Differential feed waveguide slot antenna array

Abstract

A differential feed waveguide slot antenna array disclosed by the present invention comprises a radiation layer and a feed layer, the radiation layer is provided with a first antenna radiation slot group and a second antenna radiation slot group, the feed layer comprises a one-to-two power divider, a first feed line and a second feed line, one end of the first feed line is connected with a first output end of the one-to-two power divider, and the other end of the first feed line is connected with a second output end of the one-to-two power divider. One end of the second feeder line is connected with the second output end of the one-to-two power divider, the other end of the first feeder line is connected with the other end of the second feeder line, and the length difference X exists between the first feeder line and the second feeder line, so that the phase difference between a first signal passing through the first feeder line and a second signal passing through the second feeder line is 180 degrees; the first antenna radiation slot group is arranged corresponding to the first feeder line, and the second antenna radiation slot group is arranged corresponding to the second feeder line. The antenna has the advantages of wide working bandwidth, low side lobe and low cost.

Description

Technical Field

[0001] The invention relates to a slot antenna array, in particular to a differentially fed waveguide slot antenna array, and belongs to the technical field of waveguide antennas. Background Art

[0002] With the rapid development of communication technology, antennas, as important components in communication systems, have a direct impact on the overall performance of the system.

[0003] Chinese patent publication number CN113904097A discloses a waveguide antenna, radar and automobile. The waveguide antenna includes an antenna body, a radiation slot group and a beam expansion radiation slot. The antenna body includes a radiation array. The radiation slot group is arranged on the radiation array and constitutes an antenna that generates a radiation signal with the antenna body; the beam expansion radiation slot is arranged on the radiation array and is located on both sides of the radiation slot group. The beam expansion radiation slot generates a radiation signal by cutting the current on the radiation array. The radiation signal of the beam expansion radiation slot is superimposed on the radiation signal of the radiation slot group to widen the beam width of the waveguide antenna. The waveguide antenna provided in this application solves the problem of narrow beam of existing waveguide antennas. This solution will cause the antenna to have higher side lobes in certain directions. If cost saving is required, a side feeding solution needs to be adopted. When the antenna frequency deviates from the center frequency, the H-plane beam pointing angle of the antenna will deviate by 0°, resulting in a narrower working bandwidth of the antenna. If a mid-feed solution is adopted, it will increase the cost, increase the installation cost, and reduce the yield.

[0004] Chinese patent publication number CN118431744A discloses a low sidelobe waveguide slot antenna, comprising a first copper layer, an EBG waveguide metal layer and a second copper layer adjacent to each other in sequence; a plurality of slots distributed in a straight line are opened on the first copper layer; a radiation ridge waveguide with an artificial electromagnetic structure and a feeding waveguide with an artificial electromagnetic structure are provided on the EBG waveguide metal layer. The low sidelobe waveguide slot antenna provided by the invention aims at the problem that the antenna has high side lobes in certain directions, and proposes a slot arrangement structure to improve the side lobes at other angles. In order to reduce the size of the antenna, the waveguide adopts a ridge waveguide, and all the slots are kept in a straight line. By changing the structure of the radiation ridge waveguide, the slot feeding amplitude meets the low sidelobe requirements. Multipath signals and interference signals are reduced, and the ghosting problem caused by millimeter wave radar is effectively avoided. This solution requires at least three layers of waveguide plates, and an additional installation, resulting in a decrease in yield and an increase in cost. This solution adopts a gap ridge waveguide solution, which has more periodic small pillars, increasing the difficulty of manufacturing. At the same time, it is necessary to ensure that the bending of the waveguide ridge controls the bottom side lobe of the antenna. When the antenna has more gaps, the bending angle of the waveguide ridge needs to be significantly increased, further increasing the difficulty of manufacturing the antenna.

[0005] Chinese patent publication number CN115939768A discloses a gap waveguide slot antenna and corner radar. The antenna includes: a plurality of radiation slots, a gap waveguide, the gap waveguide is coupled with the radiation slot, a plurality of radiation slots are arranged in a collinear manner, a waveguide ridge is provided in the gap waveguide, and the waveguide ridge and the radiation slot are arranged at intervals, wherein the waveguide ridge is staggered and bent along the collinear direction of the radiation slot, and in the collinear direction, the bending point of the waveguide ridge corresponds to the gap between adjacent radiation slots and the two ends of the overall radiation slot, and the bending direction of the waveguide ridge corresponding to adjacent radiation slots is opposite. The gap waveguide slot antenna of this scheme has no dielectric loss, high working efficiency, low cost, can reduce the difficulty of antenna processing, can realize large-scale mass production, and can achieve the performance of co-directional excitation and low side lobe of the radiation slot, but when there are more antenna units in this scheme, the angle will be relatively small, and the processing difficulty will be greater. Moreover, the side feeding scheme will cause the working bandwidth of the waveguide antenna to be narrow and the radiation pattern to be asymmetric.

[0006] In summary, although the existing waveguide slot antenna has good directivity and gain characteristics, it often faces problems such as insufficient common-mode noise suppression and complex structure in high-frequency applications; the existing side-feed solution will cause the working bandwidth of the waveguide antenna to be narrow, and the antenna will have high side lobes in certain directions. The existing center-feed solution will use at least three layers of waveguide plates, adding one installation, resulting in a decrease in yield and an increase in cost. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a differentially fed waveguide slot antenna array, so as to realize the antenna array having the advantages of wider working bandwidth, low side lobe and low cost.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: A differentially fed waveguide slot antenna array comprises a radiation layer and a feeding layer, wherein a first antenna radiation slot group and a second antenna radiation slot group are arranged on the radiation layer, and the feeding layer comprises a one-to-two power divider, a first feeder and a second feeder, wherein one end of the first feeder is connected to a first output end of the one-to-two power divider, one end of the second feeder is connected to a second output end of the one-to-two power divider, and the other end of the first feeder is connected to the other end of the second feeder, and the first feeder and the second feeder have a length difference X so that a first signal passing through the first feeder and a second signal passing through the second feeder have a phase difference of 180°, the first antenna radiation slot group is arranged corresponding to the first feeder, and the second antenna radiation slot group is arranged corresponding to the second feeder.

[0009] Furthermore, the first feeder and the second feeder are arranged in a rectangular shape, the one-to-two power divider is arranged on the first long side of the rectangle, the connecting line between the other end of the first feeder and the other end of the second feeder is located at the midpoint of the second long side of the rectangle, and the position of the one-to-two power divider is offset to one side on the first long side of the rectangle so that the length difference between the first feeder and the second feeder is X.

[0010] Furthermore, a midpoint of a connecting line between the other end of the first feeder and the other end of the second feeder is set as a symmetry point, and the first antenna radiation slot group and the second antenna radiation slot group are point symmetrical with the symmetry point as the center.

[0011] Furthermore, the first antenna radiation slot group and the second antenna radiation slot group respectively include a first radiation slot, a second radiation slot, a third radiation slot and a fourth radiation slot which are sequentially arranged from the symmetrical point to both sides.

[0012] Furthermore, the widths of the first radiation slot, the second radiation slot, the third radiation slot and the fourth radiation slot and the distances from the central axis of the feeder are controlled so that the energy distribution above the antenna aperture field is a Chebyshev distribution or a Taylor distribution.

[0013] Furthermore, two first choke slots are symmetrically arranged on the radiation layer on both sides of the first antenna radiation slot group and the second antenna radiation slot group.

[0014] Furthermore, two second choke slots are symmetrically arranged on the feed layer on both sides of the second long side of the rectangle formed by the first feed line and the second feed line, and the two second choke slots are arranged in one-to-one correspondence with the two first choke slots.

[0015] Compared with the prior art, the present invention has the following advantages and effects: 1. The present invention adopts a differential feeding scheme to expand the working bandwidth of the antenna, because differential feeding has a high degree of symmetry and can ensure the symmetry of the directional pattern; 2. The present invention adopts a differential feeding scheme. During the transmission process, the signal will be divided into positive and negative paths for transmission. This process is called differential transmission. Since the polarities of the two signals are different, they can offset some interference in the transmission process, so that the signal is transmitted more stably and all angular side lobes will not be deteriorated due to these interferences. 3. The differential feeding network of the present invention is relatively compact and is on the same side of the waveguide antenna, so only two layers of waveguide are needed to achieve it, which reduces the cost and reduces the installation of one layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a differentially fed waveguide slot antenna array of the present invention.

[0017] Figure 2It is a partial schematic diagram of a differentially fed waveguide slot antenna array of the present invention.

[0018] Figure 3 It is a return loss and gain curve diagram of a differentially fed waveguide slot antenna array of the present invention.

[0019] Figure 4 It is a 74-81 GHz horizontal plane radiation pattern of a differentially fed waveguide slot antenna array of the present invention.

[0020] Figure 5 It is a 74-81 GHz elevation plane radiation pattern of a differentially fed waveguide slot antenna array of the present invention.

[0021] Figure 6 The antenna of the differentially fed waveguide slot antenna array of the present invention has directional patterns of phi of 30°, 45°, 60° and 90° respectively at 77GHz. DETAILED DESCRIPTION

[0022] In order to elaborate on the technical scheme adopted by the present invention to achieve the predetermined technical purpose, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only partial embodiments of the present invention, rather than all embodiments, and the technical means or technical features in the embodiments of the present invention can be replaced without paying creative work. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0023] like Figure 1 As shown, a differentially fed waveguide slot antenna array of the present invention comprises a radiation layer and a feeding layer, wherein a first antenna radiation slot group 1 and a second antenna radiation slot group 2 are arranged on the radiation layer, and the feeding layer comprises a one-to-two power divider 3, a first feeder 4 and a second feeder 5, one end of the first feeder 4 is connected to a first output end of the one-to-two power divider 3, one end of the second feeder 5 is connected to a second output end of the one-to-two power divider 3, the other end of the first feeder 4 is connected to the other end of the second feeder 5, the first feeder 4 and the second feeder 5 have a length difference X so that a phase difference of a first signal passing through the first feeder 4 and a second signal passing through the second feeder 5 is 180°, the first antenna radiation slot group 1 is arranged corresponding to the first feeder 4, and the second antenna radiation slot group 2 is arranged corresponding to the second feeder 5.

[0024] The first feeder 4 and the second feeder 5 are arranged in a rectangular shape, and the four corners of the rectangle are transitioned with arc angles. The one-to-two power divider 3 is arranged on the first long side 6 of the rectangle, and the connecting line of the other end of the first feeder 4 and the other end of the second feeder 5 is located at the midpoint of the second long side 7 of the rectangle. The position of the one-to-two power divider 3 is offset to one side by X / 2 on the first long side 6 of the rectangle so that the length difference between the first feeder and the second feeder is X so that the phase difference between the first signal passing through the first feeder 4 and the second signal passing through the second feeder 5 is 180°.

[0025] The midpoint of the connecting line between the other end of the first feed line 4 and the other end of the second feed line 5 is set as the symmetry point 8, and the first antenna radiation slot group 1 and the second antenna radiation slot group 2 are point symmetrical with the symmetry point 8 as the center.

[0026] The first antenna radiation slot group 1 and the second antenna radiation slot group 2 respectively include a first radiation slot 9, a second radiation slot 10, a third radiation slot 11 and a fourth radiation slot 12 which are arranged in sequence from the symmetrical point 8 to both sides.

[0027] The width of the first radiation slot 9, the second radiation slot 10, the third radiation slot 11 and the fourth radiation slot 12 and the distance from the central axis of the feeder make the energy distribution above the antenna aperture field present Chebyshev distribution or Taylor distribution. Within a certain range, the larger the slot width, the more coupled energy, and the more the slot deviates from the center line, the more coupled energy, so controlling the slot width and the distance from the central axis can achieve low side lobes and also ensure the symmetry of the radiation pattern.

[0028] Two first choke slots 13 are symmetrically arranged on the radiation layer on both sides of the first antenna radiation slot group 1 and the second antenna radiation slot group 2, mainly to reduce surface waves and adjust the beam width of the E-plane radiation pattern.

[0029] On the feeding layer, two second choke slots 14 are symmetrically arranged on both sides of the second long side 7 of the rectangle formed by the first feed line 4 and the second feed line 5, and the two second choke slots 14 are arranged one by one corresponding to the two first choke slots 13. The second choke slots 14 and the first choke slots 13 together reduce the surface wave and adjust the beam width of the E-plane radiation pattern.

[0030] Differential feeding can achieve functions similar to traveling waves and achieve a wider working bandwidth; Figure 3 As shown, the bandwidth of the antenna's standing wave less than -10dB is 73-81GHz, the antenna's 1dB gain bandwidth is 74-81GHz, the working bandwidth is 7GHz, and the relative bandwidth is 9.1%.

[0031] Differential feeding has a high degree of symmetry, which can achieve a beam pointing angle of 0° for the elevation antenna, and a more symmetrical radiation pattern; Figure 4 and Figure 5These are the horizontal and elevation plane radiation patterns of the antenna at 74-81GHz, where the maximum gain beam pointing angle of the elevation plane radiation pattern is always at 0°, the side lobes are below -16dB, and the 6dB beam width in the horizontal plane is around 150°.

[0032] Using the differential feeding scheme, during the transmission process, the signal will be divided into positive and negative paths for transmission. This process is called differential transmission. Since the polarities of the two signals are different, they can offset some of the interference during the transmission process, so that the signal is transmitted more stably and all angular side lobes will not be deteriorated due to these interferences. Figure 6 The figure shows the antenna's radiation patterns at 77 GHz with phi of 30°, 45°, 60° and 90° respectively. The side lobes of the antenna are all below -18 dB, which is a significant improvement compared to the offset slot antenna under traditional feeding.

[0033] The differential feeding scheme offsets some of the interference in the transmission process, so that the ripple of the antenna pattern is still small in the whole device case, which is suitable for corner radar. The conventional scheme has a larger ripple of the directional pattern after the antenna units are arrayed.

[0034] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A differentially fed waveguide slot antenna array, characterized in that: The invention comprises a radiation layer and a feeding layer, wherein a first antenna radiation slot group and a second antenna radiation slot group are arranged on the radiation layer, and the feeding layer comprises a one-to-two power divider, a first feeder and a second feeder, wherein one end of the first feeder is connected to a first output end of the one-to-two power divider, one end of the second feeder is connected to a second output end of the one-to-two power divider, the other end of the first feeder is connected to the other end of the second feeder, the first feeder and the second feeder have a length difference X so that a phase difference of a first signal passing through the first feeder and a second signal passing through the second feeder is 180°, the first antenna radiation slot group is arranged corresponding to the first feeder, and the second antenna radiation slot group is arranged corresponding to the second feeder.

2. A differentially fed waveguide slot antenna array according to claim 1, characterized in that: The first feeder and the second feeder are arranged in a rectangular shape, the one-to-two power divider is arranged on the first long side of the rectangle, the connecting line of the other end of the first feeder and the other end of the second feeder is located at the midpoint of the second long side of the rectangle, and the position of the one-to-two power divider is offset to one side on the first long side of the rectangle so that the length difference between the first feeder and the second feeder is X.

3. A differentially fed waveguide slot antenna array according to claim 2, characterized in that: The midpoint of the connecting line between the other end of the first feeder and the other end of the second feeder is set as a symmetry point, and the first antenna radiation slot group and the second antenna radiation slot group are point symmetrical with the symmetry point as the center.

4. A differentially fed waveguide slot antenna array according to claim 3, characterized in that: The first antenna radiation slot group and the second antenna radiation slot group respectively include a first radiation slot, a second radiation slot, a third radiation slot and a fourth radiation slot which are arranged in sequence from a symmetrical point to both sides.

5. A differentially fed waveguide slot antenna array according to claim 4, characterized in that: The widths of the first radiation slot, the second radiation slot, the third radiation slot and the fourth radiation slot and the distances from the central axis of the feeder are controlled so that the energy distribution above the antenna aperture field is a Chebyshev distribution or a Taylor distribution.

6. A differentially fed waveguide slot antenna array according to claim 2, characterized in that: Two first choke slots are symmetrically arranged on the radiation layer on both sides of the first antenna radiation slot group and the second antenna radiation slot group.

7. A differentially fed waveguide slot antenna array according to claim 6, characterized in that: Two second choke slots are symmetrically arranged on the feed layer on both sides of the second long side of the rectangle formed by the first feed line and the second feed line, and the two second choke slots are arranged one by one corresponding to the two first choke slots.

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