MIMO beam scanning antenna, imaging device and imaging method

Abstract

The invention provides an MIMO beam scanning antenna, an imaging device and an imaging method. The MIMO beam scanning antenna comprises a transmitting antenna array which comprises N multi-branch antenna units with the spacing of D1, and N is greater than or equal to 2; the receiving antenna array comprises M single-branch antenna units with the spacing being D2, M is larger than or equal to 2, and D1 is equal to M * D2; and a transmit-receive chip providing a transmit signal allocated to the transmit antenna array and receiving a receive signal from the receive antenna array. The N multi-branch antenna units are arranged side by side in a first direction, the M single-branch antenna units are arranged side by side in the first direction, and the multi-branch antenna units and the single-branch antenna units are arranged in the same plane and are separated in the middle in a second direction different from the first direction. In N * M virtual antennas formed by the multi-branch antenna unit and the single-branch antenna unit, the distance D3 between adjacent virtual antennas is fixed to D2 / 2, D2 is larger than or equal to lambda / 2, and lambda is the wavelength of a transmitted signal.

Description

Technical Field

[0001] This disclosure relates to the field of antennas, and more particularly to a MIMO beam scanning antenna, imaging device, and imaging method. Background Technology

[0002] Imaging technology has been widely applied in many fields. However, current imaging solutions have some problems in terms of cost, speed, and resolution, and are difficult to meet the requirements of real-time and high precision.

[0003] For example, current millimeter-wave imaging systems are mainly divided into four categories: SISO (Single Input Single Output) passive array architecture, SISO switched array architecture, vertical MIMO systems, and reflective phased arrays. The SISO passive array architecture uses two rows of T / R (transmit / receive) modules with frequency-modulated continuous wave signals. While it can achieve basic imaging, its hardware cost is high and its scanning speed is limited. The SISO switched array architecture uses M T / R modules with frequency-modulated continuous wave signals. While it can achieve basic imaging, its hardware cost is high and its scanning speed is limited. The vertical MIMO system improves speed through an array of M×N T / R modules and frequency-modulated continuous wave signals, but it suffers from range ambiguity. Reflective phased arrays rely on antenna elements and a single-frequency millimeter-wave source, offering a significant speed advantage, but they are costly and require stringent imaging conditions.

[0004] These four types of imaging systems have the following obvious problems: cost issues, such as the high manufacturing cost due to the hardware complexity of vertical MIMO systems and reflective phased arrays; performance issues: the speed of SISO passive array architecture and SISO switched array architecture is slow, vertical MIMO systems suffer from imaging blur, and reflective phased arrays have harsh testing conditions; resolution issues: all solutions have insufficient detail recognition capabilities, making it difficult to meet the requirements of high precision. Summary of the Invention

[0005] This disclosure provides a MIMO beam scanning antenna, an imaging device, and an imaging method.

[0006] According to one aspect of this disclosure, a MIMO beam scanning antenna is provided for scanning an imaging target, comprising: a transmitting antenna array including N multi-stub antenna elements spaced D1, where N≥2; a receiving antenna array including M single-stub antenna elements spaced D2, where M≥2 and D1=M×D2; and a transceiver chip for providing a transmitted signal allocated to the transmitting antenna array and receiving a received signal from the receiving antenna array; wherein the N multi-stub antenna elements are arranged side-by-side in a first direction, and the M single-stub antenna elements are arranged side-by-side in a first direction. The multi-stub antenna elements are arranged side-by-side in the first direction. The N multi-stub antenna elements and the M single-stub antenna elements arranged side-by-side are set in the same plane and spaced apart in a second direction different from the first direction. Each multi-stub antenna element and each single-stub antenna element constitute a virtual antenna. In the N×M virtual antennas formed by the N multi-stub antenna elements and the M single-stub antenna elements, the spacing D3 between adjacent virtual antennas is fixed at D2 / 2, where D2≥λ / 2, and λ is the wavelength of the transmitted signal.

[0007] According to one technical solution, the transmitting antenna array and the receiving antenna array are arranged in parallel to form a virtual antenna array. This arrangement offers advantages such as a fixed period (spacing between adjacent virtual antennas) and maximized quantity. By configuring the transmitting antenna array as a multi-stub and the receiving antenna array as a single-stub, the transmit signal gain and receive signal sampling density can be improved, thereby increasing the imaging distance, suppressing imaging artifacts, and improving imaging resolution. Overall, MIMO beam scanning antennas offer advantages such as small size, ease of fabrication and integration, high transmit gain, multiple scanning beams, and fast scanning speed.

[0008] According to at least one embodiment of the present disclosure, the multi-stub antenna element includes n radiating stubs, where n≥2, and the single-stub antenna element includes one radiating stub, each radiating stub consisting of a transmission line segment and multiple radiating patches.

[0009] According to the technical solution of this embodiment, the transmitting antenna element adopts a multi-stub configuration, which can improve the transmitted signal gain, increase the imaging distance, and enhance the image artifact suppression capability. The receiving antenna element adopts a single-stub configuration, achieving a high-density receiving antenna element layout, which can improve imaging resolution.

[0010] According to at least one embodiment of this disclosure, it further includes power dividers, the number of which is N, each power divider splitting the received transmitted signal into n paths to provide to the n radiating branches respectively.

[0011] According to the technical solution of this embodiment, the power divider can achieve amplitude / phase consistent feeding of multi-stub antennas, thereby improving transmit gain and beam stability.

[0012] According to at least one embodiment of this disclosure, a switching switch is further included, the number of which is equal to the number of transmit channels of the transceiver chip, the switching switch being used to selectively provide transmit signals received from the transmit channels to m power dividers, where 2≤m≤N.

[0013] According to the technical solution of this embodiment, flexible connection between the transmission channel and multiple power dividers is realized, more antenna elements are driven with fewer transmission channels, reducing hardware costs, while supporting beam switching or time-division scanning.

[0014] According to at least one embodiment of this disclosure, a beam control module is further included, which selectively controls the switching of the transmit channel and receive channel of the transceiver chip and selectively controls the switching of the switching switch to control the beam scanning switching of the transmit antenna array and the receive antenna array.

[0015] According to the technical solution of this embodiment, the beam control module coordinates the transmit and receive channels and switching switches in a unified manner to achieve flexible, fast and orderly beam scanning, thereby improving imaging efficiency and system controllability.

[0016] According to at least one embodiment of this disclosure, it further includes a target sensing module, which is used to sense the distance information and shape information of the imaging target, and the beam control module is able to change at least one of the number of scanning beams, scanning period and scanning time according to the distance information and shape information.

[0017] According to the technical solution of this embodiment, the target perception module can achieve adaptive scanning, dynamically adjust beam parameters according to the distance and shape of the target, and improve imaging efficiency, resolution and system resource utilization.

[0018] According to at least one embodiment of this disclosure, the transmitting antenna array includes a first transmitting antenna array and a second transmitting antenna array; the receiving antenna array includes a first receiving antenna array and a second receiving antenna array; the transceiver chip includes a first transceiver chip and a second transceiver chip; the first transmitting antenna array includes N first multi-stub antenna elements and the second transmitting antenna array includes N second multi-stub antenna elements; the first receiving antenna array includes M first single-stub antenna elements and the second receiving antenna array includes M second single-stub antenna elements; wherein the N first multi-stub antenna elements and the M second single-stub antenna elements... The M first single-stub antenna elements and the N second multi-stub antenna elements are arranged side-by-side in the first direction. Each first multi-stub antenna element and each first single-stub antenna element constitute a virtual antenna, and each second multi-stub antenna element and each second single-stub antenna element constitute a virtual antenna. In the 2×N×M virtual antenna array formed by the N first multi-stub antenna elements, the M first single-stub antenna elements, and the N second multi-stub antenna elements and the M second single-stub antenna elements, the spacing D3 between adjacent virtual antennas is fixed at D2 / 2.

[0019] According to the technical solution of this embodiment, a complementary MIMO beam scanning antenna is provided, which has the advantages of small size, large number of beams, high resolution, and cascading capability.

[0020] According to at least one embodiment of this disclosure, in the N first multi-stub antenna elements and the M second single-stub antenna elements arranged side by side, the spacing between adjacent first multi-stub antenna elements and second single-stub antenna elements is D4 = D2 / 2, and in the M first single-stub antenna elements and the N second multi-stub antenna elements arranged side by side, the spacing between adjacent first single-stub antenna elements and second multi-stub antenna elements is D4 = D2 / 2.

[0021] According to the technical solution of this embodiment, the spacing between the virtual antennas formed by two complementary MIMO beam scanning antennas can be fixed to a constant value. In particular, the spacing between adjacent virtual antennas of one MIMO beam scanning antenna and another MIMO beam scanning antenna is the same as the spacing between other adjacent virtual antennas, thereby ensuring that the spacing between all adjacent virtual antennas is a constant value.

[0022] According to another aspect of this disclosure, an imaging device is provided, comprising: a beam scanning module equipped with a MIMO beam scanning antenna as described in any of the preceding claims, wherein the number of MIMO beam scanning antennas is one or more, wherein the MIMO beam scanning antennas are used to perform beam scanning in one direction; and a mechanical control device that controls the beam scanning module to perform mechanical movement in another direction to perform mechanical scanning in the other direction, wherein the one direction is perpendicular to the other direction, and the scanning areas of the beam scanning and the mechanical scanning cover the imaging area of ​​the imaging target.

[0023] According to another aspect of this disclosure, an imaging method for the imaging device described above is provided, comprising: dividing the imaging region into multiple small-aperture regions according to the number of virtual antennas and the number of mechanical movements; scanning the imaging region by the imaging device; processing the scan data of each small-aperture region in parallel to generate an image of each small-aperture region; and stitching the images of each small-aperture region together to obtain an image of the imaging region. Attached Figure Description

[0024] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the description thereof, serve to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification.

[0025] Figure 1 A schematic diagram of the structure of a MIMO beam scanning antenna according to an embodiment of the present disclosure is shown.

[0026] Figure 2 It shows the way Figure 1 A schematic diagram of a MIMO virtual antenna array formed by a transmit antenna array and a receive antenna array in an embodiment.

[0027] Figure 3 A schematic diagram of another embodiment of the MIMO beam scanning antenna is shown.

[0028] Figure 4 A schematic diagram of a MIMO virtual antenna array formed by a transmit antenna array and a receive antenna array according to an embodiment is shown.

[0029] Figure 5 A schematic diagram of a MIMO virtual antenna array formed by a transmit antenna array and a receive antenna array according to an embodiment is shown.

[0030] Figure 6 A schematic diagram of an imaging apparatus according to an embodiment of the present disclosure is shown.

[0031] Figure 7 A flowchart of an imaging method according to an embodiment of the present disclosure is shown.

[0032] Figure 8 The verification results of the MIMO beam scanning antenna, imaging device and imaging algorithm disclosed herein are shown. Detailed Implementation

[0033] The present disclosure will now be described in further detail with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present disclosure are shown in the accompanying drawings.

[0034] It should be noted that, where there is no conflict, the embodiments and features described in this disclosure can be combined with each other. The technical solutions of this disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] According to one embodiment of this disclosure, a MIMO (Multiple-Input, Multiple-Output) beam scanning antenna is provided. In the technical solution of this disclosure, the MIMO beam scanning antenna is preferably a millimeter-wave MIMO beam scanning antenna.

[0036] Figure 1 A schematic diagram of a MIMO beam scanning antenna according to an embodiment of the present disclosure is shown. Figure 1 As shown, the MIMO beam scanning antenna 100 in this embodiment may include a transmitting antenna array 110, a receiving antenna array 120, and a transceiver chip 130.

[0037] The transmitting antenna array 110 includes N multi-stub antenna elements 111, where N ≥ 2, preferably N ≥ 12. Figure 1 An example of 12 multi-stub antenna elements (shown in dashed boxes) is shown below, and some of the following descriptions will be based on this. The principle is the same or similar for other numbers of elements.

[0038] N multi-stub antenna elements 111 are arranged side-by-side along a first direction X, thus forming an antenna array along the first direction. Each multi-stub antenna element 111 may include n radiating stubs, where n ≥ 2, preferably n ≥ 4. Figure 1 The diagram illustrates an example of a multi-stub antenna element comprising four radiating stubs. Each radiating stub consists of a transmission line 112 and multiple radiating patches 113. The position and size of the radiating patches 113 can be designed according to specific requirements to achieve optimal radiation performance. Figure 1 In the example, there are 6 radiation patches.

[0039] The receiving antenna array 120 includes M single-stub antenna elements 121, where M ≥ 2, preferably M ≥ 4. Figure 1 An example with four single-stub antenna elements (shown in dashed boxes) is shown below, and some of the following descriptions will be based on this. The principle is the same or similar for other numbers of elements.

[0040] The transmitting antenna element adopts a multi-stub design, which can improve the transmitted signal gain, increase the imaging distance, and enhance the image artifact suppression capability. The receiving antenna element adopts a single-stub design, which can achieve a high-density receiving antenna element layout, thereby increasing the sampling density of the received signal (it can be closely arranged to increase the number of effective receiving sampling points per unit length) and improving the imaging resolution.

[0041] M single-stub antenna elements 121 are arranged side-by-side along a first direction X, thus forming an antenna array along the first direction. Each single-stub antenna element 121 includes one radiating stub. Each radiating stub consists of a transmission line 122 and multiple radiating patches 123. The position and size of the radiating patches 123 can be designed according to actual conditions to obtain the best radiation effect.

[0042] The transceiver chip 130 is used to provide transmit signals allocated to the transmit antenna array 110 and to receive receive signals from the receive antenna array 120. Figure 1 The diagram shows a transceiver chip 130 with 4 transmit channels 131 and 4 receive channels 132. It should be understood that transceiver chips with other numbers of transmit and receive channels can also be used, such as single-transmit / receive chip, single-transmit / multiple-receive chip, multiple-transmit / single-receive chip, or multiple-transmit / multiple-receive chip.

[0043] like Figure 1 As shown, the MIMO beam scanning antenna 100 may further include a transmit feed line 141 and a receive feed line 142. The transceiver chip 130 provides transmit signals to the transmit antenna array 110 via the transmit channel 131 and the transmit feed line 141, and receives receive signals from the receive antenna array 120 via the receive channel 132 and the receive feed line 142. According to... Figure 1 For example, the 12 multi-stub antenna elements 111 are divided into 4 groups, with each group comprising 3 multi-stub antenna elements 111. Each group corresponds to one transmit feed line 141. To control the 3 multi-stub antenna elements 111 in each group via one transmit feed line 141, the MIMO beam scanning antenna 100 may further include a switching switch 150. The switching switch 150 inputs the transmit signal to each multi-stub antenna element 111. Figure 1In the illustrated embodiment, the switching switch 150 is a 3-way switching switch, which can be a single-pole triple-throw switch. Furthermore, since each multi-stub antenna element 111 includes four radiating stubs, each multi-stub antenna element 111 can be correspondingly configured with a power divider 160. The power divider 160 distributes the transmitted signal from the switching switch 150, splitting the transmitted signal into multiple signals to be provided to the multiple radiating stubs in each multi-stub antenna element 111. Figure 1 In the example, since each multi-stub antenna element 111 includes 4 radiating stubs, each power divider is a 4-way power divider, with each way connecting to one radiating stub. The number of power dividers is N, and each power divider splits the received transmitted signal into n paths to provide to the aforementioned n radiating stubs respectively.

[0044] exist Figure 1 In the example, the receiving antenna array 120 is shown to include four stub antenna elements 121, and the transceiver chip 130 includes four receiving channels 132. Therefore, the four stub antenna elements 121 can be connected to the four receiving channels 132 through four receiving feed lines 142, so that the transceiver chip 130 can receive the received signal from the receiving antenna array 120.

[0045] Although Figure 1 The example shows a transceiver chip 130 with 4 transmit channels 131 and 4 receive channels 132. As mentioned above, other forms of transceiver chips can also be used. For example, a single-transmit, single-receive transceiver chip can be used, with N switches configured to provide the transmit signal of the transceiver chip to N multi-stub antenna elements 111, and M switches configured to provide the receive signal of M single-stub antenna elements 121 to the transceiver chip. Alternatively, a transceiver chip with N transmit channels and M (or more) receive channels can be used. In this way, each transmit channel is connected to one multi-stub antenna element, and each receive channel is connected to one single-stub antenna element. Those skilled in the art will understand that various forms can be implemented using transceiver chips with a suitable number of channels, switch arrays (switches) with a suitable number of channels, etc., which will not be elaborated here. In the case of using a single transceiver chip, the number of switches is equal to the number of transmit channels of the transceiver chip. The switches are used to selectively provide the transmit signal received from the transmit channels of the transceiver chip to m power dividers, where 2≤m≤N.

[0046] In the technical solution disclosed herein, the transmitting antenna array 110 and the receiving antenna array 120 are arranged in the same plane. The transmitting antenna array 110 transmits a scanning beam towards the front of the plane, and the receiving antenna array 120 receives the reflected beam. N first multi-stub antenna elements are arranged side by side to form a first row of antennas, and M first single-stub antenna elements are arranged side by side to form a second row of antennas. The first row of antennas and the second row of antennas are spaced apart, for example, by a predetermined distance in the second direction Y (which forms an angle with the first direction X, and may be equal to or not equal to 90 degrees). Other components of the MIMO beam scanning antenna may or may not be arranged in this plane. According to the arrangement of the transmitting antenna array 110 and the receiving antenna array 120 of this application, the MIMO beam scanning antenna can be called a parallel MIMO beam scanning antenna, that is, the first row of antennas and the second row of antennas are arranged in parallel.

[0047] According to a further embodiment, the MIMO beam scanning antenna 100 may also include a beam control module 170 and a target sensing module 180.

[0048] The beam control module 170 selectively controls the switching of the transmit and receive channels of the transceiver chip and selectively controls the switching of the switching switch to control the beam scanning switching of the transmit antenna array and the receive antenna array. The beam control module 170 is connected to the transceiver chip 130 and is used for beam scanning switching control of the transmit antenna array 110 and the receive antenna array 120. The beam control module 170 controls the operating time of the N multi-stub antenna elements 111 of the transmit antenna array 110 and the M single-stub antenna elements 121 of the receive antenna array 120, realizing a MIMO virtual antenna array. The beam control module 170 can be implemented using a microcontroller or an FPGA. Additionally, the beam control module 170 is connected to the switching switch 150 to control the transmit signals of the three multi-stub antenna elements 111 in each group of antenna elements.

[0049] The control process of the beam control module 170 is as follows. The beam control module 170 provides a first control signal to the transceiver chip 130. The transceiver chip 130 transmits the signal through its first transmit channel (…). Figure 1 The first channel from the left in the middle will provide the transmission signal to the first switch 150 ( Figure 1The first element from the left in the middle section provides a transmit signal to each multi-stub antenna element in the first group of antenna elements. Additionally, the beam control module 170 can provide a switch control signal to the first switching switch, which switches the transmit signal provided to each multi-stub antenna element, controlling each multi-stub antenna element to transmit the scanning beam sequentially. Simultaneously, the receiving antenna array 120 receives the reflected signal from the scanning beam and provides it to the transceiver chip 130. The beam control module 170 continues the above operation, and by adjusting the transmit channel of the transceiver chip 130 and the selection of the switching switch, N multi-stub antenna elements can be scanned sequentially until all multi-stub antenna elements have completed transmitting the scanning beam. Simultaneously, the M single-stub antenna elements of the receiving antenna array receive the reflected signal from the scanning beam.

[0050] The target perception module 180 senses the distance and shape information of the imaging target and transmits this information to the beam control module 170. The beam control module 170 modifies the number of beam scans, the scan cycle, and the scan time based on the target's distance and shape information to achieve the best imaging effect. For example, the target perception module 180 can identify the target and select an appropriate beam scanning area as needed. As an example, during security checks, scanning of the target's privacy areas can be avoided, thus protecting privacy. The target perception module can consist of multiple distance detection sensors, which can obtain the distance and shape of the imaging target through the mechanical movement of the imaging device described below. Furthermore, adding the acquired target distance information to the imaging algorithm reduces algorithm computation time; it also corrects the measurement time of the transmitting and receiving antennas and the position of the imaging focal plane, improving imaging quality. Additionally, using the target shape information, the beam scanning module can control the beam scanning density at different locations, achieving high-precision imaging of key security areas and low-precision imaging of non-key areas, thus obtaining the optimal imaging effect in the shortest time. The beam control module 170 controls the power supply network (such as the power supply line and switch array) and the transceiver chip 130 to switch the transmission channel based on the data collected by the target sensing module 180. The transceiver chip outputs the transmission signal to the power supply network, so that the transmission beam is radiated out from each multi-stub antenna element in sequence. After being reflected by the imaging target, the reflected signal is transmitted to the transceiver chip by the receiving antenna array.

[0051] Figure 1 In this embodiment, the transmitting and receiving antennas are arranged in parallel to form a virtual antenna array. This arrangement has the advantage of maximizing the number of antennas, for example... Figure 2As shown, a 12×4 beamwidth (48 beamwidths) MIMO antenna array can be obtained through the arrangement method disclosed herein. When the number of multi-stub antenna elements (transmit antenna array) is N and the number of single-stub antenna elements (receive antenna array) is M, an N×M beamwidth MIMO antenna array can be obtained. To achieve higher imaging resolution, a larger number of antennas can be arranged, while to achieve lower imaging resolution, a smaller number of antennas can be arranged. The MIMO beam scanning antenna disclosed herein has advantages such as ease of expansion and can achieve the desired imaging resolution.

[0052] Figure 2 It shows the way Figure 1 A schematic diagram of a MIMO virtual antenna array formed by a transmit antenna array and a receive antenna array in an embodiment. According to... Figure 1 The arrangement of the embodiments will form Figure 2 The MIMO virtual antenna array shown is illustrated. For ease of explanation, reference will be made to... Figure 2 Come to Figure 1 The configuration of the MIMO virtual antenna array in the embodiment is further explained. Each multi-stub antenna element 111 in the transmitting antenna array 110 and each single-stub antenna element 121 in the receiving antenna array 120 constitute a virtual antenna. Thus, N multi-stub antenna elements 111 and M single-stub antenna elements 121 form N×M virtual antennas, thereby constituting the MIMO virtual antenna array.

[0053] exist Figure 1 and Figure 2 In this embodiment, the spacing between adjacent multi-stub antenna elements 111 in the transmitting antenna array 110 is set to D1. The spacing between adjacent single-stub antenna elements 121 in the receiving antenna array 120 is set to D2. The relationship between the spacing D1 between multi-stub antenna elements and the spacing D2 between single-stub antenna elements is set to D1 = M × D2, where M is the number of single-stub antenna elements. Through this configuration, a virtual antenna array with a fixed period can be obtained. A virtual antenna array with a fixed period means that the spacing D3 between each virtual antenna is fixed. Thus, according to the arrangement of this disclosure, not only can the desired imaging resolution be obtained, but it can also ensure that each scanning beam forms a fixed resolution (the spacing D3 between virtual antennas remains unchanged).

[0054] Another embodiment of a MIMO beam scanning antenna is also provided in this disclosure. Figure 3A schematic diagram of another embodiment of a MIMO beam scanning antenna is shown. In this embodiment, a complementary transmit / receive antenna array is provided. Specifically, two sets of transmit / receive antennas are alternately arranged to achieve a complementary antenna array. Thus, the MIMO beam scanning antenna according to this embodiment further has the advantages of small size and cascadability. The following will refer to… Figures 3 to 5 The MIMO beam scanning antenna of this embodiment will be described in detail.

[0055] like Figure 3 As shown, the complementary MIMO beam scanning antenna includes a first set of MIMO beam scanning antennas 1000 and a second set of MIMO beam scanning antennas 2000. The specific details of the first set of MIMO beam scanning antennas 1000 and the second set of MIMO beam scanning antennas 2000 are respectively... Figure 1 The implementation method is the same. A brief description of the two sets of MIMO beam scanning antennas will follow; any content not described herein can be found by referring to... Figure 1 The corresponding content in the embodiments.

[0056] The first MIMO beam scanning antenna 1000 includes a first transmitting antenna array 1010, a first receiving antenna array 1020, and a first transceiver chip 1030. The first transmitting antenna array 1010 includes N first multi-stub antenna elements 1011, where N ≥ 2. The N first multi-stub antenna elements 1011 are arranged side-by-side along a first direction X. Each first multi-stub antenna element 1011 may include n radiating stubs, where n ≥ 2, preferably n ≥ 4. The first receiving antenna array 1020 includes M first single-stub antenna elements 1021, where M ≥ 2, preferably M ≥ 4. The M first single-stub antenna elements 1021 are arranged side-by-side along the first direction X. The antenna array formed by the N first multi-stub antenna elements 1011 and the antenna array formed by the M first single-stub antenna elements 1021 are spaced apart in a second direction Y. The first transceiver chip 1030 is used to provide the transmitted signal allocated to the first transmitting antenna array 1010 and to receive the received signal from the first receiving antenna array 1020.

[0057] The first MIMO beam scanning antenna 1000 may further include a first transmit feed line 1041 and a first receive feed line 1042. A first transceiver chip 1030 provides transmit signals to the first transmit antenna array 1010 via the first transmit channel 1031 and the first transmit feed line 1041, and receives receive signals from the first receive antenna array 1020 via the first receive channel 1032 and the first receive feed line 1042. The first MIMO beam scanning antenna 1000 may further include a first switching switch 1050. The first switching switch 1050 inputs the first transmit signal to the first multi-stub antenna element 1011. Each first multi-stub antenna element 1011 may be correspondingly configured with a first power divider 1060. The first power divider 1060 distributes the first transmit signal from the first switching switch 1050, dividing the first transmit signal into multiple signals to be provided to multiple radiating stubs in each first multi-stub antenna element 1011.

[0058] The first MIMO beam scanning antenna 1000 may also include a first beam control module 1070 and a first target sensing module 1080. See the description above for details, which will not be repeated here.

[0059] The second MIMO beam scanning antenna 2000 includes a second transmit antenna array 2010, a second receive antenna array 2020, and a second transceiver chip 2030. The second transmit antenna array 2010 includes N second multi-stub antenna elements 2011, where N ≥ 2. The N second multi-stub antenna elements 2011 are arranged side-by-side along a second direction X. Each second multi-stub antenna element 2011 may include n radiating stubs, where n ≥ 2, preferably n ≥ 4. The second receive antenna array 2020 includes M second single-stub antenna elements 2021, where M ≥ 2, preferably M ≥ 4. The M second single-stub antenna elements 2021 are arranged side-by-side along a first direction X. The antenna array formed by the N second multi-stub antenna elements 2011 and the antenna array formed by the M second single-stub antenna elements 2021 are spaced apart in a second direction Y. The second transceiver chip 2030 is used to provide transmit signals allocated to the second transmit antenna array 2010 and to receive receive signals from the second receive antenna array 2020.

[0060] The second MIMO beam scanning antenna 2000 may further include a second transmit feed line 2041 and a second receive feed line 2042. The second transceiver chip 2030 provides transmit signals to the second transmit antenna array 2010 via the second transmit channel 2031 and the second transmit feed line 2041, and receives receive signals from the second receive antenna array 2020 via the second receive channel 2032 and the second receive feed line 2042. The second MIMO beam scanning antenna 2000 may further include a second switching switch 2050. The second transmit signal is input to the second multi-stub antenna element 2011 via the second switching switch 2050. Each second multi-stub antenna element 2011 may be correspondingly configured with a second power divider 2060. The second power divider 2060 distributes the second transmit signal from the second switching switch 2050, dividing the second transmit signal into multiple signals to be provided to multiple radiating stubs in each second multi-stub antenna element 2011.

[0061] The second MIMO beam scanning antenna 2000 may also include a second beam control module 2070 and a second target sensing module 2080. See the description above for details, which will not be repeated here.

[0062] like Figure 3 As shown, in this embodiment, N first multi-stub antenna elements 1011 of the first transmitting antenna array 1010 are arranged side-by-side along the first direction X to form a first row of antennas. Simultaneously, M second single-stub antenna elements 2021 of the second receiving antenna array 2020 are arranged side-by-side with the N first multi-stub antenna elements 1011 of the first transmitting antenna array 1010 along the first direction X, forming part of the first row of antennas. The M first single-stub antenna elements 1021 of the first transmitting antenna array 1010 are arranged side-by-side along the first direction X to form a second row of antennas. Simultaneously, N second multi-stub antenna elements 2011 of the second receiving antenna array 2020 are arranged side-by-side with the M first single-stub antenna elements 1021 of the first transmitting antenna array 1010 along the first direction X, forming part of the second row of antennas. The first row of antennas and the second row of antennas are spaced apart in a second direction at an angle to the first direction X.

[0063] Figure 4 and Figure 5Schematic diagrams of MIMO virtual antenna arrays formed by transmit antenna arrays and receive antenna arrays in different embodiments are shown. Each first multi-stub antenna element 1011 of the first transmit antenna array 1010 and each first single-stub antenna element 1021 in the first receive antenna array 1020 constitute a virtual antenna. Each second multi-stub antenna element 2011 of the second transmit antenna array 2010 and each second single-stub antenna element 2021 in the second receive antenna array 2020 constitute a virtual antenna. Thus, N first multi-stub antenna elements 1011 and M first single-stub antenna elements 1021, and N second multi-stub antenna elements 2011 and M second single-stub antenna elements 2021 constitute 2×N×M virtual antennas, thereby forming... Figure 4 and Figure 5 The MIMO virtual antenna array of the embodiment.

[0064] exist Figure 4 In one embodiment, the first row of antennas and the second row of antennas are spaced apart in a second direction Y at a 90° angle to the first direction X. The first transmitting antenna array 1010, the first receiving antenna array 1020, the second transmitting antenna array 2010, and the second receiving antenna array 2020 are arranged in the same plane.

[0065] The spacing between adjacent first multi-stub antenna elements 1011 in the first transmitting antenna array 1010 is set to D1, and the spacing between adjacent second multi-stub antenna elements 2011 in the second transmitting antenna array 2010 is set to D1. The relationship between the spacing D1 between the first multi-stub antenna elements 1011 in the first transmitting antenna array 1010 and the spacing D2 between the first single-stub antenna elements 1021 in the first transmitting antenna array 1010 is set to D1 = M × D2. The relationship between the spacing D1 between the second multi-stub antenna elements 2011 in the second transmitting antenna array 2010 and the spacing D2 between the second single-stub antenna elements 2021 in the second transmitting antenna array 2010 is set to D1 = M × D2. Furthermore, the spacing between the first multi-stub antenna elements 1011 in the first transmitting antenna array 1010 and the second single-stub antenna elements 2021 in the second transmitting antenna array 2010 is D4. Here, D4 ​​refers to the spacing between adjacent first multi-stub antenna elements 1011 and second single-stub antenna elements 2021. The spacing between the first single-stub antenna element 1021 in the first transmitting antenna array 1010 and the second multi-stub antenna element 2011 in the second transmitting antenna array 2010 is D4. Here, D4 ​​refers to the spacing between adjacent second single-stub antenna elements 1021 and second multi-stub antenna elements 2011. Through the above arrangement, the spacing D3 between any two adjacent virtual antennas in the virtual antenna array formed by the first group of MIMO beam scanning antennas 1000 and the second group of MIMO beam scanning antennas 2000 is fixed.

[0066] Figure 5 Another embodiment of a complementary MIMO beam scanning antenna is shown, with Figure 4 The difference in the embodiments lies in the fact that the first row of antennas and the second row of antennas are spaced apart in a second direction Y that is not 90° from the first direction X. Other details can be found in the description above and will not be repeated here. Figure 4 and Figure 5 As can be seen from the embodiments, as long as the first row of antennas and the second row of antennas are spaced apart in the second direction Y, the spacing D3 between the virtual antennas can remain unchanged.

[0067] according to Figure 4 and Figure 5 A specific example is that 96 consecutive scanning beams can be achieved using two complementary 12(N)×4(M) antenna arrays, with a beam resolution half the spacing D2 between single-stub antenna elements. Moreover, regardless of... Figure 1 The embodiments are still Figure 3 The embodiments all have good scalability; for example, two MIMO beam scanning antennas can be cascaded. Figure 1 In the embodiments, 96 scanning beams can be achieved. Figure 3 In the embodiments, a scanning beam of 192 can be achieved. Alternatively, for a single MIMO beam scanning antenna, multiple stub antenna elements of the transmit antenna array and single stub antenna elements of the receive antenna array can be added to achieve more scanning beams, for example, for... Figure 3 In one embodiment, 192 consecutive scanning beams can be achieved through two complementary 24(N)×8(M) antenna arrays.

[0068] In the technical solution disclosed herein, the spacing between the M single-stub antenna elements (including the first single-stub antenna element and the second single-stub antenna element) is set to be greater than or equal to λ / 2, where λ is the wavelength of the transmitted signal (including the first transmitted signal and the second transmitted signal). This ensures lower mutual coupling, higher reliability, and manufacturability.

[0069] Additionally, it should be noted that although the first direction is shown as horizontal in the attached diagram, it can also be other directions. For example, the first direction X can be vertical in the attached diagram. Therefore, the meaning of the first row and second row of antennas mentioned above is not the usual meaning of "row" (arranged horizontally), but should also cover other situations, such as the usual meaning of "column" (arranged vertically).

[0070] According to the technical solution disclosed herein, the MIMO beam scanning antenna can be a millimeter-wave beam scanning antenna, and the transceiver chip can be a transceiver chip operating in the 77~81GHz frequency band.

[0071] According to further embodiments of this disclosure, an imaging device is also provided. This imaging device can be applied in suitable fields such as security inspection, industrial inspection, intelligent transportation, and medical inspection. The following detailed description will use security inspection as an example; for applications in other fields, the same principle and structure can be used.

[0072] Figure 6 A schematic diagram of an imaging device 10 according to an embodiment of the present disclosure is shown. The imaging device 10 may include the MIMO beam scanning antenna described above. As an example, the imaging device 10 is used to achieve an imaging resolution of 5.2 mm and an imaging field of view (imaging area) of 1 m wide × 2 m high. Therefore, the imaging device 10 may include two such... Figure 3The MIMO beam scanning antenna described in this embodiment consists of two horizontally arranged MIMO beam scanning antennas. These two antennas will achieve 192 (2×96) horizontal scanning beams, covering a width of approximately 5.2mm × 192 ≈ 1m. Using a mechanical control device, the MIMO beam scanning antennas move vertically by 385 points, each spaced 5.2mm apart. This results in a horizontal coverage height of approximately 5.2mm × 385 ≈ 2m. For imaging fields of other sizes, the MIMO beam scanning antennas and their vertical movement can be adjusted according to the actual situation. See below for reference. Figure 6 The imaging device 10 is described below.

[0073] Imaging device 10 may include a beam scanning module 11. The beam scanning module 11 is equipped with a MIMO beam scanning antenna. The MIMO beam scanning antenna is arranged horizontally. Imaging device 10 also includes a moving track 12. The beam scanning module 11 is controlled to move vertically along the moving track 12. At each moving point, the MIMO beam scanning antenna scans the imaging target once (as shown by the dashed line). The movement of the beam scanning module 11 can be controlled by a mechanical control module, which can be configured by those skilled in the art according to the actual situation. Imaging device 10 may also include a data processing module 13 and a display module 14. The data processing module 13 is used to run imaging algorithms to generate images based on the transmitted and received signals from the MIMO beam scanning antenna. The display module 14 is used to display the final imaging image.

[0074] To achieve the required resolution and imaging area, the spacing D2 of the single-stub antenna elements in the receiving antenna array is 5.2 mm. The spacing D1 of the multi-stub antenna elements in the transmitting antenna array is 4 × 5.2 mm. A mechanical control module drives the vertical movement of the beam scanning module (two 96-beam MIMO beam scanning antennas). By controlling the beam scanning module to move vertically 385 times in one cycle, with each movement interval of 5.2 mm, transmitting and receiving 192 beams each time, a 192 × 385 beam scan is achieved in one cycle. By combining this horizontal electronic beam scanning and vertical mechanical beam scanning structure, a total imaging field of view of approximately 1 × 2 m is covered in one cycle.

[0075] The millimeter-wave imaging time is primarily determined by the modulation period of the millimeter-wave signal generated by the transceiver chip. For example, the AWR2944 transceiver chip from TI (Texas Instruments) has four transmit channels and four receive channels, with a signal modulation period of 160µs. Therefore, the minimum switching time for each beam is 160µs. Since each MIMO beam scanning antenna has 12 transmit signals, the four receive channels of the millimeter-wave transceiver chip can operate simultaneously. Each MIMO beam scanning antenna can also operate in parallel. Therefore, the horizontal scanning time is 160 × 12µs. Simultaneously, because the mechanical beam scanning switching time must be greater than or equal to the total horizontal electronic beam scanning time, the scanning imaging time of the imaging device 10 using the AWR2944 transceiver chip is: 160µs × 12 × 400 = 0.768s.

[0076] It should be noted that, although in Figure 6 In one embodiment, the MIMO beam scanning antenna is arranged horizontally, and the mechanical control module moves the MIMO beam scanning antenna vertically. However, the MIMO beam scanning antenna can also be arranged vertically, and the mechanical control module moves the MIMO beam scanning antenna horizontally. This also achieves an imaging field of view of 2m × 1m. Furthermore, other orientations can be used depending on the needs of the imaging field of view. In summary, the MIMO beam scanning antenna performs scanning in one direction, and the mechanical control module controls the movement of the MIMO beam scanning antenna to perform scanning in another direction, with this first direction being perpendicular to the second.

[0077] In addition, depending on the imaging field of view requirements, the number of MIMO beam scanning antennas, the number of transmitting antenna arrays and receiving antenna arrays can be increased or decreased, and the number of mechanical control movements can be increased or decreased.

[0078] According to a further embodiment of this disclosure, an imaging method for the above-described imaging apparatus is provided. Figure 7 A flowchart of an imaging method M700 according to an embodiment of the present disclosure is shown. The imaging method M700 may include steps S710 to S740.

[0079] In step S710, the imaging area is divided into multiple small-aperture regions based on the number of beams (the number of virtual antennas) that the MIMO beam scanning antenna can generate and the number of mechanical movements.

[0080] For example in Figure 6In this embodiment, the 192 beams are divided into several groups of 32 beams each (limited to the range of 20-50) in the horizontal direction. This divides the 192 beams into 6 columns (192 ÷ 32) in the horizontal direction. In the vertical direction, the 385 scans are divided into several segments of 35 scans each (limited to the range of 20-50). This divides the 385 scans into 11 rows (385 ÷ 35) in the vertical direction. Ultimately, the imaging area is divided into 66 (6 columns × 11 rows) small-aperture regions.

[0081] In step S720, the imaging area is scanned by an imaging device.

[0082] In step S730, the scan data of each small-aperture region is processed in parallel to image each small-aperture region. That is, the scan data of each small-aperture region can be calculated simultaneously to generate an image of each small-aperture region.

[0083] In step S740, the images of each small-aperture region are stitched together to obtain the image of the entire imaging region. This process can employ noise reduction and spatial filtering techniques.

[0084] Finally, the inventors of this application have conducted corresponding verifications of the MIMO beam scanning antenna, imaging device, and imaging algorithm of this application, for example, see [link to relevant documentation]. Figure 8 Due to the large aperture of the multi-segment antenna, there are no obvious artifacts. The imaging algorithm based on aperture stitching and the hardware-software parallel architecture integrating multiple MIMO beam scanning antennas significantly improve the imaging rate and provide excellent perspective imaging of the target.

[0085] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., refer to specific features, structures, or characteristics described in connection with that embodiment / mode or example, which are included in at least one embodiment / mode or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0086] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0087] Those skilled in the art should understand that the above embodiments are merely for illustrating the present disclosure and are not intended to limit the scope of the disclosure. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present disclosure.

Claims

1. A MIMO beam scanning antenna for scanning an imaging target, characterized in that, include: The transmitting antenna array comprises N multi-stub antenna elements with a spacing of D1, where N≥2; The receiving antenna array comprises M single-stub antenna elements spaced at a distance of D2, where M ≥ 2 and D1 = M × D2; A transceiver chip is used to provide transmit signals allocated to the transmit antenna array and to receive receive signals from the receive antenna array; The N multi-stub antenna elements are arranged side-by-side in a first direction, and the M single-stub antenna elements are also arranged side-by-side in the first direction. The N multi-stub antenna elements and the M single-stub antenna elements are arranged side-by-side in the same plane and are spaced apart in a second direction different from the first direction. Each multi-stub antenna element and each single-stub antenna element constitute a virtual antenna. In the N×M virtual antennas composed of the N multi-stub antenna elements and the M single-stub antenna elements, the spacing D3 between adjacent virtual antennas is fixed at D2 / 2, where D2≥λ / 2, and λ is the wavelength of the transmitted signal.

2. The MIMO beam scanning antenna as described in claim 1, characterized in that, The multi-stub antenna element includes n radiating stubs, where n≥2, and the single-stub antenna element includes 1 radiating stub, each radiating stub consisting of a transmission line segment and multiple radiating patches.

3. The MIMO beam scanning antenna as described in claim 2, characterized in that, It also includes power dividers, of which there are N power dividers, each of which splits the received transmitted signal into n paths to provide to the n radiating branches respectively.

4. The MIMO beam scanning antenna as described in claim 3, characterized in that, It also includes switching switches, the number of which is equal to the number of transmit channels of the transceiver chip. The switching switches are used to selectively provide the transmit signals received from the transmit channels to m power dividers, where 2≤m≤N.

5. The MIMO beam scanning antenna as described in claim 4, characterized in that, It also includes a beam control module, which selectively controls the switching of the transmit and receive channels of the transceiver chip and selectively controls the switching of the switching switch to control the beam scanning switching of the transmit antenna array and the receive antenna array.

6. The MIMO beam scanning antenna as described in claim 5, characterized in that, It also includes a target perception module, which is used to perceive the distance information and shape information of the imaging target. The beam control module can change at least one of the number of scanning beams, scanning period and scanning time according to the distance information and shape information.

7. The MIMO beam scanning antenna as described in claim 4, characterized in that, The transmitting antenna array includes a first transmitting antenna array and a second transmitting antenna array; the receiving antenna array includes a first receiving antenna array and a second receiving antenna array; the transceiver chip includes a first transceiver chip and a second transceiver chip; the first transmitting antenna array includes N first multi-stub antenna elements and the second transmitting antenna array includes N second multi-stub antenna elements; the first receiving antenna array includes M first single-stub antenna elements and the second receiving antenna array includes M second single-stub antenna elements. In this configuration, the N first multi-stub antenna elements and the M second single-stub antenna elements are arranged side-by-side in the first direction, and the M first single-stub antenna elements and the N second multi-stub antenna elements are also arranged side-by-side in the first direction. Each first multi-stub antenna element and each first single-stub antenna element constitute a virtual antenna, and each second multi-stub antenna element and each second single-stub antenna element constitute a virtual antenna. In the 2×N×M virtual antennas formed by the N first multi-stub antenna elements, the M first single-stub antenna elements, and the N second multi-stub antenna elements and the M second single-stub antenna elements, the spacing D3 between adjacent virtual antennas is fixed at D2 / 2.

8. The MIMO beam scanning antenna as described in claim 7, characterized in that, In the N first multi-stub antenna elements and M second single-stub antenna elements arranged side by side, the spacing D4 between adjacent first multi-stub antenna elements and second single-stub antenna elements is D2 / 2. In the M first single-stub antenna elements and the N second multi-stub antenna elements arranged side by side, the spacing D4 between adjacent first single-stub antenna elements and second multi-stub antenna elements is D2 / 2.

9. An imaging device, characterized in that, include: A beam scanning module, wherein the beam scanning module is equipped with a MIMO beam scanning antenna as described in any one of claims 1 to 8, wherein the number of MIMO beam scanning antennas is one or two or more, wherein the MIMO beam scanning antennas are used to achieve beam scanning in one direction; A mechanical control device controls the beam scanning module to make mechanical movement in another direction to achieve mechanical scanning in the other direction, wherein one direction is perpendicular to the other direction, and the scanning areas of the beam scanning and mechanical scanning cover the imaging area of ​​the imaging target.

10. An imaging method for the imaging apparatus of claim 9, characterized in that, include: The imaging area is divided into multiple small-aperture regions based on the number of virtual antennas and the number of mechanical movements. The imaging area is scanned using the imaging device. The scan data for each small-aperture region are processed in parallel to generate an image for each small-aperture region; as well as The image of the imaging region is obtained by stitching together the images of each small-aperture region.

Images