A curved ridge waveguide millimeter wave radar antenna

Abstract

The present invention discloses a curved ridge waveguide millimeter wave radar antenna, comprising a 1-to-2 power splitter, 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. The 1-to-2 power splitter equally splits an electromagnetic wave signal generated by excitation into two electromagnetic wave signals, which are then output to two curved ridge waveguides in a one-to-one correspondence. Both curved ridge waveguides transmit the electromagnetic wave signal transmitted thereto to the n rectangular radiating waveguides. Each rectangular radiating waveguide couples the electromagnetic wave signal transmitted thereto to the horn, which radiates the electromagnetic wave signal thereto into free space. The antenna has the advantages of low loss, low side lobes on the H-plane, a wide E-plane 3dB beamwidth, and a small size. When used as an antenna unit in an antenna array, the antenna can meet the condition that each antenna unit is arranged according to half a wavelength, and is easy to process.

Description

Technical Field

[0001] The present invention relates to a millimeter wave radar antenna, in particular to a curved ridge waveguide millimeter wave radar antenna. Background Art

[0002] With the advancement of wireless communication technology, millimeter-wave radar antennas have found widespread application in a variety of fields, including automotive, the Internet of Things, drones, security, and sports. As a crucial component of millimeter-wave radar systems, their performance directly impacts their detection range, accuracy, and stability. Waveguide technology is particularly important in millimeter-wave radar antenna design, as it influences both signal transmission efficiency and the antenna's radiation characteristics.

[0003] Existing millimeter-wave radar antennas are typically based on a rectangular waveguide design and are series-fed leaky-wave antennas. They primarily consist of a power divider, a rectangular waveguide, and multiple radiating ports with staggered locations. The rectangular waveguide transmits the signal to the multiple radiating ports for radiation. This millimeter-wave radar antenna exhibits low loss performance. By staggering the multiple radiating ports, the antenna modulates the energy at each port, achieving low sidelobes in the H-plane. While this millimeter-wave radar antenna has a simple structure and is easy to fabricate, the staggered distribution of the multiple radiating ports, however, results in a narrow 3dB beamwidth in the E-plane, impacting the detection range, accuracy, and stability of the millimeter-wave radar system. Furthermore, the rectangular waveguide design of this millimeter-wave radar antenna results in its large size. When used as an antenna element in an antenna array within a millimeter-wave radar system, it cannot meet the requirement for half-wavelength spacing between antenna elements within the array, resulting in certain limitations in practical applications.

[0004] U.S. Patent No. US12126081B2 discloses an antenna with an H-plane waveguide curved structure. The antenna also has the low sidelobe effect of the H-plane, the characteristics of a wide beam, and easy processing. However, the cross-sectional area of the waveguide makes it impossible to arrange the antenna unit in a half-wavelength layout.

[0005] The international patent publication number WO2022122319A1 discloses millimeter-wave radar antennas based on H-plane ridge waveguides and E-plane waveguides. These millimeter-wave radar antennas also have the low sidelobe effect and wide beam characteristics of the H-plane, and can also be arranged in a half-wavelength format. However, the conversion structure between the E-plane waveguide and the H-plane ridge waveguide contains many matching structures, and the radiation structure also contains a large number of discontinuity structures, making the processing difficult. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a curved ridge waveguide millimeter wave radar antenna that has low loss, low side lobes in the H plane, a wide E plane 3dB beam width, and a small size. When used as an antenna unit in an antenna array, it can meet the condition that each antenna unit is arranged according to half a wavelength and is easy to process.

[0007] The technical solution adopted by the present invention to solve the above technical problems is: a curved ridge waveguide millimeter wave radar antenna, including a 1-to-2 power divider, two curved ridge waveguides, a horn and n rectangular radiating waveguides, 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, and the two groups of rectangular radiating waveguides correspond one-to-one to the two curved ridge waveguides. The 1-to-2 power divider is used to divide the electromagnetic wave signal generated by the excitation into two electromagnetic wave signals, and then output the two electromagnetic wave signals one-to-one to the two curved ridge waveguides, each curved ridge waveguide is used to transmit the electromagnetic wave signal transmitted thereto to the n / 2 rectangular radiating waveguides corresponding thereto, and each rectangular radiating waveguide is used to couple the electromagnetic wave signal transmitted thereto to the horn, and the horn is used to radiate the electromagnetic wave signal output thereto by the n rectangular radiating waveguides into free space.

[0008] Compared with the prior art, the advantage of the present invention is that the electromagnetic wave signal is transmitted to n rectangular radiation waveguides by setting two curved ridge waveguides. When the electromagnetic wave signal is transmitted to the two curved ridge waveguides, due to the bending characteristics of the curved ridge waveguide, its surface curvature can be designed according to actual usage requirements. Therefore, 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 controlled, 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, thereby achieving H-plane low sidelobe performance, thereby eliminating the need to control the energy distribution by staggering the distribution of n rectangular radiation waveguides. The n rectangular radiation waveguides can be set on the same straight line to achieve a wide E-plane 3dB beam characteristic. In addition, the horn setting can not only maintain the wide E-plane 3dB beam characteristics, but also change the horn size can change the E-plane 3dB beam width, so that the actual required E-plane 3dB beam width can be directly obtained by setting the horn size during the design process. At the same time, the use of the curved ridge waveguide ensures the operating frequency while reducing the size, so that when the millimeter-wave radar antenna is used as an antenna unit in the antenna array, it can meet the requirement that the antenna units in the array antenna are arranged according to half a wavelength. Therefore, the present invention has low loss and low H-plane sidelobes, as well as a wide E-plane 3dB beam and a small size. When used as an antenna unit in the antenna array, it can meet the condition that each antenna unit is arranged according to half a wavelength. In addition, the 1-to-2 power splitter directly inputs the electromagnetic wave signal into the two curved ridge waveguides, without the need to add a matching structure to achieve low loss, and is easy to process. 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 in the operating frequency band of 76GHz-81GHz is below -20 dB, and the H-plane sidelobe suppression is maintained at 20 dB or more.

[0009] Furthermore, the 1-to-2 power divider includes seven rectangular waveguides, the length directions of the seven rectangular waveguides are the same, which is used as the left-right direction, the width directions are the same, which is used as the front-to-back direction, and the height directions are the same, which is used as the up-down direction. The seven rectangular waveguides are respectively referred to as 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 bilaterally symmetrical is referred to as 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 downward. 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 downward. The two inverted U-shaped structures are bilaterally symmetrical about the first symmetry plane.

[0010] Furthermore, the second rectangular waveguide is arranged on the left side of the first rectangular waveguide, and the upper end faces and front end faces of the two are respectively located 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 arranged 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 front-to-back symmetric is called the second symmetry plane, the third rectangular waveguide and the fourth rectangular waveguide are front-to-back symmetric 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 left-right symmetric with respect to the first symmetry plane, the third rectangular waveguide and the sixth rectangular waveguide are left-right symmetric with respect to the first symmetry plane, and the fourth rectangular waveguide and the seventh rectangular waveguide are left-right symmetric with respect to the first symmetry plane.

[0011] Furthermore, the 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, and the first curved ridge waveguide is realized by setting a curved waveguide block inside a curved waveguide. The curved waveguide is referred to as the first curved waveguide, and the curved waveguide block is referred to as the first curved waveguide block. The first curved waveguide is formed by bending a waveguide with a rectangular structure, and the first curved waveguide block is formed by bending a waveguide with a rectangular structure. The second curved ridge waveguide is located on the right side of the 1-to-2 power divider, and the intersection of the plane where the central axis of the second rectangular waveguide in the vertical direction and the central axis of the fifth rectangular waveguide in the vertical direction are located and the first symmetry plane is used as the first axis. If the first curved ridge waveguide is rotated 180 degrees with the first axis as the rotation axis, it will completely overlap with the second curved ridge waveguide.

[0012] Furthermore, the outer side surface of the first curved waveguide is formed by sequentially splicing together six end surfaces distributed in the directions of up, down, left, right, front, and back. The left and right end surfaces of the first curved waveguide are both rectangular surfaces, the upper and lower end surfaces are both S-shaped planes, and the front and rear end surfaces are S-shaped curved surfaces. If the upper end surface is translated downward, it can completely overlap with the lower end surface; if the front end surface is translated backward, it can completely overlap with the rear end surface; if the left end surface is translated rightward, it can completely overlap with the right end surface; the upper end surface of the first curved waveguide overlaps with the upper end surface of the first curved waveguide. The upper end surface of a rectangular waveguide is located in the same plane, the lower end surface of the first curved waveguide and the lower end surface of the third rectangular waveguide are located in the same plane, the right end surface of the first curved waveguide is connected to and in a bonded state with the left end surface of the second rectangular waveguide, the left end surface of the third rectangular waveguide, and the left end surface of the fourth rectangular waveguide; the front side of the right end surface of the first curved waveguide and the front end surface of the third rectangular waveguide are located in the same plane, and the rear side of the right end surface of the first curved waveguide and the rear end surface of the fourth rectangular waveguide are located in the same plane.

[0013] Furthermore, the outer side shape of the first curved waveguide block is the same as that of the first curved waveguide; the lower end face, left end face and right end face of the first curved waveguide block are respectively located in the same plane as the lower end face, left end face and 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 distance between the two, the left end face of the first curved waveguide block and the left end face of the first curved waveguide are both front-to-back symmetrical about the same plane, and the length of the left end face of the first curved waveguide block in the front-to-back direction is smaller than the length of the left end face of the first curved waveguide in the front-to-back direction; if the upper end face of the first curved waveguide block is vertically mapped to 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 be completely overlapped 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 be completely overlapped with the rear side edge of the upper end face of the first curved waveguide after being translated backward.

[0014] Furthermore, the two groups of rectangular radiating waveguides are respectively referred to as a first group of rectangular radiating waveguides and a second group of rectangular radiating waveguides, the first group of rectangular radiating waveguides corresponds to the first curved ridge waveguide, the second group of rectangular radiating waveguides corresponds to the second curved ridge waveguide, the n / 2 rectangular radiating waveguides of the first group of rectangular radiating waveguides are evenly spaced from left to right above the first curved ridge waveguide, the n / 2 rectangular radiating waveguides of the second group of rectangular radiating waveguides are evenly spaced from left to right above the second curved ridge waveguide, and the first group of rectangular radiating waveguides and the second group of rectangular radiating waveguides are bilaterally symmetrical about the first symmetry plane.

[0015] Furthermore, the length directions of the n / 2 rectangular radiation waveguides of the first group 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 group 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 group of rectangular radiation waveguides are all connected to the upper end face of the first curved ridge waveguide and are in a fitted state. The center of the first group of rectangular radiation waveguides is located in the same plane. The plane where the left end surface of the leftmost rectangular radiation waveguide is located is located to the right of the left end surface of the first curved ridge waveguide, the plane where the right end surface of the rightmost rectangular radiation waveguide in the first group of rectangular radiation waveguides is located to the left of the right end surface of the first curved ridge waveguide, the plane where the left end surface of the leftmost rectangular radiation waveguide in the second group of rectangular radiation waveguides is located to the right of the left end surface of the second curved ridge waveguide, and the plane where the right end surface of the rightmost rectangular radiation waveguide in the second group of rectangular radiation waveguides is located to the left of the right end surface of the second curved ridge waveguide.

[0016] Furthermore, the outer side surface of the horn is a hexahedron formed by six end faces distributed in the upper, lower, left, right, front and rear directions, and 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 lower end face of the horn are both rectangular, the lengths of the upper end face and lower end face of the horn are both along the left-right direction, and the widths are both along the front-to-back direction; the horn is located above the n rectangular radiation waveguides, and the lower end face of the horn is connected to the upper end faces of the n rectangular radiation waveguides and is in a fitted state; the left side of the lower end face of the horn is located on the left side of the plane where the left end face of the first curved ridge waveguide is located, the right side of the lower end face of the horn is located on the right side of the plane where the right end face of the second curved ridge waveguide is located, the front side of the lower end face of the horn is located in front of the plane where the front end faces of the n rectangular radiation waveguides are located, and the rear side of the lower end face of the horn is located behind the plane where the rear end faces of the n rectangular radiation waveguides are located.

[0017] Furthermore, the upper end face and the lower end face of the horn are both left-right symmetrical about the first symmetry plane, the upper end face and the lower end face of the horn are both front-to-back symmetrical about the same plane, the width of the upper end face of the horn in the front-to-back direction is greater than the width of its lower end face in the front-to-back direction, and the length of the upper end face of the horn in the left-to-right direction is greater than the length of its lower end face in the left-to-right direction; the upper base of the left end face of the horn completely coincides with the left side of the upper end face of the horn, the lower base of the left end face of the horn completely coincides with the left side of the lower end face of the horn, the upper base of the front end face of the horn completely coincides with the front side of the upper end face of the horn, the lower base of the front end face of the horn completely coincides with the front side of the lower end face of the horn, and the horn The upper bottom of the rear end face of the horn completely coincides with the rear side of the upper end face of the horn, and the lower bottom of the rear end face of the horn completely coincides with the rear side 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 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 of the rear end face of the horn; the upper bottom of the right end face of the horn completely coincides with the right side of the upper end face of the horn, and the lower bottom of the right end face of the horn completely coincides with the right side 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 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 of the rear end face of the horn. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural diagram of a curved ridge waveguide millimeter wave radar antenna of the present invention;

[0019] Figure 2 An exploded view of a curved ridge waveguide millimeter wave radar antenna according to the present invention;

[0020] Figure 3 This is a top view of a horn-less curved ridge waveguide millimeter-wave radar antenna of the present invention after the horn is removed;

[0021] Figure 4 This is an exploded view of a 1-to-2 power splitter of a curved ridge waveguide millimeter-wave radar antenna of the present invention;

[0022] Figure 5 This is a structural diagram of a first curved ridge waveguide of a curved ridge waveguide millimeter wave radar antenna of the present invention;

[0023] Figure 6 This is a structural diagram of a horn of a curved ridge waveguide millimeter wave radar antenna of the present invention;

[0024] Figure 7 A reflection coefficient simulation diagram of a curved ridge waveguide millimeter wave radar antenna of the present invention when simulated using a first set of parameters;

[0025] Figure 8 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when simulated using the first set of parameters;

[0026] Figure 9 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when simulated using the second set of parameters;

[0027] Figure 10 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when simulated using the third set of parameters;

[0028] Figure 11 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when simulated using the fourth set of parameters;

[0029] Figure 12 A half-wavelength layout diagram of a curved ridge waveguide millimeter-wave radar antenna of the present invention when used as an antenna unit in an antenna array;

[0030] Figure 13 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when used as a first antenna unit;

[0031] Figure 14 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when used as a second antenna unit;

[0032] Figure 15 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when used as the third antenna unit;

[0033] Figure 16 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when used as the fourth antenna unit;

[0034] Figure 17 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when used as the fifth antenna unit;

[0035] Figure 18 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when used as the sixth antenna unit;

[0036] Figure 19 The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when used as the seventh antenna unit;

[0037] Figure 20The E-plane and H-plane directional patterns of a curved ridge waveguide millimeter-wave radar antenna of the present invention when used as the eighth antenna unit. DETAILED DESCRIPTION

[0038] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0039] Example 1: Figures 1 to 3 As shown, a curved ridge waveguide millimeter wave radar antenna includes a 1-to-2 power divider 1, two curved ridge waveguides, a horn 2 and n rectangular radiating waveguides 3, where n is an even number greater than or equal to 4. The n rectangular radiating waveguides 3 are distributed along a straight line and are evenly divided into two groups of rectangular radiating waveguides 3. Each group of rectangular radiating waveguides 3 includes n / 2 rectangular radiating waveguides 3. The two groups of rectangular radiating waveguides 3 correspond one-to-one to the two curved ridge waveguides. 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 one-to-one to the two curved ridge waveguides. Each curved ridge waveguide is used to transmit the electromagnetic wave signal transmitted thereto to the n / 2 rectangular radiating waveguides 3 corresponding thereto. Each rectangular radiating waveguide 3 is used to couple the electromagnetic wave signal transmitted thereto to the horn 2. The horn 2 is used to radiate the electromagnetic wave signal outputted thereto by the n rectangular radiating waveguides 3 into free space.

[0040] In this embodiment, the electromagnetic wave signal is transmitted to n rectangular radiation waveguides 3 by setting two curved ridge waveguides. When the electromagnetic wave signal is transmitted to the two curved ridge waveguides, due to the bending characteristics of the curved ridge waveguide, its surface curvature can be designed according to actual use requirements. Therefore, by controlling the curvature of the curved ridge waveguide, the energy distribution at each rectangular radiation waveguide 3 can be changed, 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, thereby eliminating the need to control the energy distribution by staggering the n rectangular radiation waveguides 3. The n rectangular radiation waveguides 3 can be set A wide E-plane 3dB beam characteristic is achieved on the same straight line. In addition, the setting of the horn 2 can not only maintain the wide E-plane 3dB beam characteristic, but the change of the size of the horn 2 can also change the E-plane 3dB beam width, so that during the design process, the actually 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, so that when the millimeter-wave radar antenna is used as an antenna unit in the antenna array, it can meet the requirement that the antenna units in the array antenna are arranged according to half a wavelength. In addition, the 1-to-2 power splitter 1 directly inputs the electromagnetic wave signal into the two curved ridge waveguides, without the need for additional matching structure, and is easy to process.

[0041] Example 2: This example is basically the same as Example 1, except that: in this example, Figure 4 As shown, the 1-to-2 power splitter 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 the left-right direction, the length direction is the front-to-back direction, and the height direction is 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-to-back direction, and the height directions are all along the up-down direction. The plane in which the rectangular waveguide 4 is bilaterally symmetrical 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 is located in the same plane as the upper end face of the first rectangular waveguide 4. The front end face of the second rectangular waveguide 5 is located in the same plane as the front end face of the first rectangular waveguide 4. The lower end face of the second rectangular waveguide 5 is located 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 located 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 the left end face of the first rectangular waveguide 4 and is in a fitted state. 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 located 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 located in the same plane, the rear end face of the third rectangular waveguide 6 is located 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 the lower end face of the second rectangle and is in a fitted state, the lower end face of the third rectangular waveguide 6 is located 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 the left end face of the first rectangular waveguide 4 and is in a fitted state; the plane that makes the second rectangular waveguide 5 front-to-back symmetrical is called the second symmetry plane, and the fourth rectangular waveguide 7 is located in the On the rear side of the three rectangular waveguides 6, the third rectangular waveguide 6 and the fourth rectangular waveguide 7 are front-to-back symmetrical 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 symmetrical 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 symmetrical about the first symmetry plane, the seventh rectangular waveguide 10 is located on the right side of the first rectangular waveguide 4, and the fourth rectangular waveguide 7 and the seventh rectangular waveguide 10 are left-right symmetrical about the first symmetry plane.

[0042] In this embodiment, 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, and 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 is left and right Symmetrical structure, and the structure composed of the second rectangular waveguide 5, the third rectangular waveguide 6 and the fourth rectangular waveguide 7 and the structure composed of the fifth rectangular waveguide 8, the sixth rectangular waveguide 9 and the seventh rectangular waveguide 10 are bilaterally symmetrical, and the electromagnetic wave signal transmitted through the left end face of the second rectangular waveguide 5, the third rectangular waveguide 6 and the fourth rectangular waveguide 7 and the electromagnetic wave signal transmitted through the right end face 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 signal outputs by the 1-to-2 power divider 1.

[0043] Example 3: This example is basically the same as Example 2, except that: in this example, Figure 5As shown, 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. The curved waveguide is referred to as the first curved waveguide 13, and the curved waveguide block is referred to as the first curved waveguide block 14. The first curved waveguide 13 is formed by bending a waveguide with a rectangular structure. The outer side surface is formed by sequentially splicing six end surfaces distributed in the upper, lower, left, right, front, and rear directions. The left and right end surfaces of the first curved waveguide 13 are both rectangular surfaces, the upper and lower end surfaces are both S-shaped planes, and the front and rear end surfaces are S-shaped curved surfaces. If the upper end surface is translated downward, it can be aligned with the lower end surface. The upper end face of the first curved waveguide 13 and the upper end face of the first rectangular waveguide 4 are located 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 located in the same plane, the right end face of the first curved waveguide 13 is connected to 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 and are in a fitted state; the front side of the right end face of the first curved waveguide 13 and the front end face of the third rectangular waveguide 6 are located in the same plane, and the rear side of the right end face of the first curved waveguide 13 and the rear end face of the fourth rectangular waveguide 7 are located in the same plane; the first curved waveguide block 1 4 is formed by bending a rectangular parallelepiped waveguide, and its outer side surface is formed by sequentially joining six end surfaces distributed in the directions of up, down, left, right, front, and rear. The left and right end surfaces of the first curved waveguide block 14 are both rectangular surfaces, the upper and lower end surfaces are both S-shaped planes, and the front and rear end surfaces are both S-shaped curved surfaces. If the upper end surface is translated downward, it can completely overlap with its lower end surface; if the front end surface is translated backward, it can completely overlap with its rear end surface; if the left end surface is translated rightward, it can completely overlap with its right end surface; the lower end surface of the first curved waveguide block 14 and the lower end surface of the first curved waveguide 13 are located in the same plane, the upper end surface of the first curved waveguide block 14 is located below the upper end surface of the first curved waveguide 13, and there is a distance between the two. The left end surface of the curved waveguide block 14 and the left end surface of the first curved waveguide 13 are located in the same plane, and both are front-to-back symmetric about the same plane. The length of the left end surface of the first curved waveguide block 14 in the front-to-back direction is shorter than the length of the left end surface of the first curved waveguide 13 in the front-to-back direction. The right end surface of the first curved waveguide block 14 and the right end surface of the first curved waveguide 13 are located in the same plane. If the upper end surface of the first curved waveguide block 14 is perpendicularly projected onto the upper end surface of the first curved waveguide 13, then the front side of the upper end surface of the first curved waveguide block 14 can completely overlap with the front side of the upper end surface of the first curved waveguide 13 after forward translation, and the rear side of the upper end surface of the first curved waveguide block 14 can completely overlap with the rear side of the upper end surface of the first curved waveguide 13 after backward translation.The second curved ridge waveguide 12 is located on the right side of the 1-to-2 power divider 1. The intersection of the plane containing the vertical center axis of the second rectangular waveguide 5 and the vertical center axis of the fifth rectangular waveguide 8 and the first symmetry plane serves as the first axis. If the first curved ridge waveguide 11 is rotated 180° about the first axis, it will completely overlap with the second curved ridge waveguide 12.

[0044] In this embodiment, when 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 splitter 1 for transmission, the 1-to-2 power splitter 1 divides the electromagnetic wave signal into two equal electromagnetic wave signals, one of which 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 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, and the first curved ridge waveguide 11 is connected to the first curved ridge waveguide 11. The energy distribution at the corresponding n / 2 rectangular radiation waveguides 3 is changed, the energy obtained by the corresponding n / 2 rectangular radiation waveguides 3 is controlled, and the energy is output 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 output electromagnetic wave energy, thereby concentrating the energy at the rectangular radiation waveguide 3 close to the center of the millimeter wave radar antenna. The first curved ridge waveguide 11 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 keeps the antenna operating frequency band operating in 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 via 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 output electromagnetic wave energy, thereby concentrating the energy on the rectangular radiation waveguide 3 close to the center of the millimeter-wave radar antenna.

[0045] 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, the 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-to-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 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, and the lower end faces 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-to-back direction, and the height directions are all along the up-down direction. The upper end faces of the first curved ridge waveguide 11 are connected and in a fitted state; the 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, and the first group of rectangular radiation waveguides 3 and the second group of rectangular radiation waveguides 3 are bilaterally symmetrical 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 located to the right 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 located to the left 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 located to the right 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 to the left of the right end face of the second curved ridge waveguide 12.

[0046] Example 5: This example is basically the same as Example 4, except that: in this example, Figure 6As shown, the outer side surface of the speaker 2 is a hexahedron formed by sequentially splicing and surrounding six end surfaces distributed in the directions of up, down, left, right, front and back. The right end surface, left end surface, front end surface and rear end surface of the speaker 2 are all isosceles trapezoids. The upper end surface and lower end surface of the speaker 2 are both rectangular. The lengths of the upper end surface and lower end surface of the speaker 2 are both along the left-right direction, and the widths are both along the front-back direction. The upper end surface of the speaker 2 is bilaterally symmetrical about the first symmetry plane, the lower end surface of the speaker 2 is bilaterally symmetrical about the first symmetry plane, the upper end surface of the speaker 2 and its lower end surface are both front-back symmetrical about the same plane, and the upper end surface of the speaker 2 is symmetrical about the first symmetry plane. The width of the surface along the front-to-back direction is greater than the width of its lower end surface along the front-to-back direction, and the length of the upper end surface of the speaker 2 along the left-to-right direction is greater than the length of its lower end surface along the left-to-right direction; the upper bottom of the left end surface of the speaker 2 completely coincides with the left side of the upper end surface of the speaker 2, the lower bottom of the left end surface of the speaker 2 completely coincides with the left side of the lower end surface of the speaker 2, the upper bottom of the front end surface of the speaker 2 completely coincides with the front side of the upper end surface of the speaker 2, the lower bottom of the front end surface of the speaker 2 completely coincides with the front side of the lower end surface of the speaker 2, the upper bottom of the rear end surface of the speaker 2 completely coincides with the rear side of the upper end surface of the speaker 2, and the speaker 2 The lower bottom of the rear end face of the speaker 2 completely coincides with the rear side of the lower end face of the speaker 2; the waist of the left end face of the speaker 2 located on the front side completely coincides with the left side of the front end face of the speaker 2, and the waist of the left end face of the speaker 2 located on the rear side completely coincides with the left side of the rear end face of the speaker 2; the upper bottom of the right end face of the speaker 2 completely coincides with the right side of the upper end face of the speaker 2, the lower bottom of the right end face of the speaker 2 completely coincides with the right side of the lower end face of the speaker 2, the waist of the right end face of the speaker 2 located on the front side completely coincides with the right side of the front end face of the speaker 2, the waist of the right end face of the speaker 2 located on the rear side coincides with the rear end face of the speaker 2 The right side of the speaker 2 completely overlaps; the speaker 2 is located above the n rectangular radiation waveguides 3, and the lower end face of the speaker 2 is connected to the upper end faces of the n rectangular radiation waveguides 3 and is in a fitted state; the left side of the lower end face of the speaker 2 is located on the left side of the plane where the left end face of the first curved ridge waveguide 11 is located, and the right side of the lower end face of the speaker 2 is located on the right side of the plane where the right end face of the second curved ridge waveguide 12 is located, the front side of the lower end face of the speaker 2 is located on the front side of the plane where the front end faces of the n rectangular radiation waveguides 3 are located, and the rear side of the lower end face of the speaker 2 is located on the rear side of the plane where the rear end faces of the n rectangular radiation waveguides 3 are located.

[0047] In this embodiment, the smallest aperture portion of the speaker 2 contacts the n rectangular radiation waveguides 3 to receive energy. As energy is transferred in the speaker 2, the aperture of the speaker 2 becomes larger and larger, making the aperture field distribution more concentrated in the central area. The far-field radiation energy is therefore more concentrated in a smaller angular range, thereby changing the E-plane 3dB beamwidth while maintaining the wide E-plane 3dB beam characteristic. During the design process, the length and width of the lower end surface of the speaker 2 and the length and width of the upper end surface of the speaker 2 are adjusted according to actual usage requirements to achieve the desired E-plane 3dB beamwidth. The smaller the length and width of the upper end surface of the speaker 2, the wider the E-plane 3dB beamwidth, and the larger the length and width of the lower end surface of the speaker 2, the wider the E-plane 3dB beamwidth. The energy is transferred from the upper surface of the n rectangular radiation waveguides 3 to the lower surface of the speaker 2, and then transferred upward from the lower surface of the speaker 2, and finally radiated from the upper surface of the speaker 2 to free space.

[0048] In order to verify the performance of the curved ridge waveguide millimeter wave radar antenna of the present invention, the curved ridge waveguide millimeter wave radar antenna of the present invention is simulated by HFSS. During the simulation, four groups of parameters were set for simulation, among which the first group of parameters was specifically set as follows: the number of rectangular radiation waveguides 3 was 4, the length of each rectangular radiation waveguide 3 in the left-right direction was 2.18 mm, the width in the front-to-back direction was 0.7 mm, and the height in the up-down direction was 0.5 mm; each group of rectangular radiation waveguides 3 included 2 rectangular radiation waveguides 3, and the spacing between the 2 rectangular radiation waveguides 3 was 2.95 mm; the length of the upper surface of the speaker 2 in the left-right direction was 13.82 mm, and the width in the front-to-back direction was 3.2 mm; the length of the lower surface of the speaker 2 in the left-right direction was 13.72 mm, and the width in the front-to-back direction was 1.6 mm; the distance between the upper surface of the speaker 2 and the lower surface of the speaker 2 was 1 mm; the length of the first rectangular waveguide 4 in the front-to-back direction was 3 mm, the width in the left-to-right direction was 0.64 mm, and the height in the up-down direction was 2.4 mm; the length of the second rectangular waveguide 5 in the front-to-back direction was 1.4 mm, the width in the left-to-right direction was 0.4 mm, and the height in the up-down direction was 0.4 The length of the third rectangular waveguide 6 in the front-to-back direction is 0.45 mm, 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 and right end faces of the first curved ridge waveguide 11 is 6.16 mm, the spacing between the upper and lower end faces is 1 mm, and the width of the left end face in the front-to-back direction is 1.4 mm; the spacing between the upper and lower end faces of the first curved ridge waveguide 11 groove is 0.6 mm, and the width of the left end face in the front-to-back direction is 0.5 mm; the front end face of the first curved ridge waveguide 11 bends backward near the rectangular radiation waveguide 3 on the right side of the first group of rectangular radiation waveguides 3, and bends forward near the rectangular radiation waveguide 3 on the left side of the first group of rectangular radiation waveguides 3. The curvature of the front end face of the first curved ridge waveguide 11 when bending backward near the rectangular radiation waveguide 3 on the right side of the first group of rectangular radiation waveguides 3 is greater than the curvature of the front end face of the first curved ridge waveguide 11 when bending forward near the rectangular radiation waveguide 3 on the left side of the first group of rectangular radiation waveguides 3. The second set of parameters is the same as the first set of data except for the dimensions of the speaker 2. In the second set of parameters, the length of the upper surface of the speaker 2 in the left-right direction is 16.47 mm, and the width in the front-to-back direction is 3.8 mm. The length of the lower surface of the speaker 2 in the left-right direction is 13.72 mm, and the width in the front-to-back direction is 1.6 mm. The distance between the upper surface of the speaker 2 and the lower surface of the speaker 2 is 1 mm.The third set of parameters, except for the dimensions of speaker 2, are identical to the first set. In the third set of parameters, the left-right length of the upper surface of speaker 2 is 15.76 mm, and the front-to-back width is 3 mm. The left-right length of the lower surface of speaker 2 is 13.72 mm, and the front-to-back width is 1.6 mm. The distance between the upper and lower surfaces of speaker 2 is 1 mm. The fourth set of parameters, except for the dimensions of speaker 2, are identical to the first set. In the fourth set of parameters, the left-right length of the upper surface of speaker 2 is 14.76 mm, and the front-to-back width is 2.4 mm. The left-right length of the lower surface of speaker 2 is 13.72 mm, and the front-to-back width is 1.6 mm. The distance between the upper and lower surfaces of speaker 2 is 1 mm.

[0049] The reflection coefficient simulation diagram of the curved ridge waveguide millimeter wave radar antenna of the present invention when the first set of parameters is used for simulation is as follows: Figure 7 As shown, the E-plane and H-plane directional patterns of the curved ridge waveguide millimeter wave radar antenna of the present invention when simulated using the first set of parameters are as follows: Figure 8 As shown, the E-plane and H-plane directional patterns of the curved ridge waveguide millimeter wave radar antenna of the present invention when simulated using the second set of parameters are as follows: Figure 9 As shown, the E-plane and H-plane directional patterns of the curved ridge waveguide millimeter wave radar antenna of the present invention when simulated using the third set of parameters are as follows: Figure 10 As shown, the E-plane and H-plane directional patterns of a curved ridge waveguide millimeter wave radar antenna of the present invention when simulated using the fourth set of parameters are as follows: Figure 11 shown.

[0050] like Figure 12 As shown, eight curved ridge waveguide millimeter-wave radar antennas using the first set of parameters are used as eight antenna units and distributed at a certain interval to form an antenna array, wherein the eight antenna units are respectively referred to as the first antenna unit 15, the second antenna unit 16, the third antenna unit 17, the fourth antenna unit 18, the fifth antenna unit 19, the sixth antenna unit 20, the seventh antenna unit 21 and the eighth antenna unit 22, and the eight antenna units are fed through a feeding network. HFSS is used for simulation to obtain the E-plane and H-plane directivity patterns of the eight antenna units, as shown in FIG. Figures 13 to 20 shown.

[0051] analyze Figure 7 It can be seen that the reflection coefficient S of the curved ridge waveguide millimeter wave radar antenna of the present invention is 11The reflection coefficient in the operating frequency band of 76-81 GHz is around -20 dB. This shows that the curved ridge waveguide millimeter-wave radar antenna of the present invention directly inputs electromagnetic wave signals into two curved ridge waveguides via a 1-to-2 power splitter, eliminating the need for additional matching structures. It exhibits low loss, excellent reflection coefficient, and low-loss characteristics.

[0052] analyze Figure 8 As can be seen, at the center frequency of 78.5 GHz, the curved ridge waveguide millimeter-wave radar antenna of the present invention exhibits a wide E-plane 3dB beamwidth, reaching approximately 131°. H-plane sidelobe suppression exceeds 20 dB, demonstrating excellent H-plane sidelobe suppression. Within the 76-81 GHz operating frequency band, the curved ridge waveguide millimeter-wave radar antenna of the present invention also achieves an E-plane 3dB beamwidth of approximately 131°, with H-plane sidelobe suppression exceeding 20 dB. This demonstrates that the curved ridge waveguide millimeter-wave radar antenna of the present invention exhibits low H-plane sidelobes and a wide E-plane 3dB beamwidth.

[0053] analyze Figure 9 It can be seen that at the center frequency of 78.5 GHz, when the horn size adopts the second set of parameters, the E-plane 3dB beamwidth of the curved ridge waveguide millimeter-wave radar antenna of the present invention also changes. The E-plane 3dB beamwidth can reach about 74°, and the H-plane sidelobe suppression can reach more than 20 dB, indicating a good H-plane sidelobe suppression effect. Figure 10 It can be seen that at the center frequency of 78.5 GHz, when the horn size adopts the third set of parameters, the E-plane 3dB beamwidth of the curved 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 As can be seen, at the center frequency of 78.5 GHz, when the horn size adopts the fourth set of parameters, the E-plane 3dB beamwidth of the curved ridge waveguide millimeter-wave radar antenna of the present invention also changes, reaching approximately 112°. H-plane sidelobe suppression exceeds 20 dB, demonstrating excellent H-plane sidelobe suppression. This demonstrates that changing the horn size in the curved ridge waveguide millimeter-wave radar antenna of the present invention can also change the E-plane 3dB beamwidth, allowing the desired E-plane 3dB beamwidth to be directly obtained during the design process by simply setting the horn size.

[0054] analyze Figures 12 to 20It can be seen that when the curved ridge waveguide millimeter-wave radar antenna of the present invention is used as an antenna unit in an antenna array, the E-plane and H-plane radiation patterns of each antenna unit can maintain the excellent characteristics of wide beam and low sidelobe, provided that the antenna units are arranged at half a wavelength. Therefore, it can be seen that when the curved ridge waveguide millimeter-wave radar antenna of the present invention is used as an antenna unit in an antenna array, the antenna units can be arranged at half a wavelength.

[0055] The curved ridge waveguide millimeter-wave radar antenna of the present invention can be implemented using an air waveguide during actual production. By cutting a slot in a metal rectangular waveguide and filling the slot with air, a 1-to-2 power splitter 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. The first curved waveguide block 14 and the portion of the second curved waveguide that can overlap with the first curved waveguide block 14 are part of the metal rectangular waveguide.

[0056] In summary, the curved ridge waveguide millimeter-wave radar antenna of the present invention ensures the operating frequency while reducing the size by using a 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 half a wavelength. Two curved ridge waveguides are set to transmit the electromagnetic wave signal to n rectangular radiating waveguides 3. Based on the bending characteristics of the curved ridge waveguide, the energy distribution of each rectangular radiating waveguide 3 is regulated by controlling the curvature of the curved ridge waveguide near the rectangular radiating waveguide 3, so that the rectangular radiating waveguide 3 near the edge of the millimeter-wave radar antenna obtains less energy, and the rectangular radiating waveguide 3 near the center of the millimeter-wave radar antenna obtains more energy, achieving H-plane low sidelobe performance, so that the n rectangular radiating 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 beamwidth can be changed by setting the size of the horn 2 to meet the actual E-plane 3dB beamwidth. 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 curved ridge waveguide millimeter wave radar antenna, characterized in that It includes a 1-to-2 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, and the two groups of rectangular radiating waveguides correspond one-to-one to the two curved ridge waveguides. The 1-to-2 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 one-to-one to the two curved ridge waveguides, each curved ridge waveguide is used to transmit the electromagnetic wave signal transmitted thereto to the corresponding n / 2 rectangular radiating waveguides, each rectangular radiating waveguide is used to couple the electromagnetic wave signal transmitted thereto to the horn, and the horn is used to radiate the electromagnetic wave signal output thereto by the n rectangular radiating waveguides into free space; The 1-to-2 power divider includes seven rectangular waveguides. The length directions of the seven rectangular waveguides are the same, which is used as the left-right direction, the width directions are the same, which is used as the front-to-back direction, and the height directions are the same, which is used as the up-down direction. The seven rectangular waveguides are respectively referred to as 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 bilaterally symmetrical is referred to as 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 downward. 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 downward. The two inverted U-shaped structures are bilaterally symmetrical about the first symmetry plane.

2. The curved ridge waveguide millimeter wave radar antenna according to claim 1, characterized in that The second rectangular waveguide is arranged on the left side of the first rectangular waveguide, and the upper end surfaces and front end surfaces of the two are respectively located 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 arranged below the second rectangular waveguide and on the left side of the first rectangular waveguide. The left end surface and front end surface of the third rectangular waveguide are respectively located in the same plane as the left end surface and front end surface 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 front-to-back symmetric is called the second symmetry plane. The third rectangular waveguide and the fourth rectangular waveguide are front-to-back symmetric 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 bilaterally symmetric with respect to the first symmetry plane. The third rectangular waveguide and the sixth rectangular waveguide are bilaterally symmetric with respect to the first symmetry plane. The fourth rectangular waveguide and the seventh rectangular waveguide are bilaterally symmetric with respect to the first symmetry plane.

3. The curved ridge waveguide millimeter wave radar antenna according to claim 2, characterized in that The 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. The curved waveguide is referred to as the first curved waveguide, and the curved waveguide block is referred to as the first curved waveguide block. The first curved waveguide is formed by bending a waveguide with a rectangular structure, and the first curved waveguide block is formed by bending a waveguide with a rectangular structure. The second curved ridge waveguide is located on the right side of the 1-to-2 power divider. The intersection of the plane where the central axis of the second rectangular waveguide in the vertical direction and the central axis of the fifth rectangular waveguide in the vertical direction are located and the first symmetry plane is used as the first axis. If the first curved ridge waveguide is rotated 180 degrees with the first axis as the rotation axis, it will completely overlap with the second curved ridge waveguide.

4. The curved ridge waveguide millimeter wave radar antenna according to claim 3, characterized in that The outer side surface of the first curved waveguide is formed by sequentially splicing six end surfaces distributed in the directions of up, down, left, right, front and back. The left and right end surfaces of the first curved waveguide are both rectangular surfaces, the upper and lower end surfaces are both S-shaped planes, and the front and rear end surfaces are S-shaped curved surfaces. If the upper end surface is translated downward, it can completely coincide with the lower end surface; if the front end surface is translated backward, it can completely coincide with the rear end surface; if the left end surface is translated rightward, it can completely coincide with the right end surface; the upper end surface of the first curved waveguide is aligned with the first rectangular surface. The upper end surface of the first curved waveguide is located in the same plane, the lower end surface of the first curved waveguide and the lower end surface of the third rectangular waveguide are located in the same plane, the right end surface of the first curved waveguide is connected to and in a fitted state with the left end surface of the second rectangular waveguide, the left end surface of the third rectangular waveguide, and the left end surface of the fourth rectangular waveguide; the front side of the right end surface of the first curved waveguide and the front end surface of the third rectangular waveguide are located in the same plane, and the rear side of the right end surface of the first curved waveguide and the rear end surface of the fourth rectangular waveguide are located in the same plane.

5. The curved ridge waveguide millimeter wave radar antenna according to claim 4, characterized in that The outer side shape of the first curved waveguide block is the same as that of the first curved waveguide; the lower end face, left end face and right end face of the first curved waveguide block are respectively located in the same plane as the lower end face, left end face and 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 distance between the two; the left end face of the first curved waveguide block and the left end face of the first curved waveguide are both front-to-back symmetrical about the same plane; the length of the left end face of the first curved waveguide block in the front-to-back direction is smaller than the length of the left end face of the first curved waveguide in the front-to-back 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, then the front side of the upper end face of the first curved waveguide block can completely overlap with the front side of the upper end face of the first curved waveguide after being translated forward, and the rear side of the upper end face of the first curved waveguide block can completely overlap with the rear side of the upper end face of the first curved waveguide after being translated backward.

6. The curved ridge waveguide millimeter wave radar antenna according to claim 5, characterized in that The two groups of rectangular radiating waveguides are respectively referred to as the first group of rectangular radiating waveguides and the second group of rectangular radiating waveguides. The first group of rectangular radiating waveguides corresponds to the first curved ridge waveguide, and the second group of rectangular radiating waveguides corresponds to the second curved ridge waveguide. The n / 2 rectangular radiating waveguides of the first group of rectangular radiating waveguides are evenly spaced from left to right above the first curved ridge waveguide, and the n / 2 rectangular radiating waveguides of the second group of rectangular radiating waveguides are evenly spaced from left to right above the second curved ridge waveguide. The first group of rectangular radiating waveguides and the second group of rectangular radiating waveguides are bilaterally symmetrical about the first symmetry plane.

7. The curved ridge waveguide millimeter wave radar antenna according to claim 6, characterized in that The length directions of the n / 2 rectangular radiation waveguides of the first group 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, rear end faces, upper end faces, and lower end faces of the n / 2 rectangular radiation waveguides of the first group of rectangular radiation waveguides are located in the same plane. The lower end faces of the n / 2 rectangular radiation waveguides of the first group of rectangular radiation waveguides are all connected to the upper end face of the first curved ridge waveguide and are in a fitted state. The rectangular radiation waveguides located at the bottom of the first group of rectangular radiation waveguides are all connected to the upper end face of the first curved ridge waveguide and are in a fitted state. The plane where the left end surface of the rectangular radiation waveguide on the left is located on the right side of the left end surface of the first curved ridge waveguide, the plane where the right end surface of the rightmost rectangular radiation waveguide in the first group of rectangular radiation waveguides is located on the left side of the right end surface of the first curved ridge waveguide, the plane where the left end surface of the leftmost rectangular radiation waveguide in the second group of rectangular radiation waveguides is located on the right side of the left end surface of the second curved ridge waveguide, and the plane where the right end surface of the rightmost rectangular radiation waveguide in the second group of rectangular radiation waveguides is located on the left side of the right end surface of the second curved ridge waveguide.

8. The curved ridge waveguide millimeter wave radar antenna according to claim 7, characterized in that The outer side surface of the horn is a hexahedron formed by six end faces distributed in the upper, lower, left, right, front and rear directions, and 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 lower end face of the horn are both rectangular. The lengths of the upper end face and lower end face of the horn are both in the left-right direction, and the widths are both in the front-to-back direction. The horn is located above the n rectangular radiation waveguides, and the lower end face of the horn is connected to the upper end faces of the n rectangular radiation waveguides and is in a fit state. The left side of the lower end face of the horn is located on the left side of the plane where the left end face of the first curved ridge waveguide is located, and the right side of the lower end face of the horn is located on the right side of the plane where the right end face of the second curved ridge waveguide is located. The front side of the lower end face of the horn is located in front of the plane where the front end faces of the n rectangular radiation waveguides are located, and the rear side of the lower end face of the horn is located in rear of the plane where the rear end faces of the n rectangular radiation waveguides are located.

9. The curved ridge waveguide millimeter wave radar antenna according to claim 8, characterized in that The upper end face and the lower end face of the horn are both left-right symmetrical about the first symmetry plane, the upper end face and the lower end face of the horn are both front-to-back symmetrical about the same plane, the width of the upper end face of the horn in the front-to-back direction is greater than the width of its lower end face in the front-to-back direction, the length of the upper end face of the horn in the left-to-right direction is greater than the length of its lower end face in the left-to-right direction; the upper base of the left end face of the horn completely coincides with the left side of the upper end face of the horn, the lower base of the left end face of the horn completely coincides with the left side of the lower end face of the horn, the upper base of the front end face of the horn completely coincides with the front side of the upper end face of the horn, the lower base of the front end face of the horn completely coincides with the front side of the lower end face of the horn, and the rear end of the horn The upper bottom of the face completely coincides with the rear side of the upper end face of the horn, and the lower bottom of the rear end face of the horn completely coincides with the rear side 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 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 of the rear end face of the horn; the upper bottom of the right end face of the horn completely coincides with the right side of the upper end face of the horn, and the lower bottom of the right end face of the horn completely coincides with the right side 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 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 of the rear end face of the horn.

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