Flat panel antenna for Ka high-throughput satellite communication terminals

Abstract

The present invention discloses a flat antenna suitable for Ka high-throughput satellite communication terminals, including a square waveguide horn array antenna, which is connected to an orthogonal mode coupler to realize the conversion from circular polarization to dual-line polarization, and obtains a dual-line polarization signal from the straight-through port and the coupling port of the orthogonal mode coupler; a duplexer to separate the transmitting and receiving frequency bands; a 3dB bridge to synthesize left-right circular polarization signals, wherein a phase shifter is arranged between the duplexer and the 3dB to compensate for the phase difference; and a dual-channel radio frequency module for polarization switching. The circular polarization is decomposed into two-way polarization signals by the orthogonal mode coupler, and the two-way polarization signals are synthesized into circular polarization by the 3dB bridge. The phase of the feed network is compensated by the phase shifter to compensate for the phase error caused by processing and assembly, and the phase consistency of the transmitting and receiving array elements under the entire bandwidth is ensured. The influence of the profile height of the polarization switch is overcome, and the overall profile size of the antenna is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of antenna design, and in particular to a flat panel antenna suitable for a Ka high-throughput satellite communication terminal. Background Art

[0002] In the related technology, the Ka antenna uses an orthogonal mode coupler to separate the circularly polarized wave into dual-line polarized signals, and then synthesizes the circularly polarized wave through a 3dB bridge, requiring the phases of the two-line polarized signals to be strictly equal. The processing error of the feed network and the multi-layer assembly error can easily lead to a large phase error of the two-line polarized signals of the antenna, affecting the antenna axial ratio. Since the transmission and reception are radiated through one unit, the co-aperture of the transmission and reception will lead to the mutual coupling of the transmission and reception signals, the difficulty of impedance matching design of the radiation unit, and the problem of grating lobes due to poor antenna sidelobe suppression.

[0003] Traditional Ka satellite terminal flat-panel antennas are mostly made of metal materials due to the high processing precision requirements. The antenna adopts a full-array design, and the weight of the whole machine is large, which makes it difficult to meet the requirements of lightweight use.

[0004] The automatic circular polarization switching of Ka high-throughput satellite flat-panel antennas is mostly achieved by using polarization switches. The cross-sectional size of the polarization switch is large, and it is difficult to make the antenna thinner and lighter. In addition, the cost of the polarization switch is high, making it difficult to achieve low cost. Summary of the invention

[0005] The main purpose of the present invention is to provide a flat panel antenna suitable for a Ka high-throughput satellite communication terminal to solve the deficiencies existing in the related art.

[0006] In order to achieve the above-mentioned purpose, a flat-panel antenna suitable for a Ka high-throughput satellite communication terminal is provided, which is characterized in that it includes: a square waveguide horn array antenna connected to an orthogonal mode coupler, for realizing circular polarization to dual-linear polarization conversion, so as to obtain a dual-linear polarization signal from the through port and the coupling port of the orthogonal mode coupler; a duplexer, for separating the transmitting and receiving frequency bands; a 3dB bridge, for synthesizing left and right circularly polarized signals, wherein a phase shifter is arranged between the duplexer and the 3dB, for compensating for the phase difference; and a dual-channel RF module, for polarization switching.

[0007] Optionally, the phase shifter includes a phase shift pair and a phase shift gasket, wherein the phase shift pair is used to simultaneously adjust the phases of dual linear polarization signals; and the phase shift gasket is used to compensate for the phase difference before the dual linear polarization signals are synthesized into circular polarization signals.

[0008] Optionally, the dual-channel radio frequency module comprises a dual-channel LNB, wherein an electronic switch is added after the primary amplifier in the dual-channel LNB.

[0009] Optionally, the dual-channel radio frequency module includes a dual-channel BUC, wherein an electronic switch is added before the final amplifier of the dual-channel BUC.

[0010] Optionally, the dual-channel RF ports are directly connected to the left and right output ports of the antenna 3dB bridge through short waveguides, and the reception of left and right signals is switched through an electronic switch.

[0011] Optionally, array elements at four corners of the square waveguide horn array antenna are cut off.

[0012] Optionally, the panel substrate in the antenna is made of non-metallic material.

[0013] Optionally, layered processing, layered electroplating, and stacked assembly are performed when processing the antenna to improve the consistency of phase relationships between different array elements.

[0014] Optionally, each layer is produced by a one-time molding process; the surface of the molded part is treated by plasma; and the metal layer is vacuum sputtered.

[0015] Optionally, solder paste is printed on the discontinuous or staggered soldering areas and reflow furnace soldering is performed to achieve continuous closed soldering of the waveguide cavity.

[0016] This embodiment is applicable to the flat antenna of Ka high-throughput satellite communication terminal, including a square waveguide horn array antenna, connected to an orthogonal mode coupler, for realizing the conversion from circular polarization to dual-line polarization, so as to obtain a dual-line polarization signal from the straight-through port and the coupling port of the orthogonal mode coupler; a duplexer, for separating the transmitting and receiving frequency bands; a 3dB bridge, for synthesizing left-hand and right-hand circular polarization signals, wherein a phase shifter is provided between the duplexer and the 3dB to compensate for the phase difference; and a dual-channel RF module, for polarization switching. The two-way polarization signals are synthesized into circular polarization through the orthogonal mode coupler and the 3dB bridge, and the phase of the feed network is compensated by the phase shifter to compensate for the phase error caused by processing and assembly, so as to ensure the phase consistency of the transmitting and receiving array elements under the entire bandwidth. Through the special design of the radiation unit, the horn unit can simultaneously meet the signal transmission and reception. By designing a decoupling structure, the mutual coupling effect caused by the common aperture of the transmitting and receiving is reduced, and the low axial ratio characteristic is achieved. The dual-channel RF module design overcomes the influence of the profile height of the polarization switch, and the overall profile size of the antenna is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 1 is a schematic diagram of a flat panel antenna structure applicable to a Ka high-throughput satellite communication terminal according to an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of a dual-channel LNB according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of a dual-channel BUC according to an embodiment of the present invention;

[0021] Figure 4a is a schematic diagram of an antenna surface without corner cutting according to an embodiment of the present invention;

[0022] Figure 4b is a schematic diagram of the cutting angle of the antenna surface according to an embodiment of the present invention;

[0023] Figure 4c It is a schematic diagram of the directional diagram of the 256-unit speaker array and the power division network receiving frequency band f=20.2GHz according to an embodiment of the present invention;

[0024] Figure 4d It is a schematic diagram of the direction of the 208-unit speaker array and the power division network receiving frequency band f=20.2GHz in an embodiment of the present invention;

[0025] Figure 5 It is a schematic diagram of local weight reduction of the antenna surface according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0028] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] According to an embodiment of the present invention, a flat-panel antenna suitable for a Ka high-throughput satellite communication terminal is provided, comprising: a square waveguide horn array antenna connected to an orthogonal mode coupler for realizing circular polarization to dual-linear polarization conversion, so as to obtain a dual-linear polarization signal from a straight-through port and a coupling port of the orthogonal mode coupler; a duplexer for separating the transmitting and receiving frequency bands; a 3dB bridge for synthesizing the dual-linear polarization signal into a left-handed circularly polarized signal, wherein a phase shifter is arranged between the duplexer and the 3dB for compensating for the phase difference; and a dual-channel radio frequency module for polarization switching.

[0030] In this embodiment, two-way polarization signals are synthesized into circular polarization through an orthogonal mode coupler and a 3dB bridge, and the phase of the feed network is compensated by the phase shifter 2 and the shifting gasket to make up for the phase error caused by processing and assembly, thereby ensuring the phase consistency of the transmitting and receiving array elements under the entire bandwidth. Through the special design of the radiation unit, the speaker unit can simultaneously meet the needs of signal transmission and reception. By designing a decoupling structure, the mutual coupling effect caused by the common aperture of the transmitting and receiving is reduced to achieve a low axial ratio characteristic. By adopting a cutting angle design for the antenna, the number of antenna array elements and the scale of the feeding network are reduced while reducing the antenna side lobes. The metal coating design of non-metallic materials is adopted to achieve the overall lightweight of the antenna surface. The dual-channel RF module design overcomes the influence of the cross-sectional height of the polarization switch, and the overall cross-sectional size of the antenna is reduced.

[0031] like Figure 1 As shown in the figure, in the dual circular polarization design, the antenna adopts the method of synthesizing circular polarization by dual linear polarization plus orthogonal mode coupler. The radiation part consists of a cross grid, a speaker unit and an orthogonal mode coupler (hereinafter referred to as OMT). The radiation unit is directly connected to the OMT, and the vertical polarization wave TE10 and the horizontal polarization wave TE01 with equal amplitude, phase and orthogonal polarization are obtained by the straight-through port and coupling port of the OMT. The synthesis and decomposition of different array element signals are realized through the waveguide power division synthesis network. The duplexer is used at the end to separate the transmit and receive frequency bands, and the phase shifter and 3dB bridge are combined to synthesize the left and right circular polarization signals. Polarization switching is achieved through a dual-channel RF module (BUC and LNB). Furthermore, the mutual coupling problem under the common aperture and the impedance matching difficulty caused by the wide frequency of transmission and reception can be solved by adding a cross grid layer to the waveguide speaker radiation unit and designing a step-gradient waveguide speaker.

[0032] The conversion from circular polarization to dual-linear polarization is realized through the speaker unit and orthogonal mode coupler, and the separation of transmission and reception and the synthesis of circular polarization are realized through the device-type duplexer, the shifting pair, the shifting pad and the 3dB bridge. The standing wave bandwidth is widened through the three-layer gradient speaker design; through the combination of cross gratings and step gradient waveguide speakers, good impedance matching is achieved in a wide band, and the field distribution of the transmit and receive array element aperture is more uniform, and the antenna side lobe is reduced; through the design of RF shifting pairs and phase shifting pads, the phase consistency of dual-linear polarization and the antenna axial ratio are guaranteed, and the transmit and receive co-aperture design is realized.

[0033] As an optional implementation of this embodiment, the phase shifter includes a phase shift pair and a phase shift gasket, wherein the phase shift pair is used to simultaneously adjust the phases of dual linear polarization signals; and the phase shift gasket is used to compensate for the phase difference before the dual linear polarization signals are synthesized into circular polarization signals.

[0034] In this optional implementation, the problem of inconsistent phase difference between high and low frequency signals of the Ka high-throughput satellite antenna dual-polarization synthesized circularly polarized antenna is addressed. Since the transmit and receive frequency bands of the Ka flat antenna are 10 GHz apart, the phase difference between the upper and lower sidebands of the high and low frequency bands is seriously unbalanced, resulting in a deterioration of the axial ratio. In order to solve the problem of inconsistent phase relationship across the entire frequency band, on the one hand, an RF transmit and receive shift pair is designed (the dual-polarization phase is adjusted simultaneously), and the consistency of the phase difference across the entire frequency band is achieved by changing the length of the transmission line. Through simulation design, the length difference between the two line polarization signals meets the phase difference requirement of the circular polarization axial ratio, and the phase difference imbalance is less than 10°, which guarantees to the greatest extent that the signals reaching the two input ports of the 3dB bridge are of equal amplitude and phase. On the other hand, due to the existence of processing and assembly errors, the error in the actual processed phase makes it difficult to ensure that it is completely consistent with the simulation results. In order to solve the problem of inconsistency between actual processing and simulation, a phase shifting gasket is specially designed. By adding a phase shifting gasket between the duplexer and the 3dB bridge, the phase difference caused by the processing error can be compensated before the dual linear polarization synthesizes the circular polarization signal, which plays a role in adjusting the antenna axial ratio after processing. The maximum phase shifting capacity of each gasket is limited. According to the measured axial ratio results, the phase difference and the number of gaskets that need to be compensated can be calculated, and multiple gaskets can be added to compensate.

[0035] As an optional implementation of this embodiment, the dual-channel radio frequency module includes a dual-channel LNB, wherein an electronic switch is added after the primary amplifier in the dual-channel LNB.

[0036] refer to Figure 2The schematic diagram of the dual-channel LNB is shown. An electronic switch is added after the primary amplifier of the dual-channel LNB. The MCU can control the opening and closing of the amplifier link power supply, so that the RF device only receives and amplifies one signal. For example, a dual-channel LNB is specially designed this time. The RF ports of the dual channels are directly connected to the left and right output ports of the antenna 3dB bridge through short waveguides, and the switching of receiving left and right signals is achieved through the electronic switch inside the dual-channel RF device.

[0037] As an optional implementation of this embodiment, the dual-channel RF module includes a dual-channel BUC, wherein an electronic switch is added before the final amplifier of the dual-channel BUC. The dual-channel RF ports are directly connected to the left and right output ports of the antenna 3dB bridge through short waveguides, and the electronic switch is used to switch the received left and right signals.

[0038] In this optional implementation, reference Figure 3 , an electronic switch is added before the final amplifier of the dual-channel BUC. The MCU can control the opening and closing of the amplifier link power supply, so that the RF device only receives and amplifies one signal. The receiving end uses a dual-channel RF module. The electronic switch inside the RF unit realizes the opening and closing of the left and right channels, which satisfies the polarization switching and reduces the antenna profile size.

[0039] The above-mentioned special design of dual-channel BUC and dual-channel LNB directly connects the dual-channel RF ports to the left and right output ports of the antenna 3dB bridge through short waveguides, and realizes the switching of receiving left and right rotation signals through the electronic switch inside the dual-channel RF device. This method makes it unnecessary to design a polarization switch for the antenna separately, which reduces the cost, reduces the cross-sectional size of the flattened RF module, and is more conducive to the design requirements of thin and light antennas. It overcomes the common method of using polarization switches to achieve dual circular polarization switching in related technologies. The polarization switch is usually a 4-port device, with 2 ports as input ports, 1 port as load port, and 1 port as output port. The two-way rotation direction signal is injected into the polarization switch through 2 input ports, and the polarization switch is internally controlled by voltage to realize the motor rotation to realize the paddle switching. However, the overall price of the polarization switch is relatively high, and a pair of antennas need to send and receive two polarization switches, so the antenna surface is overall and it is difficult to achieve lightweight and flattening.

[0040] As an optional implementation of this embodiment, the array elements at four corners of the square waveguide horn array antenna are cut off.

[0041] In this optional implementation, the physical size of the waveguide horn of the transmitting and receiving common aperture antenna does not meet the problem of the spacing of the grating-free array elements. Since the physical size of the radiating unit is determined by the cut-off frequency, the lower receiving frequency leads to a larger horn size, which cannot meet the requirement that the spacing of the transmitting array elements is less than λ / 2. Figure 1Side lobes and grating lobes are bound to appear, and the only way to shape the radiation pattern is through Taylor distribution, reducing the antenna side lobes and concentrating the main lobe energy.

[0042] In this embodiment, the square waveguide speaker array is cut corners to shape the design, and the array elements at the four corners of the antenna are removed, such as Figure 4a , Schematic diagram of the antenna surface without cutting corners and Figure 4b , Schematic diagram of antenna angle cutting. By cutting the array angle, the antenna sidelobe suppression is improved, such as Figure 4c , 256-unit speaker array + power division network receiving frequency band f = 20.2GHz directional diagram and Figure 4d , 208-unit speaker array + power division network receiving frequency band f = 20.2GHz radiation pattern. This method minimizes the number of array elements and the scale of the feed network while the overall gain of the antenna meets the gain requirements, while improving the sidelobe suppression of the antenna and achieving lightweight. Through the cut-angle shaping design, the number of array elements and the scale of the feed network are reduced, and the weight of the antenna is minimized.

[0043] As an optional implementation of this embodiment, the panel substrate of the antenna is made of non-metallic material.

[0044] In this optional implementation, the lightweight design of the antenna can be achieved through material selection and processing technology. The metal material can be replaced with a metal alloy material with lower density or a non-metallic material with low density, strong vibration and impact resistance, high strength, and high and low temperature stability can be metallized on the surface, such as PEI, ABS, PP materials, etc. In addition, the antenna area and cavity wall thickness can also be optimized by removing excess non-waveguide cavity corner materials to minimize the wall thickness and reduce the weight of the antenna panel, such as Figure 5 To further reduce weight, metal parts such as adapters and RF supports that do not affect product performance can be replaced with non-metallic materials, the wall thickness of RF devices can be reduced, and a miniature two-input and two-output polarization switching module can be designed and integrated into the antenna panel until all test requirements are met.

[0045] In this optional implementation, the weight of the antenna array is minimized by reducing the density of the antenna surface material, transitioning from metal materials to non-metal materials, and selecting the non-metal material with the lowest density. In antenna design, the number of array elements and the scale of the feed network are minimized to the greatest extent possible while meeting the gain requirements through corner cutting and shaping, reducing the wall thickness and the weight of non-core components, and reducing the weight of the antenna.

[0046] As an optional implementation of this embodiment, layered processing, layered electroplating, and stacked assembly are performed when processing the antenna to improve the consistency of the phase relationship between different array elements.

[0047] As an optional implementation of this embodiment, each layer is manufactured by a one-time molding process; the surface of the molded component is treated by plasma; and the metal layer is vacuum sputtered.

[0048] As an optional implementation of this embodiment, solder paste is printed on the welding areas arranged in an intermittent or staggered manner, and reflow furnace welding is performed to achieve continuous closed welding of the waveguide cavity.

[0049] In the above optional implementation, in the antenna surface electroplating process, in order to improve the electroplating efficiency and reduce the electroplating cost, the antenna adopts layered processing, layered electroplating, and stacked assembly design. Each layer of the antenna panel is made by CNC precision machinery in one-time molding, which minimizes the weight and wall thickness of each layer, and then the surface of the molded part is treated with plasma; then the metal layer is vacuum sputtered, such as sputtering a silver metal layer on the copper substrate; finally, solder paste is printed on the intermittent or staggered welding area, and reflow furnace soldering is performed to achieve continuous closed welding of the waveguide cavity.

[0050] This embodiment designs and implements the synthesis of dual circular polarization through dual linear polarization plus orthogonal mode coupler, improves the consistency of phase relationship between different array elements through layered processing of antenna panel, compensates for the phase error caused by the wide bandwidth of the antenna by designing the transmit and receive phase shifter + phase shifter gasket, improves the axial ratio of the antenna array, and increases the antenna gain, thereby achieving transmit and receive co-aperture in the Ka band.

[0051] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A flat panel antenna suitable for a Ka high-throughput satellite communication terminal, characterized in that: include: A square waveguide horn array antenna is connected to an orthogonal mode coupler to realize the conversion from circular polarization to dual-linear polarization, so as to obtain a dual-linear polarization signal from a through port and a coupling port of the orthogonal mode coupler; A duplexer separates the transmit and receive frequency bands; 3dB bridge, synthesizing left-hand and right-hand circular polarization signals, wherein a phase shifter is provided between the duplexer and 3dB to compensate for the phase difference; and, a dual-channel RF module for polarization switching.

2. The flat panel antenna suitable for Ka high-throughput satellite communication terminal according to claim 1, characterized in that: The phase shifter comprises a phase shifter pair and a phase shifter pad, wherein the phase shifter pair is used to adjust the phases of dual linear polarization signals simultaneously; and the phase shifter pad is used to compensate for the phase difference before the dual linear polarization signals are synthesized into circular polarization signals.

3. The flat panel antenna suitable for Ka high-throughput satellite communication terminal according to claim 2, characterized in that: The dual-channel radio frequency module includes a dual-channel LNB, wherein an electronic switch is added after a primary amplifier in the dual-channel LNB.

4. The flat panel antenna suitable for Ka high-throughput satellite communication terminal according to claim 3, characterized in that: The dual-channel radio frequency module includes a dual-channel BUC, wherein an electronic switch is added before the final amplifier of the dual-channel BUC.

5. The flat panel antenna suitable for Ka high-throughput satellite communication terminal according to claim 2 or 4, characterized in that: The dual-channel RF port is directly connected to the left and right output ports of the antenna 3dB bridge through a short waveguide, and the reception of left and right signals is switched through an electronic switch.

6. The flat panel antenna suitable for Ka high-throughput satellite communication terminal according to claim 1, characterized in that: The array elements at four corners of the square waveguide horn array antenna are cut off.

7. The flat panel antenna suitable for Ka high-throughput satellite communication terminal according to claim 1, characterized in that: In the antenna, the panel substrate is made of non-metallic material.

8. The flat panel antenna suitable for Ka high-throughput satellite communication terminal according to claim 1, characterized in that: When processing the antenna, layered processing, layered electroplating, and stacked assembly are performed to improve the consistency of the phase relationship between different array elements.

9. The flat panel antenna suitable for Ka high-throughput satellite communication terminal according to claim 8, characterized in that: Each layer is produced by a one-time molding process; the surface of the molded part is treated by plasma; and the metal layer is deposited by vacuum sputtering.

10. The flat panel antenna suitable for Ka high-throughput satellite communication terminal according to claim 9, characterized in that: By printing solder paste on the intermittent or staggered welding area and performing reflow furnace soldering, continuous closed soldering of the waveguide cavity can be achieved.

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