Bent ridge waveguide millimeter wave radar antenna

Abstract

The invention discloses a bent ridge waveguide millimeter wave radar antenna, which comprises a one-to-two power divider, two bent ridge waveguides, a horn and n rectangular radiation waveguides, n is an even number greater than or equal to 4, and the n rectangular radiation waveguides are distributed along a straight line and are averagely divided into two groups of rectangular radiation waveguides, the one-to-two power divider equally divides an electromagnetic wave signal generated by excitation into two paths of electromagnetic wave signals and then outputs the two paths of electromagnetic wave signals to the two bent ridge waveguides in a one-to-one correspondence manner, and the two bent ridge waveguides transmit the electromagnetic wave signals transmitted to the bent ridge waveguides to the n rectangular radiation waveguides. Each rectangular radiation waveguide couples and outputs the electromagnetic wave signal transmitted to the rectangular radiation waveguide to the loudspeaker, and the loudspeaker radiates the electromagnetic wave signal at the loudspeaker to a free space; the antenna has the advantages of low loss, H-plane low side lobe, wide E-plane 3dB beam width and small size, can meet the condition that antenna units are arranged according to half wavelength when being applied to an antenna array as an antenna unit, and is easy to process.

Description

Technical Field

[0001] The present invention relates to a millimeter-wave radar antenna, and more particularly to a bent-ridge waveguide millimeter-wave radar antenna. Background Art

[0002] With the development of wireless communication technology, millimeter-wave radar antennas have been widely used in many fields such as automobiles, the Internet of Things, drones, security, and sports. As an important part of the millimeter-wave radar system, the performance of the millimeter-wave radar antenna directly affects the detection range, accuracy, and stability of the millimeter-wave radar system. In the design of millimeter-wave radar antennas, waveguide technology is particularly important because it is related to the signal transmission efficiency in the millimeter-wave radar antenna and the radiation characteristics of the millimeter-wave radar antenna.

[0003] Existing millimeter-wave radar antennas are usually designed based on rectangular waveguides and are series-fed leaky-wave antennas, which mainly include a power divider, a rectangular waveguide, and multiple radiation ports. The multiple radiation ports are misaligned. The rectangular waveguide transmits the signal to the multiple radiation ports for radiation. This millimeter-wave radar antenna has low-loss performance. This millimeter-wave radar antenna changes the energy at each radiation port by misaligning the multiple radiation ports to achieve energy regulation and the effect of low side lobes in the H-plane. Although this millimeter-wave radar antenna has a simple structure and is easy to process. However, on the one hand, since the multiple radiation ports are misaligned and not on the same line, the 3dB beam width in the E-plane is relatively narrow, affecting the detection range, accuracy, and stability of the millimeter-wave radar system. On the other hand, the use of a rectangular waveguide design for this millimeter-wave radar antenna results in a relatively large size. When used as an antenna element to form an antenna array in a millimeter-wave radar system, it cannot meet the condition that the antenna elements in the antenna array are arranged at intervals of half a wavelength, and thus has certain limitations in practical applications.

[0004] The US patent with publication number US12126081B2 discloses an antenna with an H-plane waveguide bend structure. This antenna also has the effects of low side lobes in the H-plane, wide beam characteristics, and is easy to process. However, the cross-sectional area of the waveguide makes it impossible to arrange the antenna elements at half-wavelength intervals.

[0005] The international patent with publication number WO2022122319A1 discloses millimeter-wave radar antennas based on H-plane ridge waveguides and E-plane waveguides. This millimeter-wave radar antenna also has the effects of low side lobes in the H-plane and wide beam characteristics, and can also be arranged at half-wavelength intervals. However, the conversion structure between its E-plane waveguide and H-plane ridge waveguide contains many matching structures, and the radiation structure also contains a large number of discontinuity structures, resulting in high processing difficulty. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a bent ridge waveguide millimeter-wave radar antenna that has low loss and low H-plane side lobes, while also having a wide E-plane 3dB beam width, a small size, and can meet the condition that the antenna elements are arranged at intervals of half a wavelength when applied as antenna elements in an antenna array, and is easy to process.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows: A bent ridge waveguide millimeter-wave radar antenna includes a 1-to-2 power divider, two bent ridge waveguides, a horn, and n rectangular radiation waveguides, where n is an even number greater than or equal to 4. The n rectangular radiation waveguides are distributed along a straight line and are evenly divided into two groups of rectangular radiation waveguides. Each group of rectangular radiation waveguides includes n / 2 rectangular radiation waveguides. The two groups of rectangular radiation waveguides correspond one-to-one to the two bent ridge waveguides. The 1-to-2 power divider is used to equally divide the electromagnetic wave signals generated by the excitation into two paths of electromagnetic wave signals, and then output the two paths of electromagnetic wave signals to the two bent ridge waveguides respectively. Each bent ridge waveguide is used to transmit the electromagnetic wave signals transmitted to it to the n / 2 rectangular radiation waveguides corresponding to it. Each rectangular radiation waveguide is used to couple and output the electromagnetic wave signals transmitted to it to the horn. The horn is used to radiate the electromagnetic wave signals output from the n rectangular radiation waveguides to free space.

[0008] Compared with the prior art, the advantages of the present invention are as follows: By arranging two curved ridge waveguides to transmit electromagnetic wave signals to n rectangular radiation waveguides, when the electromagnetic wave signals are transmitted to the two curved ridge waveguides, due to the bending characteristics of the curved ridge waveguides, the surface curvature can be designed according to actual usage requirements. Thus, by controlling the curvature of the curved ridge waveguide near the rectangular radiation waveguide, the energy distribution at each rectangular radiation waveguide can be flexibly adjusted, so that the rectangular radiation waveguide near the edge of the millimeter-wave radar antenna obtains less energy, and the rectangular radiation waveguide near the center of the millimeter-wave radar antenna obtains more energy, achieving the H-plane low sidelobe performance. Therefore, there is no need to control the energy distribution by misaligning the n rectangular radiation waveguides, and the n rectangular radiation waveguides can be arranged on the same straight line to achieve the wide E-plane 3dB beam characteristic. In addition, the setting of the horn can not only maintain the wide E-plane 3dB beam characteristic, but also the change of the horn size can change the E-plane 3dB beam width. Thus, during the design process, the actual required E-plane 3dB beam width can be directly obtained by setting the horn size. At the same time, the use of the curved ridge waveguide ensures the operating frequency while reducing the size. When the millimeter-wave radar antenna is used as an antenna element in an antenna array, it can meet the requirement that the antenna elements in the array antenna are arranged according to half a wavelength. Therefore, the present invention has a low loss, H-plane low sidelobe, a wide E-plane 3dB beam, and a small size. When used as an antenna element in an antenna array, it can meet the condition that the antenna elements are arranged according to half a wavelength. In addition, the 1-to-2 power divider directly inputs the electromagnetic wave signals into the two curved ridge waveguides, without the need to add a matching structure to achieve low loss, and is easy to process; the experimental simulation results show that the E-plane 3dB beam width of the curved ridge waveguide millimeter-wave radar antenna of the present invention can reach about 131°, the loss is below -20 dB in the operating frequency band of 76GHz - 81GHz, and the H-plane sidelobe suppression is maintained above 20 dB.

[0009] Further, the 1-to-2 power divider includes seven rectangular waveguides. The length directions of the seven rectangular waveguides are the same, which is regarded as the left-right direction, the width directions are the same, which is regarded as the front-back direction, and the height directions are the same, which is regarded as the up-down direction. These seven rectangular waveguides are respectively called the first rectangular waveguide, the second rectangular waveguide, the third rectangular waveguide, the fourth rectangular waveguide, the fifth rectangular waveguide, the sixth rectangular waveguide, and the seventh rectangular waveguide. The plane that makes the first rectangular waveguide symmetric left and right is called the first symmetry plane. The second rectangular waveguide, the third rectangular waveguide, and the fourth rectangular waveguide are all located on the left side of the first rectangular waveguide, and the three form an inverted U-shaped structure with the opening facing down. The fifth rectangular waveguide, the sixth rectangular waveguide, and the seventh rectangular waveguide are all located on the right side of the first rectangular waveguide, and the three form an inverted U-shaped structure with the opening facing down. The two inverted U-shaped structures are symmetric left and right with respect to the first symmetry plane.

[0010] Further, the second rectangular waveguide is disposed in a fitting manner on the left side of the first rectangular waveguide, and the upper end faces and the front end faces of both are located in the same plane respectively. The width of the second rectangular waveguide is smaller than the width of the first rectangular waveguide. The third rectangular waveguide is disposed in a fitting manner below the second rectangular waveguide and on the right side of the first rectangular waveguide. The left end face and the front end face of the third rectangular waveguide are respectively located in the same plane as the left end face and the front end face of the second rectangular waveguide. The sum of the heights of the third rectangular waveguide and the second rectangular waveguide is smaller than the height of the first rectangular waveguide. The plane that makes the second rectangular waveguide be symmetric front and back is called the second symmetry plane. The third rectangular waveguide and the fourth rectangular waveguide are symmetric front and back with respect to the second symmetry plane; the sum of the widths of the third rectangular waveguide and the fourth rectangular waveguide is smaller than the width of the second rectangular waveguide; the second rectangular waveguide and the fifth rectangular waveguide are symmetric left and right with respect to the first symmetry plane, the third rectangular waveguide and the sixth rectangular waveguide are symmetric left and right with respect to the first symmetry plane, and the fourth rectangular waveguide and the seventh rectangular waveguide are symmetric left and right with respect to the first symmetry plane.

[0011] Further, the two curved ridge waveguides are respectively called the first curved ridge waveguide and the second curved ridge waveguide. The first curved ridge waveguide is located on the left side of the 1-to-2 power divider. The first curved ridge waveguide is realized by arranging a curved waveguide block inside a curved waveguide. This curved waveguide is called the first curved waveguide, and this curved waveguide block is called the first curved waveguide block. The first curved waveguide is formed by bending a waveguide with a cuboid structure. The first curved waveguide block is formed by bending a waveguide with a cuboid structure. The second curved ridge waveguide is located on the right side of the 1-to-2 power divider. The intersection line of the plane where the central axis of the second rectangular waveguide in the up-down direction and the central axis of the fifth rectangular waveguide in the up-down direction lies and the first symmetry plane is used as the first axis. If the first curved ridge waveguide rotates 180 degrees with the first axis as the rotation axis, it will completely coincide with the second curved ridge waveguide.

[0012] Further, the outer side surface of the first bent waveguide is sequentially formed by splicing six end faces distributed according to the upper, lower, left, right, front, and rear orientations. The left end face and the right end face of the first bent waveguide are both rectangular faces, the upper end face and the lower end face are both s-shaped planes, and the front end face and the rear end face are s-shaped curved surfaces. If its upper end face is translated downward, it can completely coincide with its lower end face. If its front end face is translated backward, it can completely coincide with its rear end face. If its left end face is translated rightward, it can completely coincide with its right end face. The upper end face of the first bent waveguide and the upper end face of the first rectangular waveguide are in the same plane. The lower end face of the first bent waveguide and the lower end face of the third rectangular waveguide are in the same plane. The right end face of the first bent waveguide is connected and in a fitting state with the left end faces of the second rectangular waveguide, the third rectangular waveguide, and the fourth rectangular waveguide. The front side edge of the right end face of the first bent waveguide and the front end face of the third rectangular waveguide are in the same plane. The rear side edge of the right end face of the first bent waveguide and the rear end face of the fourth rectangular waveguide are in the same plane.

[0013] Further, the shape of the outer side surface of the first bent waveguide block is the same as that of the first bent waveguide. The lower end face, the left end face, and the right end face of the first bent waveguide block are respectively in the same plane as the lower end face, the left end face, and the right end face of the first bent waveguide. The upper end face of the first bent waveguide block is located below the upper end face of the first bent waveguide, and there is a distance between them. The left end face of the first bent waveguide block and the left end face of the first bent waveguide are symmetric about the same plane in the front and rear directions. The length of the left end face of the first bent waveguide block in the front and rear directions is less than the length of the left end face of the first bent waveguide in the front and rear directions. If the upper end face of the first bent waveguide block is vertically mapped onto the upper end face of the first bent waveguide, at this time, the front side edge of the upper end face of the first bent waveguide block can completely coincide with the front side edge of the upper end face of the first bent waveguide after being translated forward, and the rear side edge of the upper end face of the first bent waveguide block can completely coincide with the rear side edge of the upper end face of the first bent waveguide after being translated backward.

[0014] Further, the two groups of rectangular radiation waveguides are respectively referred to as the first group of rectangular radiation waveguides and the second group of rectangular radiation waveguides. The first group of rectangular radiation waveguides corresponds to the first bent ridge waveguide, and the second group of rectangular radiation waveguides corresponds to the second bent ridge waveguide. n / 2 rectangular radiation waveguides of the first group of rectangular radiation waveguides are evenly spaced from left to right above the first bent ridge waveguide. n / 2 rectangular radiation waveguides of the second group of rectangular radiation waveguides are evenly spaced from left to right above the second bent ridge waveguide. The first group of rectangular radiation waveguides and the second group of rectangular radiation waveguides are symmetric about the first symmetry plane in the left and right directions.

[0015] Further, the lengths of n / 2 rectangular radiation waveguides in the first group of rectangular radiation waveguides are all along the left-right direction, the widths are all along the front-back direction, and the heights are all along the up-down direction. The front end faces of the n / 2 rectangular radiation waveguides in the first group of rectangular radiation waveguides are in the same plane, the rear end faces are in the same plane, the upper end faces are in the same plane, and the lower end faces are in the same plane. The lower end faces of the n / 2 rectangular radiation waveguides in the first group of rectangular radiation waveguides are all connected to and in a conforming state with the upper end face of the first curved ridge waveguide; the plane where the left end face of the leftmost rectangular radiation waveguide in the first group of rectangular radiation waveguides is located is on the right side of the left end face of the first curved ridge waveguide, the plane where the right end face of the rightmost rectangular radiation waveguide in the first group of rectangular radiation waveguides is located is on the left side of the right end face of the first curved ridge waveguide, the plane where the left end face of the leftmost rectangular radiation waveguide in the second group of rectangular radiation waveguides is located is on the right side of the left end face of the second curved ridge waveguide, and the plane where the right end face of the rightmost rectangular radiation waveguide in the second group of rectangular radiation waveguides is located is on the left side of the right end face of the second curved ridge waveguide.

[0016] Further, the outer side surface of the horn is a hexahedron formed by sequentially splicing and surrounding six end faces distributed in the upper, lower, left, right, front, and rear directions. The right end face, left end face, front end face, and rear end face of the horn are all isosceles trapezoids, the upper end face and the lower end face of the horn are both rectangles, and the lengths of the upper end face and the lower end face of the horn are all along the left-right direction, and the widths are all along the front-back direction; the horn is located above the n rectangular radiation waveguides, and the lower end face of the horn is connected to and in a conforming state with the upper end faces of the n rectangular radiation waveguides; the left side edge of the lower end face of the horn is on the left side of the plane where the left end face of the first curved ridge waveguide is located, the right side edge of the lower end face of the horn is on the right side of the plane where the right end face of the second curved ridge waveguide is located, the front side edge of the lower end face of the horn is on the front side of the plane where the front end faces of the n rectangular radiation waveguides are located, and the rear side edge of the lower end face of the horn is on the rear side of the plane where the rear end faces of the n rectangular radiation waveguides are located.

[0017] Further, the upper end face and the lower end face of the horn are both left-right symmetric about the first symmetry plane, the upper end face and the lower end face of the horn are both front-back symmetric about the same plane, the width of the upper end face of the horn in the front-back direction is greater than the width of the lower end face of the horn in the front-back direction, and the length of the upper end face of the horn in the left-right direction is greater than the length of the lower end face of the horn in the left-right direction; the lower bottom of the left end face of the horn completely coincides with the left side edge of the upper end face of the horn, the upper bottom of the left end face of the horn completely coincides with the left side edge of the lower end face of the horn, the lower bottom of the front end face of the horn completely coincides with the front side edge of the upper end face of the horn, the upper bottom of the front end face of the horn completely coincides with the front side edge of the lower end face of the horn, the lower bottom of the rear end face of the horn completely coincides with the rear side edge of the upper end face of the horn, and the upper bottom of the rear end face of the horn completely coincides with the rear side edge of the lower end face of the horn; the waist of the left end face of the horn located on the front side completely coincides with the left side edge of the front end face of the horn, and the waist of the left end face of the horn located on the rear side completely coincides with the left side edge of the rear end face of the horn; the lower bottom of the right end face of the horn completely coincides with the right side edge of the upper end face of the horn, the upper bottom of the right end face of the horn completely coincides with the right side edge of the lower end face of the horn, the waist of the right end face of the horn located on the front side completely coincides with the right side edge of the front end face of the horn, and the waist of the right end face of the horn located on the rear side completely coincides with the right side edge of the rear end face of the horn. Description of the Drawings

[0018] Figure 1 is a structural diagram of a bent ridge waveguide millimeter-wave radar antenna according to the present invention; Figure 2 is an exploded view of a bent ridge waveguide millimeter-wave radar antenna according to the present invention; Figure 3 is a top view after removing the horn of a horn-removed bent ridge waveguide millimeter-wave radar antenna according to the present invention; Figure 4 is an exploded view of a 1-to-2 power divider of a bent ridge waveguide millimeter-wave radar antenna according to the present invention; Figure 5 is a structural diagram of a first bent ridge waveguide of a bent ridge waveguide millimeter-wave radar antenna according to the present invention; Figure 6 is a structural diagram of a horn of a bent ridge waveguide millimeter-wave radar antenna according to the present invention; Figure 7 is a reflection coefficient simulation diagram when a bent ridge waveguide millimeter-wave radar antenna according to the present invention performs simulation with a first set of parameters; Figure 8 are the radiation patterns of the E-plane and the H-plane when a bent ridge waveguide millimeter-wave radar antenna according to the present invention performs simulation with a first set of parameters; Figure 9The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when simulated with the second set of parameters; Figure 10 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when simulated with the third set of parameters; Figure 11 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when simulated with the fourth set of parameters; Figure 12 The layout diagram of a bent ridged waveguide millimeter-wave radar antenna of the present invention when applied as an antenna element in an antenna array with a half-wavelength spacing; Figure 13 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when used as the first antenna element; Figure 14 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when used as the second antenna element; Figure 15 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when used as the third antenna element; Figure 16 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when used as the fourth antenna element; Figure 17 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when used as the fifth antenna element; Figure 18 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when used as the sixth antenna element; Figure 19 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when used as the seventh antenna element; Figure 20 The E-plane and H-plane radiation patterns of a bent ridged waveguide millimeter-wave radar antenna of the present invention when used as the eighth antenna element. Detailed implementation manners

[0019] The present invention will be further described in detail below with reference to the embodiments in the accompanying drawings.

[0020] Embodiment 1: As Figures 1 to 3As shown in the figure, a millimeter-wave radar antenna with a curved ridge waveguide includes a 1-to-2 power divider 1, two curved ridge waveguides, a horn 2, and n rectangular radiation waveguides 3, where n is an even number greater than or equal to 4. The n rectangular radiation waveguides 3 are distributed along a straight line and are evenly divided into two groups of rectangular radiation waveguides 3. Each group of rectangular radiation waveguides 3 includes n / 2 rectangular radiation waveguides 3. The two groups of rectangular radiation waveguides 3 correspond to the two curved ridge waveguides one by one. The 1-to-2 power divider 1 is used to equally divide the electromagnetic wave signal generated by the excitation into two electromagnetic wave signals, and then output the two electromagnetic wave signals to the two curved ridge waveguides one by one. Each curved ridge waveguide is used to transmit the electromagnetic wave signal transmitted to it to the n / 2 rectangular radiation waveguides 3 corresponding to it. Each rectangular radiation waveguide 3 is used to couple and output the electromagnetic wave signal transmitted to it to the horn 2. The horn 2 is used to radiate the electromagnetic wave signals output from the n rectangular radiation waveguides 3 to free space.

[0021] In this embodiment, by setting two curved ridge waveguides to transmit the electromagnetic wave signal to the n rectangular radiation waveguides 3, when the electromagnetic wave signal is transmitted to the two curved ridge waveguides, due to the bending characteristics of the curved ridge waveguides, the surface curvature can be designed according to actual usage requirements. Thus, by controlling the curvature of the curved ridge waveguides, the energy distribution at each rectangular radiation waveguide 3 can be changed, so that the rectangular radiation waveguides 3 near the edge of the millimeter-wave radar antenna obtain less energy, and the rectangular radiation waveguides 3 near the center of the millimeter-wave radar antenna obtain more energy, realizing the low sidelobe performance in the H-plane. Therefore, there is no need to control the energy distribution by the staggered distribution of the n rectangular radiation waveguides 3. The n rectangular radiation waveguides 3 can be arranged on the same straight line to achieve the wide E-plane 3dB beam characteristic. In addition, the setting of the horn 2 can not only maintain the wide E-plane 3dB beam characteristic, but also the change in the size of the horn 2 can change the E-plane 3dB beam width. Thus, in the design process, the actual required E-plane 3dB beam width can be directly obtained by setting the size of the horn 2. At the same time, the use of the curved ridge waveguide ensures the operating frequency while reducing the size. When the millimeter-wave radar antenna is used as an antenna element in an antenna array, it can meet the requirement that the antenna elements in the array antenna are arranged according to half a wavelength. In addition, the 1-to-2 power divider 1 directly inputs the electromagnetic wave signal to the two curved ridge waveguides without the need to add an additional matching structure, which is easy to process.

[0022] Embodiment 2: This embodiment is basically the same as Embodiment 1, except that: in this embodiment, as Figure 4As shown, the 1-way to 2-way power divider 1 includes seven rectangular waveguides, which are respectively referred to as the first rectangular waveguide 4, the second rectangular waveguide 5, the third rectangular waveguide 6, the fourth rectangular waveguide 7, the fifth rectangular waveguide 8, the sixth rectangular waveguide 9, and the seventh rectangular waveguide 10. The width direction of the first rectangular waveguide 4 is taken as the left-right direction, the length direction is taken as the front-back direction, and the height direction is taken as the up-down direction. The width directions of the second rectangular waveguide 5, the third rectangular waveguide 6, the fourth rectangular waveguide 7, the fifth rectangular waveguide 8, the sixth rectangular waveguide 9, and the seventh rectangular waveguide 10 are all along the left-right direction, the length directions are all along the front-back direction, and the height directions are all along the up-down direction. The plane that makes the first rectangular waveguide 4 left-right symmetric is called the first symmetry plane. The second rectangular waveguide 5 is located on the left side of the first rectangular waveguide 4. The upper end face of the second rectangular waveguide 5 and the upper end face of the first rectangular waveguide 4 are in the same plane. The front end face of the second rectangular waveguide 5 and the front end face of the first rectangular waveguide 4 are in the same plane. The lower end face of the second rectangular waveguide 5 is above the plane where the lower end face of the first rectangular waveguide 4 is located. The rear end face of the second rectangular waveguide 5 is in front of the plane where the rear end face of the first rectangular waveguide 4 is located. The right end face of the second rectangular waveguide 5 is connected to and in contact with the left end face of the first rectangular waveguide 4. The third rectangular waveguide 6 is located below the second rectangular waveguide 5. The left end face of the third rectangular waveguide 6 and the left end face of the second rectangular waveguide 5 are in the same plane. The front end face of the third rectangular waveguide 6 and the front end face of the second rectangular waveguide 5 are in the same plane. The rear end face of the third rectangular waveguide 6 is in front of the rear end face of the second rectangular waveguide 5. The upper end face of the third rectangular waveguide 6 is connected to and in contact with the lower end face of the second rectangular waveguide. The lower end face of the third rectangular waveguide 6 is above the plane where the lower end face of the first rectangular waveguide 4 is located. The right end face of the third rectangular waveguide 6 is connected to and in contact with the left end face of the first rectangular waveguide 4. The plane that makes the second rectangular waveguide 5 front-back symmetric is called the second symmetry plane. The fourth rectangular waveguide 7 is located behind the third rectangular waveguide 6. The third rectangular waveguide 6 and the fourth rectangular waveguide 7 are front-back symmetric about the second symmetry plane. The sum of the widths of the third rectangular waveguide 6 and the fourth rectangular waveguide 7 is less than the width of the second rectangular waveguide 5. The fifth rectangular waveguide 8 is located on the right side of the first rectangular waveguide 4. The second rectangular waveguide 5 and the fifth rectangular waveguide 8 are left-right symmetric about the first symmetry plane. The sixth rectangular waveguide 9 is located on the right side of the first rectangular waveguide 4. The third rectangular waveguide 6 and the sixth rectangular waveguide 9 are left-right symmetric about the first symmetry plane. The seventh rectangular waveguide 10 is located on the right side of the first rectangular waveguide 4. The fourth rectangular waveguide 7 and the seventh rectangular waveguide 10 are left-right symmetric about the first symmetry plane.

[0023] In this embodiment, the electromagnetic wave signal generated by the excitation is input from the rear end face of the first rectangular waveguide 4 into the 1-to-2 power divider 1. The electromagnetic wave signal is transmitted through the first rectangular waveguide 4 to the second rectangular waveguide 5, the third rectangular waveguide 6, the fourth rectangular waveguide 7, the fifth rectangular waveguide 8, the sixth rectangular waveguide 9, and the seventh rectangular waveguide 10, and finally transmitted out through the left end faces of the second rectangular waveguide 5, the third rectangular waveguide 6, and the fourth rectangular waveguide 7, and the right end faces of the fifth rectangular waveguide 8, the sixth rectangular waveguide 9, and the seventh rectangular waveguide 10. Since the first rectangular waveguide 4 itself has a left-right symmetric structure, and the structures formed by the second rectangular waveguide 5, the third rectangular waveguide 6, and the fourth rectangular waveguide 7, and the structures formed by the fifth rectangular waveguide 8, the sixth rectangular waveguide 9, and the seventh rectangular waveguide 10 are left-right symmetric, accordingly, the electromagnetic wave signals transmitted through the left end faces of the second rectangular waveguide 5, the third rectangular waveguide 6, and the fourth rectangular waveguide 7 and the electromagnetic wave signals transmitted through the right end faces of the fifth rectangular waveguide 8, the sixth rectangular waveguide 9, and the seventh rectangular waveguide 10 have the same energy, that is, the electromagnetic wave signal generated by the excitation is equally divided into two electromagnetic wave signals and output by the 1-to-2 power divider 1.

[0024] Embodiment 3: This embodiment is basically the same as Embodiment 2, except that: in this embodiment, as Figure 5As shown in the figure, the two curved ridge waveguides are respectively referred to as the first curved ridge waveguide 11 and the second curved ridge waveguide 12. The first curved ridge waveguide 11 is located on the left side of the 1-to-2 power splitter 1. The first curved ridge waveguide 11 is realized by arranging a curved waveguide block inside a curved waveguide. This curved waveguide is called the first curved waveguide 13, and this curved waveguide block is called the first curved waveguide block 14. The first curved waveguide 13 is formed by bending a waveguide with a cuboid structure. Its outer side is surrounded by six end faces distributed in the up, down, left, right, front, and rear directions in sequence. The left end face and the right end face of the first curved waveguide 13 are both rectangular faces, the upper end face and the lower end face are both s-shaped planes, and the front end face and the rear end face are s-shaped curved surfaces. If its upper end face is translated downward, it can completely coincide with its lower end face. If its front end face is translated backward, it can completely coincide with its rear end face. If its left end face is translated to the right, it can completely coincide with its right end face. The upper end face of the first curved waveguide 13 and the upper end face of the first rectangular waveguide 4 are in the same plane. The lower end face of the first curved waveguide 13 and the lower end face of the third rectangular waveguide 6 are in the same plane. The right end face of the first curved waveguide 13 is connected and in a fitting state with the left end face of the second rectangular waveguide 5, the left end face of the third rectangular waveguide 6, and the left end face of the fourth rectangular waveguide 7. The front side edge of the right end face of the first curved waveguide 13 and the front end face of the third rectangular waveguide 6 are in the same plane. The rear side edge of the right end face of the first curved waveguide 13 and the rear end face of the fourth rectangular waveguide 7 are in the same plane. The first curved waveguide block 14 is formed by bending a waveguide with a cuboid structure. Its outer side is surrounded by six end faces distributed in the up, down, left, right, front, and rear directions in sequence. The left end face and the right end face of the first curved waveguide block 14 are both rectangular faces, the upper end face and the lower end face are both s-shaped planes, and the front end face and the rear end face are both s-shaped curved surfaces. If its upper end face is translated downward, it can completely coincide with its lower end face. If its front end face is translated backward, it can completely coincide with its rear end face. If its left end face is translated to the right, it can completely coincide with its right end face. The lower end face of the first curved waveguide block 14 and the lower end face of the first curved waveguide 13 are in the same plane. The upper end face of the first curved waveguide block 14 is located below the upper end face of the first curved waveguide 13, and there is a certain distance between them. The left end face of the first curved waveguide block 14 and the left end face of the first curved waveguide 13 are in the same plane, and both are symmetric about the same plane in the front and back directions. The length of the left end face of the first curved waveguide block 14 in the front and back direction is less than the length of the left end face of the first curved waveguide 13 in the front and back direction. The right end face of the first curved waveguide block 14 and the right end face of the first curved waveguide 13 are in the same plane. If the upper end face of the first curved waveguide block 14 is vertically mapped onto the upper end face of the first curved waveguide 13, at this time, the front side edge of the upper end face of the first curved waveguide block 14 can completely coincide with the front side edge of the upper end face of the first curved waveguide 13 after being translated forward, and the rear side edge of the upper end face of the first curved waveguide block 14 can completely coincide with the rear side edge of the upper end face of the first curved waveguide 13 after being translated backward.The second curved ridge waveguide 12 is located on the right side of the 1-to-2 power divider 1. The intersection line of the plane where the central axis of the second rectangular waveguide 5 in the up-and-down direction and the central axis of the fifth rectangular waveguide 8 in the up-and-down direction lies with the first symmetry plane is taken as the first axis. If the first curved ridge waveguide 11 rotates 180° around the first axis, it will completely coincide with the second curved ridge waveguide 12.

[0025] In this embodiment, when the electromagnetic wave signal generated by the excitation is input into the 1-to-2 power divider 1 from the rear end face of the first rectangular waveguide 4 for transmission, the 1-to-2 power divider 1 equally divides the electromagnetic wave signal into two electromagnetic wave signals. One of the electromagnetic wave signals is transmitted to the right end face of the first curved ridge waveguide 11 through the left end faces of the second rectangular waveguide 5, the third rectangular waveguide 6, and the fourth rectangular waveguide 7, and the other electromagnetic wave signal is transmitted to the left end face of the second curved ridge waveguide 12 through the right end faces of the fifth rectangular waveguide 8, the sixth rectangular waveguide 9, and the seventh rectangular waveguide 10. The electromagnetic wave signal transmitted to the right end face of the first curved ridge waveguide 11 enters the first curved ridge waveguide 11 for transmission. The first curved ridge waveguide 11 changes the energy distribution at the corresponding n / 2 rectangular radiation waveguides 3, controls the energy obtained by the corresponding n / 2 rectangular radiation waveguides 3, and outputs it to the corresponding n / 2 rectangular radiation waveguides 3 through the upper end face of the first curved ridge waveguide 11. Due to the change in the curvature of the first curved ridge waveguide 11, the greater the curvature of the upper end face of the first curved ridge waveguide 11, the greater the electromagnetic wave energy output, so that the energy can be concentrated at the rectangular radiation waveguide 3 close to the center of the millimeter-wave radar antenna. The first curved ridge waveguide groove in the first curved ridge waveguide 11 is used to reduce the size of the curved ridge waveguide, so that the smaller curved ridge waveguide can keep the antenna operating frequency band within the required frequency band. Similarly, the electromagnetic wave signal transmitted to the left end face of the second curved ridge waveguide 12 enters the second curved ridge waveguide 12 for transmission and is output to the corresponding n / 2 rectangular radiation waveguides 3 through the upper end face of the second curved ridge waveguide 12. Due to the change in the curvature of the second curved ridge waveguide 12, the greater the curvature of the upper end face of the second curved ridge waveguide 12, the greater the electromagnetic wave energy output, so that the energy can be concentrated at the rectangular radiation waveguide 3 close to the center of the millimeter-wave radar antenna.

[0026] Embodiment 4: This embodiment is basically the same as Embodiment 3, except that: in this embodiment, the two groups of rectangular radiation waveguides 3 are respectively referred to as the first group of rectangular radiation waveguides 3 and the second group of rectangular radiation waveguides 3. The first group of rectangular radiation waveguides 3 corresponds to the first curved ridge waveguide 11, and the second group of rectangular radiation waveguides 3 corresponds to the second curved ridge waveguide 12. n / 2 rectangular radiation waveguides 3 of the first group of rectangular radiation waveguides 3 are evenly spaced from left to right above the first curved ridge waveguide 11. The length directions of the n / 2 rectangular radiation waveguides 3 of the first group of rectangular radiation waveguides 3 are all along the left-right direction, the width directions are all along the front-back direction, and the height directions are all along the up-down direction. The front end faces of the n / 2 rectangular radiation waveguides 3 of the first group of rectangular radiation waveguides 3 are in the same plane, the rear end faces are in the same plane, the upper end faces are in the same plane, and the lower end faces are in the same plane. The lower end faces of the n / 2 rectangular radiation waveguides 3 of the first group of rectangular radiation waveguides 3 are all connected to the upper end face of the first curved ridge waveguide 11 and are in a fitting state; n / 2 rectangular radiation waveguides 3 of the second group of rectangular radiation waveguides 3 are evenly spaced from left to right above the second curved ridge waveguide 12. The first group of rectangular radiation waveguides 3 and the second group of rectangular radiation waveguides 3 are symmetric about the first symmetry plane; the plane where the left end face of the leftmost rectangular radiation waveguide 3 in the first group of rectangular radiation waveguides 3 is located is on the right side of the left end face of the first curved ridge waveguide 11, the plane where the right end face of the rightmost rectangular radiation waveguide 3 in the first group of rectangular radiation waveguides 3 is located is on the left side of the right end face of the first curved ridge waveguide 11, the plane where the left end face of the leftmost rectangular radiation waveguide 3 in the second group of rectangular radiation waveguides 3 is located is on the right side of the left end face of the second curved ridge waveguide 12, and the plane where the right end face of the rightmost rectangular radiation waveguide 3 in the second group of rectangular radiation waveguides 3 is located is on the left side of the right end face of the second curved ridge waveguide 12.

[0027] Embodiment 5: This embodiment is basically the same as Embodiment 4, except that: in this embodiment, as Figure 6As shown, the outer side surface of the horn 2 is a hexahedron formed by sequentially splicing and surrounding six end faces distributed in the up, down, left, right, front, and rear directions. The right end face, left end face, front end face, and rear end face of the horn 2 are all isosceles trapezoids, and the upper end face and lower end face of the horn 2 are both rectangles. The lengths of the upper end face and lower end face of the horn 2 are both in the left-right direction, and the widths are both in the front-rear direction. The upper end face of the horn 2 is left-right symmetric about the first symmetry plane, the lower end face of the horn 2 is left-right symmetric about the first symmetry plane, the upper end face and the lower end face of the horn 2 are both front-rear symmetric about the same plane. The width of the upper end face of the horn 2 in the front-rear direction is greater than the width of the lower end face in the front-rear direction, and the length of the upper end face of the horn 2 in the left-right direction is greater than the length of the lower end face in the left-right direction. The lower base of the left end face of the horn 2 completely coincides with the left side edge of the upper end face of the horn 2, the upper base of the left end face of the horn 2 completely coincides with the left side edge of the lower end face of the horn 2, the lower base of the front end face of the horn 2 completely coincides with the front side edge of the upper end face of the horn 2, the upper base of the front end face of the horn 2 completely coincides with the front side edge of the lower end face of the horn 2, the lower base of the rear end face of the horn 2 completely coincides with the rear side edge of the upper end face of the horn 2, and the upper base of the rear end face of the horn 2 completely coincides with the rear side edge of the lower end face of the horn 2. The waist of the left end face of the horn 2 located on the front side completely coincides with the left side edge of the front end face of the horn 2, and the waist of the left end face of the horn 2 located on the rear side completely coincides with the left side edge of the rear end face of the horn 2. The lower base of the right end face of the horn 2 completely coincides with the right side edge of the upper end face of the horn 2, the upper base of the right end face of the horn 2 completely coincides with the right side edge of the lower end face of the horn 2, the waist of the right end face of the horn 2 located on the front side completely coincides with the right side edge of the front end face of the horn 2, and the waist of the right end face of the horn 2 located on the rear side completely coincides with the right side edge of the rear end face of the horn 2. The horn 2 is located above n rectangular radiating waveguides 3, and the lower end face of the horn 2 is connected to the upper end faces of the n rectangular radiating waveguides 3 and is in a fitting state. The left side edge of the lower end face of the horn 2 is located on the left side of the plane where the left end face of the first bent ridge waveguide 11 is located, the right side edge of the lower end face of the horn 2 is located on the right side of the plane where the right end face of the second bent ridge waveguide 12 is located, the front side edge of the lower end face of the horn 2 is located on the front side of the plane where the front end faces of the n rectangular radiating waveguides 3 are located, and the rear side edge of the lower end face of the horn 2 is located on the rear side of the plane where the rear end faces of the n rectangular radiating waveguides 3 are located.

[0028] In this embodiment, the smallest diameter part of the horn 2 contacts with n rectangular radiation waveguides 3 to access energy. When the energy is transmitted in the horn 2, the diameter of the horn 2 becomes larger and larger, making the aperture field distribution more concentrated in the central region. As a result, the far-field radiation energy is more concentrated in a smaller angular range, thereby changing the E-plane 3dB beamwidth. However, the wide E-plane 3dB beam characteristics can still be maintained. During the design process, according to the actual usage requirements, adjusting the length and width of the lower end face of the horn 2 and the length and width of the upper end face of the horn 2 can achieve the required E-plane 3dB beamwidth. The smaller the length and width of the upper end face of the horn 2, the wider the E-plane 3dB beamwidth; the larger the length and width of the lower end face of the horn 2, the wider the E-plane 3dB beamwidth. The energy is transmitted from the upper surface of the n rectangular radiation waveguides 3 to the lower surface of the horn 2, then transmitted upward from the lower surface of the horn 2, and finally radiated from the upper surface of the horn 2 into the free space.

[0029] To verify the performance of the bent ridge waveguide millimeter-wave radar antenna of the present invention, the bent ridge waveguide millimeter-wave radar antenna of the present invention is simulated by HFSS. During the simulation, four groups of parameters are set for simulation respectively. The specific settings of the first group of parameters are as follows: the number of rectangular radiation waveguides 3 is 4, the length of each rectangular radiation waveguide 3 in the left-right direction is 2.18 mm, the width in the front-back direction is 0.7 mm, and the height in the up-down direction is 0.5 mm. Each group of rectangular radiation waveguides 3 contains 2 rectangular radiation waveguides 3, and the spacing between the 2 rectangular radiation waveguides 3 is 2.95 mm. The length of the upper surface of the horn 2 in the left-right direction is 13.82 mm, the width in the front-back direction is 3.2 mm. The length of the lower surface of the horn 2 in the left-right direction is 13.72 mm, the width in the front-back direction is 1.6 mm. The distance between the upper surface and the lower surface of the horn 2 is 1 mm. The length of the first rectangular waveguide 4 in the front-back direction is 3 mm, the width in the left-right direction is 0.64 mm, and the height in the up-down direction is 2.4 mm. The length of the second rectangular waveguide 5 in the front-back direction is 1.4 mm, the width in the left-right direction is 0.4 mm, and the height in the up-down direction is 0.4 mm. The length of the third rectangular waveguide 6 in the front-back direction is 0.45 mm, and the height in the up-down direction is 0.6 mm (the height in the up-down direction is 0.6 mm). The spacing between the left end face and the right end face of the first bent ridge waveguide 11 is 6.16 mm, the spacing between the upper end face and the lower end face is 1 mm, and the width of the left end face in the front-back direction is 1.4 mm. The spacing between the upper end face and the lower end face of the groove of the first bent ridge waveguide 11 is 0.6 mm, and the width of the left end face in the front-back direction is 0.5 mm. The front end face of the first bent ridge waveguide 11 bends backward at the rectangular radiation waveguide 3 on the right side in the first group of rectangular radiation waveguides 3 and bends forward at the rectangular radiation waveguide 3 on the left side in the first group of rectangular radiation waveguides 3. The curvature of the front end face of the first bent ridge waveguide 11 bending backward at the rectangular radiation waveguide 3 on the right side in the first group of rectangular radiation waveguides 3 is greater than the curvature of the front end face of the first bent ridge waveguide 11 bending forward at the rectangular radiation waveguide 3 on the left side in the first group of rectangular radiation waveguides 3. The second group of parameters is the same as the first group of data except for the size of the horn 2. In the second group of parameters, the length of the upper surface of the horn 2 in the left-right direction is 16.47 mm, the width in the front-back direction is 3.8 mm, the length of the lower surface of the horn 2 in the left-right direction is 13.72 mm, the width in the front-back direction is 1.6 mm, and the distance between the upper surface and the lower surface of the horn 2 is 1 mm.The third set of parameters are the same as the first set of data except for the size of the horn 2. In the third set of parameters, the length of the upper surface of the horn 2 in the left-right direction is 15.76 mm, the width in the front-back direction is 3 mm, the length of the lower surface of the horn 2 in the left-right direction is 13.72 mm, the width in the front-back direction is 1.6 mm, and the distance between the upper surface and the lower surface of the horn 2 is 1 mm. The fourth set of parameters are the same as the first set of data except for the size of the horn 2. In the fourth set of parameters, the length of the upper surface of the horn 2 in the left-right direction is 14.76 mm, the width in the front-back direction is 2.4 mm, the length of the lower surface of the horn 2 in the left-right direction is 13.72 mm, the width in the front-back direction is 1.6 mm, and the distance between the upper surface and the lower surface of the horn 2 is 1 mm.

[0030] The simulation diagram of the reflection coefficient when the curved ridge waveguide millimeter-wave radar antenna of the present invention is simulated with the first set of parameters is as Figure 7 shown. The radiation patterns of the E-plane and H-plane when the curved ridge waveguide millimeter-wave radar antenna of the present invention is simulated with the first set of parameters are as Figure 8 shown. The radiation patterns of the E-plane and H-plane when the curved ridge waveguide millimeter-wave radar antenna of the present invention is simulated with the second set of parameters are as Figure 9 shown. The radiation patterns of the E-plane and H-plane when the curved ridge waveguide millimeter-wave radar antenna of the present invention is simulated with the third set of parameters are as Figure 10 shown. The radiation patterns of the E-plane and H-plane when the curved ridge waveguide millimeter-wave radar antenna of the present invention is simulated with the fourth set of parameters are as Figure 11 shown.

[0031] As Figure 12 shown, eight curved ridge waveguide millimeter-wave radar antennas with the first set of parameters are used as eight antenna elements and distributed at a certain interval to form an antenna array. Among them, the eight antenna elements are respectively called the first antenna element 15, the second antenna element 16, the third antenna element 17, the fourth antenna element 18, the fifth antenna element 19, the sixth antenna element 20, the seventh antenna element 21, and the eighth antenna element 22, and the eight antenna elements are fed through a feeding network. HFSS is used for simulation to obtain the radiation patterns of the E-plane and H-plane of the eight antenna elements, as Figures 13 to 20 shown.

[0032] Analysis Figure 7 shows that: the reflection coefficient S of the curved ridge waveguide millimeter-wave radar antenna of the present invention 11The reflection coefficients in the operating frequency band of 76 - 81 GHz are all around -20 dB. It can be seen that the bent ridge waveguide millimeter-wave radar antenna of the present invention directly inputs electromagnetic wave signals into two bent ridge waveguides through a 1-to-2 power divider, without the need to additionally increase a matching structure, has low loss, excellent reflection coefficient, and has the characteristic of low loss.

[0033] Analysis Figure 8 It can be seen that at the center frequency point of 78.5 GHz, the bent ridge waveguide millimeter-wave radar antenna of the present invention has a wide E-plane 3dB beamwidth, and the E-plane 3dB beamwidth can reach about 131°; the H-plane sidelobe suppression can reach more than 20 dB, and the H-plane sidelobe suppression effect is good. In the operating frequency band of 76 - 81 GHz, the E-plane 3dB beamwidth of the bent ridge waveguide millimeter-wave radar antenna of the present invention can also reach about 131°, and the H-plane sidelobe suppression can reach more than 20 dB. This shows that the bent ridge waveguide millimeter-wave radar antenna of the present invention has the characteristics of low H-plane sidelobes and wide E-plane 3dB beamwidth.

[0034] Analysis Figure 9 It can be seen that at the center frequency point of 78.5 GHz, when the horn size adopts the second set of parameters, the E-plane 3dB beamwidth of the bent ridge waveguide millimeter-wave radar antenna of the present invention also changes, the E-plane 3dB beamwidth can reach about 74°, the H-plane sidelobe suppression can reach more than 20 dB, and the H-plane sidelobe suppression effect is good; Analysis Figure 10 It can be seen that at the center frequency point of 78.5 GHz, when the horn size adopts the third set of parameters, the E-plane 3dB beamwidth of the bent ridge waveguide millimeter-wave radar antenna of the present invention also changes, and the E-plane 3dB beamwidth can reach about 95°; Analysis Figure 11 It can be seen that at the center frequency point of 78.5 GHz, when the horn size adopts the fourth set of parameters, the E-plane 3dB beamwidth of the bent ridge waveguide millimeter-wave radar antenna of the present invention also changes, the E-plane 3dB beamwidth can reach about 112°; the H-plane sidelobe suppression can reach more than 20 dB, and the H-plane sidelobe suppression effect is good. This shows that the change of the horn size in the bent ridge waveguide millimeter-wave radar antenna of the present invention can also change the E-plane 3dB beamwidth, so that the actually required E-plane 3dB beamwidth can be directly obtained through the setting of the horn size during the design process.

[0035] Analysis Figures 12 to 20It can be seen that when the curved ridge waveguide millimeter wave radar antenna of the present invention is applied to an antenna array as an antenna unit, the E-plane and H-plane radiation patterns of each antenna unit can maintain good characteristics of wide beam and low side lobe under the condition that the antenna units are arranged according to half a wavelength. It can be seen that when the curved ridge waveguide millimeter wave radar antenna of the present invention is applied to an antenna array as an antenna unit, the condition that the antenna units are arranged according to half a wavelength can be met.

[0036] The curved ridge waveguide millimeter wave radar antenna of the present invention can be implemented by an air waveguide during actual production. A 1-to-2 power divider 1, a first curved waveguide 13, a portion of the second curved waveguide that can overlap with the first curved waveguide 13, a horn 2 and n rectangular radiation waveguides 3 are realized by opening a groove in a metal rectangular waveguide and filling the groove with air. The first curved waveguide block 14 and a portion of the second curved waveguide that can overlap with the first curved waveguide block 14 are part of the metal rectangular waveguide.

[0037] In summary, the curved ridge waveguide millimeter wave radar antenna of the present invention reduces the size while ensuring the operating frequency by using the curved ridge waveguide. When used as an antenna unit in an antenna array, it can meet the condition that each antenna unit is arranged according to a half wavelength. Two curved ridge waveguides are arranged to transmit the electromagnetic wave signal to n rectangular radiation waveguides 3. Based on the bending characteristics of the curved ridge waveguide, the curvature of the curved ridge waveguide close to the rectangular radiation waveguide 3 is controlled to regulate the energy distribution at each rectangular radiation waveguide 3, so that the rectangular radiation waveguide 3 close to the edge of the millimeter wave radar antenna obtains less energy, and the rectangular radiation waveguide 3 close to the center of the millimeter wave radar antenna obtains more energy, thereby achieving H-plane low sidelobe performance, so that the n rectangular radiation waveguides 3 do not need to be staggered and can be arranged on the same straight line, thereby achieving a wide E-plane 3dB beam characteristic under the conditions of low H-plane sidelobe and low loss. The E-plane 3dB beam width can reach about 131°. In the operating frequency band of 76-81 GHz, the loss is below -20 dB, and the H-plane sidelobe suppression is maintained at 20 dB or more, in addition, the E-plane 3dB beam width can be changed by setting the size of the speaker 2 to meet the actual E-plane 3dB beam width. Therefore, the curved ridge waveguide millimeter wave radar antenna of the present invention has broad application prospects and practical significance in millimeter wave radar systems.

Claims

1. A bent ridge waveguide millimeter-wave radar antenna, characterized in that It includes a 1-way 2-way power divider, two curved ridge waveguides, a horn, and n rectangular radiating waveguides, where n is an even number greater than or equal to 4. The n rectangular radiating waveguides are distributed along a straight line and are evenly divided into two groups of rectangular radiating waveguides. Each group of rectangular radiating waveguides includes n / 2 rectangular radiating waveguides. The two groups of rectangular radiating waveguides correspond one-to-one with the two curved ridge waveguides. The 1-way 2-way power divider is used to equally divide the electromagnetic wave signal generated by the excitation into two electromagnetic wave signals and then output the two electromagnetic wave signals to the two curved ridge waveguides one-to-one. Each curved ridge waveguide is used to transmit the electromagnetic wave signal transmitted to it to the n / 2 rectangular radiating waveguides corresponding to it. Each rectangular radiating waveguide is used to couple and output the electromagnetic wave signal transmitted to it to the horn. The horn is used to radiate the electromagnetic wave signals output from the n rectangular radiating waveguides to free space.

2. The curved ridge waveguide millimeter-wave radar antenna according to claim 1, characterized in that The 1-way 2-way power divider includes seven rectangular waveguides. The length directions of the seven rectangular waveguides are the same, which is regarded as the left-right direction. The width directions are the same, which is regarded as the front-back direction. The height directions are the same, which is regarded as the up-down direction. These seven rectangular waveguides are respectively called the first rectangular waveguide, the second rectangular waveguide, the third rectangular waveguide, the fourth rectangular waveguide, the fifth rectangular waveguide, the sixth rectangular waveguide, and the seventh rectangular waveguide. The plane that makes the first rectangular waveguide symmetric about the left and right is called the first symmetry plane. The second rectangular waveguide, the third rectangular waveguide, and the fourth rectangular waveguide are all located on the left side of the first rectangular waveguide, and the three form an inverted U-shaped structure with the opening facing down. The fifth rectangular waveguide, the sixth rectangular waveguide, and the seventh rectangular waveguide are all located on the right side of the first rectangular waveguide, and the three form an inverted U-shaped structure with the opening facing down. The two inverted U-shaped structures are symmetric about the first symmetry plane in the left-right direction.

3. The bend ridge waveguide millimeter-wave radar antenna according to claim 2, characterized in that The second rectangular waveguide is attached to the left side of the first rectangular waveguide, and their upper end faces and front end faces are respectively in the same plane. The width of the second rectangular waveguide is smaller than the width of the first rectangular waveguide. The third rectangular waveguide is attached to the lower side of the second rectangular waveguide and the right side of the first rectangular waveguide. The left end face and the front end face of the third rectangular waveguide are respectively in the same plane as the left end face and the front end face of the second rectangular waveguide. The sum of the heights of the third rectangular waveguide and the second rectangular waveguide is smaller than the height of the first rectangular waveguide. The plane that makes the second rectangular waveguide symmetric about the front and back is called the second symmetry plane. The third rectangular waveguide and the fourth rectangular waveguide are symmetric about the second symmetry plane in the front-back direction. The sum of the widths of the third rectangular waveguide and the fourth rectangular waveguide is smaller than the width of the second rectangular waveguide. The second rectangular waveguide and the fifth rectangular waveguide are symmetric about the first symmetry plane in the left-right direction. The third rectangular waveguide and the sixth rectangular waveguide are symmetric about the first symmetry plane in the left-right direction. The fourth rectangular waveguide and the seventh rectangular waveguide are symmetric about the first symmetry plane in the left-right direction.

4. The bent ridge waveguide millimeter-wave radar antenna according to claim 3, characterized in that Two curved ridge waveguides are respectively referred to as the first curved ridge waveguide and the second curved ridge waveguide. The first curved ridge waveguide is located on the left side of the 1-to-2 power divider. The first curved ridge waveguide is realized by arranging a curved waveguide block inside a curved waveguide. This curved waveguide is called the first curved waveguide, and this curved waveguide block is called the first curved waveguide block. The first curved waveguide is formed by bending a waveguide with a cuboid structure. The first curved waveguide block is formed by bending a waveguide with a cuboid structure. The second curved ridge waveguide is located on the right side of the 1-to-2 power divider. The intersection line of the plane where the central axis of the second rectangular waveguide in the up-down direction and the central axis of the fifth rectangular waveguide in the up-down direction lies and the first symmetry plane is taken as the first axis. If the first curved ridge waveguide rotates 180 degrees with the first axis as the rotation axis, it will completely coincide with the second curved ridge waveguide.

5. The curved ridge waveguide millimeter-wave radar antenna according to claim 4, characterized in that The outer side surface of the first curved waveguide is sequentially surrounded by six end faces distributed according to the upper, lower, left, right, front, and rear orientations. The left end face and the right end face of the first curved waveguide are both rectangular faces. The upper end face and the lower end face are both s-shaped planes. The front end face and the rear end face are s-shaped curved surfaces. If its upper end face is translated downward, it can completely coincide with its lower end face. If its front end face is translated backward, it can completely coincide with its rear end face. If its left end face is translated to the right, it can completely coincide with its right end face. The upper end face of the first curved waveguide and the upper end face of the first rectangular waveguide are in the same plane. The lower end face of the first curved waveguide and the lower end face of the third rectangular waveguide are in the same plane. The right end face of the first curved waveguide is connected and in a fitting state with the left end face of the second rectangular waveguide, the left end face of the third rectangular waveguide, and the left end face of the fourth rectangular waveguide. The front side edge of the right end face of the first curved waveguide and the front end face of the third rectangular waveguide are in the same plane. The rear side edge of the right end face of the first curved waveguide and the rear end face of the fourth rectangular waveguide are in the same plane.

6. The bent ridge waveguide millimeter-wave radar antenna according to claim 5, wherein The shape of the outer side surface of the first curved waveguide block is the same as that of the first curved waveguide. The lower end face, the left end face, and the right end face of the first curved waveguide block are respectively in the same plane as the lower end face, the left end face, and the right end face of the first curved waveguide. The upper end face of the first curved waveguide block is located below the upper end face of the first curved waveguide, and there is a certain distance between them. The left end face of the first curved waveguide block and the left end face of the first curved waveguide are symmetric about the same plane in the front-rear direction. The length of the left end face of the first curved waveguide block in the front-rear direction is less than the length of the left end face of the first curved waveguide in the front-rear direction. If the upper end face of the first curved waveguide block is vertically mapped onto the upper end face of the first curved waveguide, at this time, the front side edge of the upper end face of the first curved waveguide block can completely coincide with the front side edge of the upper end face of the first curved waveguide after being translated forward, and the rear side edge of the upper end face of the first curved waveguide block can completely coincide with the rear side edge of the upper end face of the first curved waveguide after being translated backward.

7. The bent ridge waveguide millimeter-wave radar antenna according to claim 6, characterized in that Two sets of rectangular radiation waveguides are respectively referred to as the first set of rectangular radiation waveguides and the second set of rectangular radiation waveguides. The first set of rectangular radiation waveguides corresponds to the first curved ridge waveguide, and the second set of rectangular radiation waveguides corresponds to the second curved ridge waveguide. n / 2 rectangular radiation waveguides of the first set of rectangular radiation waveguides are evenly spaced from left to right above the first curved ridge waveguide, and n / 2 rectangular radiation waveguides of the second set of rectangular radiation waveguides are evenly spaced from left to right above the second curved ridge waveguide. The first set of rectangular radiation waveguides and the second set of rectangular radiation waveguides are symmetric about the first symmetry plane in the left-right direction.

8. The curved ridge waveguide millimeter-wave radar antenna according to claim 7, characterized in that The length directions of the n / 2 rectangular radiation waveguides of the first set of rectangular radiation waveguides are all along the left-right direction, the width directions are all along the front-back direction, and the height directions are all along the up-down direction. The front end faces of the n / 2 rectangular radiation waveguides of the first set of rectangular radiation waveguides are located in the same plane, the rear end faces are located in the same plane, the upper end faces are located in the same plane, and the lower end faces are located in the same plane. The lower end faces of the n / 2 rectangular radiation waveguides of the first set of rectangular radiation waveguides are all connected to and in contact with the upper end faces of the first curved ridge waveguide; the plane where the left end face of the leftmost rectangular radiation waveguide in the first set of rectangular radiation waveguides is located is on the right side of the left end face of the first curved ridge waveguide, the plane where the right end face of the rightmost rectangular radiation waveguide in the first set of rectangular radiation waveguides is located is on the left side of the right end face of the first curved ridge waveguide, the plane where the left end face of the leftmost rectangular radiation waveguide in the second set of rectangular radiation waveguides is located is on the right side of the left end face of the second curved ridge waveguide, and the plane where the right end face of the rightmost rectangular radiation waveguide in the second set of rectangular radiation waveguides is located is on the left side of the right end face of the second curved ridge waveguide.

9. The bend ridge waveguide millimeter-wave radar antenna according to claim 8, wherein The outer side surface of the horn is a hexahedron formed by sequentially splicing and surrounding six end faces distributed in the up, down, left, right, front, and back directions. The right end face, left end face, front end face, and back end face of the horn are all isosceles trapezoids, and the upper end face and lower end face of the horn are both rectangles. The lengths of the upper end face and lower end face of the horn are all along the left-right direction, and the widths are all along the front-back direction; the horn is located above n rectangular radiation waveguides, and the lower end face of the horn is connected to and in contact with the upper end faces of the n rectangular radiation waveguides; the left side edge of the lower end face of the horn is on the left side of the plane where the left end face of the first curved ridge waveguide is located, the right side edge of the lower end face of the horn is on the right side of the plane where the right end face of the second curved ridge waveguide is located, the front side edge of the lower end face of the horn is on the front side of the plane where the front end faces of the n rectangular radiation waveguides are located, and the rear side edge of the lower end face of the horn is on the rear side of the plane where the rear end faces of the n rectangular radiation waveguides are located.

10. The bent ridge waveguide millimeter-wave radar antenna according to claim 9, wherein The upper and lower end faces of the horn are both symmetric about the left and right with respect to the first symmetry plane, and the upper and lower end faces of the horn are both symmetric about the front and back with respect to the same plane. The width of the upper end face of the horn in the front and back direction is greater than the width of its lower end face in the front and back direction, and the length of the upper end face of the horn in the left and right direction is greater than the length of its lower end face in the left and right direction. The lower bottom of the left end face of the horn completely coincides with the left side edge of the upper end face of the horn, and the upper bottom of the left end face of the horn completely coincides with the left side edge of the lower end face of the horn. The lower bottom of the front end face of the horn completely coincides with the front side edge of the upper end face of the horn, and the upper bottom of the front end face of the horn completely coincides with the front side edge of the lower end face of the horn. The lower bottom of the rear end face of the horn completely coincides with the rear side edge of the upper end face of the horn, and the upper bottom of the rear end face of the horn completely coincides with the rear side edge of the lower end face of the horn. The waist on the front side of the left end face of the horn completely coincides with the left side edge of the front end face of the horn, and the waist on the rear side of the left end face of the horn completely coincides with the left side edge of the rear end face of the horn. The lower bottom of the right end face of the horn completely coincides with the right side edge of the upper end face of the horn, and the upper bottom of the right end face of the horn completely coincides with the right side edge of the lower end face of the horn. The waist on the front side of the right end face of the horn completely coincides with the right side edge of the front end face of the horn, and the waist on the rear side of the right end face of the horn completely coincides with the right side edge of the rear end face of the horn.

Images