the center line of the third metal strip line 423. The first metal sub-strip line is connected to the third metal sub-strip line through the second metal sub-strip line. This UHF band antenna has the characteristics of simple structure, simple feeding, and good circular polarization performance. Optionally, by adjusting the antenna diameter D1, antenna height H2, and spiral winding, parameters such as the unit pattern (such as gain) can be adjusted to adapt to different application scenarios. Through the cooperation of the first metal strip line and the third metal strip line, the antenna bandwidth is extended, and the performance parameters of a single UHF band antenna such as Figure 12 As shown, it can meet the application in the frequency band of 300 MHz - 330 MHz.

[0071] Optionally, this UHF band antenna can be processed by processes such as flexible PCB and LDS. The manufacturing cost is low, the processing accuracy is relatively high, and good index consistency can be achieved. At the same time, this UHF band antenna has the characteristic of being resistant to higher power compared with other microstrip antennas and can be applied to high-power antenna application scenarios.

[0072] Furthermore, when different sub-arrays of the UHF band antenna are excited, the pattern is as shown in Figure 13. The pattern after superimposing the patterns when all sub-arrays are excited (at different operating frequencies) is as Figure 14 shown. The 3D pattern when one of the sub-arrays is excited is as Figure 9 shown. The 2D patterns on different cross-sections when one of the sub-arrays is excited are as Figure 15 shown. Taking Figure 13(a) as an example, the UHF band antenna in the embodiment is divided into UHF antennas No. 1 - No. 9. Among them, Figure 13(a) is the combined pattern when the No. 1 and No. 2 UHF antennas are excited at the same frequency. The area covered by the pattern shown in Figure 13(a) is the No. 1 and No. 2 UHF antennas. Similarly, Figure 13(b) is the combined pattern when the No. 2 and No. 3 UHF antennas are excited at another frequency. The synthesis methods of the other 7 groups of patterns are similar. From Figure 13, Figure 14 it can be seen that 9 beams can cover the specified off-axis angle state and the 0 - 360° rotation range. From Figure 15 it can be seen that the beam of a single sub-array has a coverage range of 40° in terms of rotation direction. The maximum gain at an off-axis angle of 58° is 8.2 dBi, the minimum gain is 6.8 dBi, and the normal gain is 4.2 dBi.

[0073] In one example, the X-band receiving antenna (downlink antenna) and the X-band transmitting antenna (uplink antenna) have the same structure, and the X-band receiving antenna and the X-band transmitting antenna are defined as feeding antennas. As Figure 16 shown, the feeding antenna includes a dielectric plate 52, on which a metal patch 51 is attached, and a shielding block 53 is provided at the edge of the dielectric plate 52. Optionally, the feeding antenna includes a circular dielectric plate, with a ring-shaped metal patch attached in the middle of the dielectric plate, and a metal shielding block provided around the dielectric plate. Further, the operating frequency band of the uplink antenna is 7243 MHz to 7249.9 MHz, operating in a right-handed circular polarization state, and the parameters are as Figure 17 - Figure 19 shown. The operating frequency band of the downlink antenna is 8025 MHz to 8031.9 MHz, operating in a left-handed circular polarization state, and the parameters of the downlink antenna are as Figure 20 - 22 shown. As Figure 16 shown, the antenna has a simple and reliable structure, excellent performance in various pattern indexes, and meets the requirements of narrowband circular polarization antennas. From Figure 17 - Figure 22 it can be seen that both the uplink antenna and the downlink antenna meet the antenna index coverage requirement of being greater than 0 dB within the range of ±55° during the satellite's flight scanning process, enabling normal satellite communication.

[0074] Combining the above examples, the preferred system of the present invention is obtained. At this time, the system includes a forward communication subsystem and a reverse communication subsystem. The forward communication subsystem includes an X-band receiving antenna, a first filter, a first low-noise amplifier, a first fixed attenuator, a second low-noise amplifier, a first switch matrix, a forward link unit, a second switch matrix, a first power distribution network, a first power amplifier unit, a receive blocking filter unit, a second power amplifier unit, and a duplexer unit connected in sequence; the reverse communication subsystem includes a duplexer unit, a third power amplifier unit, a transmit blocking filter unit, a fourth power amplifier unit, a second power distribution network, a third switch matrix, a reverse link unit, a fourth switch matrix, a third low-noise amplifier, a second fixed attenuator, a fourth low-noise amplifier, and a second filter connected in sequence. The X-band receiving antenna, the X-band transmitting antenna, the first transponder, the second transponder, and the UHF-band antenna unit are all arranged on a metal support frame, and the installation inclination angle of the metal support frame is less than 90°; the X-band receiving antenna and the X-band transmitting antenna are parallel to the horizontal plane, the first transponder and the second transponder are arranged inside the metal support, and the metal support frame includes multiple inclined surfaces, and UHF-band antennas are arranged on each inclined surface. Further, a metal plate is provided on the hypotenuse of the inclined surface.

[0075] Furthermore, the UHF-band antenna includes a tubular dielectric, on which a metal strip line and a feeding network are attached. The metal strip line and the feeding network form a right-handed circularly polarized antenna. Further, the metal strip line includes a first metal sub-strip line, a second metal sub-strip line, and a third metal sub-strip line. The length of the first metal sub-strip line is 0.25λ and its width is gradually variable. The length of the second metal sub-strip line is 0.01λ - 0.04λ. The length of the third metal sub-strip line is 0.22λ - 0.24λ. The angle between the first metal sub-strip line and the horizontal plane is 35° - 42°. The center line of the first metal sub-strip line is parallel to the center line of the third metal sub-strip line. The first metal sub-strip line is connected to the third metal sub-strip line via the second metal sub-strip line. Further, the X-band receiving antenna and the X-band transmitting antenna have the same structure, and both include a dielectric plate, on which metal patches are attached, and shielding blocks are provided at the edges of the dielectric plate.

[0076] The satellite payload system of the present invention adopts an X-band multi-band (narrowband) signal input mode, and uses forward link frequency conversion, a feeding network, and a first radio frequency front-end unit to achieve signal coverage of different frequencies in the 0° - 360° rotation range of the main radiation surface in the fully open state of the UHF-band antenna unit. Similarly, in the fully open state of the UHF-band antenna unit, multi-band (narrowband) signals are received, and the use of reverse link frequency conversion, the feeding network, and the second radio frequency front-end unit realizes the multi-band signal transmission of the X-band feeding antenna. In this transceiver mode, in the fully open state of the UHF-band antenna unit, signal coverage of different frequencies in the 0° - 360° rotation range of the main radiation beam can be achieved. The structure is simple, the cost is low, and the reliability is high.

[0077] At the same time, the satellite payload system adopts a method of mutual conversion between UHF-band and X-band signals, making full use of the advantages of the UHF-band in Internet of Things communication and the advantages of the X-band in data transmission, and ensuring the reliability of system data acquisition and transmission.

[0078] The above specific embodiments are detailed descriptions of the present invention. It cannot be determined that the specific embodiments of the present invention are only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions and substitutions can still be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. An Internet of Things satellite payload system, characterized in that: The system comprises a forward communication subsystem and a reverse communication subsystem, wherein the forward communication subsystem comprises an X-band receiving antenna, a first transponder and a UHF-band antenna unit connected in sequence, and the reverse communication subsystem comprises a UHF-band antenna unit, a second transponder and an X-band transmitting antenna connected in sequence, and the UHF-band antenna unit comprises a plurality of UHF-band antennas; The first transponder includes a first signal conditioning unit, a first switch matrix, a forward link unit, a second switch matrix, and a first RF front-end unit connected in sequence; during forward communication, the X-band receiving antenna receives a plurality of X-band signals, and the first transponder is used to perform signal conditioning, frequency conversion processing, and RF front-end processing on the plurality of X-band signals to obtain a plurality of UHF band signals, and each UHF band antenna radiates the UHF band signal outward, thereby achieving omnidirectional signal coverage when the UHF band antenna is fully open; The second repeater includes a second RF front-end unit, a third switch matrix, a reverse link unit, a fourth switch matrix, and a second signal conditioning unit which are connected in sequence; during reverse communication, each UHF band antenna receives multiple UHF band signals, and the second repeater is used to perform RF front-end processing, frequency conversion processing, and signal conditioning on the multiple UHF band signals to obtain multiple X band signals, and the X band transmitting antenna radiates the multiple X band signals outward to achieve omnidirectional signal coverage when the UHF band antenna is fully open.

2. The Internet of Things satellite payload system according to claim 1, characterized in that: The first RF front-end unit includes a first power division network, a first power amplifier unit, a rejection filter unit, a second power amplifier unit and a duplexer unit connected in sequence; the second RF front-end unit includes a duplexer unit, a third power amplifier unit, a rejection filter unit, a fourth power amplifier unit and a second power division network connected in sequence.

3. The Internet of Things satellite payload system according to claim 1, characterized in that: The first signal conditioning unit includes a first filter, a first low noise amplifier, a first fixed attenuator, and a second low noise amplifier connected in sequence; the second signal conditioning unit includes a third low noise amplifier, a second fixed attenuator, a fourth low noise amplifier, and a second filter connected in sequence.

4. The Internet of Things satellite payload system according to claim 1, characterized in that: The UHF frequency band antenna comprises a tubular medium, a metal strip line and a feeding network are attached to the tubular medium, and the metal strip line and the feeding network form a right-hand circularly polarized antenna.

5. The Internet of Things satellite payload system according to claim 4, characterized in that: The metal strip line includes a first metal sub-strip line, a second metal sub-strip line and a third metal sub-strip line, the first metal sub-strip line has a length of 0.25λ and a gradual width, the second metal sub-strip line has a length of 0.01λ to 0.04λ, and the third metal sub-strip line has a length of 0.22λ to 0.24λ; The angle between the first metal sub-strip line and the horizontal plane is 35° to 42°, the center line of the first metal sub-strip line is parallel to the center line of the third metal sub-strip line, and the first metal sub-strip line is connected to the third metal sub-strip line via the second metal sub-strip line.

6. The Internet of Things satellite payload system according to claim 1, characterized in that: The X-band receiving antenna and the X-band transmitting antenna have the same structure, both comprising a dielectric plate, a metal patch attached to the dielectric plate, and a shielding block provided at the edge of the dielectric plate.

7. The Internet of Things satellite payload system according to claim 1, characterized in that: The X-band receiving antenna, X-band transmitting antenna, first transponder, second transponder, and UHF band antenna unit are all arranged on a metal support frame, and the installation inclination angle of the metal support frame is less than 90°; the X-band receiving antenna and the X-band transmitting antenna are parallel to the horizontal plane, the first transponder and the second transponder are arranged inside the metal bracket, and the metal support frame includes multiple inclined surfaces, and a UHF band antenna is arranged on each inclined surface.

8. The Internet of Things satellite payload system according to claim 7, characterized in that: A metal plate is arranged on the oblique side of the inclined surface.

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