Antenna array and radar device

Abstract

Provided is technology for efficiently improving angular resolution through arrangement of an antenna array and signal processing.　The present technology provides an antenna array comprising N (N being 4 or more) antenna elements that are arranged side by side in a straight line. The interval between each of the antenna elements is an integer multiple of the shortest interval. The relative arrangement position \{uk\} (0 = u1 < u2 <... < uN) of each of the antenna elements is the solution of formula (1) defined as a maximization problem for maximizing the aperture length A.

Description

Antenna arrays and radar equipment

[0001] The technology disclosed herein (hereinafter also referred to as "this technology") relates to antenna arrays and radar equipment.

[0002] Conventionally, MIMO (Multiple-Input Multiple-Output) technology, which uses a transmitting antenna and a receiving antenna, has been widely used in FMCW radar systems. In this technology, the transmitting antenna array and the receiving antenna array are arranged linearly, and the signals transmitted from each antenna element are controlled using methods such as time-division multiplexing (TDM) or code-division multiplexing (CDMA), thereby virtually increasing the number of antenna elements and improving angular resolution.

[0003] For example, Patent Document 1 discloses a technique for achieving the performance of a large-aperture antenna array even with a small number of antenna elements.

[0004] Japanese Patent Publication No. 2019-71529

[0005] However, since Patent Document 1 does not describe a specific configuration for obtaining a large aperture length, it is difficult to realize.

[0006] Therefore, the primary objective of this technology is to provide a technique that efficiently improves angular resolution through antenna array arrangement and signal processing.

[0007] This technology comprises N (where N is 4 or more) antenna elements arranged in a straight line, the spacing between each of the antenna elements is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements is {u ｋ} (0 = u １ <u ２ <...<u Ｎ The present invention provides an antenna array in which the given value is the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A. Furthermore, the present technology provides a radar device including a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array. In the radar device, both the transmitting antenna array and the receiving antenna array may be the antenna array. The radar device includes a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array, and the transmitting antenna array and the receiving antenna array may be arranged parallel to each other. Among the transmitting antenna array and the receiving antenna array, the interval between the antenna elements of the antenna array with fewer antenna elements may be an integer multiple of the interval between the antenna elements of the antenna array with more antenna elements. Also, the present technology provides an antenna array in which a plurality of antenna elements are arranged in a square shape. The square has a pair of opposing sides along a first direction and a pair of opposing sides along a second direction orthogonal to the first direction. The antenna array includes a plurality of antenna arrays in which a plurality of the antenna elements are arranged linearly along the first direction. In at least one of the plurality of antenna arrays, the interval between each of the antenna elements is an integer multiple of the shortest interval, and the relative arrangement positions {u ｋ} (0 = u １ < u ２ <... < u Ｎ ) of each of the antenna elements are solutions of the following mathematical formula (1) defined as a maximization problem for maximizing the aperture length A. In all of the plurality of antenna arrays, the interval between each of the antenna elements is an integer multiple of the shortest interval, and the relative arrangement positions {u ｋ} (0 = u １ < u ２ <... < u Ｎ) may be the solution to equation (1) defined as a maximization problem for maximizing the aperture length A. The technology also provides a radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array. The radar device comprises a transmitting antenna array and a receiving antenna array, wherein both the transmitting antenna array and the receiving antenna array may be the antenna array. The radar device comprises a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array, and the first direction of the transmitting antenna array and the first direction of the receiving antenna array may be arranged parallel to each other. The spacing of the antenna elements in the antenna array with fewer antenna elements may be an integer multiple of the spacing of the antenna elements in the antenna array with more antenna elements. Furthermore, this technology is an antenna array in which a plurality of antenna elements are arranged in a rectangular shape, wherein the rectangle has a pair of opposing sides along a first direction and a pair of opposing sides along a second direction perpendicular to the first direction, and comprises a plurality of first antenna arrays including a plurality of antenna elements arranged linearly along the first direction, and a plurality of second antenna arrays including a plurality of antenna elements arranged linearly along the second direction, wherein in both the plurality of first antenna arrays and the plurality of second antenna arrays, the spacing between each of the antenna elements in at least one antenna array is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements in at least one antenna array {u ｋ} (0 = u １ <u ２ <...<u Ｎ The present invention provides an antenna array in which the given value is the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A. In all of the above-mentioned antenna arrays, the spacing between each antenna element is an integer multiple of the shortest spacing, and the relative arrangement position of each antenna element {u ｋ} (0 = u １ <u ２ <...<u Ｎ) may be the solution to formula (1) defined as a maximization problem for maximizing the aperture length A. The technology also provides a radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array. The radar device comprises a transmitting antenna array and a receiving antenna array, wherein both the transmitting antenna array and the receiving antenna array may be the antenna array. The radar device comprises a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array, and the first direction of the transmitting antenna array and the first direction of the receiving antenna array may be arranged parallel to each other. In the first direction, the spacing of the antenna elements in the antenna array with fewer antenna elements may be an integer multiple of the spacing of the antenna elements in the antenna array with more antenna elements. The second direction of the transmitting antenna array and the second direction of the receiving antenna array may be arranged parallel to each other. In the second direction, the spacing between the antenna elements of the antenna array with fewer antenna elements among the transmitting antenna array and the receiving antenna array may be an integer multiple of the spacing between the antenna elements of the antenna array with more antenna elements. The antenna array comprises at least a first group of antenna elements corresponding to a first polarization and a second group of antenna elements corresponding to a second polarization different from the first polarization, and at least one of the first group of antenna elements and the second group of antenna elements may have the configuration of the antenna array.Furthermore, the present technology provides a radar device comprising: a transmitting antenna array; a receiving antenna array; and a signal processing unit for processing signals received by the receiving antenna array, wherein the transmitting antenna array is configured to transmit a transmission signal having a first circular polarization; the receiving antenna array includes a first group of receiving antenna elements that receive the same circular polarization as the first circular polarization and a second group of receiving antenna elements that receive a second circular polarization orthogonal to the first circular polarization; at least one of the transmitting antenna array, the first group of receiving antenna elements, and the second group of receiving antenna elements has the configuration of the antenna array described in claim 1; and the signal processing unit is configured to distinguish between a single reflection of the transmission signal and two or more reflections of the transmission signal based on the characteristic difference between the signal from the first group of receiving antenna elements and the signal from the second group of receiving antenna elements. Each of the first group of receiving antenna elements and the second group of receiving antenna elements may have the configuration of the antenna array. The signal processing unit may be configured to calculate at least one of the distance difference and angular difference between the distinguished single reflected wave and the two or more reflected waves. The signal processing unit may be configured to estimate at least one of the relative positional relationship between the target object and other objects, the presence or proximity of obstacles near the target object, and the size of the space, based on at least one of the calculated distance difference and angular difference. The radar device may further include a calculation unit configured to estimate vital information of a human body based on signals received by the receiving antenna array. The vital information may include at least one of respiration and heart rate. The calculation unit may be configured to estimate the vital information by detecting minute phase fluctuations contained in the received signal. The radar device may further include a control unit configured to output a control signal for controlling the operation of an external device based on the positional information of the detected target object, or at least one of the estimated relative positional relationship, proximity, and size of the space. The external device may include an acoustic device.The number of antenna elements constituting the first receiving antenna element group may be different from the number of antenna elements constituting the second receiving antenna element group. At least a portion of the antenna elements constituting the first receiving antenna element group and at least a portion of the antenna elements constituting the second receiving antenna element group may be arranged in a spatially overlapping manner. The transmitting antenna array may include a first transmitting antenna element group having the first circular polarization and a second transmitting antenna element group having the second circular polarization.

[0008] According to this technology, angular resolution can be efficiently improved by arranging the antenna array and processing the signals. The effects described herein are not necessarily limited to those described herein and may include any of the effects described herein.

[0009] This is a schematic diagram showing an example of antenna array arrangement. This is a schematic diagram showing an example of antenna array arrangement. This is a schematic diagram showing an example of antenna array arrangement. This is a matrix showing the positions of antenna elements extended by an additive array. This is a matrix showing the positions of antenna elements extended by an additive array. This is a schematic diagram showing an example of antenna array arrangement. This is a graph showing the effects of this technology. This is a schematic diagram showing an example of antenna array arrangement. This is a schematic diagram showing an example of antenna array arrangement. This is a matrix showing the positions of antenna elements extended by an additive array. This is a table showing an example of antenna array arrangement according to one embodiment of this technology. This is a table showing an example of antenna array arrangement according to one embodiment of this technology. This is a map showing an example of antenna array arrangement according to one embodiment of this technology. This is a block diagram showing an example of the configuration of a radar device 100 according to one embodiment of this technology. This is a flowchart showing an example of the signal processing flow of a radar device 100 according to one embodiment of this technology. This is a schematic diagram showing an example of antenna array arrangement according to one embodiment of this technology. This is a table showing an example of antenna array arrangement according to one embodiment of this technology. This is a matrix showing an example of the arrangement of an antenna array according to one embodiment of this technology. This is a table showing an example of the arrangement of an antenna array according to one embodiment of this technology. This is a table showing an example of the arrangement of an antenna array according to one embodiment of this technology. This is a table showing an example of the arrangement of an antenna array according to one embodiment of this technology. This is a table showing an example of the arrangement of an antenna array according to one embodiment of this technology. This is a table showing an example of the arrangement of an antenna array according to one embodiment of this technology. This is a table showing an example of the arrangement of an antenna array according to one embodiment of this technology. This is a table showing an example of the arrangement of an antenna array according to one embodiment of this technology. This is a matrix showing the aperture length of the antenna array. This is a matrix showing the aperture length of the antenna array. This is a graph showing the effects of this technology.This is a schematic diagram showing an example of antenna array arrangement according to one embodiment of this technology. This is a schematic diagram showing an example of antenna array arrangement according to one embodiment of this technology. This is a schematic diagram showing an example of antenna array arrangement. This is a schematic diagram showing an example of antenna array arrangement. Figure 37A is a schematic diagram showing an example of antenna array arrangement according to one embodiment of this technology. Figure 37B is an excerpt of a part of the table shown in Figure 21. Figure 38A is a schematic diagram showing an example of antenna array arrangement according to one embodiment of this technology. Figure 38B is an excerpt of a part of the table shown in Figure 21. This is a schematic diagram showing an example of antenna array arrangement according to one embodiment of this technology. This is a schematic diagram for explaining the problems in conventional radar systems. This is a schematic diagram for explaining the principle of reflected wave separation in a multipath environment in a radar system according to one embodiment of this technology. This is a block diagram showing an example of the configuration of a radar system 100 according to one embodiment of this technology. This is a schematic diagram showing one example of antenna array arrangement when receiving different types of circularly polarized waves. This is a schematic diagram showing multiple variations in the arrangement of left-hand circular polarization antenna element groups and right-hand circular polarization antenna element groups in an antenna array according to one embodiment of this technology. This is a block diagram showing an example configuration of a radar device 100 according to one embodiment of this technology. This is a graph showing the distance spectrum in the signal processing unit 34 according to one embodiment of this technology. This is a conceptual diagram visually illustrating the principle of angle separation by the signal processing unit 34 according to one embodiment of this technology. This is a conceptual diagram showing the physical arrangement relationship corresponding to Figure 48. This is a block diagram showing an example configuration of a radar device 100 according to one embodiment of this technology. This is a block diagram showing an example configuration of a radar device 100 according to one embodiment of this technology. This is a conceptual diagram showing the physical arrangement relationship. This is a block diagram showing an example configuration of a radar device 100 according to one embodiment of this technology. This is a graph showing the distance spectrum in the signal processing unit 34 according to one embodiment of this technology. This is a conceptual diagram visually illustrating the principle of angle separation by the signal processing unit 34 according to one embodiment of this technology. This is a conceptual diagram showing the physical arrangement relationship corresponding to Figure 55. This is a conceptual diagram showing the physical arrangement relationship. This is a block diagram showing an example configuration of a radar device 100 according to one embodiment of this technology.This is a conceptual diagram showing the physical arrangement. This is a block diagram showing an example configuration of a radar device 100 according to one embodiment of this technology. This is a conceptual diagram showing the physical arrangement.

[0010] Hereinafter, preferred embodiments for implementing this technology will be described with reference to the drawings. The embodiments described below are merely examples of typical embodiments of this technology and do not limit the scope of this technology. Furthermore, this technology can be implemented by combining any of the following embodiments and their modifications.

[0011] In the following description of embodiments, configurations may be described using terms with "approximately" attached, such as "approximately parallel" and "approximately orthogonal." For example, "approximately parallel" means not only that they are perfectly parallel, but also that they are substantially parallel, that is, that is, they are deviated from a perfectly parallel state by, for example, a few percent. The same applies to other terms with "approximately." Also, each figure is a schematic diagram and is not necessarily a strictly accurate representation. The scale of the drawings is exaggerated to make the technical features easier to understand. Therefore, it should be noted that the scale of the drawings and the scale of the actual device are not necessarily the same.

[0012] Unless otherwise specified, in drawings, "up" means the upper direction or upper side in the drawing, "down" means the lower direction or lower side in the drawing, "left" means the left direction or left side in the drawing, and "right" means the right direction or right side in the drawing. In addition, in drawings, the same or equivalent elements or components are denoted by the same reference numeral, and redundant explanations are omitted.

[0013] In this specification, an antenna element refers to one or more radiating elements that constitute an antenna. An antenna element is a component that functions as an individual radiator or receiver. An antenna element is a basic component that radiates or receives a specific signal. When radiating a signal, an antenna element is a transmitting antenna element. When receiving a signal, an antenna element is a receiving antenna element.

[0014] In this specification, an antenna array is a larger unit composed of multiple antenna elements. Each antenna functions as part of the antenna array, working together to radiate or receive signals. When radiating signals, the antenna array becomes a transmitting antenna array. When receiving signals, the antenna array becomes a receiving antenna array. Using an antenna array makes it possible to improve characteristics such as directionality, gain, and reception range. The number of antenna elements that make up an antenna array is not particularly limited.

[0015] The explanation will proceed in the following order: 1. First Embodiment of the Technology (Example 1 of Antenna Arrays) (1) Theory related to the Technology (2) Addition Array (3) Overview of the Technology 2. Second Embodiment of the Technology (Example 1 of Radar Devices) (1) Configuration of the Radar Device (2) Processing Flow of the Radar Device (3) Antenna Array (4) Calculation Procedure (5) Effects (6) Application Examples of the Radar Device 3. Third Embodiment of the Technology (Example 2 of Antenna Arrays) 4. Fourth Embodiment of the Technology (Example 3 of Antenna Arrays) 5. Fifth Embodiment of the Technology (Example 2 of Radar Devices) 6. Sixth Embodiment of the Technology (Example 4 of Antenna Arrays) 7. Seventh Embodiment of the Technology (Example 3 of Radar Devices) 8. Eighth Embodiment of the Technology (Example 5 of Antenna Arrays) 9. Ninth Embodiment of the Technology (Example 4 of Radar Devices) 10. Tenth Embodiment of the Technology (Example 5 of Radar Devices) 11. Eleventh Embodiment of the Technology (Example 6 of Radar Devices) 12. 12th Embodiment of this Technology (Example 7 of a Radar Device) 13. 13th Embodiment of this Technology (Example 8 of a Radar Device) 14. 14th Embodiment of this Technology (Example 9 of a Radar Device) 15. 15th Embodiment of this Technology (Example 10 of a Radar Device) 16. 16th Embodiment of this Technology (Example 11 of a Radar Device)

[0016] [1. First Embodiment of the Technology (Example 1 of Antenna Arrays)] [(1) Theory related to the Technology] Conventionally, in FMCW radars arranged linearly at equal intervals, the phase resolution Δω and angular resolution Δθ of the antennas are known to have the following relationship given by equation (2).

[0017]

[0018] Here, N is the number of antennas, k is the wavenumber of the carrier frequency, d is the spacing between antenna elements, and θ indicates the direction. When the angular resolution Δθ is very small, the following approximate equation (3) is derived.

[0019]

[0020] However, this approximation formula may contradict its assumptions and become invalid when the obtained value becomes large. Strictly speaking, the angular resolution on the positive side of angle θ is expressed by the following formula (4).

[0021]

[0022] Similarly, the negative angular resolution with respect to angle θ is expressed by the following equation (5).

[0023]

[0024] As is clear from these formulas, the larger the aperture length D = Nd, the higher the angular resolution. In other words, Δθ can be reduced.

[0025] This technology provides even higher angular resolution than conventional technologies through antenna arrangement and signal processing. Specifically, since the product of the number of antenna elements N and the element spacing d affects angular resolution, providing an optimal arrangement position for the antenna elements dramatically improves the radar resolution. This enables highly accurate measurements.

[0026] Next, we will consider the case where the transmitting antenna array and the receiving antenna array are arranged in a straight line and parallel to each other, referring to Figures 1 and 2. Figures 1 and 2 are schematic diagrams showing examples of antenna array arrangements.

[0027] As shown in Figure 1, the transmitting antenna array TX ｋ The radar signal transmitted from is reflected by an object O that is far enough away, and the receiving antenna array RX １ When received, the received signal x(k,l) is expressed by the following formula (6).

[0028] Here, A is a constant, ω is the angular frequency, and m ｋ TX ｋThe relative position of n ｌ RX １ The relative position is given by , d is the reference spacing between the antenna elements, θ is the angle as seen from the radar device, and λ is the wavelength.

[0029] If such calculations hold true, the receiving antenna that receives the received signal x(k,l) is virtually (m ｋ +n ｌ It can be considered to be at position d.

[0030] As shown in Figure 2, in this configuration example, the transmitting antenna array TX has two antenna elements (unfilled circles indicate positions where no antenna elements are placed), and the receiving antenna array RX has four antenna elements. By performing signal processing, it can be considered that there are eight antenna elements. This concept is called a virtual receiving antenna array and is realized by techniques such as time-division multiplexing (TDM-MIMO) and code-division multiplexing (CDMA).

[0031] Furthermore, a sequence of integers {m} that does not contain duplicates. ｋ +n ｌ The longer the continuous length of the}, the wider the virtual aperture formed by the antenna array, resulting in improved angular resolution. Specifically, the aperture length can be expanded by interpolating and extrapolating the virtual receiving antenna array. For example, by applying summation array signal processing, an expanded received signal can be obtained by calculating the following equation (7).

[0032]

[0033] Here, y(k, k', l, l') represents the extended received signal, which is obtained by adding the virtual received signals x(k, l). Also, the aforementioned integer sequence {m ｋ +n ｌ For}, this extended received signal is an integer sequence {m ｋ +n ｌ +m ｋ’ +n ｌ’ Therefore, it is possible to achieve a larger angular resolution.

[0034] Additive array signal processing is achieved by combining all virtual received signals x(k,l) into a column vector x, and then performing the following equation (8) using an operator representing the Kronecker product. Furthermore, the column vector formed by combining the phase terms is called the steering vector.

[0035]

[0036] In this technology, an integer sequence {m} represents a virtual receiving antenna array. ｋ +n ｌ An extended integer sequence {m} ｋ +n ｌ +m ｋ’ +n ｌ’ By applying additive array signal processing that yields}, the angular resolution can be efficiently improved.

[0037] Here, the array extended by the following equation (9) with respect to steering vectors a and b is called a difference coarray.

[0038]

[0039] On the other hand, an array extended by the following equation (10) is called a sum coarray.

[0040]

[0041] Virtual array a constructed by TDM-MIMO ＭＩＭＯ This can be expressed as an additive array of the transmitting antenna array TX and the receiving antenna array RX by the following formula (11).

[0042]

[0043] Furthermore, using KR product extension, the summation array a of the virtual array ＳＣ The result can be expressed by the following formula (12).

[0044]

[0045] While equally spaced linear arrays are widely used for array configurations, arranging them at unequal intervals allows for a larger aperture length, enabling the achievement of higher angular resolution.

[0046] This will be explained with reference to Figure 3. Figure 3 is a schematic diagram showing an example of an antenna array arrangement.

[0047] As shown in Figure 3A, for example, the transmitting antenna array TX and the receiving antenna array RX are arranged orthogonally to each other. Using the transmitting antenna array TX and the receiving antenna array RX arranged in this manner, a virtual two-dimensional array is generated using technologies such as TDM-MIMO, as shown in Figure 3B.

[0048] Furthermore, this two-dimensional array can be extended using the technique called additive array described above. As shown in Figure 3C, using an additive array increases the number of elements in the array, resulting in the formation of a virtual array with a high-density structure. This makes it possible to achieve a higher angular resolution than before.

[0049] The method for expanding an antenna array that is expanded by an additive array will be explained with reference to Figure 4. Figure 4 is a matrix showing the positions of the antenna elements expanded by the additive array.

[0050] Let the row label q of the table be, for example, the transmitting antenna array TX, and the column label p be the receiving antenna array. Based on this coordinate system, each element constituting the summation array is represented. For example, if the position of the transmitting antenna array is q １ The position of the receiving antenna array is p １ When p １ +q １ A virtual antenna array is generated at the specified location. In this example, by adding the positions of each element of the transmitting antenna array TX and each element of the receiving antenna array RX, a virtual antenna array is generated at nine different locations. This results in a new array configuration, which is shown as the sum of each combination.

[0051] Figure 5 shows a concrete example. Figure 5 is a matrix showing the positions of antenna elements extended by an additive array. With (0,0) as the origin, (1,0) represents the position one step forward in the X-axis direction, and (0,1) represents the position one step forward in the Y-axis direction. For example, when the position of the transmitting array is (0,1) and the position of the receiving array is (2,0), a virtual antenna array is generated at the position of (2,1).

[0052] The positions of the antenna elements may be relative and one-dimensional. This will be explained with reference to Figure 6. Figure 6 is a matrix showing the positions of antenna elements extended by an additive array.

[0053] As shown in Figure 6, the numbers in the column and row labels represent the relative positions of each antenna element. By adding these numbers together, the relative positions where the virtual antenna array is generated can be represented.

[0054] If the positions of the extended antenna elements overlap, you may, for example, select one of them or calculate the average value of multiple positions.

[0055] [(2) Additive Array] In this technology, a transmitting antenna array TX and a receiving antenna array RX are arranged orthogonally to each other, for example, using technologies such as TDM-MIMO, and the arrangement is extended to a two-dimensional configuration using an additive array. This will be explained with reference to Figure 7. Figure 7 is a schematic diagram showing an example of antenna array arrangement.

[0056] As shown in Figure 7A, for example, the transmitting antenna array TX and the receiving antenna array RX are arranged orthogonally to each other. This is a real (physical) arrangement. The transmitting antenna array TX has 4 antenna elements, and the receiving antenna array RX has 4 antenna elements. Using the transmitting antenna array TX and receiving antenna array RX arranged in this way, a two-dimensional array is virtually generated by TDM-MIMO, as shown in Figure 7B.

[0057] However, the number of antenna elements in the vertical direction where the transmitting antenna array TX extends and the horizontal direction where the receiving antenna array RX extends remains at four, and does not change in the generation of the summing array by TDM-MIMO.

[0058] Therefore, this technology applies KR product extension to change the number of antenna elements in each array direction. This makes it possible to discuss each direction of the antenna array independently, resulting in a comprehensive and general representation. In discussing this technology, it is possible to consider only one-dimensional arrays (either the direction in which the transmitting antenna array TX extends or the direction in which the receiving antenna array RX extends).

[0059] Furthermore, this technology makes it possible to achieve an equivalent or greater number of antenna elements in the extended array in either the direction in which the transmitting antenna array TX extends or the direction in which the receiving antenna array RX extends compared to conventional methods. This is the result of the inventor's search for and discovery of the optimal array arrangement. This effect enables superior angular resolution compared to conventional techniques, and allows for more precise signal processing.

[0060] This will be explained with reference to Figure 8. Figure 8 is a graph showing the effect of this technology. This graph shows a comparison of the number of antenna elements in an expanded array using this technology and in a conventional nested array. The horizontal axis shows the "actual number of antenna elements," and the vertical axis shows the "number of antenna elements in the expanded array."

[0061] Nested arrays are a technique that significantly expands the aperture length by arranging antenna elements at different intervals, thereby achieving more degrees of freedom (DOF) than uniform linear arrays (ULAs). A nested array consists of multiple sub-arrays, each with antenna elements at different intervals. This creates a virtually wider array aperture, making it possible to estimate the direction of a signal with higher resolution.

[0062] As this graph shows, the expanded array of this technology achieves a greater number of elements than conventional nested arrays as the actual number of antenna elements increases. In particular, the superiority of the expanded array of this technology becomes clear as the actual number of antenna elements increases.

[0063] Specifically, the extended array of this technology can secure an equivalent or greater number of antenna elements than conventional nested arrays, even at intermediate numbers of antenna elements, and this difference becomes more pronounced as the number of antenna elements increases. This result indicates that higher precision angular resolution can be achieved by optimizing the antenna arrangement.

[0064] Therefore, this technology makes it possible to form an extended array with more antenna elements for the same number of antenna elements compared to conventional nested arrays, thereby significantly improving the performance of radar equipment.

[0065] In this technology, the number of antenna elements or aperture length of the extended array refers to the longest sub-array portion of the extended array that is continuously arranged with a reference element spacing (=1). The reason for this definition is to avoid adverse effects such as grating lobes and to improve the accuracy of signal processing. Therefore, only the longest sub-array portion mentioned above is extracted and used, rather than the entire extended array.

[0066] Specific examples will be explained with reference to Figures 9 and 10. Figures 9 and 10 are schematic diagrams showing examples of antenna array arrangements. These schematic diagrams focus on one axis in Figure 7B (either the direction in which the transmitting antenna array TX extends or the direction in which the receiving antenna array RX extends).

[0067] As shown in Figure 9, the relative positions of the actual antenna elements are assumed to be "0, 1, 2, 5, 8, 11, 12, 13". Conversely, no antenna elements are placed at positions "3, 4, 6, 7, 9, 10".

[0068] In this case, the arrangement of antenna elements in the expanded array of this technology increases to 27 elements, as in "0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26". Since this expanded array is entirely continuous, the aperture length in this case is treated as 27. The specific method for deriving this expanded array will be described later.

[0069] As another example, let's assume that the actual antenna element arrangement is "0, 2, 3, 7, 8, 12, 13, 15" as shown in Figure 10. In this case, the antenna element arrangement in the extended array would be "0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30".

[0070] However, in this configuration, continuity is not maintained between "0" and "2", and between "28" and "30". Therefore, adverse effects such as grating lobes may occur. For this reason, this technology excludes such discontinuous parts and defines only the most continuous part as the aperture length. In this example, "0" and "30" are excluded. As a result, the longest continuous part shown in the underlined section is defined as the aperture length. In this case, the aperture length is treated as 27. This definition ensures the accuracy of signal processing.

[0071] The method for deriving the extended array in this example will be explained with reference to Figure 11. Figure 11 is a matrix showing the positions of the antenna elements extended by the additive array.

[0072] The matrix shown in Figure 11 is created on the premise that the actual antenna element arrangement is "0, 2, 3, 7, 8, 12, 13, 15". The column and row labels are each assigned the numerical values ​​"0, 2, 3, 7, 8, 12, 13, 15", and the sum of these values ​​is shown in each cell of the matrix.

[0073] Based on this addition result, sections where continuity is maintained (the numbers increase by one) are connected by auxiliary lines, and sections where continuity is broken are marked with an "X". In particular, since continuity is not maintained between "0" and "2", and between "28" and "30", the "0" and "30" corresponding to these positions are excluded. In this way, the longest continuous section is defined as the opening length.

[0074] In this configuration, the sections connected by lines with values ​​increasing by one indicate that continuity is maintained in the extended array. On the other hand, the sections marked with an "x" indicate a breakdown in continuity, which may lead to adverse effects such as grating lobes.

[0075] [(3) Overview of the Technology] This technology is based on the calculation method of such additive arrays and enables more accurate signal processing by searching for the optimal arrangement with the aperture length through a brute-force approach. Specifically, the relative arrangement positions of the antenna elements are calculated by deriving the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A.

[0076]

[0077] In other words, this technology comprises N (where N is 4 or more) antenna elements arranged in a straight line, the spacing between each of the antenna elements is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements {u ｋ} (0 = u １ <u ２ <...<u Ｎ The present invention provides an antenna array in which the solution to the above equation (1), defined as a maximization problem that maximizes the aperture length A, is given.

[0078] This technology uses an integer sequence {u ｎ This concerns a maximization problem involving {u}. In this maximization problem, the object to be maximized is "A", and the objective is to maximize the integer sequence {u}. ｎ The task is to determine {u}. Specifically, the integer sequence {u} ｎ} represents the relative arrangement position of the antenna elements, and "0 = u １ <u ２ <...<u Ｎ The condition is that this integer sequence {u ｎ The summation array of} is an integer sequence {u ｍ +u ｎ It is expressed as} and, as mentioned above, is generated by addition within the matrix.

[0079] In the above formula (1), the integer sequence {u} is such that the longest continuous subset is obtained starting from "k" and going up to "k + A - 1". ｍ +u ｎ We search for the largest possible A such that the longest set of consecutive subsets is achieved.

[0080] Figures 12 and 13 describe the results of the search. Figures 12 and 13 are tables showing an example of antenna array arrangement according to one embodiment of this technology.

[0081] As shown in Figures 12 and 13, this table shows the number of elements in the corresponding extended array and the arrangement of the actual antenna elements to increase the aperture length, based on the actual number of antenna elements.

[0082] The "Actual Number of Elements" column lists the actual number of antenna elements that will be placed. This number represents the initial condition for determining the antenna placement. The "Expanded Array Number of Elements" column shows the number of elements in the expanded array calculated based on the actual element placement. The "Actual Array Placement" column specifically lists the relative arrangement positions of the antenna elements.

[0083] For example, if the actual number of elements is "7", there are three possible relative arrangement positions for the antenna elements: "0, 1, 2, 5, 8, 9, 10", "0, 1, 3, 5, 7, 9, 10", and "0, 3, 7, 8, 9, 13, 16". These arrangement positions can be calculated from the above formula (1). When the antenna elements are arranged in this way, the number of elements in the extended array becomes "21".

[0084] The tables shown in Figures 12 and 13 illustrate the arrangement of 16 sets of antenna elements found based on the above formula (1). When the number of antenna elements exceeds 17, the number of arrangement patterns becomes extremely large, so they are omitted here. Even with 17 or more antenna elements, it is possible to derive the arrangement positions of the antenna elements based on the above formula (1).

[0085] Furthermore, when the "actual number of elements" is two or three, the corresponding array positions are limited to "0,1" and "0,1,2," which coincide with an equally spaced array arrangement. Therefore, the array positions of four or more antenna elements are of particular importance. This technology specifically provides the relative array positions of four or more antenna elements.

[0086] Figure 14 visually represents the "actual array arrangement" shown in the tables in Figures 12 and 13. Figure 14 is a map showing an example of the arrangement of an antenna array according to one embodiment of this technology. The dark-colored cells in each cell indicate the relative arrangement position of the antenna elements.

[0087] The vertical axis shows the combination of "actual number of elements" and "type of arrangement pattern." The horizontal axis shows the relative arrangement position of the antenna elements.

[0088] For example, if the actual number of elements is four, there is only one type of array pattern, so one array pattern "4-1" is shown. If the actual number of elements is seven, three array patterns "7-1", "7-2", and "7-3" are shown.

[0089] By arranging the antenna elements as shown in this figure and performing signal processing, the aperture length can be increased. As a result, the angular resolution can be efficiently improved. This effect also occurs in other embodiments described later. Therefore, in the descriptions of other embodiments, the effect may be omitted again.

[0090] Note that this diagram shows the arrangement positions for up to 16 antenna elements. However, as mentioned above, even if the number of antenna elements is 17 or more, it is possible to derive the arrangement positions of the antenna elements based on the above formula (1).

[0091] The above description of the antenna array according to the first embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0092] [2. Second Embodiment of the Present Technology (Example 1 of Radar Device)] [(1) Configuration of Radar Device] The present technology provides a radar device comprising a transmitting antenna array and a receiving antenna array. An example of the configuration of this radar device will be described with reference to Figure 15. Figure 15 is a block diagram showing an example of the configuration of a radar device 100 according to one embodiment of the present technology. As shown in Figure 15, the radar device 100 comprises a transmitting unit 1, a receiving unit 2, a transmitting control unit 32, a signal generation unit 33, a signal processing unit 34, and a calculation unit 31.

[0093] The transmitting unit 1 includes one or more transmitting antenna arrays TX, an amplifier 11, a phase shifter 12, and a switch 13, through which a chirp signal is generated and transmitted. This signal is reflected by an external object and then received by the receiving unit 2.

[0094] The receiving unit 2 includes one or more receiving antenna arrays RX, an amplifier 21, mixers 22 and 26, a phase shifter 25, low-pass filters (LPFs) 23 and 27, and an analog-to-digital converter (ADC) 82.

[0095] The signal received by the receiving antenna array RX is quadrature detected using a quadrature detector and then bandwidth-limited by low-pass filters 23 and 27. The bandwidth-limited signal is down-converted to a digital signal by analog-to-digital converters 24 and 28. The down-converted digital signal is output as data divided into a real part (I component) and an imaginary part (Q component). This divided data is sent to the signal processing unit 34 for further detailed signal processing.

[0096] The arithmetic unit 31 may be, for example, a microcontroller unit (MCU). The arithmetic unit 31 is mainly responsible for controlling the transmission unit 1 and adjusting the timing and phase of the generated chirp signal. The arithmetic unit 31 is also responsible for analyzing the received data, generating radar images, and executing necessary signal processing algorithms.

[0097] [(2) Processing Flow of the Radar Device] An example of the processing flow of the transmission control of this radar device 100 will be explained with reference to Figure 16. Figure 16 is a flowchart showing an example of the signal processing flow of the radar device 100 according to one embodiment of this technology.

[0098] First, in step S11, the radar device 100 transmits radio waves that have been subjected to a predetermined frequency modulation from the transmitting antenna array TX. The transmitted radio waves travel toward the object to be detected and are reflected.

[0099] The transmitting antenna array TX transmits signals using a division-multiplexing scheme. This flowchart shows the processing flow when each sub-array transmits signals using time division multiplexing (TDM). In addition to time division multiplexing, other division-multiplexing schemes such as code division multiplexing (CDM) or frequency division multiplexing (FDM) can also be used.

[0100] TDM-MIMO (Time Division Multiplexing - Multiple Input Multiple Output) is a combination of time-division multiplexing technology and communication technology that uses multiple transmit and receive antennas. This technology is implemented as a way to assign multiple data streams to different time slots and share a single channel. Each transmit antenna array TX transmits chirp signals in a specific order. Each receive antenna array RX can identify the received signal based on this transmission order and determine which transmit antenna the signal originated from.

[0101] This radar system can generate a virtual array using TDM-MIMO. A virtual array using TDM-MIMO is a technique that uses time-division multiplexing (TDM) to make an array function as if it had many more antennas, even though it uses a physically limited number of antennas.

[0102] Code division multiplexing (CDC) is a communication technique designed to prevent interference between different communication channels using the same frequency band simultaneously. In this method, each antenna is assigned a unique code (spreading code), and the transmitted signal is spread using this code. The receiving end uses the same code to decode the signal and separate it from other signals.

[0103] Frequency division multiplexing (FDM) is a communication method in which different signals are transmitted simultaneously in different frequency bands. In this method, the available bandwidth is divided into multiple independent frequency bands, and each channel uses a different frequency band for communication. Each frequency band is separated by a guard band to prevent interference between signals.

[0104] Next, in step S12, the radar device 100 receives radio waves reflected from the object with the receiving antenna array RX. By comparing this received signal with the transmitted signal, the object's position and velocity information is derived.

[0105] Next, in step S13, the received radio signal is converted into an intermediate frequency (IF) signal by mixing with the transmitted signal. The IF signal is then converted from analog to digital (ADC) and sent as a digital signal to the next processing step.

[0106] Next, in step S14, a Fourier transform is applied to the digitized IF signal to calculate the distance spectrum. This spectrum contains distance information to the object.

[0107] Next, in step S15, if necessary, a velocity spectrum is calculated based on the distance spectrum. This allows for the analysis of the relative velocity of the objects. This step may be omitted.

[0108] Next, in step S16, an extended signal is calculated for each BIN (discrete interval) of the distance spectrum using an additive array. This process improves the angular resolution and the accuracy of the signal processing.

[0109] Next, in step S17, an angular spectrum is calculated based on the summed array expansion signal calculated. This spectrum is used to detect the direction of an object with high precision.

[0110] Finally, in step S18, the calculated distance spectrum, velocity spectrum, and angle spectrum information are integrated to detect the object's position and movement with high accuracy. This step allows for the detection of the object's presence and analysis of its dynamics.

[0111] [(3) Antenna Array] At least one of the transmitting antenna array TX and the receiving antenna array RX of the radar device 100 may be an antenna array according to the first embodiment. In this case, for example, the receiving antenna array TX adopts a special arrangement based on the first embodiment, thereby increasing the angular resolution. The higher the angular resolution, the better the radar device 100 can distinguish the direction of arrival of signals within a finer angular range.

[0112] A configuration example in which at least one of the transmitting antenna array TX and the receiving antenna array RX is an antenna array according to the first embodiment will be described with reference to Figure 17. Figure 17 is a schematic diagram showing an example of the arrangement of antenna arrays.

[0113] As shown in Figure 17, at least one of the transmitting antenna array TX and the receiving antenna array RX is an antenna array according to the first embodiment. In this example, the relative arrangement positions of the antenna elements in the receiving antenna array RX are the solution to the above formula (1), which is "0, 1, 3, 4".

[0114] As shown in Figure 17A, the transmitting antenna array TX and the receiving antenna array RX may be arranged orthogonally to each other, for example.

[0115] Furthermore, as shown in Figure 17B, the transmitting antenna array TX may be arranged diagonally with respect to the receiving antenna array RX.

[0116] Furthermore, as shown in Figure 17C, the transmitting antenna array TX and the receiving antenna array RX may be arranged parallel to each other.

[0117] Alternatively, both the transmitting antenna array TX and the receiving antenna array RX may be antenna arrays according to the first embodiment. In this case, by employing an advanced array arrangement for both transmission and reception, the overall signal processing capability of the system is dramatically improved. With such a system configuration, it is possible to maintain high detection accuracy even for minute objects and low-reflectivity objects that were difficult to detect with conventional technology.

[0118] The case where both the transmitting antenna array TX and the receiving antenna array RX are antenna arrays according to the first embodiment will be explained with reference to Figure 18. Figure 18 is a schematic diagram showing an example of the arrangement of antenna arrays according to one embodiment of this technology.

[0119] As shown in Figure 18, both the transmitting antenna array TX and the receiving antenna array RX are antenna arrays according to the first embodiment. In other words, in both antenna arrays, the relative arrangement positions of the antenna elements are the solution to the above equation (1), which is "0, 1, 3, 4".

[0120] As shown in Figure 18A, the transmitting antenna array TX and the receiving antenna array RX may be arranged orthogonally to each other, for example.

[0121] Furthermore, as shown in Figure 18B, the transmitting antenna array TX may be arranged diagonally with respect to the receiving antenna array RX.

[0122] Furthermore, as shown in Figure 18C, the transmitting antenna array TX and the receiving antenna array RX may be arranged parallel to each other.

[0123] Furthermore, as shown in Figure 18D, the transmitting antenna array TX and the receiving antenna array RX may be arranged parallel to each other. The spacing between the antenna elements of the antenna array with fewer antenna elements may be an integer multiple of the spacing between the antenna elements of the antenna array with more antenna elements. In this example configuration, the spacing between the antenna elements of the transmitting antenna array TX with fewer antenna elements is an integer multiple (9 times) of the spacing between the antenna elements of the receiving antenna array RX with more antenna elements.

[0124] [(4) Calculation Procedure] The procedure for deriving the optimal array arrangement of antenna elements when the transmitting antenna array TX and the receiving antenna array RX are arranged in parallel to each other will be explained with reference to Figure 19. Figure 19 is a table showing an example of the arrangement of an antenna array according to one embodiment of this technology.

[0125] This table shows the optimal array configuration for each number of elements, and lists the "minimum array multiplier" and "maximum array configuration" for each number of elements.

[0126] First, the arrangement of the antenna array with the larger number of antenna elements between the transmitting antenna array TX and the receiving antenna array RX is determined. In the example shown in Figure 18D, the transmitting antenna array TX has 2 antenna elements, and the receiving antenna array RX has 4 antenna elements. Therefore, in the table in Figure 19, when there are 4 antenna elements, the arrangement positions "0, 1, 3, 4" are adopted. The arrangement positions of the antenna elements in the receiving antenna array RX are determined to be "0, 1, 3, 4".

[0127] Next, we refer to the antenna array with the fewer elements. If there are two elements, the arrangement "0,1" is adopted. The "minimum element array multiplier" is applied to this arrangement. Specifically, since the receiving antenna array RX has four antenna elements, its arrangement position is "0,1,3,4", and the minimum element array multiplier is "9". Multiplying this "9" by the arrangement "0,1" gives the arrangement position "0,9". The arrangement position of the antenna elements in the transmitting antenna array TX is determined to be "0,9". In this way, the antenna array arrangement shown in Figure 18D is derived.

[0128] Next, a method for calculating an extended array from the antenna array shown in Figure 18D will be explained with reference to Figure 20. Figure 20 is a matrix showing an example of the arrangement of an antenna array according to one embodiment of this technology.

[0129] Figure 20A shows a virtual antenna array generated by TDM-MIMO. This virtual antenna array is formed based on the arrangement of the transmit antenna array TX and the receive antenna array RX. Specifically, if the arrangement x of the transmit antenna is "0, 9", this is set as the column label. If the arrangement y of the receive antenna array RX is "0, 1, 3, 4", this is set as the row label. Then, by adding the numbers of the column label and the row label, the virtual antenna array array "0, 1, 3, 4, 9, 10, 12, 13" is obtained.

[0130] Figure 20B shows the KR product extended antenna array generated based on the virtual antenna array. The column and row labels are assigned the arrangement positions of the virtual antenna array "0, 1, 3, 4, 9, 10, 12, 13", and the result of adding these values ​​is shown in each cell in the matrix. Based on this addition result, auxiliary lines are used to connect the parts where continuity is maintained. This yields the arrangement of the extended antenna array "0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26".

[0131] Figures 21 to 29 are tables showing examples of antenna array arrangements according to one embodiment of this technology. Figures 21 to 29 show specific examples where the transmitting antenna array TX and the receiving antenna array RX are arranged parallel to each other. In this example, the arrangement positions are specifically shown when each of the transmitting antenna array TX and the receiving antenna array RX has 16 antenna elements.

[0132] Figures 21 to 29 show possible combinations of the transmitting antenna array TX and the receiving antenna array RX, depending on the number of elements. In particular, several patterns are listed based on one-dimensional arrangement to obtain the optimal combination for both the array with a large number of elements and the array with a small number of elements. The optimal array arrangement is determined based on these patterns.

[0133] "num_large" indicates the number of elements in the maximum element array, representing the part where the most antenna elements are used overall. "num_small" indicates the number of elements in the minimum element array, representing the part where the minimum number of elements is used within the arrangement. "coeff" indicates the array magnification for the minimum element array. "array_large" indicates the specific arrangement position of the maximum element array. "array_small" indicates the specific arrangement position of the minimum element array.

[0134] The array configurations shown in Figures 21 to 29 can be used as a reference for optimizing the placement of the transmitting antenna array TX and the receiving antenna array RX. The listed combinations allow designers to select the optimal configuration for specific requirements. This configuration enables high angular resolution in radar systems, providing superior performance compared to conventional technologies.

[0135] [(5) Effects] The effects of this technology will be explained with reference to Figures 30 and 31. Figures 30 and 31 are matrices showing the aperture lengths of antenna arrays. The row labels of each matrix shown in Figures 30 and 31 contain the number of antenna elements in the transmitting antenna array TX. The column labels contain the number of antenna elements in the receiving antenna array RX. The numbers displayed in each cell represent the aperture length obtained by the combination of the number of elements in the corresponding row and column.

[0136] Figure 30 is a matrix showing the aperture length of an antenna array according to one embodiment of this technology. Figure 31 is a matrix showing the maximum aperture length obtainable with nested arrays of two levels or less, as a comparative example. When the number of elements is four or more, the aperture length shown in Figure 30 is greater than the aperture length shown in Figure 31. Thus, this technology increases the aperture length compared to the conventional technology, and therefore improves the angular resolution.

[0137] Figure 32 is a graph illustrating the effects of this technology. Specifically, it is a graph comparing an antenna array according to one embodiment of this technology with a comparative example of an equally spaced antenna array and its summation array. This graph shows the angular characteristics of each array arrangement when the number of antenna elements is five.

[0138] In the comparative example, the antenna element arrangement is "0, 1, 2, 3, 4," while in this technology, the antenna element arrangement is "0, 1, 3, 5, 6." The reference antenna element spacing is set to 0.5 wavelengths (=1) of the carrier frequency.

[0139] This graph shows the spectra obtained when radio waves arriving from the front (0°) of the antenna array are received by each antenna, the received signals are associated with the antenna positions, and then an angular Fourier transform (Angle FFT) is performed in the spatial direction.

[0140] As is clear from this figure, compared to the equally spaced arrangement of the conventional technology, the arrangement of this technology results in a narrower main beam width and reduced side lobes. This indicates that the antenna array arrangement using this technology achieves higher angular resolution and lower side lobe characteristics compared to the conventional technology. In particular, the sharper main beam enables accurate direction detection of targets, contributing to improved radar system performance.

[0141] [(6) Examples of Radar Device Applications] The radar device relating to this technology is expected to be effective in applications in fields such as autonomous vehicles, autonomous robots, drones, and vital sensing. Furthermore, it can be applied to devices such as FMCW radar and MIMO radar, and further performance improvements can be achieved by combining it with these technologies.

[0142] The radar system related to this technology is used to enable autonomous vehicles to perceive their surroundings more accurately. In particular, by using a multi-element, high-gain antenna, it is possible to effectively detect other vehicles, pedestrians, and obstacles, significantly improving safety. Furthermore, in autonomous driving and advanced driver assistance systems (ADAS), it enables highly reliable real-time perception of the surrounding situation and supports rapid decision-making.

[0143] Robots equipped with radar devices related to this technology can detect objects within factories and warehouses. This allows robots to accurately identify surrounding obstacles and carry out tasks efficiently. Furthermore, it can be applied to spatial recognition and posture analysis of autonomous robots, further improving the accuracy and safety of robot operation.

[0144] In drone operations, obstacle detection and avoidance during flight are crucial. By using the radar system related to this technology, drones can detect obstacles in real time during flight and take rapid evasive action. This improves the operational efficiency and safety of drones.

[0145] This technology, which can suppress distortions in the human shape and accurately grasp it, can also be applied to vital sign sensing. In particular, by accurately grasping the shape of a person, it can provide information for accurately identifying specific body parts such as the heart and abdomen. This will contribute to diagnostic support in the medical field. Furthermore, it is expected to have various interactive applications in gesture recognition and posture analysis by detecting movement with high accuracy.

[0146] The above description of the radar device according to the second embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0147] [3. Third Embodiment of the Technology (Example 2 of Antenna Arrays)] The above antenna array shows an example of an antenna array in which multiple antenna elements are arranged in a linear fashion. Alternatively, the multiple antenna elements may be arranged in a two-dimensional shape (for example, a rectangular shape).

[0148] This technology is an antenna array in which a plurality of antenna elements are arranged in a rectangular shape, wherein the rectangle has a pair of opposing sides along a first direction and a pair of opposing sides along a second direction perpendicular to the first direction, and comprises a plurality of antenna arrays including a plurality of antenna elements arranged in a straight line along the first direction, wherein in at least one of the plurality of antenna arrays, the spacing between each of the antenna elements is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements {u ｋ} (0 = u １ <u ２ <...<u Ｎ The present invention provides an antenna array in which the given value is the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A.

[0149]

[0150] An example of the configuration of the antenna array according to this embodiment will be described with reference to Figure 33. Figure 33 is a schematic diagram showing an example of the arrangement of an antenna array according to one embodiment of this technology.

[0151] Figure 33 shows an antenna array in which multiple antenna elements are arranged in a rectangular shape. This rectangle has a pair of opposing sides along a first direction s1 and a pair of opposing sides along a second direction s2 perpendicular to the first direction s1. This antenna array comprises multiple antenna arrays, each containing multiple antenna elements arranged linearly along the first direction s1.

[0152] In this first direction s1, in at least one antenna array (the bottom row in this figure), the spacing between each antenna element is an integer multiple of the shortest spacing. And in this antenna array (the bottom row), the relative arrangement position of each antenna element {u ｋ} (0 = u １ <u ２ <...<u Ｎ ) is the solution to the above equation (1), which is defined as a maximization problem that maximizes the opening length A.

[0153] In other words, among the multiple antenna arrays extending in the first direction s1, there may be some whose relative arrangement positions of antenna elements do not match the solution of equation (1) above. In this example configuration, the relative arrangement positions of the antenna elements in the bottom row of antenna arrays match the solution of equation (1) above. However, the relative arrangement positions of the antenna elements in the other antenna arrays do not match the solution of equation (1) above.

[0154] The above description of the antenna array according to the third embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0155] [4. A fourth embodiment of the present technology (Example 3 of an antenna array)] In the antenna array according to this embodiment, in all of the plurality of antenna arrays, the spacing between each antenna element is an integer multiple of the shortest spacing, and the relative arrangement position of each antenna element {u ｋ} (0 = u １ <u ２ <...<u ＮThe antenna array is the solution to the above equation (1), which is defined as a maximization problem that maximizes the aperture length A.

[0156] An example of the configuration of the antenna array according to this embodiment will be described with reference to Figure 34. Figure 34 is a schematic diagram showing an example of the arrangement of an antenna array according to one embodiment of this technology.

[0157] Figure 34 shows an antenna array in which multiple antenna elements are arranged in a rectangular shape. This rectangle has a pair of opposing sides along a first direction s1 and a pair of opposing sides along a second direction s2 that is perpendicular to the first direction s1. This antenna array comprises multiple antenna arrays, each containing multiple antenna elements arranged linearly along the first direction s1.

[0158] In this first direction s1, among the multiple antenna arrays, the spacing between each antenna element in all antenna arrays is an integer multiple of the shortest spacing. And in each antenna array, the relative arrangement position of each antenna element {u ｋ} (0 = u １ <u ２ <...<u Ｎ ) is the solution to the above equation (1), which is defined as a maximization problem that maximizes the opening length A.

[0159] The above description of the antenna array according to the fourth embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0160] [5. Fifth Embodiment of the Technology (Example 2 of Radar Apparatus)] The technology provides a radar apparatus comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is an antenna array according to the third or fourth embodiment.

[0161] Since the configuration example and processing flow example of this radar system have been explained above, we will omit further explanation. Here, we will describe an example of the configuration of the antenna array that the radar system is equipped with.

[0162] At least one of the transmitting antenna array TX and receiving antenna array RX of this radar system may be an antenna array according to the third or fourth embodiment. This example configuration will be described with reference to Figure 35. Figure 35 is a schematic diagram showing an example of the arrangement of antenna arrays.

[0163] As shown in Figure 35, at least one of the transmitting antenna array TX and the receiving antenna array RX may be an antenna array according to the third or fourth embodiment. In this configuration example, the receiving antenna array RX is an antenna array according to the third or fourth embodiment. That is, in the receiving antenna array RX, the antenna elements of at least one of the multiple antenna arrays extending in the first direction s1 satisfy the above formula (1), and their relative arrangement positions are "0, 1, 3, 4".

[0164] As shown in Figure 35A, the transmitting antenna array TX and the receiving antenna array RX may be arranged orthogonally to each other, for example. The first direction s1 of the transmitting antenna array and the first direction s1 of the receiving antenna array are arranged orthogonally to each other. The second direction s2 of the transmitting antenna array and the second direction s2 of the receiving antenna array are arranged orthogonally to each other.

[0165] Furthermore, as shown in Figure 35B, the transmitting antenna array TX may be arranged diagonally with respect to the receiving antenna array RX.

[0166] Furthermore, as shown in Figure 35C, the transmitting antenna array TX and the receiving antenna array RX may be arranged parallel to each other. The first direction s1 of the transmitting antenna array and the first direction s1 of the receiving antenna array are arranged parallel to each other. The second direction s2 of the transmitting antenna array and the second direction s2 of the receiving antenna array are arranged parallel to each other.

[0167] Alternatively, both the transmitting antenna array TX and the receiving antenna array RX may be antenna arrays according to the third or fourth embodiment. This configuration example will be described with reference to Figure 36. Figure 36 is a schematic diagram showing an example of antenna array arrangement.

[0168] As shown in Figure 36, both the transmitting antenna array TX and the receiving antenna array RX may be antenna arrays according to the third or fourth embodiment. That is, in the transmitting antenna array TX and the receiving antenna array RX, the antenna elements of at least one antenna array among the multiple antenna arrays extending in the first direction s1 satisfy the above formula (1), and their relative arrangement positions are "0, 1, 3, 4".

[0169] As shown in Figure 36A, the transmitting antenna array TX and the receiving antenna array RX may be arranged orthogonally to each other, for example. The first direction s1 of the transmitting antenna array and the first direction s1 of the receiving antenna array are arranged orthogonally to each other. The second direction s2 of the transmitting antenna array and the second direction s2 of the receiving antenna array are arranged orthogonally to each other.

[0170] Furthermore, as shown in Figure 36B, the transmitting antenna array TX may be arranged diagonally with respect to the receiving antenna array RX.

[0171] Furthermore, as shown in Figure 36C, the transmitting antenna array TX and the receiving antenna array RX may be arranged parallel to each other. The first direction s1 of the transmitting antenna array and the first direction s1 of the receiving antenna array are arranged parallel to each other. The second direction s2 of the transmitting antenna array and the second direction s2 of the receiving antenna array are arranged orthogonally to each other.

[0172] Furthermore, as shown in Figure 36D, the transmitting antenna array TX and the receiving antenna array RX may be arranged parallel to each other. The spacing between the antenna elements of the antenna array with fewer antenna elements may be an integer multiple of the spacing between the antenna elements of the antenna array with more antenna elements. In this example configuration, the spacing between the antenna elements of the transmitting antenna array TX with fewer antenna elements is an integer multiple (9 times) of the spacing between the antenna elements of the receiving antenna array RX with more antenna elements.

[0173] Other configuration examples of the antenna array according to this embodiment will be described with reference to Figure 37. Figure 37A is a schematic diagram showing an example of the arrangement of an antenna array according to one embodiment of this technology. Figure 37B is an excerpt of a portion of the table shown in Figure 21.

[0174] As shown in Figure 37A, the receiving antenna array RX is arranged in a one-dimensional (linear) configuration, and the transmitting antenna array TX is arranged in a two-dimensional (rectangular) configuration. The receiving antenna array RX has four antenna elements. Referring to the table in Figure 37B, the relative arrangement position (array_large) for four elements is "0, 1, 3, 4", and therefore it is arranged in that manner.

[0175] In the transmitting antenna array TX, the multiple antenna elements arranged in the lateral region r1 are selected from the multiple antenna elements of the transmitting antenna array TX that are arranged parallel to the receiving antenna array RX. The antenna array located in this region r1 and the receiving antenna array RX form a pair. The relative arrangement positions of the multiple antenna elements located in this region r1 can be derived in the same way as in Figure 18D by referring to the table in Figure 37B.

[0176] In the transmitting antenna array TX, the multiple antenna elements arranged in the vertical region r2 are positioned orthogonally to the receiving antenna array RX. There are five antenna elements arranged in this region r2. Referring to the table in Figure 37B, the relative arrangement positions (array_large) for five elements are "0, 1, 3, 5, 6", and they are arranged in that manner.

[0177] Note that the spacing d of the multiple antenna elements in the receiving antenna array RX ｘ The spacing d of multiple antenna elements arranged orthogonally with respect to the receiving antenna array RX ｙ They may be the same or they may be different.

[0178] Other configuration examples of the antenna array according to this embodiment will be described with reference to Figure 38. Figure 38A is a schematic diagram showing an example of the arrangement of an antenna array according to one embodiment of this technology. Figure 38B is an excerpt of a portion of the table shown in Figure 21.

[0179] As shown in Figure 38A, the receiving antenna array RX and the transmitting antenna array TX are arranged in a two-dimensional (rectangular) shape. The arrangement pattern of the multiple antenna elements arranged in the lateral regions r1 and r3 is the same as in Figure 37, so its explanation is omitted.

[0180] The antenna array located in region r2 and the antenna array located in region r4 form a pair. The relative positions of the multiple antennas arranged in region r2 are derived as "0, 1, 3, 5, 6", as in Figure 37. Referring to Figure 38B, the "coeff" in this arrangement pattern is "13". Therefore, the position of the antenna array arranged in region r4 is "0, 1" multiplied by "13", resulting in "0, 13".

[0181] Note that the spacing d of the multiple antenna elements in the receiving antenna array RX ｘ The spacing d of multiple antenna elements arranged orthogonally with respect to the receiving antenna array RX ｙThey may be the same or different. The same applies to the transmission antenna array TX.

[0182] The above content described for the radar device according to the fifth embodiment of the present technology can be applied to other embodiments of the present technology as long as there is no particular technical contradiction.

[0183] [6. Sixth Embodiment of the Present Technology (Example 4 of Antenna Array)] The antenna array according to this embodiment is an antenna array in which antenna elements of an array antenna arranged in a two-dimensional shape (for example, a square shape) are arranged in a specific arrangement in both axial directions (the first direction and the second direction).

[0184] Specifically, the present technology is an antenna array in which a plurality of antenna elements are arranged in a square shape, the square has a pair of opposing sides along the first direction and a pair of opposing sides along the second direction orthogonal to the first direction, a plurality of first antenna arrays including a plurality of the antenna elements arranged linearly along the first direction, and a plurality of second antenna arrays including a plurality of the antenna elements arranged linearly along the second direction, and in both the plurality of first antenna arrays and the plurality of second antenna arrays, the interval between each of the antenna elements in "at least one" antenna array is an integer multiple of the shortest interval, and the relative arrangement positions {u ｋ} (0 = u １ < u ２ <... < u Ｎ ) is the solution of the following mathematical formula (1), which is defined as a maximization problem of maximizing the aperture length A, providing an antenna array).

[0185]

[0186] Alternatively, in all of the plurality of antenna arrays, the interval between each of the antenna elements is an integer multiple of the shortest interval, and the relative arrangement positions {u ｋ} (0 = u １ < u ２ <... < uＮ The solution of the above formula (1) defined as a maximization problem of maximizing the aperture length A may be used. A configuration example of this antenna array will be described while referring to FIG. 39. FIG. 39 is a schematic diagram showing an example of the arrangement of an antenna array according to an embodiment of the present technology.

[0187] FIG. 39 shows an antenna array in which a plurality of antenna elements are arranged in a rectangular shape. The rectangle has a pair of opposite sides along the first direction s1 and a pair of opposite sides along the second direction s2 orthogonal to the first direction s1. This antenna array includes a plurality of first antenna arrays including a plurality of antenna elements arranged linearly along the first direction s1, and a plurality of second antenna arrays including a plurality of the antenna elements arranged linearly along the second direction s2.

[0188] In both the plurality of first antenna arrays and the plurality of second antenna arrays, the interval between each antenna element in "at least one" or "all" of the antenna arrays is an integer multiple of the shortest interval, and the relative arrangement positions {u ｋ} (0 = u １ < u ２ <... < u Ｎ ) is the solution of the above formula (1) defined as a maximization problem of maximizing the aperture length A. 6]

[0189] The interval d ｘ between the plurality of antenna elements included in the first antenna array and the interval d ｙ [[ID=q22]] between the plurality of antenna elements included in the second antenna array may be the same or different.

[0190] The above content described for the antenna array according to the sixth embodiment of the present technology can be applied to other embodiments of the present technology as long as there is no particular technical contradiction.

[0191] [7. Seventh Embodiment of the Technology (Example 3 of Radar Apparatus)] The technology provides a radar apparatus comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is an antenna array according to the sixth embodiment.

[0192] Since the configuration example and processing flow example of this radar system have been explained above, we will omit further explanation. Here, we will describe an example of the configuration of the antenna array that the radar system is equipped with.

[0193] At least one of the transmitting antenna array TX and the receiving antenna array RX of this radar system may be the antenna array according to the sixth embodiment. Alternatively, both the transmitting antenna array TX and the receiving antenna array RX may be the antenna array according to the sixth embodiment.

[0194] Alternatively, at least one or both of the transmitting antenna array TX and the receiving antenna array RX may be antenna arrays according to the sixth embodiment, and the first direction s1 of the transmitting antenna array TX and the first direction s1 of the receiving antenna array RX may be arranged parallel to each other. This configuration example will be described with reference to Figure 40. Figure 40 is a schematic diagram showing an example of the arrangement of antenna arrays according to one embodiment of the present technology.

[0195] As shown in Figure 40, both the transmitting antenna array TX and the receiving antenna array RX are antenna arrays according to the sixth embodiment. The first direction s1 of the transmitting antenna array and the first direction s1 of the receiving antenna array are arranged parallel to each other.

[0196] Furthermore, in the first direction s1, it is preferable that the spacing between the antenna elements of the antenna array with fewer antenna elements (of the transmitting antenna array TX and the receiving antenna array RX) is an integer multiple of the spacing between the antenna elements of the antenna array with more antenna elements. In the example configuration shown in this figure, in the first direction s1, the spacing between the antenna elements of the transmitting antenna array TX with fewer antenna elements is an integer multiple of the spacing between the antenna elements of the receiving antenna array RX with more antenna elements.

[0197] Furthermore, as shown in the example configuration in this figure, the second direction s2 of the transmitting antenna array TX and the second direction s2 of the receiving antenna array RX may be arranged parallel to each other.

[0198] Furthermore, in the second direction s2, it is preferable that the spacing between the antenna elements of the antenna array with fewer antenna elements (of the transmitting antenna array TX and the receiving antenna array RX) is an integer multiple of the spacing between the antenna elements of the antenna array with more antenna elements. In the example configuration shown in this figure, in the second direction s2, the spacing between the antenna elements of the receiving antenna array RX with fewer antenna elements is an integer multiple of the spacing between the antenna elements of the transmitting antenna array TX with more antenna elements.

[0199] [8. Eighth Embodiment of the Technology (Antenna Array Example 5)] Figure 41 is a schematic diagram illustrating the problems in conventional radar systems, and in particular, it shows the concept of the ghost phenomenon that can be observed in a multipath environment. The transmitted wave radiated from the transmitting antenna array TX is reflected by the target object T1 (e.g., a person) and received directly as a reflected wave by the receiving antenna array RX. However, if there is an object with high radio wave reflectivity, such as a wall T2, around the target object T1, the transmitted wave is reflected not only by the target object T1 but also by the wall surface, and is received by the receiving antenna array RX via multiple propagation paths. For example, a path in which the transmitted wave is reflected by the wall surface and then reflected back by the target object T1, or a path in which it is reflected by the target object T1 and then reflected again by the wall surface, can be considered, and these become multipath components. Such multipath components cause unwanted interference in the received signal and can be a factor in forming a virtual image T3 (ghost) as if the target object were located in a place where it does not actually exist. The generation of such virtual images (T3) not only hinders the accurate positioning of the target object (T1), but also significantly reduces the accuracy of detecting subtle vital information such as respiration and heart rate.

[0200] This embodiment relates to an antenna array that utilizes multiple different polarizations and applies the KR product extension arrangement rule defined by the above formula (1) to at least one of the antenna element groups corresponding to each polarization. This makes it possible to enjoy the basic effect of improved angular resolution while taking advantage of the unique benefits obtained by various polarization combinations, thereby enabling more advanced sensing and optimization for specific applications.

[0201] Specifically, the antenna array of this embodiment comprises a first group of antenna elements that transmit and receive signals in accordance with at least a first polarization (for example, right-hand circular polarization, vertical linear polarization, or a first polarization mode in a specific frequency band), and a second group of antenna elements that transmit and receive signals in accordance with a second polarization different from the first polarization (for example, left-hand circular polarization, horizontal linear polarization, or a second polarization mode in the specific frequency band).

[0202] Furthermore, at least one of the first antenna element group and the second antenna element group has a specific antenna array configuration, namely, consisting of N (N is 4 or more) antenna elements arranged in a straight line, where the spacing between each antenna element is an integer multiple of the shortest spacing, and the relative arrangement position {uk} of each antenna element (0 = u1 < u2 < ... < uN) is the solution to equation (1), which is defined as a maximization problem that maximizes the aperture length A. By applying this arrangement rule based on the KR product extension, the antenna element group can increase the effective aperture length without increasing the physical number of elements, and as a result achieve high angular resolution.

[0203] The following are some examples of combinations of "different polarizations" that can be used in this embodiment, although they are not limited to these.

[0204] (a) A combination of mutually orthogonal circular polarizations: For example, the first polarization is right-hand circular polarization (RHCP) and the second polarization is left-hand circular polarization (LHCP). This combination is particularly effective when separating reflection paths (such as distinguishing between a wave reflected once and a wave reflected two or more times) by utilizing the polarization reversal characteristics during reflection, as detailed in the eighth embodiment and subsequent embodiments.

[0205] (b) A combination of mutually orthogonal linear polarizations: For example, the first polarization may be vertical polarization and the second polarization may be horizontal polarization. This combination may be used to identify and classify targets, or to suppress clutter in a specific polarization direction, when the scattering characteristics of each polarization differ depending on the material and shape of the target.

[0206] (c) Combination of circular polarization and linear polarization: For example, the first polarization may be circular polarization (RHCP or LHCP) and the second polarization may be linear polarization (vertical polarization or horizontal polarization). Such combinations may be applicable to the detection of targets with specific scattering characteristics or to the utilization of polarization diversity effects.

[0207] (d) Other different polarization modes: For example, elliptic polarization and polarizations with different frequency bands or spatial modes can also be considered as "different polarizations" in this embodiment.

[0208] By providing a group of antenna elements corresponding to these different polarizations and applying the KR product extension arrangement rule to at least one of them, it becomes possible to acquire multifaceted information utilizing polarization information while ensuring high angular resolution for signals received or transmitted in each polarization channel. For example, when applied to radar equipment, it is expected to not only detect the presence and location of targets with high resolution, but also to estimate information about the material and shape of targets from differences in polarization characteristics, selectively suppress unwanted reflections (clutter) with specific polarization states, or improve signal separation capabilities in multipath environments.

[0209] This embodiment extends the scope of application of this technology to a wider range of polarization utilization technologies, without limiting it to specific polarizations (e.g., circular polarization only), and contributes to achieving both flexibility and performance improvement in antenna array design and its application. For example, it makes it possible to bring the benefits of increased angular resolution through KR product extension to various system configurations, such as a configuration in which the transmitting antenna array uses a first polarization and the receiving antenna array receives both the first and second polarizations, or an advanced MIMO system in which multiple different polarizations are used for both transmission and reception by time division, frequency division, or spatially switching.

[0210] [9. Ninth Embodiment of the Technology (Example 4 of a Radar Device)] The radar device according to this embodiment utilizes the characteristics of circular polarization (CP). There are two types of circular polarization: right-hand circular polarization (RHCP), in which the electric field vector rotates clockwise with respect to the direction of propagation over time, and left-hand circular polarization (LHCP), in which it rotates counterclockwise. RHCP and LHCP are polarization states that are orthogonal to each other. An important characteristic is that when circular polarization is reflected by a mirror surface (for example, a wall or a metal surface, or many common object surfaces), its direction of rotation reverses. That is, a wave transmitted in RHCP becomes LHCP after one reflection, and returns to the original RHCP after another reflection.

[0211] Figure 42 is a schematic diagram illustrating the principle of reflected wave separation in a radar system under a multipath environment according to one embodiment of this technology. This figure shows a concept that addresses the conventional problems shown in Figure 41 by distinguishing between one-reflected and two-reflected waves using the characteristics of circular polarization, thereby suppressing ghost phenomena and improving detection accuracy.

[0212] In this embodiment, the transmitting antenna array TX radiates a transmission signal, for example, a right-hand circularly polarized (RHCP) signal. Circular polarization has the property that its direction of rotation reverses when reflected by an object. Therefore, the directly reflected wave (solid arrow from target object T1 to left-hand circularly polarized antenna array RX in the figure), which is reflected once from the target object T1 (a person) and returns to the receiving antenna array RX, has its right-hand circular polarization reversed and becomes a left-hand circularly polarized (LHCP) signal.

[0213] On the other hand, a wave that is reflected once by a person (target object T1) and then reflected a second time by a surrounding object T2 such as a wall before returning to the receiving antenna array RX is received in its original right-hand circular polarization (RHCP) state because the direction of rotation of the circular polarization is reversed twice.

[0214] The receiving antenna array RX comprises at least one antenna element (or group of antenna elements, indicated as "left-hand circular polarization" in the figure) that receives left-hand circular polarization and one antenna element (or group of antenna elements, indicated as "right-hand circular polarization" in the figure) that receives right-hand circular polarization. This allows the radar system to distinguish between a single reflection from a target (received as left-hand circular polarization) and a double reflection that has passed through a wall or other obstacle (received as right-hand circular polarization) based on the rotation direction of the received circular polarization. This separation of reflection paths is expected to reduce false detections of ghosts caused by multipath interference and to improve positioning accuracy and vital information detection accuracy by more clearly extracting signals from the target.

[0215] Figure 43 is a block diagram showing an example configuration of a radar device 100 according to one embodiment of the present technology. As shown in Figure 43, the radar device according to this embodiment includes a transmitting antenna array TX, receiving antenna arrays RX1 to RXN, and a signal processing unit 34 that processes signals received by the receiving antenna arrays RX1 to RXN.

[0216] The transmitting antenna array TX is configured to transmit a transmit signal having a first circular polarization (e.g., RHCP).

[0217] The receiving antenna arrays RX1 to RXN include at least two groups of antenna elements. Specifically, they include a first group of receiving antenna elements that receive the same circular polarization as the first circular polarization (RHCP) (hereinafter sometimes referred to as the "same polarization receiving group") and a second group of receiving antenna elements that receive a second circular polarization (i.e., LHCP) that is orthogonal to the first circular polarization (RHCP) (hereinafter sometimes referred to as the "orthogonal polarization receiving group").

[0218] At least one of the transmitting antenna array TX, the first receiving antenna element group (same polarization receiving group), and the second receiving antenna element group (orthogonal polarization receiving group) is configured according to the arrangement rule based on the KR product extension described above.

[0219] The transmitting antenna array TX radiates a transmission signal into space, for example, a right-hand circularly polarized signal. This transmission signal is reflected by the target object and its surrounding environment and received by multiple receiving antenna arrays RX1, RX2, RX3, ..., RXN.

[0220] Each receiving antenna element constituting a receiving antenna array is configured to selectively receive a specific circular polarization. For example, as shown in the figure, receiving antenna arrays RX1 and RX2 receive left-hand circular polarization, while receiving antenna arrays RX3 and RXN receive right-hand circular polarization. By providing a group of antenna elements that receive the same polarization as the transmitted circular polarization (right-hand in this example) and a group of antenna elements that receive polarization orthogonal to it (left-hand in this example), it becomes possible to obtain information to distinguish between a wave reflected once and a wave reflected two or more times by utilizing the change in polarization state during reflection.

[0221] The high-frequency signals received by each receiving antenna array (RX1 to RXN) are input to their respective mixers. Each mixer is also supplied with a local oscillator signal from a common local oscillator, and the received signals are down-converted to intermediate frequency (IF) signals.

[0222] The IF signal for each channel is converted into a digital signal by an analog-to-digital converter (ADC1, ADC2, ADC3, ..., ADCN). The multiple digitized received signals are input to the signal processing unit 34.

[0223] The signal processing unit 34 is configured to distinguish between a single-reflection wave and two or more-reflection waves of the transmitted signal based on the characteristic difference (e.g., difference in received signal strength) between the signal from the first receiving antenna element group and the signal from the second receiving antenna element group.

[0224] Specifically, the signal processing unit 34 performs basic radar signal processing such as distance FFT processing, angle FFT processing (DOA estimation), and velocity FFT processing based on the input digital received signal to detect the distance, angle, velocity, etc. of the target object. Furthermore, in this embodiment, the signal processing unit 34 compares and analyzes the characteristics (e.g., received intensity, phase difference, etc.) of the signal from the left-hand circularly polarized channel and the signal from the right-hand circularly polarized channel to perform advanced signal processing that takes advantage of the characteristics of circular polarization, such as separating and identifying the single-reflection wave component from the two or more-reflection wave component, and ghost suppression processing based on this.

[0225] The target information and environmental information obtained by the signal processing unit 34 are further output to the calculation unit 31. Based on this information, the calculation unit 31 performs higher-level application processing, such as estimating vital information (respiration, heart rate, etc.), tracking, classifying, and displaying target information, or controlling external devices.

[0226] Figure 44 is a schematic diagram showing one example of an antenna array configuration for a radar system utilizing circular polarization when receiving different types of circular polarization (e.g., left-hand circular polarization and right-hand circular polarization). This type of configuration illustrates a general arrangement concept seen when no specific optimization arrangement rules, such as KR product extension, are applied.

[0227] In the diagram, the rectangular block groups shown on the left represent, as an example, a first antenna element group that receives left-hand circular polarization, while the rectangular block groups shown on the right represent a second antenna element group that receives right-hand circular polarization. Each of these first and second antenna element groups consists of multiple antenna elements, and each group is arranged in a linear fashion.

[0228] In this configuration, separate groups of antenna elements are required to correspond to different polarizations, thus necessitating physical space for each group. As shown in the diagram, if left-hand circular polarization antenna elements and right-hand circular polarization antenna elements are arranged side-by-side, for example, on the same substrate, the area required by each antenna element group is simply added together, resulting in the entire antenna array occupying a large area. In particular, if a sufficient number of antenna elements are secured for each polarization to achieve the desired receiving sensitivity and angular resolution for the radar device, the physical dimensions of the antenna array increase, which can limit the miniaturization of the entire device and the freedom of layout when mounting in a limited space.

[0229] Figure 45 is a schematic diagram showing several variations in the arrangement of left-hand circularly polarized antenna elements and right-hand circularly polarized antenna elements in an antenna array according to one embodiment of this technology. These variations demonstrate that there is design freedom in terms of the number of antenna elements and their physical arrangement.

[0230] Figure 455A shows an example configuration in which a first group of antenna elements that receives left-hand circular polarization and a second group of antenna elements that receive right-hand circular polarization are composed of approximately the same number of antenna elements and are physically separated (or adjacent to each other).

[0231] Figure 45B shows an example configuration in which the number of antenna elements in the first antenna element group (left-hand polarization) and the second antenna element group (right-hand polarization) are different. In this example, the number of elements in the left-hand polarization antenna element group is shown to be greater than the number of elements in the right-hand polarization antenna element group. Such an asymmetrical element configuration can be applied when prioritizing the reception characteristics of a specific polarization component or when adjusting the size of one of the element groups according to mounting area constraints.

[0232] Figure 45C shows an example configuration in which the first group of antenna elements (left-hand circular polarization) and the second group of antenna elements (right-hand circular polarization) are composed of approximately the same number of antenna elements, but these antenna elements are arranged to partially overlap or mix spatially. The figure shows how the left-hand and right-hand circular polarization antenna elements share or are arranged in close proximity to each other, which is expected to reduce the overall area occupied by the antenna array.

[0233] Figure 45D shows an example configuration in which the number of antenna elements differs between the first antenna element group (left-hand circular polarization) and the second antenna element group (right-hand circular polarization), and these antenna elements are spatially partially overlapping or mixed. This corresponds to a configuration that combines the asymmetry in the number of elements shown in Figure 45B with the overlapping arrangement shown in Figure 45C.

[0234] These configuration variations are selected or combined as appropriate depending on the application, required performance, and implementation constraints of the radar equipment. In particular, by applying the KR product extension configuration rule to the internal arrangement of each antenna element group, it becomes possible to maintain high angular resolution in these variations while also utilizing the characteristics of circular polarization to separate reflection paths and optimize the occupied area.

[0235] Furthermore, the specific form of the antenna elements constituting the transmitting antenna array TX, the first receiving antenna element group (same polarization), and the second receiving antenna element group (orthogonal polarization) is not particularly limited as long as they are capable of generating or receiving circular polarization. For example, various known circular polarization antenna element technologies such as patch antennas using microstrip lines, slot antennas, and helical antennas can be applied. The mounting form is also irrelevant, whether they are formed on a substrate or on a semiconductor chip.

[0236] [10. Tenth Embodiment of the Technology (Example 5 of a Radar Device)] In the ninth embodiment, "at least one" of the transmitting array, the same polarization receiving group, and the orthogonal polarization receiving group had a KR product extended array. In this embodiment, more specifically, "each of the first receiving antenna element group (same polarization receiving group) and the second receiving antenna element group (orthogonal polarization receiving group)" that constitute the receiving antenna array RX has an independent KR product extended array.

[0237] For example, the arrangement of antenna elements for receiving left-hand circular polarization (LHCP) and the arrangement of antenna elements for receiving right-hand circular polarization (RHCP) may be determined according to the rules of formula (1) above. Similarly, the transmitting antenna array TX (e.g., RHCP transmission) may also be arranged according to formula (1) above, or it may be a different arrangement (e.g., single elements or equally spaced arrangement).

[0238] In this way, by applying the KR product extension array independently to each polarization, high angular resolution can be obtained for signals received in each polarization channel, and reflection path separation using polarization information also becomes possible. As a result, it is expected that both angular resolution and multipath suppression performance will be achieved at a high level.

[0239] [11. Eleventh Embodiment of the Technology (Example 6 of a Radar Device)] Figure 46 is a block diagram showing an example configuration of a radar device 100 according to one embodiment of the Technology. As shown in Figure 46, receiving antenna arrays RX1 and RX3 receive left-hand circular polarization, and receiving antenna arrays RX2 and RXN receive right-hand circular polarization.

[0240] The signal processing unit 34 performs range FFT processing on the received signal and detects a single reflected wave from the target object based on the circular polarization component orthogonal to the circular polarization radiated from the transmitting antenna array TX (for example, the left-hand circular polarization component if the transmission is right-hand circular polarization).

[0241] Next, the calculation unit 31 identifies or confirms that the target is a person by analyzing minute fluctuations caused by a person's breathing or heartbeat from the detected single-reflection wave signal.

[0242] Next, the signal processing unit 34 detects waves that have undergone two or more reflections (for example, waves that have been reflected by a nearby obstacle such as a wall and then reflected by the target object, or waves that have followed the reverse path) based on the same circular polarization component as the circularly polarized waves radiated from the transmitting antenna array TX (for example, the right-hand circular polarization component if the transmission is right-hand circular polarization). This allows the system to detect the presence of an obstacle such as a wall near the target object.

[0243] Next, the signal processing unit 34 performs direction of arrival estimation (DOA estimation, for example, angle FFT processing) for both the first-reflected wave and the second-reflected wave, and separates and identifies the directions of arrival for both.

[0244] Finally, the signal processing unit 34 or calculation unit 31 calculates the difference (at least one of the distance difference and the angle difference) between the arrival distance and arrival angle of the first reflected wave and the second reflected wave, respectively. Based on this geometric difference information, the exact distance between the person and the wall is estimated, for example, by applying the principle of triangulation.

[0245] Figure 47 is a graph showing the distance spectrum in a signal processing unit 34 according to one embodiment of this technology, where the horizontal axis represents distance and the vertical axis represents the signal intensity (level) of the reflected wave. It schematically depicts how a single reflected wave W1 from a person and a double reflected wave W2 that has passed through a wall or the like are detected at different distances and with different signal intensities. Generally, the double reflected wave W2 travels a longer propagation path than the single reflected wave W1, so a peak appears at a greater distance.

[0246] Figure 48 is a conceptual diagram visually illustrating the principle of angle separation by the signal processing unit 34 according to one embodiment of this technology. It shows that the direction of the target object, person T1, as seen from the radar device 100, and the signal caused by wall reflection (for example, the direction of the ghost image T3 of the person reflected from the wall, or the direction of the wall itself) can be separated as different arrival angles by, for example, angle FFT processing. The first reflected wave corresponds to the direct reflection path from the person, and the second reflected wave corresponds to the reflection path involving the wall.

[0247] Figure 49 is a conceptual diagram showing the physical arrangement corresponding to Figure 48. It shows the physical arrangement of the radar device 100, person T1, and wall T2. If the arrival distance and arrival angle (including the relative angle difference between the person and the wall) of the one-time reflected wave from person T1 and the two-time reflected wave via wall T2 are known, it is possible to calculate the physical distance D between the person and the wall with high accuracy using this information.

[0248] As shown in this diagram, the circular polarization radar system can accurately determine the relative positional relationship between a person and obstacles such as walls, even in complex reflective environments, through the coordinated operation of each component and processing step. This provides useful information in a variety of application fields, such as monitoring systems and autonomous driving assistance.

[0249] [12. Twelfth Embodiment of the Technology (Example 7 of a Radar Device)] Figures 50 and 51 are block diagrams showing an example configuration of a radar device 100 according to one embodiment of the Technology.

[0250] Figure 50 shows an example of a simpler one-channel receiver configuration comprising a transmitting antenna array TX, a single receiving antenna array (e.g., a broadband circularly polarized antenna capable of receiving either left-hand circular polarization or right-hand circular polarization, or both), an analog-to-digital converter (ADC1), a signal processing unit 34, and an arithmetic unit 31.

[0251] Figure 51 shows an example of a two-channel receiving configuration comprising a transmitting antenna array TX, antenna arrays for receiving at least two types of circular polarization (for example, RX1 for left-hand circular polarization and RX2 for right-hand circular polarization), ADC1 and ADC2 for digitizing each signal, a signal processing unit 34, and a calculation unit 31.

[0252] First, the signal processing unit 34 performs range FFT processing on the received signal and detects a single reflected wave from the target object based on the circular polarization component orthogonal to the circular polarization radiated from the transmitting antenna array TX.

[0253] Next, the calculation unit 31 identifies or confirms that the target is a person by analyzing minute fluctuations caused by a person's breathing or heartbeat from the detected single-reflection wave signal.

[0254] Next, the signal processing unit 34 detects waves that have undergone two or more reflections based on the same circular polarization component as the circularly polarized waves radiated from the transmitting antenna array TX. This allows it to detect the presence of obstacles such as walls in the vicinity of a person.

[0255] Finally, the signal processing unit 34 or calculation unit 31 extracts the difference (distance difference) between the arrival distance of the detected first reflected wave and the arrival distance of the detected second reflected wave. This distance difference serves as an indicator of the degree of proximity between a person and an obstacle.

[0256] Figure 52 is a conceptual diagram showing the physical arrangement. It schematically illustrates the physical arrangement of the radar device 100, person T1, and wall T2, as well as the paths of the single reflected wave from person T1 and the double reflected wave passing through wall T2. In this configuration, it is possible to determine whether a person is approaching an obstacle, or their relative proximity, solely from the distance information of the single and double reflected waves, without using angular information.

[0257] As shown in this diagram, the system and processing described herein allow for the detection of obstacles near a person and the estimation of their proximity by using a relatively simple receiving configuration (e.g., one or two channels) and utilizing the characteristics of circular polarization to separate and compare distance information between a single reflected wave and a double reflected wave. This function is expected to have applications, for example, in automatic door opening and closing devices that automatically open and close doors when a person approaches them.

[0258] [13. Thirteenth Embodiment of the Technology (Example 8 of a Radar Device)] Figure 53 is a block diagram showing an example configuration of a radar device 100 according to one embodiment of the Technology. As shown in Figure 53, the radar device comprises a transmitting antenna array TX, a plurality of circularly polarized receiving antenna arrays (RX1 to RXN), a group of analog-to-digital converters (ADC1 to ADCN), a signal processing unit 34, and a calculation unit 31.

[0259] First, the signal processing unit 34 performs range FFT processing on the received signal and detects a single reflected wave from an object such as a wall based on the circular polarization component that is orthogonal to the circular polarization radiated from the transmitting antenna array TX.

[0260] Next, the calculation unit 31 analyzes the vital information from the detected single-reflection wave signal and confirms that no features indicating the presence of a person (minor fluctuations caused by respiration or heart rate) are detected. Based on this, it is determined that there is no person in the monitored space.

[0261] Next, the signal processing unit 34 extracts the difference in arrival distance between the detected single reflected wave (direct reflection from a wall, etc.) and two or more reflected waves (for example, waves reflected multiple times between different walls) detected based on the same circular polarization component as the circularly polarized wave radiated from the transmitting antenna array TX.

[0262] Next, the signal processing unit 34 performs direction of arrival estimation (DOA estimation, for example, angle FFT processing) for each of the detected single-reflection waves and two or more-reflection waves, and separates and identifies the direction from which those waves are arriving.

[0263] Finally, the signal processing unit 34 or the calculation unit 31 estimates the size of the space (for example, the dimensions and shape of a room, the position of walls, etc.) based on the arrival distance (and the difference) of each reflected wave and the arrival angle (and the difference) of each reflected wave.

[0264] Figure 54 is a graph showing the distance spectrum in a signal processing unit 34 according to one embodiment of this technology, where the horizontal axis represents distance and the vertical axis represents the signal intensity (level) of the reflected wave. It schematically depicts how a single reflected wave W1 from a wall or the like and a double reflected wave W2 that has traveled a more complex path are detected at different distances and signal intensities.

[0265] Figure 55 is a conceptual diagram visually illustrating the principle of angle separation by the signal processing unit 34 according to one embodiment of this technology. This figure shows that, as viewed from the radar device 100, a single reflected wave from the front wall T4 and two or more reflected waves (wall ghosts T5, T6) that have passed through the left and right walls and the front wall T4 can be separated and detected as having different arrival angles (θ1, θ2, etc.).

[0266] Figure 56 is a conceptual diagram showing the physical arrangement corresponding to Figure 55. This diagram depicts the walls of a room where the radar device 100 is installed, and schematically shows the paths (single reflection and multiple reflections) of the transmitted waves from the radar that are reflected back from each wall. By analyzing the arrival distance and arrival angle (θ1, θ2) of these reflected waves, it is possible to identify the positions of the walls in the room and, as a result, estimate the size and shape of the space.

[0267] Figure 57 is also a conceptual diagram showing the physical arrangement. It explains the series of processing concepts from when the radar device 100 first estimates the size of the surveillance space, then optimizes the surveillance range based on that information, detects a person T1 in the space, and acquires their vital information.

[0268] First, the signal processing unit 34 receives the wave that has been reflected back by an object such as a wall from the circularly polarized signal radiated from the transmitting antenna array TX of the radar device 100, and performs range FFT processing. Then, based on the circularly polarized component orthogonal to the transmitted polarization, it detects the wave that has been reflected once from the wall or other object.

[0269] Next, the calculation unit 31 analyzes the signal of this single reflected wave to determine whether or not vital information is present, and confirms that no clear vital signs indicating the presence of a person are detected at this stage. Based on this, it is determined that the initial observation target is mainly a stationary object (such as a wall).

[0270] Next, the signal processing unit 34 extracts the difference in arrival distance between a single reflected wave and two or more reflected waves (for example, waves reflected multiple times between different walls) detected based on the same circular polarization component as the transmitted polarization.

[0271] Next, the signal processing unit 34 performs direction estimation (for example, angle FFT processing) for each of these single-reflected waves and two or more-reflected waves to separate and identify the direction from which each reflected wave is arriving.

[0272] Next, the calculation unit 31 estimates the size of the space being monitored by the radar device, such as the position of walls or the dimensions of a room, based on the information regarding these distance and angle differences.

[0273] After the spatial extent is estimated, the signal processing unit 34 intentionally restricts the radar's monitoring range based on that information. Specifically, it limits the distance range to be evaluated in the range FFT processing, or sets an effective monitoring angle range in the angle FFT processing, as shown in the figure. This angle restriction may mean, for example, concentrating the radar's sensitivity in an angle range inside the estimated wall position, i.e., corresponding to the interior space of the room.

[0274] Finally, within a limited and optimized monitoring range dynamically or statically set based on environmental information, the signal processing unit 34 performs the detection process of a single reflected wave from the object again. The calculation unit 31 detects extremely minute phase fluctuations contained in the received signal identified as a single reflected wave from a person. These phase fluctuations are caused by periodic displacements of several millimeters to more than 10 millimeters of the rib cage associated with a person's respiratory movements, and even finer periodic vibrations of tens to hundreds of micrometers of the body surface associated with the beating of the heart, which result in minute changes in the round-trip propagation path length of the radar wave.

[0275] The calculation unit 31 applies the extracted phase time-series data to, for example, the suppression of unwanted components using an adaptive noise canceller (ANC), the separation and extraction of the respiratory band (e.g., 0.1 Hz to 0.5 Hz) and the heart rate band (e.g., 0.8 Hz to 2.0 Hz) using a bandpass filter, and high-resolution frequency analysis (e.g., spectral estimation using an autoregressive model, MUSIC algorithm, ESPRIT algorithm, etc.) or time-frequency analysis (e.g., continuous wavelet transform or short-time Fourier transform) to each band component. This separates weak vital signal components from noise and precisely quantifies their periodicity and amplitude.

[0276] As a result, the calculation unit 31 estimates not only basic indicators such as respiratory rate and / or heart rate as vital information of the target person, but also more detailed and complex information indicating the physiological state, such as parameters related to respiratory depth, respiratory pattern stability, and heart rate variability (HRV), depending on the situation.

[0277] Thus, according to the system and processing of this embodiment, the circularly polarized radar device can acquire information about the size and shape of a space by analyzing reflected waves from walls, even when no people are present in the monitored space. This has the potential to be applied to indoor mapping in smart home environments and monitoring the status of vacant rooms.

[0278] [14. Fourteenth Embodiment of the Technology (Example 9 of a Radar Device)] Figure 58 is a block diagram showing an example configuration of a radar device 100 according to one embodiment of the Technology. The receiving processing system includes a transmitting antenna array TX (capable of transmitting left-hand or right-hand circular polarization), a plurality of circular polarization receiving antenna arrays RX1 to RXN, an analog-to-digital converter group ADC1 to ADCN for digitizing each received signal, a signal processing unit 34, and a calculation unit 31. The basic configuration of this receiving system is the same as that shown in the previous figure.

[0279] Furthermore, this figure shows a plurality of control units 37, each connected to an external device (for example, an audio device 35 such as a speaker) and a motor 36 for physically adjusting its orientation, etc., based on the output from the signal processing unit 34.

[0280] The control unit 37 is configured to output a control signal that controls the operation of an external device based on the detected target object's position information, or at least one of the estimated relative position, proximity, and spatial area.

[0281] First, the signal processing unit 34 performs range FFT processing on the received signal and detects a single reflected wave from the target object based on the circular polarization component orthogonal to the circular polarization radiated from the transmitting antenna array TX.

[0282] Next, the calculation unit 31 identifies or confirms that the target is a person by analyzing minute fluctuations caused by a person's breathing or heartbeat from the detected single-reflection wave signal.

[0283] Next, the signal processing unit 34 detects two or more reflected waves from surrounding objects such as walls, based on the same circular polarization component as the circular polarization radiated from the transmitting antenna array TX, and recognizes the presence of obstacles such as walls nearby.

[0284] Next, the signal processing unit 34 detects the presence of the acoustic device 35 based on "vibration information" by capturing weak electromagnetic waves emitted by the acoustic device 35 itself, or modulation of ambient radio waves or subtle changes in reflection characteristics caused by vibrations of the acoustic device 35's casing. This vibration information can be particularly noticeable when the acoustic device 35 is emitting sound.

[0285] Next, the signal processing unit 34 performs direction of arrival estimation (DOA estimation, for example, angle FFT processing) on ​​the signal from the acoustic device 35 whose presence has been suggested (or the signal modulated by the acoustic device 35) to determine the position of each acoustic device 35 in space.

[0286] Finally, each control unit 37 adjusts the physical orientation of each sound device 35 using a motor 36, or electrically controls the output volume, phase, delay time, etc., from each sound device 35, based on the location information of the identified person and the location information of each identified sound device 35.

[0287] Figure 59 is a conceptual diagram showing the physical arrangement. It schematically illustrates a situation where a person T1 is in the space monitored by the radar device 100, and multiple acoustic devices 35 are arranged around them. The radar device 100 adjusts the orientation and output of each acoustic device 35 based on the position of person T1, so that the sound from each acoustic device 35 reaches the person optimally, or so that a specific sound effect (e.g., 3D surround sound) is achieved.

[0288] Thus, according to the system and processing of this embodiment, it is possible to detect the position of a person in space with high precision using a circularly polarized radar device, and at the same time identify the position of external devices such as acoustic devices present in the space (for example, by using their vibration information), and to intelligently control the operation of external devices based on this position information. As a result, it is expected that a higher quality, personalized acoustic experience will be provided according to the user's location and situation.

[0289] [15. Fifteenth Embodiment of the Technology (Example 10 of a Radar Device)] Figure 60 is a block diagram showing an example configuration of a radar device 100 according to one embodiment of the Technology. The receiving processing system includes a transmitting antenna array TX (capable of transmitting left-hand or right-hand circular polarization), a plurality of circular polarization receiving antenna arrays RX1 to RXN, a group of analog-to-digital converters ADC1 to ADCN that digitize each received signal, a signal processing unit 34, and a calculation unit 31. The basic configuration of this receiving system is the same as that shown in the previous figure. Furthermore, this figure shows a control unit 37 that adjusts the acoustic characteristics of an acoustic device 35, which is integrated with or located near the radar device 100, based on the output from the signal processing unit 34.

[0290] First, the signal processing unit 34 performs range FFT processing on the received signal and detects a single reflected wave from the target object (such as a person) based on the circular polarization component that is orthogonal to the circular polarization radiated from the transmitting antenna array TX.

[0291] Next, the calculation unit 31 identifies or confirms that the target is a person by analyzing minute fluctuations caused by a person's breathing or heartbeat from the detected single-reflection wave signal.

[0292] Next, the signal processing unit 34 performs environmental recognition processing. First, it detects two or more reflected waves from nearby obstacles such as walls, based on the same circular polarization component as the circularly polarized wave radiated from the transmitting antenna array TX. Next, it extracts the difference in arrival distance between the detected single reflected wave and the two or more reflected waves, thereby estimating the proximity between the target object and the obstacle. Furthermore, it performs arrival direction estimation (DOA estimation, e.g., angle FFT processing) for each of these single and two or more reflected waves to separate and identify the direction from which each reflected wave is arriving.

[0293] Finally, the control unit 37 comprehensively analyzes the information from each reflection point obtained in this way, such as the position of the person, the position and direction of obstacles such as walls, and the distance relationship between them. Based on this analysis, it precisely controls the output characteristics of the acoustic devices (e.g., the intensity, phase, and directivity of each frequency component) so that sound waves emitted from one or a few acoustic devices are effectively reflected off the walls of the room, forming a virtual surround sound field at the person's position, as if there were multiple sound sources.

[0294] Figure 61 is a conceptual diagram showing the physical arrangement. It schematically illustrates a situation where a person T1 is present in the space monitored by the radar device 100, and an acoustic device (not shown) is installed integrally with or near the radar device 100. Conceptually, it shows how the radar device 100 captures reflected waves from the surrounding environment, including the person and the wall, and uses this information to perform acoustic control so that sound from the acoustic device is reflected off the wall as intended, producing the desired acoustic effect (for example, sound from behind or the side) at the person's location.

[0295] Thus, according to the system and processing of this embodiment, it is possible to accurately grasp the position of a person in space and the surrounding reflective environment (such as the position of walls) using a circularly polarized radar device, and to utilize this three-dimensional acoustic spatial information to provide an immersive virtual surround sound experience even with a limited number of sound devices.

[0296] [16. Sixteenth Embodiment of the Technology (Example 11 of a Radar Device)] In the above embodiment, the transmitting antenna array TX was described as a configuration that mainly transmits a transmission signal having a first circular polarization (e.g., RHCP), but the present invention is not limited thereto. In other embodiments, the transmitting antenna array TX may be physically configured to include a first group of transmitting antenna elements that generate and radiate a transmission signal having a first circular polarization (e.g., RHCP), and a second group of transmitting antenna elements that generate and radiate a transmission signal having a second circular polarization (e.g., LHCP) that is different from (e.g., orthogonal to) the first circular polarization.

[0297] In such a configuration, the transmitting antenna array TX may be controlled by a control unit (e.g., a calculation unit 31 or a dedicated transmitting control unit) to perform one or more of the following operating modes:

[0298] Polarization-selective transmission mode: Depending on the measurement target, environmental conditions, or specific sensing purpose, either the first or second group of transmitting antenna elements is selected to selectively radiate the corresponding circularly polarized (RHCP or LHCP) transmission signal. This makes it possible, for example, to improve the detection sensitivity of targets that show a unique response to a particular polarization, or to reduce the influence of clutter components with a specific polarization state.

[0299] Polarization Time-Division Transmission Mode: The first group of transmitting antenna elements and the second group of transmitting antenna elements are activated alternately at predetermined time intervals, and the RHCP transmission signal and the LHCP transmission signal are radiated sequentially in a time-division manner. On the receiving side, by receiving and processing the reflected waves corresponding to each transmitted polarization, the polarization scattering characteristics of the target object can be understood in more detail.

[0300] Polarization Simultaneous Transmission Mode (Frequency Division or Code Division): The first group of transmitting antenna elements and the second group of transmitting antenna elements simultaneously radiate RHCP and LHCP transmission signals using different frequency carriers or different spreading codes. The receiving side can obtain observation data in both polarizations in real time by separating each polarization component based on frequency or code.

[0301] By adopting this type of transmitting antenna array configuration, the following advantages can be obtained.

[0302] [More Advanced Sensing Control] By actively controlling the transmission polarization, it may be possible to acquire richer information about the material, shape, and surface condition of the target object. Furthermore, by optimizing the transmission polarization in a multipath environment, more advanced signal separation and ghost suppression control can be expected, emphasizing desired reflected waves and suppressing unwanted ones.

[0303] [Potential for simplifying the receiver configuration] For example, even if the receiving antenna array has a relatively simple configuration that selectively receives a single circular polarization (e.g., RHCP only), by switching between RHCP and LHCP on the transmitting side, it may be possible to observe the response of the target object to both circular polarizations in time-division multiplexing and obtain the information necessary to separate single-reflection waves from two or more reflections. This may reduce the number of elements and complexity of the receiving antenna array in certain applications.

[0304] [Acquisition of new measurement parameters] By analyzing signals with various combinations of transmit and receive polarization (e.g., transmit RHCP / receive RHCP, transmit RHCP / receive LHCP, transmit LHCP / receive RHCP, transmit LHCP / receive LHCP), new measurement parameters (e.g., elements of the polarization transformation matrix) that could not be obtained with conventional single-polarization transmission can be acquired, leading to a more detailed characterization of the target object.

[0305] Furthermore, the embodiments relating to this technology are not limited to the embodiments described above, and various modifications are possible without departing from the gist of this technology. The specific numerical values, shapes, materials (including composition), etc. described in each embodiment are examples only and are not limited thereto.

[0306] Furthermore, this technology can also take the following configuration: [1] It comprises N (N is 4 or more) antenna elements arranged in a straight line, the spacing between each of the antenna elements is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements is {u ｋ} (0 = u １ <u ２ <...<u Ｎ An antenna array that is the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A. [2] A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in [1]. [3] A radar device comprising a transmitting antenna array and a receiving antenna array, wherein both the transmitting antenna array and the receiving antenna array are the antenna array described in [1]. [4] A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in [1], and the transmitting antenna array and the receiving antenna array are arranged parallel to each other. [5] The radar device according to [4], wherein the spacing of the antenna elements in the antenna array with fewer antenna elements is an integer multiple of the spacing of the antenna elements in the antenna array with more antenna elements. [6] An antenna array in which a plurality of antenna elements are arranged in a rectangular shape, wherein the rectangle has a pair of opposing sides along a first direction and a pair of opposing sides along a second direction perpendicular to the first direction, and comprises a plurality of antenna arrays including a plurality of antenna elements arranged in a straight line along the first direction, wherein in at least one of the plurality of antenna arrays, the spacing between each of the antenna elements is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements {u ｋ} (0 = u １ <u ２ <...<u Ｎ An antenna array that is the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A. [7] In all of the plurality of antenna arrays, the spacing between each antenna element is an integer multiple of the shortest spacing, and the relative arrangement position of each antenna element {u ｋ} (0 = u １ <u ２ <...<u Ｎ[6] The antenna array described in [6], wherein the first direction of the transmitting antenna array and the first direction of the receiving antenna array are arranged parallel to each other. [8] A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in [6]. [9] A radar device comprising a transmitting antenna array and a receiving antenna array, wherein both the transmitting antenna array and the receiving antenna array are the antenna array described in [6].

[10] A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in [6], wherein the first direction of the transmitting antenna array and the first direction of the receiving antenna array are arranged parallel to each other.

[11] The radar device described in

[10] , wherein the spacing of the antenna elements in the antenna array with fewer antenna elements is an integer multiple of the spacing of the antenna elements in the antenna array with more antenna elements.

[12] An antenna array in which a plurality of antenna elements are arranged in a rectangular shape, wherein the rectangle has a pair of opposing sides along a first direction and a pair of opposing sides along a second direction perpendicular to the first direction, and comprises a plurality of first antenna arrays including a plurality of antenna elements arranged linearly along the first direction, and a plurality of second antenna arrays including a plurality of antenna elements arranged linearly along the second direction, wherein in both the plurality of first antenna arrays and the plurality of second antenna arrays, the spacing between each of the antenna elements in at least one antenna array is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements in at least one antenna array {u ｋ} (0 = u １ <u ２ <...<u ＮAn antenna array whose solution is the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A.

[13] In all of the plurality of antenna arrays, the spacing between each antenna element is an integer multiple of the shortest spacing, and the relative arrangement position of each antenna element {u ｋ} (0 = u １ <u ２ <...<u Ｎ

[12] The antenna array described in

[12] , wherein the first direction of the transmitting antenna array and the first direction of the receiving antenna array are arranged parallel to each other.

[14] A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in

[12] .

[15] A radar device comprising a transmitting antenna array and a receiving antenna array, wherein both the transmitting antenna array and the receiving antenna array are the antenna array described in

[12] .

[16] A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in

[12] , wherein the first direction of the transmitting antenna array and the first direction of the receiving antenna array are arranged parallel to each other.

[17] The radar device according to

[16] , wherein, in the first direction, the spacing between the antenna elements of the antenna array with a smaller number of antenna elements among the transmitting antenna array and the receiving antenna array is an integer multiple of the spacing between the antenna elements of the antenna array with a larger number of antenna elements.

[18] The radar device according to

[16] or

[17] , wherein the second direction of the transmitting antenna array and the second direction of the receiving antenna array are arranged parallel to each other.

[19] The radar device according to

[18] , wherein, in the second direction, the spacing between the antenna elements of the antenna array with a smaller number of antenna elements among the transmitting antenna array and the receiving antenna array is an integer multiple of the spacing between the antenna elements of the antenna array with a larger number of antenna elements.

[20] An antenna array comprising a first group of antenna elements corresponding to at least a first polarization and a second group of antenna elements corresponding to a second polarization different from the first polarization, wherein at least one of the first group of antenna elements and the second group of antenna elements has the configuration of the antenna array described in any of [1] to

[19] .

[21] A radar device comprising: a transmitting antenna array; a receiving antenna array; and a signal processing unit for processing signals received by the receiving antenna array, wherein the transmitting antenna array is configured to transmit a transmission signal having a first circular polarization; the receiving antenna array includes a first group of receiving antenna elements that receive the same circular polarization as the first circular polarization and a second group of receiving antenna elements that receive a second circular polarization orthogonal to the first circular polarization; at least one of the transmitting antenna array, the first group of receiving antenna elements, and the second group of receiving antenna elements has the configuration of the antenna array described in claim 1; and the signal processing unit is configured to distinguish between a single reflection of the transmission signal and two or more reflections of the transmission signal based on the characteristic difference between the signal from the first group of receiving antenna elements and the signal from the second group of receiving antenna elements.

[22] The radar device according to

[21] , wherein each of the first group of receiving antenna elements and the second group of receiving antenna elements has the configuration of the antenna array described in claim 1.

[23] The radar device according to

[21] or

[22] , wherein the signal processing unit is configured to calculate at least one of the distance difference and the angular difference between the distinguished single reflected wave and the two or more reflected waves.

[24] The radar device according to

[23] , wherein the signal processing unit is configured to estimate at least one of the relative positional relationship between the target object and other objects, the presence or proximity of obstacles near the target object, and the size of the space, based on at least one of the calculated distance difference and angular difference.

[25] The radar device according to any one of

[21] to

[24] , further comprising a calculation unit configured to estimate vital information of a human body based on signals received by the receiving antenna array.

[26] The radar device according to

[25] , wherein the vital information includes at least one of respiration and heart rate.

[27] The radar device according to

[25] or

[26] , wherein the calculation unit is configured to estimate the vital information by detecting minute phase fluctuations contained in the received signal.

[28] The radar device according to any one of

[24] to

[27] , further comprising a control unit configured to output a control signal for controlling the operation of an external device based on the position information of a detected target, or at least one of the estimated relative position, proximity, and spatial extent.

[29] The radar device according to

[28] , wherein the external device includes an acoustic device.

[30] The radar device according to any one of

[21] to

[29] , wherein the number of antenna elements constituting the first receiving antenna element group is different from the number of antenna elements constituting the second receiving antenna element group.

[31] The radar device according to any one of

[21] to

[30] , wherein at least a portion of the antenna elements constituting the first receiving antenna element group and at least a portion of the antenna elements constituting the second receiving antenna element group are arranged in a spatially overlapping manner.

[32] The radar device according to any one of

[21] to

[31] , wherein the transmitting antenna array includes a first transmitting antenna element group having the first circular polarization and a second transmitting antenna element group having the second circular polarization.

[0307] TX Transmitting antenna array RX Receiving antenna array 100 Radar device 31 Calculation unit 32 Transmitting control unit 33 Signal generation unit 34 Signal processing unit 35 Acoustic device 36 Motor 37 Control unit

Claims

1. It comprises N (N is 4 or more) antenna elements arranged in a straight line, the spacing between each of the antenna elements is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements {u ｋ } (0 = u １ <u ２ <...<u Ｎ An antenna array whose solution is the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A.

2. A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in claim 1.

3. A radar device comprising a transmitting antenna array and a receiving antenna array, wherein both the transmitting antenna array and the receiving antenna array are the antenna arrays described in claim 1.

4. A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in claim 1, and the transmitting antenna array and the receiving antenna array are arranged parallel to each other.

5. The radar device according to claim 4, wherein the spacing between the antenna elements of the antenna array with fewer antenna elements is an integer multiple of the spacing between the antenna elements of the antenna array with more antenna elements.

6. An antenna array in which a plurality of antenna elements are arranged in a rectangular shape, wherein the rectangle has a pair of opposing sides along a first direction and a pair of opposing sides along a second direction perpendicular to the first direction, and comprises a plurality of antenna arrays including a plurality of the antenna elements arranged in a straight line along the first direction, wherein in at least one of the plurality of antenna arrays, the spacing between each of the antenna elements is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements {u ｋ } (0 = u １ <u ２ <...<u Ｎ An antenna array whose solution is the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A.

7. In all of the plurality of antenna arrays, the interval between each of the antenna elements is an integer multiple of the shortest interval, and the relative array position {u ｋ} (0 = u １ < u ２ <... < u Ｎ ) is the solution of the mathematical formula (1) defined as a maximization problem for maximizing the aperture length A. The antenna array according to claim 6.

8. A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in claim 6.

9. A radar device comprising a transmitting antenna array and a receiving antenna array, wherein both the transmitting antenna array and the receiving antenna array are the antenna arrays described in claim 6.

10. A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in claim 6, and the first direction of the transmitting antenna array and the first direction of the receiving antenna array are arranged parallel to each other.

11. The radar device according to claim 10, wherein, among the transmitting antenna array and the receiving antenna array, the spacing between the antenna elements of the antenna array with fewer antenna elements is an integer multiple of the spacing between the antenna elements of the antenna array with more antenna elements.

12. An antenna array in which a plurality of antenna elements are arranged in a rectangular shape, wherein the rectangle has a pair of opposing sides along a first direction and a pair of opposing sides along a second direction perpendicular to the first direction, and comprises a plurality of first antenna arrays including a plurality of the antenna elements arranged linearly along the first direction, and a plurality of second antenna arrays including a plurality of the antenna elements arranged linearly along the second direction, wherein in both the plurality of first antenna arrays and the plurality of second antenna arrays, the spacing between each of the antenna elements in at least one antenna array is an integer multiple of the shortest spacing, and the relative arrangement position of each of the antenna elements in at least one antenna array {u ｋ } (0 = u １ <u ２ <...<u Ｎ An antenna array whose solution is the solution to the following equation (1), which is defined as a maximization problem that maximizes the aperture length A.

13. In all of the above-mentioned antenna arrays, the spacing between each antenna element is an integer multiple of the shortest spacing, and the relative arrangement position of each antenna element {u ｋ } (0 = u １ <u ２ <...<u Ｎ The antenna array according to claim 12, wherein ) is the solution to formula (1), which is defined as a maximization problem that maximizes the aperture length A.

14. A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in claim 12.

15. A radar device comprising a transmitting antenna array and a receiving antenna array, wherein both the transmitting antenna array and the receiving antenna array are the antenna arrays described in claim 12.

16. A radar device comprising a transmitting antenna array and a receiving antenna array, wherein at least one of the transmitting antenna array and the receiving antenna array is the antenna array described in claim 12, and the first direction of the transmitting antenna array and the first direction of the receiving antenna array are arranged parallel to each other.

17. The radar device according to claim 16, wherein, in the first direction, the spacing between the antenna elements of the antenna array with fewer antenna elements among the transmitting antenna array and the receiving antenna array is an integer multiple of the spacing between the antenna elements of the antenna array with more antenna elements.

18. The radar device according to claim 16, wherein the second direction of the transmitting antenna array and the second direction of the receiving antenna array are arranged parallel to each other.

19. The radar device according to claim 18, wherein, in the second direction, the spacing between the antenna elements of the antenna array with fewer antenna elements among the transmitting antenna array and the receiving antenna array is an integer multiple of the spacing between the antenna elements of the antenna array with more antenna elements.

20. An antenna array comprising a first group of antenna elements corresponding to at least a first polarization and a second group of antenna elements corresponding to a second polarization different from the first polarization, wherein at least one of the first group of antenna elements and the second group of antenna elements has the configuration of the antenna array described in claim 1.

21. A radar device comprising: a transmitting antenna array; a receiving antenna array; and a signal processing unit for processing signals received by the receiving antenna array, wherein the transmitting antenna array is configured to transmit a transmission signal having a first circular polarization; the receiving antenna array includes a first group of receiving antenna elements that receive the same circular polarization as the first circular polarization and a second group of receiving antenna elements that receive a second circular polarization orthogonal to the first circular polarization; at least one of the transmitting antenna array, the first group of receiving antenna elements, and the second group of receiving antenna elements has the configuration of the antenna array described in claim 1; and the signal processing unit is configured to distinguish between a single reflection and two or more reflections of the transmission signal based on the characteristic difference between the signal from the first group of receiving antenna elements and the signal from the second group of receiving antenna elements.

22. The radar apparatus according to claim 21, wherein each of the first receiving antenna element group and the second receiving antenna element group has the configuration of the antenna array described in claim 1.

23. The radar device according to claim 21, wherein the signal processing unit is configured to calculate at least one of the distance difference and the angular difference between the distinguished single reflected wave and the two or more reflected waves.

24. The radar device according to claim 23, wherein the signal processing unit is configured to estimate at least one of the following based on at least one of the calculated distance difference and angle difference: the relative positional relationship between the target object and other objects, the presence or proximity of obstacles near the target object, and the size of the space.

25. The radar device according to claim 21, further comprising a calculation unit configured to estimate vital information of a human body based on signals received by the receiving antenna array.

26. The radar device according to claim 25, wherein the vital information includes at least one of respiration and heart rate.

27. The radar device according to claim 25, wherein the calculation unit is configured to estimate the vital information by detecting minute phase fluctuations contained in the received signal.

28. The radar device according to claim 24, further comprising a control unit configured to output a control signal for controlling the operation of an external device based on the positional information of a detected target, or at least one of the estimated relative positional relationship, proximity, and spatial extent.

29. The radar apparatus according to claim 28, wherein the external device includes an acoustic device.

30. The radar device according to claim 21, wherein the number of antenna elements constituting the first receiving antenna element group is different from the number of antenna elements constituting the second receiving antenna element group.

31. The radar device according to claim 21, wherein at least a portion of the antenna elements constituting the first receiving antenna element group and at least a portion of the antenna elements constituting the second receiving antenna element group are arranged in a spatially overlapping manner.

32. The radar device according to claim 21, wherein the transmitting antenna array includes a first group of transmitting antenna elements having the first circular polarization and a second group of transmitting antenna elements having the second circular polarization.

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