Antenna array for high frequency devices

Abstract

To provide a transmission-reception antenna array for a high-frequency device which can suppress generation of, for example, a grating lobe and a side lobe by reducing the number of phase shifters and can realize a wide beam scan.SOLUTION: On-elements 111a, 111c of a transmission antenna array 107 and on-elements 211a and 211c of a reception antenna array 207 are arranged so that at least a part of their arrangements is compensated for from the center part to the four corners in a two-dimensional arrangement and so that the density becomes lower from the center part to the four corners.SELECTED DRAWING: Figure 8A

Description

[Technical Field]

[0001] The present invention relates to antenna arrays for radio frequency devices. [Background technology]

[0002] Technological development of phased array antennas for high-frequency devices is progressing (see, for example, Patent Document 1). According to the phased array antenna described in Patent Document 1, individual array elements (hereinafter referred to as on-elements) are arranged two-dimensionally, and the individual array elements are grouped into units of eight, for example, 4x2 or 8x1 rectangular subarrays. The multiple rectangular subarrays are then tiled to reduce the periodicity of the phase centers, thereby reducing grating lobes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-503621 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 reduces the periodicity of the phase center to suppress grating lobes. However, grating lobes themselves still remain (approximately -10 dBc), and the beam scanning range with side lobe and grating lobe suppression is limited to approximately ±10°. Furthermore, reducing the periodicity of the phase center causes all phase centers to shift irregularly from the element coordinates, complicating the calculation of phase values and tapering. In other words, as the off-grid phase center position increases both vertically and horizontally, the distance between adjacent on-elements deviates from the ideal distance of 0.5λ, which is no longer a given assumption, complicating the calculation of phase values.

[0005] The inventors have also discovered that grouping adjacent individual array elements vertically or horizontally to reduce the number of phase shifters and simplify the system results in the generation of grating lobes when scanning in the same vertical or horizontal direction as the grouping. In a prior application prior to this application, the inventors have also proposed a technology that can cancel grating lobes by forming a null filter using pairs of single elements arranged at specific intervals. Meanwhile, for example, in scanning radar sensors, there is a particular need to further reduce the number of phase shifters electrically connected to phased array elements in order to reduce costs and simplify the system. Furthermore, there is a need for a technology that can suppress side lobes to suppress unwanted surrounding waves.

[0006] An object of the present invention is to provide a transmitting / receiving antenna array for a high frequency device that can reduce the number of phase shifters, suppress the occurrence of grating lobes, side lobes, etc., and achieve wide-area beam scanning. [Means for solving the problem]

[0007] According to the invention of claim 1, a radar device is provided with a transmitting antenna array and a receiving antenna array, which are used in a radar device and are arranged two-dimensionally within a predetermined area, and each of which has effective elements (which can be expressed by "1", for example) electrically connected to a phase shifter and dummy elements (which can be expressed by "0", for example) not electrically connected to the phase shifter, and which are arranged within the predetermined area.

[0008] The effective elements of the transmitting antenna array include a first grouping of elements that are grouped adjacently along a specific vertical or horizontal direction in a two-dimensional arrangement and controlled by the same phase shifter, and second single elements that are provided separately and isolated from the first grouping of elements and arranged in pairs at a specific first interval in the specific direction.

[0009] The effective elements of the receiving antenna array include third grouping-on elements which are grouped adjacently along a specific vertical or horizontal direction in a two-dimensional arrangement and controlled by the same phase shifter, and fourth single-on elements which are provided separately and isolated from the third grouping-on elements and arranged in pairs at a specific second interval in the specific direction.

[0010] According to claim 1, the elements are arranged so that at least a part of the arrangement of each element is complementary from the center to the four corners of the two-dimensional array, and the density decreases from the center to the four corners. For example, it is advisable to use the receiving array as the base design and design the transmitting array so that the element arrangement is complementary.

[0011] Furthermore, according to the invention described in claim 2, if the on-elements of the transmitting antenna array and the on-elements of the receiving antenna array change the number of effective elements in one of the vertical or horizontal directions of the array (e.g., particularly in the central portion), the number (pitch) of side lobes changes, and the side lobe cancellation effect can be strengthened in the performance of the combined beam pattern for transmitting and receiving.

[0012] According to the invention of claim 3, the overlapping logical sum region (TX∪RX) of the on-elements of the transmitting antenna array and the on-elements of the receiving antenna array, i.e., the region of elements where either is "1" in the above-mentioned expression, is arranged complementarily so that the occupancy rate of effective elements within the maximum array area (16 x 12) is higher than that of the original array. The overlapping logical product region (TX∩RX) of the on-elements of the transmitting and receiving arrays, i.e., the overlapping region of elements where both elements are "1", may be connected in a diagonal direction (claim 5), or may be arranged in a ripple pattern (claim 6). With this configuration, the elements are arranged in a mutually complementary manner from the center to the four corners of the two-dimensional array, which allows for efficient cancellation of side lobes as a combined transmit and receive beam performance. Furthermore, by designing the element arrangement so that the density of elements is high in the center and low at the four corners, each array can suppress the generation of unnecessary side lobes with a small number of phase shifters. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an electrical configuration diagram of a radar device according to a first embodiment; [Figure 2] FIG. 1 is an electrical configuration diagram illustrating a transmitter according to a first embodiment; [Figure 3] FIG. 1 is an electrical configuration diagram illustrating a receiving section according to a first embodiment; [Figure 4] FIG. 1 is a diagram (base design) showing a schematic diagram of the arrangement of elements constituting a receiving antenna array according to the first embodiment; [Figure 5] An explanatory diagram of the layout dimensions of elements constituting a receiving antenna array in the first embodiment. [Figure 6] FIG. 1 is a diagram schematically illustrating the arrangement of elements constituting a transmitting antenna array according to the first embodiment. [Figure 7] FIG. 1 is an explanatory diagram of the layout dimensions of elements constituting a transmitting antenna array according to the first embodiment. [Figure 8A] Logical OR and AND analysis results of the arrangement state of the transmitting and receiving elements shown in the first embodiment [Figure 8B] 1 is a Venn diagram showing an image of an overlapping state of transmitting and receiving elements according to the first embodiment; [Figure 9] A transmit / receive combined beam pattern characteristic diagram when the main beam angle is adjusted to 0° for the antenna array of the first embodiment. [Figure 10] Logical OR analysis result of element arrangement state shown for Comparative Example 1 [Figure 11] Comparison Example 2: Logical OR and AND analysis results for the element array state [Figure 12] FIG. 10 is a diagram schematically illustrating the characteristics of a combined transmitting and receiving beam pattern when the main beam angle of the antenna array according to the first embodiment is adjusted to 17.5°. [Figure 13] FIG. 10 is a diagram showing the combined beam pattern characteristics of transmitting and receiving signals when the main beam angle is adjusted to 17.5° for Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment in which an antenna array for a high frequency device is used in a radar device 1 will be described with reference to the drawings. The radar device 1 is attached to a predetermined location on a vehicle and is used as a long range radar (LRR) that scans a predetermined range of about 10 m to several hundred m, or as a short range radar.

[0015] 1, a radar device 1 for a vehicle includes a control circuit 2, a signal generating unit 3, a transmitting unit 4, a receiving unit 5, a signal processing unit 6, a transmitting antenna array 107, and a receiving antenna array 207. The receiving antenna array 207 of the radar device 1 has, for example, a plurality of receiving RX channels, and calculates the distance to a target 8, the presence angle, etc. by combining the signals of each receiving RX channel.

[0016] The control circuit 2 executes predetermined control logic to perform various controls on the signal generating unit 3, transmitting unit 4, and receiving unit 5. At this time, the control circuit 2 controls the frequency, amplification, phase value, etc. of the radar device 1.

[0017] The signal generation unit 3 includes, for example, a PLL and a multiplier (not shown), and generates a local signal to be output to the transmission unit 4, as well as a local signal to be output to the reception unit 5. At this time, the local signal is supplied from the same PLL to the mixer 7 of the reception RX channel. The local signal indicates, for example, a signal in the 77 GHz band.

[0018] 2, the transmitter 4 includes a variable gain amplifier 11, a phase shifter 12, and an amplifier 13, and is connected to the antenna array 107 via a pad 10. The variable gain amplifier 11 is configured to be able to adjust its amplification under the control of the control circuit 2, and receives the TX signal from the signal generator 3. The phase shifter 12 shifts the output phase of the variable gain amplifier 11, and its phase value can be changed under the control of the control circuit 2. The amplifier 13 is a so-called power amplifier and amplifies the output signal of the phase shifter 12.

[0019] A transmitting antenna array 107 is electrically connected to the phase shifter 12 via an amplifier 13. The transmitting antenna array 107, which will be described in detail later, is configured with a phased array antenna and can output radar waves toward a target 8. The received waves reflected by the target 8 are input to a receiving antenna array 207.

[0020] The receiving unit 5 shown in Fig. 1 is connected to the receiving antenna array 207 via the pad 20 shown in Fig. 3. The receiving unit 5 has the same configuration for each of the multiple receiving RX channels. As shown in Fig. 3, each receiving unit 5 includes a variable gain amplifier 14, a phase shifter 15, and an amplifier 16. The phase shifter 15 is electrically connected to the receiving antenna array 207 via the variable gain amplifier 14.

[0021] When the receiver 5 receives a signal from the receiving antenna array 207, the variable gain amplifier 14 amplifies the signal received from the receiving antenna array 207, and the phase shifter 15 shifts the phase of the amplified signal from the variable gain amplifier 14 by a phase value φ.

[0022] Then, the amplifier 16 amplifies the phase-shifted signal from the phase shifter 15 and outputs it to the mixer 7 for each receiving RX channel.

[0023] On the other hand, when the signal generating unit 3 outputs a local signal to the receiving unit 5, the LO amplifier 9 amplifies the local signal and outputs it to the mixer 7. The mixer 7 mixes the output of the amplifier 16 and the output of the LO amplifier 9 and outputs the result as an IF signal to the signal processing unit 6. The signal processing unit 6 shown in FIG. 1 is configured by a processor or predetermined electronic control logic, similar to the control circuit 2.

[0024] The signal processing unit 6 filters the IF signal processed by the mixer 7 using an IF filter (not shown) and then performs A / D conversion, and then performs signal processing such as digital beam forming (DBF) using the FFT results, thereby measuring the distance to the target 8, the relative speed to the target 8, and the angle at which the target 8 exists.

[0025] The control circuit 2 controls the beam scanning angle by controlling the phase value φtx of the phase shifter 12 in the transmitter 4 and the phase value φrx of the phase shifter 15 in the receiver 5 of each receiving channel. This creates a narrow virtual beam within the sector area, enabling the scanned target 8 to be identified with higher resolution. Because the field of view can be narrowed to a sector area, the amount of calculation required can be reduced compared to conventional MIMO radar. The hybrid method is an efficient scanning method that alleviates the trade-off between reduced scan time and high resolution. It is also possible to apply techniques such as multi-signal classification (MUSIC), which can achieve higher separation capabilities for multiple targets 8 than the aforementioned DBF.

[0026] The structures of the receiving antenna array 207 and the transmitting antenna array 107 used in the radar device 1 will be described below. The receiving antenna array 207 is provided for each of the multiple receiving channels. As shown in FIG. 4, the receiving antenna array 207 for each receiving channel is used as a phased array antenna, and is configured by combining on-elements 211a and 211c electrically connected to the receiving unit 5 and off-elements 211b not electrically connected to the receiving unit 5. The on-elements 211a correspond to second grouping on-elements or active elements, and the on-elements 211c correspond to second single on-elements or active elements. The on-elements 211c are provided in pairs spaced apart in the Y direction, which is a specific direction. This pair of on-elements 211c corresponds to a pair of second single on-elements. The off-elements 211b correspond to dummy elements. It is preferable that the electrical line lengths from each of the on-elements 211a and 211c to the mixer 17 of the receiving unit 5 be configured as equal-length paths so that they are in phase with each other.

[0027] As shown in Fig. 4, the elements 211a to 211c of the receiving antenna array 207 each have a rectangular metal surface. The outer frame of the receiving antenna array 207 is configured as a square, and the rectangular elements 211a to 211c are arranged in the lattice-like vertex areas within the outer frame of the receiving antenna array 207. In this embodiment, as shown in Fig. 4, the on-elements 211a and 211c are arranged in a predetermined two-dimensional area partitioned into 16 rows and 12 columns, but this is not limiting. The receiving antenna array 207 and the transmitting antenna array 107 have outer frames with the same shape. Note that Fig. 5 shows an extracted portion of the receiving antenna array 207 shown in Fig. 4.

[0028] As shown in FIG. 6, the transmitting antenna array 107 is also used as a phased array antenna and is configured by combining on elements 111a and 111c electrically connected to the transmitting unit 4 and off elements 111b not electrically connected to the transmitting unit 4. The on elements 111a correspond to first grouping on elements or active elements, and the on elements 111c correspond to first single on elements or active elements. The on elements 111c are provided in pairs spaced apart in the Y direction, which is a specific direction, and this pair of on elements 111c corresponds to a pair of first single on elements. The off elements 111b correspond to dummy elements. It is preferable that the electrical line lengths from the output of the phase shifter 12 of the transmitting unit 4 to the on elements 111a and 111c be configured as equal-length paths so that they are in phase with each other.

[0029] 6, the elements 111a to 111c of the transmitting antenna array 107 each have a rectangular metal surface. The outer frame of the transmitting antenna array 107 is configured in a square shape, and the rectangular elements 111a to 111c are arranged in the areas of the vertices of a lattice pattern within the outer frame of the transmitting antenna array 107.

[0030] The elements 111a to 111c of the transmitting antenna array 107 and the elements 211a to 211c of the receiving antenna array 207 have a center-to-center spacing between adjacent elements 111a to 111c and 211a to 211c set to half the radar wavelength λ, and each element 111a to 111c and 211a to 211c is configured to be rectangular. Although a rectangular configuration is shown here, it may also be configured to be hexagonal or octagonal. The transmitting antenna array 107 and the receiving antenna array 207 are each arranged on the XY plane, and transmit and receive beams from the +Z-axis direction orthogonal to the XY plane.

[0031] Although this embodiment is simply shown in Figures 3 to 6, dummy elements (not shown) may be separately arranged on the outermost periphery of the two-dimensional arrangement of the transmitting antenna array 107 and the receiving antenna array 207. The dummy elements, like the off elements 111b and 211b, are not connected to the transmitting unit 4 and the receiving unit 5. By arranging the dummy elements on the outermost periphery of the two-dimensional arrangement, it is possible to improve the quality of signals transmitted and received using the transmitting antenna array 107 and the receiving antenna array 207. In this embodiment, by devising the two-dimensional arrangement of the on elements 111a, 111c, 211a, and 211c and the off elements 111b and 211b, the number of on elements 111a, 111c, 211a, and 211c that require phase shift control is reduced, making phase shift control easier.

[0032] 4 and 6, the columns of the transmitting antenna array 107 and the receiving antenna array 207 will be referred to as columns X1 to X12, and the rows of the transmitting antenna array 107 and the receiving antenna array 207 will be referred to as rows Y1 to Y16.

[0033] The arrangement areas of the elements 111a to 111c and 211a to 211c are expressed using coordinates (X, Y). For example, as shown in Fig. 6, in column X3, if the ON element 111a in row Y2 and the ON element 111a in row Y3 are electrically connected and grouped, the ON elements 111a are connected with a minus sign, as in "Y2-Y3," to indicate that the ON elements 111a are grouped.

[0034] The on-elements 111a and 111c of the transmitting antenna array 107 shown in Fig. 6 are connected to the transmitting unit 4 by a transmission line using a printed wiring board, which allows a directional transmitting beam to be formed by combining and radiating the energy of beams from the grouped on-elements 111a and the single on-elements 111c of the transmitting antenna array 107. Also, the on-elements 211a and 211c of the receiving antenna array 207 shown in Fig. 4 are connected to the receiving unit 5 by a transmission line using a printed wiring board, which allows a directional receiving beam to be formed by combining and receiving the energy of signals from the on-elements 211a and 211c of the receiving antenna array 207 at a desired angle.

[0035] <Detailed Description of the Arrangement Structure of the On-Elements 211a and 211c of the Receiving Antenna Array 207> Next, the arrangement structure of the on-elements 211a and 211c will be described in detail with reference to Fig. 4. As shown in Fig. 4, in the receiving antenna array 207, the centers of all rows are located between row Y8 and row Y9, and the centers of all columns are located between column X6 and column X7. The on-elements 211a and 211c are arranged symmetrically up and down with respect to the centers of these rows and symmetrically with respect to the centers of the columns. Furthermore, the on-elements 211a and 211c are arranged point-symmetrically with respect to the center of the receiving antenna array 207.

[0036] Specifically, the on-element 211a in the left half area of the receiving antenna array 207 is Coordinates (X1, Y3-Y4) and coordinates (X1, Y13-Y14), Coordinates (X2, Y2-Y3) and coordinates (X2, Y14-Y15), Coordinates (X2, Y5-Y6) and coordinates (X2, Y11-Y12), Coordinates (X2, Y8-Y9), Coordinates (X3, Y4-Y5) and coordinates (X3, Y12-Y13), Coordinates (X3, Y7-Y8) and coordinates (X3, Y9-Y10), They are located at the top and bottom and are arranged symmetrically.

[0037] In addition, the on-element 211a is Coordinates (X4, Y1-Y2) and coordinates (X4, Y15-Y16), Coordinates (X4, Y3-Y4) and coordinates (X4, Y13-Y14), Coordinates (X4, Y6-Y7) and coordinates (X4, Y10-Y11), Coordinates (X5, Y4-Y5) and coordinates (X5, Y12-Y13), Coordinates (X5, Y6-Y7) and coordinates (X5, Y10-Y11), Coordinates (X5,Y8-Y9), Coordinates (X6, Y2-Y3) and coordinates (X6, Y14-Y15), Coordinates (X6, Y7-Y8) and coordinates (X6, Y9-Y10), They are located at the top and bottom and are arranged symmetrically.

[0038] Furthermore, in the receiving antenna array 207, the on-element 211a in the right half region shown in the figure is Coordinates (X12, Y3-Y4) and coordinates (X12, Y13-Y14), Coordinates (X11, Y2-Y3) and coordinates (X11, Y14-Y15), Coordinates (X11, Y5-Y6) and coordinates (X11, Y11-Y12), Coordinates (X11, Y8-Y9), Coordinates (X10, Y4-Y5) and coordinates (X10, Y12-Y13), Coordinates (X10, Y7-Y8) and coordinates (X10, Y9-Y10), They are located at the top and bottom and are arranged symmetrically.

[0039] In addition, the on-element 211a is Coordinates (X9, Y1-Y2) and coordinates (X9, Y15-Y16), Coordinates (X9, Y3-Y4) and coordinates (X9, Y13-Y14), Coordinates (X9, Y6-Y7) and coordinates (X9, Y10-Y11), Coordinates (X8, Y4-Y5) and coordinates (X8, Y12-Y13), Coordinates (X8, Y6-Y7) and coordinates (X8, Y10-Y11), Coordinates (X8, Y8-Y9), Coordinates (X7, Y2-Y3) and coordinates (X7, Y14-Y15), Coordinates (X7, Y7-Y8) and coordinates (X7, Y9-Y10), They are located at the top and bottom and are arranged symmetrically.

[0040] The on-elements 211a are grouped in the Y direction, with no grouping in the X direction. Therefore, the effective elements are arranged at a λ / 2 pitch in the X direction, and grating lobes do not occur in principle. In this embodiment, the X direction corresponds to the second direction, or horizontal direction, and the Y direction corresponds to the first direction, or vertical direction.

[0041] The transmission line has a receiving power feed point at the connection center where the pair of on-elements 211a are connected, and the phase center of the grouped pair of on-elements 211a is located at the connection center. The transmission line is configured using wiring configured on a printed circuit board, and in this case, it is desirable that the electrical line lengths of the transmission line connecting the IC pad and the pair of on-elements 211a be equal to each other or have a relationship of p × λ (where p is an integer) to ensure equal phase.

[0042] 4, the on-elements 211c are arranged in pairs at a specific interval (corresponding to the second interval) in the receiving antenna array 207. Two single on-elements 211c are arranged spaced apart in the same direction as the Y direction in which the on-elements 211a are grouped, and are arranged line-symmetrically with respect to the center of the row.

[0043] The on-elements 211c are arranged in pairs at coordinates (X6, Y5) and (X6, Y12). The on-elements 211c are arranged in pairs at coordinates (X7, Y5) and (X7, Y12). The center-to-center distance d1 between the on-elements 211c in rows Y5 and Y12 is 3.5λ. These on-elements 211c spaced at a specific interval of 3.5λ act as a steerable null filter that can generate a null at the first grating lobe generation angle.

[0044] Furthermore, the on-elements 211c are provided in pairs at coordinates (X5, Y1) and (X5, Y16). Similarly, the on-elements 211c are provided in pairs at coordinates (X8, Y1) and (X8, Y16). The center-to-center distance d2 between the on-elements 211c in rows Y1 and Y16 is 7.5λ. These on-elements 211c spaced 7.5λ apart act as a second null filter.

[0045] The on-elements 211c are provided in pairs at coordinates (X3, Y2) and coordinates (X3, Y15). Similarly, the on-elements 211c are provided in pairs at coordinates (X10, Y2) and coordinates (X10, Y15). Because the row-to-row or column-to-column distance between adjacent elements 211a to 211c is 0.5λ, the center-to-center distance d3 between the on-elements 211c in rows Y3 and Y15 is 6.5λ. These on-elements 211c spaced 6.5λ apart act as a third null filter.

[0046] In this way, the on-elements 211c are single elements arranged at intervals, but the distances d1 to d3 between the centers of these on-elements 211c in the Y direction are set to specific intervals of (0.5+m)λ (where m is an integer). That is, the on-elements 211c are arranged line-symmetrically from the center of the column of the receiving antenna array 207 at intervals of (0.5+m)λ (where m=1, 2, ...).

[0047] Furthermore, in order to increase the density of the on-elements 211a and 211c in the central portion, it is desirable to intentionally set m to 3 or more. By setting m to 3 or more, the effective elements in the central portion of the receiving antenna array 207 can be densely packed, thereby making it possible to deal with side lobes. Note that FIG. 6 shows examples where m = 3, 6, and 7. Furthermore, in order to change the characteristics of the null filters, it is desirable to provide multiple sets of on-elements 211c in the receiving antenna array 207 that satisfy the condition of different m values. Because grating lobes have an angular width, it is possible to suppress grating lobes with an angular width by overlapping null filters with different attenuation characteristics near the angle at which the grating lobes occur.

[0048] 5 shows the element arrangement of columns X6 and X7. The ON elements 211a in rows Y7-Y8 adjacent in the Y direction are controlled so that the phase values of the transmitting TX phase shifter 12 and the receiving RX phase shifter 15 are the same. Therefore, the phase centers of the ON elements 211a in rows Y7-Y8 are located at the midpoint between rows Y7-Y8. Similar signals are also provided to the ON elements 211a in rows Y9-Y10, so the phase centers of the ON elements 211a in rows Y9-Y10 are located at the midpoint between rows Y9-Y10.

[0049] Because the inter-element distance in each of rows Y7-Y8 and Y9-Y10 is λ / 2, the phase center spacing d of the on-elements 211a in rows Y7-Y8 and rows Y9-Y10 is λ, which is twice λ / 2. When the theoretical grating lobe angle is calculated when the main beam angle is changed, the grating lobe occurrence angle is equivalent to that when the relationship between the phase center spacing d and the radar wavelength λ is designed to be d=1λ, and in principle, there is a risk that strong grating lobes will be generated.

[0050] This phenomenon is caused by the adverse effect of grouping adjacent elements in the Y direction to reduce the number of phase shifters 12 and 15. However, as mentioned above, the λ periodicity of the phase center spacing d can be broken by inserting a single on-element 211c. This reduces grating lobes by several dB. Furthermore, it has been confirmed that the on-element 211c has attenuation characteristics as a null filter (steerable null filter), making it possible to track and suppress grating lobes.

[0051] In other words, a pair of adjacent ON elements 211a are arranged line-symmetrically in the Y direction in the receiving antenna array 207, but a single ON element 211c is arranged in the Y direction with OFF elements 211b sandwiching it on both sides in the Y direction. Therefore, even if adjacent ON elements 211a are grouped into a pair, the periodicity of the phase center can be disrupted.

[0052] Since a single on-element 211c is arranged spaced apart from a pair of on-elements 211a adjacent to each other along the Y direction, the uniformity of the phase center interval when the on-elements 211a are grouped can be reduced, and grating lobes can be tracked and suppressed.

[0053] According to the configuration of the receiving antenna array 207 of this embodiment, by designing the density of the on-elements 211a to be high in the center and low at the four corners, it is possible to configure the array with a small number of phase shifters and keep the side lobe performance low. From the viewpoint of tapering, a design that does not have on-elements 211a and 211c at the four corners is also effective. This is because, since the distance from the center of the receiving antenna array 207 is large, a large amount of attenuation is required for the internal variable gain amplifier 14 to achieve tapering.

[0054] <Detailed Description of the Arrangement Structure of the On-Elements 111a and 111c of the Transmitting Antenna Array 107> Next, the arrangement structure of the on-elements 111a and 111c will be described in detail with reference to Figures 6 and 7. The on-elements 111a are elements that are electrically connected to the transmitter 4 in pairs adjacent to each other in the Y direction, while the on-elements 111c are elements that are electrically connected to the transmitter 4 in pairs spaced apart at a specific interval (corresponding to the first interval) in the Y direction. For this reason, the on-elements 111a and 111c are shown with different reference numerals. In Figures 6 and 7, the filled-in rectangular area indicates the on-element 111a, and the isolated on-element 111c is shown with hatching. The off-elements 111b are shown with a solid line frame and are not hatched.

[0055] 6, the on-elements 111a for transmitting TX are arranged symmetrically about the center of the rows and symmetrically about the center of the columns, similar to the on-elements 211a for receiving RX. Also, the on-elements 111a and 111c are arranged point-symmetrically about the center of the transmitting antenna array 107.

[0056] Specifically, the on-element 111a in the left half area of the transmitting antenna array 107 is Coordinates (X1, Y5-Y6) and coordinates (X1, Y11-Y12), Coordinates (X2, Y4-Y5) and coordinates (X2, Y12-Y13), Coordinates (X2, Y6-Y7) and coordinates (X2, Y10-Y11), Coordinates (X2, Y8-Y9), Coordinates (X3, Y2-Y3) and coordinates (X3, Y14-Y15), Coordinates (X3, Y5-Y6) and coordinates (X3, Y11-Y12), Coordinates (X3, Y8-Y9), They are located at the top and bottom and are arranged symmetrically.

[0057] In addition, the on-element 111a is Coordinates (X4, Y5-Y6) and coordinates (X4, Y11-Y12), Coordinates (X4, Y7-Y8) and coordinates (X4, Y9-Y10), Coordinates (X5, Y1-Y2) and coordinates (X5, Y15-Y16), Coordinates (X5, Y3-Y4) and coordinates (X5, Y13-Y14), Coordinates (X5,Y8-Y9), Coordinates (X6, Y4-Y5) and coordinates (X6, Y12-Y13), Coordinates (X6, Y6-Y7) and coordinates (X6, Y10-Y11), Coordinates (X6, Y8-Y9), They are located at the top and bottom and are arranged symmetrically.

[0058] Furthermore, in the transmitting antenna array 107, the on-element 111a in the right half area shown in the figure is Coordinates (X12, Y5-Y6) and coordinates (X12, Y11-Y12), Coordinates (X11, Y4-Y5) and coordinates (X11, Y12-Y13), Coordinates (X11, Y6-Y7) and coordinates (X11, Y10-Y11), Coordinates (X11, Y8-Y9), Coordinates (X10, Y2-Y3) and coordinates (X10, Y14-Y15), Coordinates (X10, Y5-Y6) and coordinates (X10, Y11-Y12), Coordinates (X10, Y8-Y9), They are located at the top and bottom and are arranged symmetrically.

[0059] In addition, the on-element 111a is Coordinates (X9, Y5-Y6) and coordinates (X9, Y11-Y12), Coordinates (X9, Y7-Y8) and coordinates (X9, Y9-Y10), Coordinates (X8, Y1-Y2) and coordinates (X8, Y15-Y16), Coordinates (X8, Y3-Y4) and coordinates (X8, Y13-Y14), Coordinates (X8, Y8-Y9), Coordinates (X7, Y4-Y5) and coordinates (X7, Y12-Y13), Coordinates (X7, Y6-Y7) and coordinates (X7, Y10-Y11), Coordinates (X7, Y8-Y9), They are located at the top and bottom and are arranged symmetrically.

[0060] The grouping direction of the on-elements 111a for transmission TX is the same as that of the on-elements 111a for reception RX, that is, the Y direction, and they are not grouped in the X direction. Therefore, effective elements are arranged at an ideal λ / 2 pitch in the X direction, and grating lobes do not occur in principle.

[0061] The phase center of a pair of grouped on-elements 111a is located at the center of their connection. The transmission lines are configured using wiring on a printed wiring board, and in this case, it is desirable that the electrical line lengths of the transmission lines connecting the IC pad and the pair of on-elements 111a be equal to each other or have a relationship of p × λ (where p is an integer) so that they are in phase.

[0062] 6, the on-element 111c is also arranged in the transmitting antenna array 107, but is arranged as an isolated one sandwiched between the off-elements 111b in the Y direction. Two single on-elements 111c are arranged at a first interval in the same direction as the Y direction in which the on-elements 111a are grouped, and are arranged line-symmetrically with respect to the center of all rows.

[0063] The on-elements 111c are arranged in pairs at coordinates (X4, Y3) and (X4, Y14). Similarly, the on-elements 111c are arranged in pairs at coordinates (X9, Y3) and (X9, Y14). The center-to-center distance d4 between the on-elements 111c in rows Y3 and Y14 is a specific interval of 5.5λ. These on-elements 111c spaced apart by a specific interval of 5.5λ act as a fourth null filter.

[0064] Furthermore, the ON elements 111c are arranged in pairs at coordinates (X5, Y6) and coordinates (X5, Y11). Similarly, the ON elements 111c are arranged in pairs at coordinates (X8, Y6) and coordinates (X8, Y11). The center-to-center distance d5 between the ON elements 111c in rows Y6 and Y11 is a specific interval of 2.5λ. These ON elements 111c spaced 2.5λ apart act as a fifth null filter.

[0065] Furthermore, the ON elements 111c are arranged in pairs at coordinates (X6, Y2) and coordinates (X6, Y15). Similarly, the ON elements 111c are arranged in pairs at coordinates (X7, Y2) and coordinates (X6, Y15). The center-to-center distance d6 between the ON elements 111c in rows Y2 and Y15 is a specific interval of 6.5λ. These ON elements 111c spaced 6.5λ apart act as a sixth null filter.

[0066] In this way, the on-elements 111c are spaced apart from each other and are electrically connected to the phase shifter 12, but the Y-direction distances d4 to d6 between the centers of these on-elements 111c are designed to be specific intervals of (0.5+m)λ (where m is an integer) that are different from one another. That is, the on-elements 111c are arranged line-symmetrically from the center of the column of the transmitting antenna array 107 at intervals of (0.5+m)λ (where m=1, 2, ...).

[0067] 6 shows examples where m = 2, 5, and 6. Furthermore, in order to change the characteristics of the null filters, it is desirable to provide multiple sets of on-elements 111c that satisfy the condition of different values of m in the transmitting antenna array 107. Because grating lobes also have angular widths, it is possible to suppress grating lobes with angular widths by overlapping null filters with different attenuation characteristics near the angles at which the grating lobes occur.

[0068] 7 shows the element arrangements of columns X6 and X7. The ON elements 111a in rows Y8-Y9 adjacent in the Y direction are controlled so that the phase values generated by the phase shifter 12 are the same. Therefore, the phase centers of the ON elements 111a in rows Y8-Y9 are located at the midpoint between rows Y8-Y9. Similarly, the ON elements 111a in rows Y4-Y5, Y6-Y7, Y10-Y11, and Y12-Y13 adjacent in the Y direction are controlled so that the phase values generated by the phase shifter 12 are the same.

[0069] Therefore, the phase centers of the ON elements 111a in the rows Y4-Y5, Y6-Y7, Y10-Y11, and Y12-Y13 are respectively located at the midpoints between the rows Y4-Y5, Y6-Y7, Y10-Y11, and Y12-Y13. Also, by grouping the ON elements 111a in pairs in the Y direction, or in the vertical direction in this case, the number of phase shifters can be reduced by approximately half.

[0070] 6, the density of the on-elements 111a and 111c near the center of the transmitting antenna array 107 is configured to be higher than the density at the four corners, so the side lobe level can be suppressed while reducing the number of on-elements 111a and 111c arranged compared to a random arrangement configuration. Therefore, the side lobe level can be suppressed while reducing the number of on-elements 111a and 111c arranged.

[0071] Furthermore, by arranging the on-elements 111c sandwiched between the off-elements 111b to reduce the periodicity of the phase center after grouping the on-elements 111a, and arranging the on-elements 111c in line symmetry or point symmetry so as to be at specific intervals d4 to d6, fourth to sixth null filters can be configured, which can track and suppress grating lobes.

[0072] In the design of the on-elements 111a / off-elements 111b, increasing the density of the on-elements 111a in the center and decreasing the density at the four corners simplifies phase shift control, allowing for a reduction in the number of phase shifters 12 and further reducing the side lobe level. Furthermore, by grouping adjacent on-elements 111a, it becomes possible to collectively control multiple on-elements 111a in correspondence with the same phase shifter 12, reducing the number of phase shifters 12 required by approximately half. The grating lobes that occur in this case can be suppressed at all required scan angles.

[0073] <Analysis results of overlapping logical OR and logical AND of arrays> FIG. 8A shows the overlapping OR region (TX∪RX) and overlapping region TR of the overlapping AND (TX∩RX) between the ON elements of the transmitting antenna array 107 and the ON elements of the receiving antenna array 207, and FIG. 8B shows a Venn diagram of the overlapping OR region (TX∪RX) and overlapping AND region (TX∩RX). In the receiving antenna array 207 in the upper left diagram of FIG. 8A, elements 211c hatched diagonally to the right indicate single ON elements, and solid elements 211a indicate grouped ON elements. In the transmitting antenna array 107 in the lower left diagram of FIG. 8A, elements 111c hatched diagonally to the left indicate single ON elements, and solid elements 111a indicate grouped ON elements.

[0074] As shown in the center diagram of Figure 8A, the two-dimensional arrangement of the transmit antenna array 107 and the receive antenna array 207 is considered with the on-elements 111a, 111c, 211a, 211c and the off-elements 111b, 211b overlapping in the X and Y directions. It can be seen that the on-elements 111a, 111c, 211a, or 211c are evenly arranged in all regions of the four sides constituting the structure of the transmit antenna array 107 and the receive antenna array 207, except for the centers of the X and Y sides. The occupancy rate of the area where the on-elements 111a, 111c, 211a, or 211c of either the transmit TX or receive RX are arranged can be increased to 85.4%. This can be expected to improve side lobes when combining transmit and receive beam patterns. The occupancy rate of effective elements in the base design of the receive antenna array 207 shown in Figure 4 is 60.4%. In other words, the arrangement structure of the on-elements 111a, 111c, 211a, and 211c of the transmitting antenna array 107 and the receiving antenna array 207 in this embodiment can be said to complement each other so that the sparsely arranged areas of the on-elements 111a, 111c, 211a, and 211c of the transmitting TX and receiving RX become continuous.

[0075] Furthermore, within the overall antenna array 107, 207, the on-elements of the transmitting TX and receiving RX are arranged to overlap with some overlap. In the right diagram of Fig. 8A, the elements of the overlap region TR due to the overlap logical product region (TX∩RX) are shown filled in. Furthermore, when the on-elements 111a, 111c, 211a, 211c of the transmitting TX and receiving RX are overlapped, they are arranged so that the occupation density of the overlap region TR, which overlaps in the center in the XY direction, is higher than that of the other surrounding regions.

[0076] The results of the simulation will be explained below: The inventors have performed simulations on the structures of the antenna arrays 107 and 207 in which the arrangement of the on-elements 111a, 111c, 211a, and 211c is optimized.

[0077] <Beam pattern characteristics when the main beam angle is adjusted to 0° in the Y direction> Here, we will explain the beam pattern characteristics (cross section) when the above-mentioned structure of the antenna arrays 107, 207 is adopted and the main beam angle is adjusted to 0° in the Y direction. Fig. 9 shows the characteristics of the transmitting TX and receiving RX and the combined transmitting and receiving spectrum when normalized at the peak of the main lobe level. Fig. 9 also shows the results of an analysis of the combined beam pattern of the entire radar device 1, from the transmission of radar waves from the transmitter 4 to their reception by the receiver 5, which was optimized through overlap analysis of the on-elements 111a and 111c for transmitting TX and the on-elements 211a and 211c for receiving RX.

[0078] As shown in Figure 9, comparing the spectrum during transmission TX and the spectrum during reception RX, it can be said that by changing the number of effective elements in one direction (especially the center) of the X or Y direction of each antenna array 107, 207 for transmission TX and reception RX, the number and pitch of side lobes change, and the cancellation effect of the reception RX or the transmission TX alone can be strengthened in the combined beam pattern performance of the transmission TX and reception RX. This is thought to be the effect of generating side lobes at different angles by designing the arrangement of the on-elements 111a, 111c, 211a, 211c of the transmission TX and reception RX so that they are complementary, as shown in Figure 8A.

[0079] Therefore, it has been found that when the side lobe characteristics of the transmitting TX and receiving RX are combined, the side lobes can be canceled out. In the simulation results, when the combined beam pattern of the transmitting TX and receiving RX is taken into consideration, it has been confirmed that the side lobe level of the combined transmitting and receiving beam pattern in the H-plane (horizontal cross section) under Boresight (front) conditions can be suppressed to less than -55 dBc in the field of view range required for the radar device 1 (horizontal range of -60° to 60°), as shown in Fig. 9.

[0080] Fig. 10 shows the array structure of Comparative Example 1, and Fig. 11 shows the array structure of Comparative Example 2. The array structure of Comparative Example 1 shows an example in which on-elements 111a and 111c for transmitting TX are configured in the same positions as on-elements 211a and 211c for receiving RX. The array structure of Comparative Example 2 shows the initial pattern structure before optimization in which on-elements 111a, 111c, 211a, and 211c for transmitting TX and receiving RX are arranged in appropriate positions.

[0081] In the array structure of Comparative Example 1 shown in Figure 10, the occupancy rate of the transmit TX and receive RX on-elements 111a, 111c, 211a, and 211c in the overall array, i.e., the coverage rate of the logical sum region (TX ∪ RX), remains the same as that of the single array at 60.4%, which is significantly lower than the structure of Figure 8A of this embodiment (coverage rate = 85.4%). Therefore, even if the combined beam pattern of the transmit TX and receive RX is considered, further suppression of the side lobe level cannot be expected. The side lobe level is approximately the same as the attenuation characteristic of the receive RX alone when doubled, remaining at approximately -30 dBc (-15 dBc x 2).

[0082] 11, the coverage rate of the logical sum area (TX∪RX) occupied by the on-elements 111a, 111c, 211a, and 211c of the transmitting TX and receiving RX is 81.3%. The coverage rate of the on-elements 111a, 111c, 211a, and 211c of the transmitting TX and receiving RX as a whole to cover the two-dimensional arrangement is set higher than the coverage rate (=60.4%) of each of the on-elements 111a, 111c, 211a, and 211c of the transmitting TX or receiving RX to cover the two-dimensional arrangement individually.

[0083] The array structure of Comparative Example 2 has a lower coverage rate of the logical sum region (TX ∪ RX) compared to the array structure shown in Fig. 8A, but is configured to have a higher coverage rate than Comparative Example 1. In the case of this structure, when the combined beam pattern of the transmitting TX and receiving RX is taken into consideration, the simulation result shows that the side lobe level is -45 dBc, which is a significant improvement compared to the array structure of Comparative Example 1. In other words, it can be seen that the side lobe level can be significantly suppressed by adopting an arrangement structure in which the on-elements 111a, 111c, 211a, and 211c of the transmitting TX and receiving RX complement each other.

[0084] Furthermore, in the array structure of Comparative Example 2, compared to the array structure of this embodiment shown in FIG. 8A, the area where the off-elements 111b and 211b are arranged for both the transmitting TX and receiving RX is larger within the overall structure, and so-called holes also exist. Furthermore, the central portion in the XY direction is sparse. Therefore, by adopting the structure of this embodiment shown in FIG. 8A, it is possible to increase the area where the elements complement each other, which is thought to result in further suppression of the side lobe level.

[0085] The above content will be explained in more detail. Generally, an N×N URA (Uniform Rectangular Array) generates N-2 side lobes. Unlike a URA, the array of this embodiment uses an on-off design to reduce the number of phase shifters. However, in Figure 9, the number of side lobes can be confirmed to be the same as the ideal calculated value of N-2. Details will be explained below.

[0086] In this embodiment, the transmitting antenna array 107 and the receiving antenna array 207 are both designed to have a high density of effective elements in the center. Here, the receiving antenna array 207 near the center in the Y direction has 8 effective elements in the X direction (N RX On the other hand, the transmitting antenna array 107, which is designed to be complementary to the receiving antenna array 207, has 10 effective elements in the central area in the Y direction (N = 8) in the X direction. RXIn this way, in order to change the number and pitch of the transmitting and receiving side lobes and enhance the cancellation effect of the transmitting and receiving side lobes, it is desirable to make the number of effective elements arranged different between the transmitting antenna array 107 and the receiving antenna array 207.

[0087] It can be seen from FIG. 8A that the on-elements 111a and 111c of the transmitting antenna array 107 are arranged in the arrangement area of the off-elements 211b of the receiving antenna array 207.

[0088] According to the simulation results shown in FIG. 9, the number of side lobes of the transmitting antenna array 107 is eight (N TX -2=10-2=8), and the number of side lobes of the receiving antenna array 207 is 6 (N RX A side lobe peak of -2=8-2=6 can be confirmed.

[0089] By differentiating the number of elements in the transmit antenna array 107 and the receive antenna array 207 in a complementary manner so that the logical sum region of the arrangement of the on-elements 111a, 111c, 211a, and 211c is maximized, a deviation occurs between the side lobe peak angle and the null angle, and it can be said that an improvement in the side lobes of the combined transmit and receive beam pattern is achieved. As a result, in an analysis of the combined transmit and receive beam pattern under the Boresight (front) condition of a horizontal cross section, it was confirmed that the side lobes could be suppressed to -55 dBc or less, which is stronger than when the same array arrangement is used.

[0090] <Characteristics when the main beam angle is adjusted to 17.5° in the Y direction> FIG. 12 also shows the transmission and reception characteristics of the antenna arrays 107 and 207 when the main beam angle is adjusted to 17.5° in the Y direction (vertical direction) by controlling the phase shift value φ of the phase shifters 12 and 15. Conventionally, when steering the beam to 17.5° in the vertical direction, grating lobes occur around -43° using a conventional grouping method without a null filter. However, when the array structure shown in this embodiment is adopted, it has been found that the grating lobes are canceled by the action of the null filters provided by each pair of single-on elements 111c and 211c arranged at specific intervals. Taking the main lobe level at 17.5° in the Y direction shown in the center of FIG. 12 as the reference, the peak level SLpeak of the side lobes in the off-axis (diagonal regions unrelated to the beam scanning direction) diagonally downward to the left and right is observed to be -31.3 dBc due to the combination of the transmit and receive beam patterns of the transmit TX and receive RX.

[0091] Fig. 13 shows the transmission and reception characteristics of Comparative Example 1 under the same conditions as Fig. 12. Comparative Example 1 shows the transmission and reception characteristics when the transmission and reception arrangements are the same. Taking the main lobe level at 17.5° in the Y direction shown in the center of Fig. 13 as the reference, the side lobe peak level SLpeak was observed to be -24.7 dBc.

[0092] Although not shown here, in the structure of Comparative Example 2, the side lobe peak level SLpeak was observed to be -27.5 dBc, that is, a degradation of 4 dB, when the main lobe level at 17.5° in the Y direction is used as the reference. This is thought to be due to the fact that, in Fig. 11, there are scattered areas in the diagonal direction from the center of the effective elements in the overlapping OR region (TX ∪ RX) where off elements 111b and 211b are present for both the transmitting TX and receiving RX.

[0093] 8A according to this embodiment with the structure shown in Fig. 11 of Comparative Example 2, it can be understood that the overlapping region TR (i.e., element positions where both are "1") where the on-elements 111a and 111c of the transmitting antenna array 107 and the on-elements 211a and 211c of the receiving antenna array 207 overlap when their arrangement positions are overlapped should desirably be radially and continuously arranged in diagonal directions from the center in the X and Y directions of the two-dimensional arrangement. See radial lines A in Fig. 8A.

[0094] Furthermore, the overlapping region TR formed when the on-elements 111a and 111c of the transmitting antenna array 107 and the on-elements 211a and 211c of the receiving antenna array 207 are arranged in overlapping positions may be arranged in a ripple shape, a concentric circle shape, or a concentric ellipse shape centered at the center of the two-dimensional arrangement. See the concentric circle and ellipse shape line B in Figure 8A. This provides a stronger side lobe reduction effect, including side lobes generated in oblique directions.

[0095] If the side lobe level remains strong, in the case of a radar device 1 for vehicle use, when the main beam that should be detected is adjusted in the forward direction, the received signal becomes susceptible to the influence of, for example, reflections from objects that have fallen on the road surface or reflections from a trailer passing by, which interfere with the received signal. For this reason, by suppressing the side lobe level, the influence of reflections from the road surface can be suppressed and false detection can be prevented even when applied to the radar device 1.

[0096] <Summary> According to this embodiment, the on-elements 111a, 111c, 211a, and 211c of the transmitting antenna array 107 and the receiving antenna array 207 are arranged two-dimensionally so that the occupation density is higher in the center and lower at the four corners. This allows the number of on-elements 111a, 111c, 211a, and 211c to be reduced compared to a configuration in which the on-elements 111a, 111c, 211a, and 211c are randomly arranged throughout the two-dimensional array, and also allows the number of phase shifters 12 and 15 electrically connected to the on-elements 111a, 111c, 211a, and 211c to be reduced.

[0097] Furthermore, according to this embodiment, the on-elements 111a and 111c of the transmitting antenna array 107 and the on-elements 211a and 211c of the receiving antenna array 207 are arranged so as to complement each other from the center to the four corners of the two-dimensional arrangement, so that the side lobe level can be suppressed in accordance with the transmitting beam angle and the receiving beam angle in an angle range where the Y direction angle is, for example, from 0° to 17.5°.

[0098] Furthermore, since the density of the on-elements 111a, 111c, 211a, and 211c is high in the center and low at the four corners, it is possible to suppress the generation of unnecessary side lobes, etc. By using the first to sixth null filters embedded in the two-dimensional array, it is possible to track and suppress the grating lobe angle.

[0099] The coverage rate at which the on-elements 111a, 111c of the transmitting antenna array 107 and the on-elements 211a, 211c of the receiving antenna array 207 as a whole complement a two-dimensional arrangement is set to be higher than the coverage rate at which the on-elements 111a, 111c of the transmitting antenna array 107 or the on-elements 211a, 211c of the receiving antenna array 207 alone complement a two-dimensional arrangement, and therefore a design with arrangements that complement each other can achieve further side lobe improvement effects.

[0100] A plurality of pairs of on-elements 111c of the transmitting antenna array 107 and a plurality of pairs of on-elements 211c of the receiving antenna array 207 are provided, and at least one or more pairs of on-elements 111c and pairs of on-elements 211c are arranged at specific intervals d1 to d6 that are different from each other, thereby enabling a design that is complementary and has an increased on-element coverage. Although a form in which a plurality of pairs are provided has been described, the present invention is not limited to this, and it is sufficient that one or more pairs of on-elements 111c of the transmitting antenna array 107 and pairs of on-elements 211c of the receiving antenna array 207 are provided.

[0101] Furthermore, according to this embodiment, the filter characteristics can be strengthened by combining the characteristics of the first to sixth null filters, which have different characteristics, for the transmitting TX and receiving RX. When the gain synthesis by the transmitting antenna array 107 and the receiving antenna array 207 is taken into consideration comprehensively, grating lobes can be more effectively suppressed.

[0102] (Other embodiments) The present invention is not limited to the above embodiment, and the following modifications or extensions are possible, for example: The on-elements 111a, 111c, 211a, and 211c may be configured to have a shape other than a rectangle, for example, a polygonal shape such as an octagon. Furthermore, the on-elements 111a, 111c, 211a, and 211c may have shapes different from each other.

[0103] The on-elements 111a, 111c, 211a, and 211c have been shown to have their coordinate centers regularly arranged at a predetermined period in at least a part of the two-dimensional lattice point array, but this is not limited to this, and the coordinate centers of the arranged positions may be arranged such that the coordinates are shifted two-dimensionally from the center of the lattice point array up, down, left, or right from the position of the lattice point. Note that the on-elements 111c and 211c are preferably arranged fixedly at the center position of the lattice point array.

[0104] Although the grouping of on-elements 111a, 211a has been described in terms of two groups in the Y direction, i.e., vertical direction, this is not limiting. Two groups of on-elements 111a, 211a may also be configured in the X direction, i.e., horizontal direction. Furthermore, the grouping of on-elements 111c, 211c has been described in terms of two single elements spaced apart in the Y direction, i.e., vertical direction, the present invention is not limited to this. Four or more single elements may also be arranged by using pairs of two types of single elements symmetrical about the X axis, with different specific intervals between the on-elements 111c, 211c in the Y direction.

[0105] Although the present invention has been described based on the above-described embodiment, it is understood that the present invention is not limited to the embodiment or structure. The present invention also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including one, more, or less than one element, are also within the scope and spirit of the present invention. [Explanation of symbols]

[0106] In the drawing, 107 is a transmitting antenna array (antenna array for high frequency equipment), 207 is a receiving antenna array (antenna array for high frequency equipment), 111a is an on-element (effective element, first grouping on-element) of the transmitting antenna array, 111c is an on-element (effective element, first single on-element) of the transmitting antenna array, 211a is an on-element (effective element, second grouping on-element) of the receiving antenna array, 211c is an on-element (effective element, second single on-element) of the receiving antenna array, 111b is a dummy element of the transmitting antenna array, 211b is a dummy element of the receiving antenna array, 12 and 15 are phase shifters, TR and TX∩RX are overlapping regions (logical product regions), and TX∪RX is a logical sum region.

Claims

1. a transmitting antenna array (107) and a receiving antenna array (207) used in a radar device and arranged two-dimensionally within a predetermined area, each having effective elements (111a, 111c, 211a, 211c) electrically connected to a phase shifter (12, 15) and dummy elements (111b, 211b) not electrically connected to the phase shifter, and each arranged within the predetermined area; The effective elements (111a, 111c) of the transmitting antenna array are a first grouping-on element (111a) that is grouped adjacently along a specific direction of a first direction or a second direction in the two-dimensional array and controlled by the same phase shifter; and a first single-on element (111c) that is provided separately and isolated from the first grouping-on elements and that is arranged in pairs at a specific first interval in the specific direction, The effective elements (211a, 211c) of the receiving antenna array are a second grouping-on element (211a) that is grouped adjacently along a specific direction of a first direction or a second direction in the two-dimensional array and controlled by the same phase shifter; and a second single-on element (211c) that is provided separately and isolated from the second grouping-on elements and is arranged in pairs at a specific second interval in the specific direction, An antenna array for a high frequency device, in which the effective elements of the transmitting antenna array and the effective elements of the receiving antenna array are arranged so that at least a portion of their arrangements are complementary to each other from the center to the four corners of the two-dimensional arrangement, and so that the density decreases from the center to the four corners.

2. 2. The antenna array for a high frequency device according to claim 1, wherein the number of effective elements in the first direction or the second direction is different between the transmitting antenna array and the receiving antenna array.

3. 2. An antenna array for a high frequency device as described in claim 1, wherein the elements are designed to be complementarily arranged so that the coverage rate of the logical sum area of the effective elements when the effective elements of the transmitting antenna array and the effective elements of the receiving antenna array are overlapped is higher than the coverage rate of the logical sum area of the effective elements of the transmitting antenna array or the effective elements of the receiving antenna array within a single area.

4. the pair of first single-on elements of the transmitting antenna array and the pair of second single-on elements of the receiving antenna array are provided in one or more pairs, 2. The antenna array for a high frequency device according to claim 1, wherein at least one pair of the first single-on elements and one pair of the second single-on elements are arranged at the specific intervals different from each other.

5. 2. The antenna array for a high frequency device according to claim 1, wherein the logical product area that overlaps when the arrangement positions of the effective elements of the transmitting antenna array and the effective elements of the receiving antenna array are overlapped is continuously arranged in a diagonal direction from the center of the two-dimensional arrangement.

6. 2. The antenna array for a high frequency device according to claim 1, wherein the logical product area that overlaps when the arrangement positions of the effective elements of the transmitting antenna array and the effective elements of the receiving antenna array are overlapped is arranged in a ripple shape, a concentric circle shape, or a concentric ellipse shape centered on the center of the two-dimensional arrangement.

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