A millimeter wave high-radiation-efficiency array antenna

Abstract

This invention relates to millimeter-wave high-radiation-efficiency array antenna technology, and more particularly to a millimeter-wave high-radiation-efficiency array antenna. The array antenna, from top to bottom, comprises a radiating slot layer, a resonant coupling layer, and a waveguide feed layer. The array antenna is composed of 16×16 antenna subarrays, each subarray including 2×2 radiating slot elements; therefore, the total array antenna size is 32×32 radiating slot elements. The antenna array structure of this invention is compact and possesses a wide bandwidth and high radiation efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to millimeter wave high radiation efficiency array antenna technology, and particularly relates to a millimeter wave high radiation efficiency array antenna. BACKGROUND

[0002] With the rapid development of military and civilian communication technology, the demand for the capacity of communication system increases sharply. In the millimeter wave frequency band, the spectrum resource is particularly rich, which has the characteristics of microwave and far infrared wave, has the advantages of narrow beam, wide bandwidth, high reliability, etc., and thus the millimeter wave technology is widely used in the fields of radar, remote sensing, communication, automobile, etc. At the same time, the millimeter wave antenna technology and the performance of millimeter wave devices have made great progress.

[0003] The antenna working in the millimeter wave frequency band is a millimeter wave antenna. The gain of a single antenna is limited, and thus a plurality of unit antennas are often arranged in an array to form an array antenna to obtain high gain. With the increase of the number of unit antennas arranged in an array, the scale of the corresponding feed network is also increased. The traditional microstrip patch antenna produces serious surface wave effect in the millimeter wave frequency band, and the high dielectric loss becomes unacceptable. The all-metal waveguide slot antenna is widely used in the fields of communication and radar because it has the advantages of no dielectric loss, large power capacity and can be completed by machining.

[0004] However, the existing millimeter wave waveguide slot antenna still has the disadvantages of narrow bandwidth and large size. SUMMARY

[0005] In view of the problems in the prior art, the present application provides a millimeter wave high radiation efficiency array antenna. The array antenna comprises, from top to bottom, a radiation slot layer, a resonant coupling layer and a waveguide feed layer. The array antenna is composed of 16x16 antenna subarrays. Each antenna subarray comprises 2x2 radiation slot units. Therefore, the scale of the array antenna is 32x32 radiation slot units.

[0006] Further, the radiation slot layer comprises 32x32 radiation slot units. Each radiation slot unit comprises a first slot and a second slot. The first slot and the second slot are rectangular slots arranged perpendicularly and overlapping each other. The length of the first slot is greater than the length of the second slot, and the width of the first slot is less than the width of the second slot.

[0007] Further, the length, width and thickness of the first slot are 5.2mm, 4.8mm and 1.55mm respectively, and the length, width and thickness of the second slot are 2.2mm, 5.5mm and 1mm respectively.

[0008] Further, the resonant coupling layer is composed of 16*16 resonant cavities, each of which is provided with a bow-tie coupling slot at the center of the resonant cavity, and each of the resonant cavities at the position corresponding to the narrowest width of the bow-tie coupling slot is provided with a boss on each side.

[0009] Further, the bow-tie coupling slot has a length of 3.8 mm, a maximum width of 2.1 mm, a minimum width of 1.3 mm, and a thickness of 0.7 mm.

[0010] Further, the waveguide feeding layer is composed of a 1:2 equal power division cascade, and finally forms a 1:256 waveguide feeding network.

[0011] Further, the 1 / 16 waveguide feeding network comprises four T-shaped ridges and three linear ridges, each two antenna sub-structures are combined by using one end of the T-shaped ridge in the transverse direction, the two ends of the T-shaped ridge in the transverse direction are combined together, the ends of each two T-shaped ridges are connected to one end of one linear ridge, and the one ends of the three linear ridges are connected together, and one end of one linear ridge is used as a feeding port of the 4*4 antenna array.

[0012] Further, the vertical part of the T-shaped ridge adopts a transformation structure, that is, the vertical part is composed of two metal structures with different lengths, widths and thicknesses.

[0013] Further, the length, width and thickness of the transverse part of the T-shaped ridge are 5.7 mm, 1.4 mm and 0.65 mm respectively, the length, width and thickness of the part connected to the transverse structure in the vertical part are 8.8 mm, 1.25 mm and 0.65 mm respectively, and the length, width and thickness of the other part of the vertical part are 3 mm, 1.25 mm and 0.4 mm respectively; the length, width and thickness of the linear ridge are 6.2 mm, 1.6 mm and 0.2 mm respectively.

[0014] Further, each two adjacent antennas in each column of the antenna array are combined to form a 2*1 antenna array by using the linear ridge, each two 2*1 antenna arrays are combined to form a 2*2 antenna array by using the linear ridge, each two 2*2 antenna arrays are combined to form a 2*4 antenna array by using the linear ridge, and finally, the two 2*4 antenna arrays are combined to form a 4*4 antenna array by using the linear ridge, and the output end of the linear ridge is converted into a WR-28 standard waveguide by using a step transformation.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] Firstly, the present application adopts the form of combining ridge waveguides and conventional waveguides, so that the feeding network structure is compact, and the single-layer feeding network can complete the feeding of the entire array antenna;

[0017] Secondly, the present invention has a wide operating bandwidth, with a relative bandwidth of 10.5%, which is a significant improvement compared to the relative bandwidth of the existing rectangular waveguide slot antenna, which is approximately 3%.

[0018] Finally, the present invention has high radiation efficiency, with an in-band gain of 37.7dB and a radiation efficiency of over 85%, which is higher than that of existing dielectric waveguide antennas. Attached Figure Description

[0019] Figure 1 This is an exploded view of the antenna subarray of a millimeter-wave high-radiation-efficiency array antenna according to the present invention;

[0020] Figure 2 This is a side view of the antenna subarray of a millimeter-wave high-radiation-efficiency array antenna according to the present invention;

[0021] Figure 3 This is a top view of the 1 / 16th feed network in a millimeter-wave high-radiation-efficiency array antenna of the present invention;

[0022] Figure 4 This is a side view of a one-sixteenth antenna subarray in a millimeter-wave high-radiation-efficiency array antenna according to the present invention;

[0023] Figure 5 This is an exploded view of one-sixteenth of the antenna subarray in a millimeter-wave high-radiation-efficiency array antenna of the present invention;

[0024] Figure 6 This is a diagram illustrating the transformation of a non-standard waveguide into a standard waveguide structure in a millimeter-wave high-radiation-efficiency array antenna according to the present invention.

[0025] Figure 7 This is a side view of a waveguide slot array antenna of a millimeter-wave high radiation efficiency array antenna according to the present invention;

[0026] Figure 8 This is a perspective view of a waveguide slot array antenna for a millimeter-wave high-radiation-efficiency array antenna according to the present invention.

[0027] Figure 9 This invention provides a realizable gain diagram of a millimeter-wave high-radiation-efficiency array antenna as a function of frequency.

[0028] Figure 10 This invention provides a standing wave diagram of a millimeter-wave high-radiation-efficiency array antenna;

[0029] Figure 11 This invention provides a low-frequency azimuth and elevation diagram of a millimeter-wave high-radiation-efficiency array antenna;

[0030] Figure 12 This invention provides an intermediate frequency azimuth and elevation diagram for a millimeter-wave high-radiation-efficiency array antenna;

[0031] Figure 13 This invention provides a high-frequency azimuth and elevation diagram for a millimeter-wave high-radiation-efficiency array antenna;

[0032] Figure 14 This invention discloses a typical 3D radiation pattern of a millimeter-wave high-radiation-efficiency array antenna;

[0033] Among them, 1. First slot; 2. Second slot; 3. Resonant cavity; 4. Boss; 5. Bowtie-type coupling slot; 6. Waveguide feed layer; 7. T-shaped ridge; 8. Ridge transformation segment; 9. First protrusion of feed layer; 10. Linear ridge; 11. Second protrusion of feed layer; 14. Waveguide feed layer of antenna subarray; 15. Resonant coupling layer of antenna subarray; 16. Radiation slot layer of antenna subarray; 17. Non-standard waveguide transformation standard waveguide transformation step; 18. WR-28 standard waveguide output port; 19. Waveguide feed network and port; 20. Antenna array output port. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention proposes a millimeter-wave high radiation efficiency array antenna. The array antenna, from top to bottom, includes a radiating slot layer, a resonant coupling layer, and a waveguide feeding layer. The array antenna is composed of 16×16 antenna subarrays, and each antenna subarray includes 2×2 radiating slot elements. Therefore, the array antenna has a scale of 32×32 radiating slot elements.

[0036] In this embodiment, a millimeter-wave high radiation efficiency array antenna is composed of 16×16 identical antenna subarrays, each antenna subarray including 2×2 identical radiation slot elements. Therefore, this embodiment first describes one of the antenna elements.

[0037] like Figures 1-2 As shown, along the negative vertical direction (i.e., the negative Z-axis direction) of the first plane, the antenna subarray is stacked in sequence as a radiating slot layer, a resonant coupling layer, and a waveguide feed layer, wherein:

[0038] The radiating slit layer includes two rectangular slits that are perpendicular to each other and overlap. The rectangular projection centers of the two slits overlap. The length of the first slit 1 is greater than the length of the second slit 2, and the width of the first slit 1 is less than the width of the second slit 2. The two radiating rectangular cavities operate in different operating frequency bands, effectively improving the operating bandwidth. As an optional implementation, in this embodiment, the first slit located at the top has dimensions of 5.2mm × 4.8mm × 1.55mm (length × width × thickness), and the second slit located vertically downwards along the first slit has dimensions of 2.2mm × 5.5mm × 1mm (length × width × thickness).

[0039] Vertically downwards from the radiating slot layer is the resonant coupling layer, which includes a resonant cavity 3. A bow-tie-shaped coupling slot 5 is located at the center of the resonant cavity. A boss 4 is located on each side of the resonant cavity, corresponding to the narrowest point of the bow-tie-shaped coupling slot. These two bosses divide the resonant cavity into two subspaces, with the line connecting the two bosses serving as the boundary. By adjusting the height of the resonant cavity, the electromagnetic waves fed from the lower coupling slot layer are transformed into two electromagnetic cavities with uniform wavefront phases. In practice, when the electromagnetic waves fed from the waveguide feeding layer form four electromagnetic waves with uniform wavefront phases within the resonant cavity, these waves then excite the upper radiating slot layer. A 1-feed-4 antenna subarray is formed. As an optional implementation, in this embodiment, the dimensions of the resonant cavity are 9.1mm × 9.1mm × 1.5mm (length × width × thickness), the dimensions of each boss are 1.8mm × 1.6mm × 1mm (length × width × thickness), the bowtie-type coupling slot has a length of 3.8mm, a maximum width of 2.1mm, a minimum width of 1.3mm, and a thickness of 0.7mm. The center of the bowtie-type coupling slot overlaps with the resonant cavity, and the narrowest part of the bowtie-type coupling slot is on the same straight line as the centers of the two bosses. The invention uses a slot structure with gradually changing width, which helps to improve bandwidth and increase coupling.

[0040] Below the bowtie-shaped coupling slot is the waveguide feed layer 6, with a waveguide cross-section of 4.7mm × 2mm. The waveguide of the antenna subarray is a non-standard waveguide, which is designed for a compact feed network.

[0041] In this invention, the antenna subarray comprises, from top to bottom, antenna substructures and a feeding network. Each substructure comprises, from top to bottom, a radiating slot layer, a resonant coupling layer, and a waveguide feeding layer. A one-sixteenth feeding network in a millimeter-wave high-radiation-efficiency array antenna is shown below. Figure 3 As shown, every four antenna substructures are fed through a T-shaped ridge 7. Figure 4 The power supply structure is as follows Figure 5The 8×8 radiating slot element shown is fed. In the feeding structure, every two T-shaped ridges are connected by a straight ridge 10. The two straight ridges are then connected together by another straight ridge to obtain the output of a feeding network. A feeding network and the antenna substructure set on the feeding network form an antenna element. In the antenna array, each column of two adjacent antennas are merged by a straight ridge to form a 2×1 antenna array. Every two 2×1 antenna arrays are merged by a straight ridge to form a 2×2 antenna array. Every two 2×2 antenna arrays are merged by a straight ridge to form a 2×4 antenna array. Finally, the two 2×4 antenna arrays are merged by a straight ridge to form a 4×4 antenna array. The output end of the straight ridge is converted to a WR-28 standard waveguide by a step through a step transformation. Each linear ridge evenly divides the power into two parts. The power of the array antenna is divided into 16 parts and input to each antenna element. In each antenna element, the linear ridge evenly divides the power into two parts, and the T-shaped ridge evenly divides the power into four parts. That is, the power of each antenna substructure is equivalent to 1 / 256 of the input power. Figures 4-5 This embodiment provides an antenna subarray in an antenna array, which consists of, from bottom to top, a waveguide feed layer 14, a resonant coupling layer 15, and a radiation slot layer 16 for the antenna.

[0042] In this embodiment, the T-shaped ridge is a metal ridge. The vertical part of the T-shaped ridge adopts a transformation structure, that is, it is composed of two metal structural sections with different lengths, widths, and thicknesses spliced ​​together to form the vertical part, for example, in this embodiment. Figure 4 The tail of the T-shaped ridge 7 is provided with a ridge transition section 8. One T-shaped ridge 7 and the ridge transition section 8 of another T-shaped ridge are connected by a straight ridge 10. A first feed layer protrusion 9 is provided in the middle of the T-shaped ridge. A second feed layer protrusion 11 is provided at the connection between the two T-shaped ridges and the straight ridge 10. These two protrusions serve as standing wave modulators. Those skilled in the art can optimize the size of these two protrusions to obtain better matching performance. As an optional implementation, in this embodiment, the length, width, and thickness of the horizontal part of the T-shaped ridge are 5.7 mm, 1.4 mm, and 0.65 mm, respectively. The length, width, and thickness of the part of the vertical part connected to the horizontal structure are 8.8 mm, 1.25 mm, and 0.65 mm, respectively. The length, width, and thickness of the other section of the vertical part are 3 mm, 1.25 mm, and 0.4 mm, respectively. The length, width, and thickness of the straight ridge are 6.2 mm, 1.6 mm, and 0.2 mm, respectively. In this embodiment, the length, width, and thickness of the linear ridge are 6.2 mm, 1.6 mm, and 0.2 mm, respectively. The use of a waveguide metal ridge in this invention helps achieve low wave impedance within the same dimensions, laying the foundation for the entire array to use only a single-layer feed network.

[0043] from Figures 4-5As can be seen, each feed network is used to feed the 4×4 radiating slot element. The output of each antenna element is a waveguide feed and a port, which is also a branch port of the next stage power divider. Through the one-to-two power division and hierarchical connection, the entire array is finally formed.

[0044] like Figure 5 In the antenna array, adjacent antennas in each column are merged into a 2×1 antenna array via a ridge. Every two 2×1 antenna arrays are merged into a 2×2 antenna array via a ridge, and every two 2×2 antenna arrays are merged into a 2×4 antenna array via a ridge. Finally, two 2×4 antenna arrays are merged into a 4×4 antenna array via a ridge. The output of the ridge is converted to a WR-28 standard waveguide via a step. The feed port of the entire array is located at the center of the array. A conversion structure is used to convert the non-standard waveguide of the ridge into a WR-28 standard waveguide. The conversion structure is a step structure, with one end matching the non-standard waveguide in the horizontal direction and the other end matching the standard waveguide in the numerical direction. Figure 6 The waveguide feed network and port 19 of the entire array are non-standard waveguides. They are converted to WR-28 standard waveguide output port 18 through the non-standard waveguide to standard waveguide transformation step 17. This method facilitates subsequent measurement and system integration. The present invention uses the non-standard waveguide to standard waveguide transformation step 17 to perform impedance change, which helps energy transmission. When designing this step, those skilled in the art should consider the maximum energy transmission.

[0045] like Figures 7-8 Given a 4×4 antenna array consisting of 16 antenna subarrays, the first and second antenna subarrays in the first row are connected by a vertical ridge to form a first unit. This first unit, together with the first unit formed by the two antenna subarrays in the first and second columns of the second row connected by a vertical ridge, is then grouped into a horizontal second unit. Next, this second unit, together with the second unit formed by the two antenna subarrays in the third and fourth columns of the first row and the two antenna subarrays in the third and fourth columns of the second row, is connected by a vertical ridge to form a third unit. Finally, this third unit, together with the third unit formed by the antenna units in the third and fourth rows, is connected by a horizontal ridge to form a 4×4 antenna array. Each element then outputs its signal through a waveguide output port located at the center of the array.

[0046] like Figure 9 As shown in the diagram, the realizable gain of the waveguide slot array antenna in this embodiment varies with frequency. It can be concluded that the gain has high flatness across the entire band, with gains consistently exceeding 37.8 dB, and the radiation efficiency across the entire band exceeds 85%. Figure 10As shown, the overall in-band matching performance is excellent, with a VSWR of less than 1.6. Figure 11 Low-frequency azimuth and elevation diagrams of waveguide slot array antennas Figure 12 Intermediate frequency azimuth and elevation diagrams of waveguide slot array antennas Figure 13 High-frequency azimuth and elevation diagrams of waveguide slot array antennas and Figure 14 The typical 3D radiation pattern of the waveguide slot array antenna is shown. The radiation pattern has no distortion problem, and the sidelobes are all less than -13dB.

[0047] In the description of this invention, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "outer," "front," "center," "both ends," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "rotation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A millimeter-wave high-radiation-efficiency array antenna, characterized in that, The array antenna, from top to bottom, comprises a radiating slot layer, a resonant coupling layer, and a waveguide feed layer. The array antenna consists of 16×16 antenna subarrays, each subarray comprising 2×2 radiating slot elements; wherein: The radiative slot layer consists of 32×32 radiative slot units. Each radiative slot unit includes two rectangular slots that are perpendicular to each other and overlap. The rectangular projection centers of the two slots overlap. The length of the first slot is greater than the length of the second slot and the width of the first slot is less than the width of the second slot. The two rectangular slots operate in different operating frequency bands. The radiating slot layer extends vertically downwards to form the resonant coupling layer, which consists of 16×16 resonant cavities. A bow-tie-shaped coupling slot is located at the center of each resonant cavity. A boss is located on each side of the resonant cavity corresponding to the narrowest position of the bow-tie-shaped coupling slot. The two bosses divide the resonant cavity into two subspaces, with the line connecting the two bosses serving as the boundary. By adjusting the height of the resonant cavity, the electromagnetic wave fed from the lower coupling slot becomes two electromagnetic waves with uniform wavefront phase. When the electromagnetic wave fed from the waveguide feeding layer forms four electromagnetic waves with uniform wavefront phase inside the resonant cavity, they then excite the upper radiating slot layer, forming a one-feed-four antenna subarray.

2. The millimeter-wave high-radiation-efficiency array antenna according to claim 1, characterized in that, The length, width, and thickness of the first gap are 5.2mm, 4.8mm, and 1.55mm, respectively, and the length, width, and thickness of the second gap are 2.2mm, 5.5mm, and 1mm, respectively.

3. The millimeter-wave high-radiation-efficiency array antenna according to claim 1, characterized in that, The bow tie-type coupling gap has a length of 3.8mm, a maximum width of 2.1mm, a minimum width of 1.3mm, and a thickness of 0.7mm.

4. The millimeter-wave high-radiation-efficiency array antenna according to claim 1, characterized in that, The waveguide feed layer is composed of a 1-to-2 power level cascade, which ultimately forms a 1-to-256 waveguide feed network.

5. A millimeter-wave high-radiation-efficiency array antenna according to claim 4, characterized in that, The 1 / 16 waveguide feed network consists of four T-ridges and three straight ridges. Every two antenna substructures are joined together at one end of the T-ridge in the lateral direction, and the two ends of the T-ridge in the lateral direction are joined together. The ends of every two T-ridges are connected to one end of a straight ridge. One end of a straight ridge serves as the feed port for the 4×4 antenna array. The other ends of the three straight ridges are connected together.

6. A millimeter-wave high-radiation-efficiency array antenna according to claim 5, characterized in that, The vertical part of the T-shaped ridge adopts a transformation structure, that is, it is composed of two metal structures with different lengths, widths and thicknesses spliced ​​together to form the vertical part.

7. A millimeter-wave high-radiation-efficiency array antenna according to claim 6, characterized in that, The length, width, and thickness of the transverse section of the T-shaped ridge are 5.7 mm, 1.4 mm, and 0.65 mm, respectively. The length, width, and thickness of the vertical section connected to the transverse structure are 8.8 mm, 1.25 mm, and 0.65 mm, respectively. The length, width, and thickness of the other section of the vertical structure are 3 mm, 1.25 mm, and 0.4 mm, respectively. The length, width, and thickness of the straight ridge are 6.2 mm, 1.6 mm, and 0.2 mm, respectively.

8. A millimeter-wave high-radiation-efficiency array antenna according to claim 5, characterized in that, In the antenna array, each column of adjacent antennas is merged into a 2×1 antenna array through a ridge. Every two 2×1 antenna arrays are merged into a 2×2 antenna array through a ridge. Every two 2×2 antenna arrays are merged into a 2×4 antenna array through a ridge. Finally, the two 2×4 antenna arrays are merged into a 4×4 antenna array through a ridge. The output of the ridge is converted to a WR-28 standard waveguide through a step transformation.

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