Ultra-large scale phased-array antenna digital beam forming device and method

Abstract

The invention provides a digital beam forming device and method for a super-large-scale phased-array antenna. The digital beam forming device comprises a front-stage beam forming processing module and a rear-stage beam forming processing module, the plurality of pre-stage beam forming processing modules are designed on the bottom side of the antenna, and the number of the pre-stage beam forming processing modules is the same as that of the antenna sub-arrays; the front-stage beam forming processing module and the rear-stage beam forming processing module are connected through a digital signal connector. The ultra-large-scale phased-array antenna digital beam forming device provided by the invention can solve the problems that the number of cable interfaces is large and the realization is difficult when the scale of an antenna array is increased in a traditional beam forming framework. According to the digital beam forming method for the super-large-scale phased-array antenna, when a preceding-stage beam forming processing module completing secondary synthesis is damaged, the sub-array in charge of the preceding-stage beam forming processing module can be switched to continue to participate in beam forming processing along other secondary synthesis signal links according to an instruction, and the stability is better.

Description

Technical Field

[0001] The present invention belongs to the technical field of digital beam synthesis of phased array antennas, and in particular relates to a digital beam synthesis device and method for ultra-large-scale phased array antennas. Background Art

[0002] The present invention originates from the subject of satellite internet mobile phone direct connection to satellite-borne phased array. With the vigorous development of communication technology, phased array, MIMO antenna and DBF technology are more and more widely used in satellite communication and ground 5G fields, and the scale requirements for antenna arrays are also getting higher and higher, especially for mobile phone direct connection to satellite communication system, which requires phased array to have sufficient scale to support high gain of signal reception and transmission. The traditional digital beamforming architecture is also increasingly difficult to meet the rapidly increasing demand for antenna array size, so it is necessary to study an optimized digital beamforming method to meet new demands.

[0003] Reference 1: Wu Yingqi, Research on array error correction and subarray-level beamforming technology and engineering implementation, National University of Defense Technology, 2015. This reference proposes a subarray-level beamforming architecture, which divides the array elements into multiple subarrays and forms beams according to the subarray hierarchy. It realizes digital beamforming of 32 array elements in engineering.

[0004] Reference 2: Li Weixing, Research on Key Technologies of Error Correction and Beamforming for Wideband Digital Array Radar, National University of Defense Technology, 2016. This reference proposes a three-level synthesis architecture of first-level beam synthesis, second-level beam synthesis and third-level beam synthesis to complete the digital beam synthesis architecture, where the first-level beam synthesis is responsible for the complex multiplication and summation of the weights of the subarray, and the second and third levels only complete the summation operation.

[0005] It can be seen from the current literature on digital beamforming that beamforming methods all adopt traditional architectures. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a digital beam synthesis method for ultra-large-scale phased array antennas to solve the problem in the prior art that when the antenna array scale increases, the actual function of the secondary synthesis is simple but the number of cable interfaces is huge and the implementation is difficult.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems: a very large-scale phased array antenna digital beamforming device, including a front-stage beamforming processing module and a rear-stage beamforming processing module.

[0008] The front-stage beamforming processing module is designed at the bottom side of the antenna, and there are multiple of them. The number of the front-stage beamforming processing modules is the same as the number of antenna subarrays.

[0009] The front-stage beamforming processing module and the rear-stage beamforming processing module are connected by a digital signal connector.

[0010] The present invention also includes the following technical features:

[0011] The front side of the front-stage beamforming processing module is composed of a front-stage SMP connector and an AD / DA chip for digital-to-analog conversion, and the back side is composed of a front-stage digital processing chip and a front-stage digital signal connector.

[0012] The front-stage beamforming processing modules are connected by a front-stage digital signal connector.

[0013] The post-stage beamforming processing module comprises a post-stage digital processing chip, a post-stage digital signal connector, and a product external interface connector.

[0014] The front side of the antenna subarray module corresponding to the front-stage beamforming processing module is composed of a radiation antenna unit array composed of patch antenna units, and the back side is composed of a radio frequency chip and an antenna SMP connector.

[0015] The antenna subarray module and the front-stage beamforming processing module complete signal transmission through the antenna SMP connector and the front-stage SMP connector.

[0016] The present invention also provides a method for digital beam synthesis of a very large-scale phased array antenna, which is completed by using the very large-scale phased array antenna digital beam synthesis device mentioned above.

[0017] It includes two parts: pre-stage beamforming and post-stage beamforming.

[0018] The pre-stage beamforming is performed by a pre-stage beamforming processing module, and the post-stage beamforming is performed by a post-stage beamforming processing module.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] (I) The ultra-large-scale phased array antenna digital beamforming device provided by the present invention can overcome the problems faced by traditional beamforming architectures, such as a large number of cable interfaces and difficulty in implementation, when the antenna array scale increases.

[0021] (II) The digital beamforming method for ultra-large-scale phased array antenna provided by the present invention has better stability when the front-stage beamforming processing module that completes the secondary synthesis is damaged, the subarray it is responsible for can be switched according to instructions to continue participating in the beamforming processing along other secondary synthesis signal links. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the ultra-large-scale phased array antenna digital beam synthesis device of the present invention.

[0023] Figure 2 It is a structural diagram of the front-stage beamforming processing module.

[0024] Figure 3 It is a structural diagram of the post-stage beamforming processing module.

[0025] Figure 4 It is a schematic diagram of the connection structure of the front-stage beamforming processing module of the present invention.

[0026] Figure 5 It is a schematic diagram of the antenna subarray module structure of the present invention.

[0027] Figure 6 It is an example diagram of the secondary beamforming relationship in the front-stage beamforming processing module of the present invention.

[0028] Figure 7 It is a receiving channel calibration link diagram of the present invention.

[0029] Figure 8 It is a transmission channel calibration link diagram of the present invention.

[0030] Fig. 9 This is a topological diagram of traditional digital beamforming implementation.

[0031] The symbols in the figure represent:

[0032] 1-pre-stage beamforming processing module, 2-post-stage beamforming processing module, 3-antenna subarray module.

[0033] 1-1-Front-stage SMP connector, 1-2-AD / DA chip for digital-to-analog conversion, 1-3-Front-stage digital processing chip, 1-4-Front-stage digital signal connector.

[0034] 2-1-Post-stage digital processing chip, 2-2-Post-stage digital signal connector, 2-3-Product external interface connector.

[0035] 3-1-Patch antenna unit, 3-2-RF chip, 3-3-Antenna SMP connector.

[0036] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0037] All components in the present invention, unless otherwise specified, are components known in the prior art.

[0038] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0039] Embodiment 1:

[0040] This embodiment provides a digital beamforming device for a very large-scale phased array antenna. Figure 1-Figure 8 As shown, it includes a front-stage beamforming processing module 1 and a rear-stage beamforming processing module 2.

[0041] The front-stage beamforming processing module 1 is designed at the bottom side of the antenna, and there are multiple of them. The number of the front-stage beamforming processing modules 1 is the same as the number of antenna subarrays.

[0042] The front-stage beamforming processing module 1 and the rear-stage beamforming processing module 2 are connected by a digital signal connector.

[0043] The post-stage beamforming processing module 2 can be designed to be located in a satellite cabin far away from the antenna.

[0044] The connection of adjacent front-stage beamforming processing modules 1 can enable some front-stage beamforming processing modules 1 to complete the secondary beamforming processing of the surrounding subarrays. When the number of interfaces of the front-stage beamforming processing module 1 is sufficient, the area where the secondary synthesis is completed can be further expanded to reduce the number of input ports of the rear-stage beamforming processing module 2.

[0045] The post-stage beamforming processing module 2 is mainly composed of a post-stage digital processing chip 2-1, a post-stage digital signal connector 2-2, and a product external interface connector 2-3, wherein the post-stage digital processing chip 2-1 completes the signal processing of the post-stage beamforming of the entire array, and is connected to the pre-stage beamforming processing module 1 through the post-stage digital signal connector 2-2. It is worth noting that some pre-stage beamforming processing modules 1 have completed the secondary beamforming of their surrounding sub-array modules, so the post-stage beamforming processing module 2 does not need to be directly connected to all pre-stage beamforming processing modules 1, which greatly reduces the interface pressure of the post-stage beamforming processing module 2.

[0046] For example, under normal circumstances, each front-stage beamforming processing module 1 with secondary beamforming is responsible for the secondary beamforming of itself and several other modules around it. Considering that the front-stage beamforming processing module 1 is damaged, each module with secondary beamforming can be responsible for the secondary beamforming of itself and more modules. When module 1 originally responsible for module 2 is damaged, module 3 will also be responsible for the secondary beamforming of the subarray of module 2. The damage of module 2 only affects its own subarray and cannot participate in the beamforming processing of the entire array, but will not affect the remaining modules.

[0047] As a preferred embodiment of this invention:

[0048] The front side of the front-stage beamforming processing module 1 is composed of a front-stage SMP connector 1-1 and a digital-to-analog conversion AD / DA chip 1-2, and the back side is composed of a front-stage digital processing chip 1-3 and a front-stage digital signal connector 1-4.

[0049] The front-stage beamforming processing modules 1 are connected to each other by front-stage digital signal connectors 1-4.

[0050] The digital-to-analog conversion AD / DA chip 1-2 adopts the radio frequency transceiver chip AD9361.

[0051] The front-end digital processing chips 1-3 are FPGA processing chips.

[0052] The front-stage digital signal connectors 1-4 are FMC connectors.

[0053] The post-stage beamforming processing module 2 comprises a post-stage digital processing chip 2-1, a post-stage digital signal connector 2-2, and a product external interface connector 2-3.

[0054] The post-stage digital processing chip 2-1 adopts an FPGA processing chip.

[0055] The post-stage digital signal connector 2-2 adopts an FMC connector.

[0056] The product external interface connector 2-3 adopts a J30J connector.

[0057] The AD / DA chip 1-2 of digital-to-analog conversion mainly completes the acquisition of input analog signals to digital signals and the conversion of output digital signals to analog signals.

[0058] The front-end digital processing chip 1-3 mainly completes the primary beamforming processing of the subarray.

[0059] The post-stage digital processing chip 2-1 completes the signal processing of the post-stage beamforming of the entire array, and is connected to the pre-stage beamforming processing module 1 through the post-stage digital signal connector 2-2. It is worth noting that some pre-stage beamforming processing modules 1 have completed the secondary beamforming of the surrounding sub-array modules. Therefore, the post-stage beamforming processing module 2 does not need to be directly connected to all the pre-stage beamforming processing modules 1, but only needs to be connected to the module 1 that completes the secondary synthesis, which greatly reduces the interface pressure of the post-stage beamforming processing module.

[0060] As a preferred embodiment of this invention:

[0061] The antenna subarray module 3 corresponding to the previous beamforming processing module 1

[0062] The front side is composed of a radiating antenna unit array consisting of patch antenna units 3-1, and the back side is composed of a RF chip 3-2 and an antenna SMP connector 3-3.

[0063] The antenna subarray module and the front-stage beamforming processing module 1 complete signal transmission through the antenna SMP connector 3-3 and the front-stage SMP connector 1-1.

[0064] The front-stage beamforming processing module 1 is designed on the bottom side of the antenna subarray module 3 .

[0065] This patent proposes a digital beamforming device for ultra-large-scale phased array antennas. A front-stage beamforming processing module 1 is installed on the parallel horizontal plane of each group of antenna sub-arrays, and the rich IO interfaces of the front-stage digital processing chips 1-3 in the front-stage beamforming processing module 1 are used to complete the secondary beamforming processing of some sub-arrays in the primary beamforming, which can greatly reduce the number of input signals for the final beamforming.

[0066] The architecture of the ultra-large-scale phased array antenna digital beamforming device proposed in this patent is as follows: Figure 1 As shown in FIG. 1 , the digital beamforming process is divided into two parts: the pre-stage beamforming and the post-stage beamforming.

[0067] The front-stage beamforming processing module 1 is divided into multiple processing modules according to the antenna subarray and is designed at the bottom side of the antenna, and the rear-stage beamforming processing module 2 can be designed to be located in a satellite cabin far away from the antenna.

[0068] In this architecture, the subarray modules are closely arranged. Each antenna subarray module and the corresponding front-stage beamforming processing module are responsible for the first-stage beamforming processing of their own subarray, and the back-stage beamforming processing module is responsible for completing the beamforming processing of the entire array.

[0069] The antenna subarray module 3 includes a radiation antenna unit array and a radio frequency channel module. The antenna radiation unit can be implemented in various forms, and the radio frequency channel module generally includes a low noise amplifier, a power amplifier, a frequency converter, a filter, etc. When considering product miniaturization, patch antenna units and microwave radio frequency chips are usually used as the implementation methods of the radiation antenna unit and the radio frequency channel module. Figure 5 The front of the antenna subarray module shown is an antenna radiation unit array composed of patch antenna units, and the back is a microwave channel module composed of various microwave radio frequency chips. Signal transmission is completed with the previous beam synthesis processing module through a micro SMP connector.

[0070] The main function of the front-stage beamforming processing module 1 is to complete the primary beamforming of the corresponding subarray signal, and some front-stage beamforming processing modules 1 also complete the secondary beamforming of the surrounding subarray modules.

[0071] The product external interface connector 2-3 mainly completes the external information interaction of the entire product, including synthesized beams, product control information, product parameter information input and output, etc. From the entire beam synthesis architecture, it can be seen that the post-stage beam synthesis processing module 2 is a single-point module in the entire beam synthesis processing flow. Damage to this module can directly lead to product failure. In products with high reliability requirements, especially such products on satellite platforms, it should be considered to add a post-stage beam synthesis cold backup module.

[0072] Front-stage digital signal connectors 1-4 are designed at the edge of the front-stage beamforming processing module 1, and adjacent front-stage beamforming processing modules 1 can be connected through the front-stage digital signal connectors 1-4. Figure 4 shown.

[0073] The connection of adjacent front-stage beamforming processing modules 1 can enable some front-stage beamforming processing modules 1 to complete the secondary beamforming processing of the surrounding sub-arrays. Figure 6 The module A shown can complete the secondary beamforming processing of its own module A, module B, module C, and module D, and can be expanded to the secondary beamforming of modules E, module F, etc. when necessary. The signal processed by the secondary synthesis is sent to the subsequent beamforming processing module 2 through one of the front-stage digital signal connectors 1-4 of module A.

[0074] Both the front-end and rear-end processing modules can be connected using flexible PCB cables or high-speed optical fibers. When the number of interfaces of the front-end beamforming processing module 1 is sufficient, the area for completing the secondary synthesis can be further expanded to reduce the number of input ports of the rear-end beamforming processing module 2.

[0075] Embodiment 2:

[0076] A method for digital beam synthesis of a very large-scale phased array antenna is implemented by using the very large-scale phased array antenna digital beam synthesis device as described in Example 1.

[0077] It includes two parts: pre-stage beamforming and post-stage beamforming.

[0078] The pre-stage beamforming is performed by a pre-stage beamforming processing module 1 , and the post-stage beamforming is performed by a post-stage beamforming processing module 2 .

[0079] Figure 6What is shown is an example diagram of the secondary beamforming relationship in the front-stage beamforming processing module 1. Under normal circumstances, each module with secondary beamforming is responsible for the secondary beamforming of itself and the other three modules around it. In the case of module damage, each module with secondary beamforming can be responsible for the secondary beamforming of itself and the other six modules. Under normal and backup conditions, the module numbers of the secondary synthesis that each module with secondary beamforming is responsible for are shown in Table 1. Taking module A as an example, under normal circumstances, module A is responsible for completing the secondary beamforming of module A, module 1, module 2, and module 3 subarrays. When module B, which is originally responsible for module 4, is damaged, module A will also be responsible for the secondary beamforming of module 4 subarrays. By analogy, the damage of module B only affects its own subarray and cannot participate in the beamforming processing of the entire array.

[0080] Table 1

[0081]

[0082] The ultra-large-scale phased array antenna digital beamforming device proposed in this patent can use PN code signals for calibration of the receiving channel and can use single carrier signals for calibration of the transmitting channel.

[0083] In addition to receiving the calibration signal, the receiving channel can also receive the external signal from the antenna unit. Considering the interference of the external signal, the PN code signal is used to calibrate the receiving channel.

[0084] There is no interference signal other than the calibration signal in the transmit calibration link, but there are multiple combiners in the transmit calibration link. In order to distinguish the transmit channel signals after combining, the single carrier of each channel can be allocated with a fixed interval frequency, and the calibration signals of each channel can be separated by channelization branching processing or down-conversion processing in the post-stage beamforming processing module.

[0085] Phased array antennas have actual differences between various amplifiers, filters and other analog devices in microwave RF channels and digital acquisition chips, so there will be signal amplitude and phase differences between channels. The amplitude and phase differences between channels will directly affect the beam performance. In the development and testing of phased array products, it is usually necessary to balance the channels of the products to eliminate the amplitude and phase differences between channels. However, as the working time changes, the characteristics of microwave RF channel components will change slowly, eventually causing the beam performance to deteriorate. Channel calibration is to cope with the channel amplitude and phase changes caused by the slow characteristics of components, and rebalance and calibrate the channels to restore the beam performance. Calibration usually uses a common channel to transmit or receive calibration signals, and analyzes the amplitude and phase characteristics of each channel based on the changes in the calibration signals after passing through each channel. Considering that the amplitude and phase characteristics of passive devices such as antenna units are relatively stable, the calibration of phased arrays can usually be done by internal calibration, and the calibration link does not include antenna units. Calibration signals usually use single carrier signals, PN code signals, etc. Single carrier signal calibration has the advantages of being simple and fast, but poor anti-interference performance. PN code signals have the advantages of strong anti-interference performance, but the calibration implementation is more complicated. Based on these two characteristics, the ultra-large-scale phased array antenna digital beamforming method proposed in this patent can use PN code signals for calibration of the receiving channel and single carrier signals for calibration of the transmitting channel. Figure 7 As shown in FIG. 1 , in addition to receiving the calibration signal, the receiving channel can also receive external signals from the antenna unit. Considering the interference of external signals, the PN code signal is used to calibrate the receiving channel. Figure 8 As shown, there is no other interference signal except the calibration signal in the transmit calibration link, but there are multiple combiners in the transmit calibration link. In order to distinguish the transmit channel signals after combining, the single carrier of each channel can be allocated with a fixed interval frequency, and the calibration signals of each channel can be separated by channelization branching processing or down-conversion processing in the post-stage beamforming processing module.

[0086] Comparative Example:

[0087] Traditional digital beamforming is implemented hierarchically, such as Fig. 9 When the number of input feed sources is large, usually one digital processing chip cannot complete the digital beamforming processing of all feed sources, so the feed source signals need to be divided into several groups.

[0088] Each group of divided feed source signals undergoes a first-level digital beamforming process in a digital processing chip, which mainly includes complex multiplication and summation of the feed source and the weight matrix, and storage of the weight matrix.

[0089] After the first-level processing is completed, each group of signals is input into a digital processing chip for secondary synthesis operation, which mainly includes the summation operation of each group of first-level synthesized signals.

[0090] In this architecture, the digital chip in the secondary beamforming processing usually has excess processing performance and insufficient signal interfaces. However, the product size is often larger due to the number of signal interfaces. Especially when the size of the array antenna increases dramatically, the size and weight of the secondary synthesis module will also increase dramatically. However, the secondary beamforming module usually has simple functions, which causes a large waste of the platform's load capacity. In addition, it is difficult to perform redundant backup of the secondary beamforming module when considering the reliability design of the product.

[0091] In the traditional beamforming structure, the damage of a primary beamforming module will affect the antenna array of a subarray and make it unable to participate in beamforming. By changing the weights, the beamforming can be re-performed, and only part of the beam gain performance will be lost without affecting the function of the entire phased array antenna. The damage of the secondary beamforming module will cause the failure of the entire phased array antenna. Therefore, the secondary beamforming module usually needs to consider redundant backup design. Increasing the redundant design of the secondary beamforming module requires doubling the number of cables output by the primary beamforming module. When the array scale is relatively large, the backup of the secondary beamforming module is very difficult.

[0092] Under the architecture of the digital beamforming method for ultra-large-scale phased array antenna proposed in this patent, the damage of a front-stage beamforming processing module that only completes the first-level synthesis only affects one subarray participating in the beamforming. The damage of a front-stage beamforming that completes the second-level synthesis without considering the backup will affect the subarray responsible for the second-level synthesis to participate in the beamforming. However, in the beamforming architecture proposed in this patent, there are abundant interface resources between the front-stage beamforming processing modules. When the front-stage beamforming processing module that completes the second-level synthesis is damaged, the subarray it is responsible for can be switched according to instructions to continue to participate in the beamforming processing along other second-level synthesis signal links.

[0093] The above technical solutions are only preferred specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be conceived by any technician familiar with the field within the technical scope disclosed by the present invention without creative work are all covered within the protection scope of the present invention.

Claims

1. A digital beamforming device for ultra-large-scale phased array antennas, characterized in that: It comprises a front-stage beamforming processing module (1) and a rear-stage beamforming processing module (2); The front-stage beamforming processing module (1) is designed on the bottom side of the antenna and is multiple, and the number of the front-stage beamforming processing modules (1) is the same as the number of antenna subarrays; The front-stage beamforming processing module (1) and the rear-stage beamforming processing module (2) are connected using a digital signal connector.

2. The ultra-large-scale phased array antenna digital beamforming device according to claim 1, characterized in that: The front side of the front-stage beamforming processing module (1) is composed of a front-stage SMP connector (1-1) and a digital-to-analog conversion AD / DA chip (1-2), and the back side is composed of a front-stage digital processing chip (1-3) and a front-stage digital signal connector (1-4); The front-stage beamforming processing modules (1) are connected to each other via front-stage digital signal connectors (1-4); The post-stage beamforming processing module (2) comprises a post-stage digital processing chip (2-1), a post-stage digital signal connector (2-2), and a product external interface connector (2-3).

3. The ultra-large-scale phased array antenna digital beamforming device according to claim 2, characterized in that: The front side of the antenna subarray module (3) corresponding to the previous stage beamforming processing module (1) is composed of a radiation antenna unit array composed of patch antenna units (3-1), and the back side is composed of a radio frequency chip (3-2) and an antenna SMP connector (3-3); The antenna subarray module and the front-stage beamforming processing module (1) complete signal transmission via the antenna SMP connector (3-3) and the front-stage SMP connector (1-1); The front-stage beamforming processing module (1) is designed on the bottom side of the antenna subarray module (3).

4. A method for digital beamforming of ultra-large-scale phased array antennas, characterized in that: This is accomplished by using the ultra-large-scale phased array antenna digital beamforming device as described in any one of claims 1-3.

5. The method for digital beamforming of ultra-large-scale phased array antennas according to claim 4, characterized in that: It includes two parts: pre-stage beamforming and post-stage beamforming; The pre-stage beam synthesis is performed by a pre-stage beam synthesis processing module (1), and the post-stage beam synthesis is performed by a post-stage beam synthesis processing module (2).

Images