Microstrip array antenna and two-dimensional beam control method

Abstract

This invention discloses a microstrip array antenna and a two-dimensional beam control method, including a radiating layer, a phase gradient metasurface layer, and a driving device. The radiating layer includes a first dielectric substrate, a plurality of microstrip patch antenna elements arranged in a rectangular array on the first dielectric substrate, and a feed network arranged on the first dielectric substrate. The emitted electromagnetic waves of the microstrip patch antenna elements in each column have the same phase, and the emitted electromagnetic waves of the microstrip patch antenna elements in each row have different phases, forming a phase gradient along the arrangement direction. The driving device is used to drive the radiating layer and the phase gradient metasurface layer to rotate around the same axis, enabling the microstrip array antenna to perform continuous two-dimensional beam scanning. By forming a phase gradient metasurface with radiation function on the upper surface of the first dielectric substrate, the microstrip array antenna is endowed with phase gradient capability, reducing the number of phase gradient metasurfaces, improving antenna gain, and reducing antenna profile.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, specifically to a microstrip array antenna and a two-dimensional beam control method. Background Technology

[0002] Antennas, as receiving and transmitting devices in wireless communication systems, are a crucial component of these systems. The performance of an antenna directly impacts the overall performance of the communication system. Therefore, researchers have raised increasingly higher requirements for antenna performance in various aspects.

[0003] Microstrip array antennas have been widely used. A microstrip array antenna mainly consists of three parts: a ground plane, a feed network, and radiating patches for each element. The feed network feeds each array element, and the radiating patches receive and transmit electromagnetic waves. Microstrip phased array antennas facilitate beam control. Beam control is achieved by inserting active phase shifters into the feed network to control the feed phase of the array elements. However, this beam control method increases losses and power consumption.

[0004] Planar Risley prisms, primarily used for precise beam control in optics, have been introduced into antenna systems. The industry uses Risley prisms to reduce the complexity of the electronic phase control systems in microstrip array antennas. Planar Risley prism technology has demonstrated great potential in radar, satellite communications, wireless networks, and other high-frequency applications due to its unique beam control capabilities.

[0005] Traditional Risley prisms consist of two wedge-shaped dielectric prisms. Two-dimensional (elevation and azimuth) continuous beam control is achieved by coaxially rotating the two wedge-shaped prisms. This system utilizes the passive nature of Risley prisms to replace traditional active components, reducing antenna system cost and complexity. However, the prisms are relatively bulky, presenting certain limitations. In subsequent developments, with the deepening research into phase-gradient metasurfaces, it was discovered that using two coaxial, thinner metasurfaces with a thickness less than the wavelength, and by coaxially rotating the two phase-gradient metasurfaces, two-dimensional (elevation and azimuth) continuous beam control (such as...) can be achieved. Figure 1 This has greatly promoted the development of microstrip array antennas. However, this method requires two phase-gradient metasurfaces separated by air, which significantly increases the antenna profile. Therefore, researching a Risley Prisms microstrip array antenna that can reduce the antenna profile is of great significance. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a microstrip array antenna and a two-dimensional beam control method, which only requires a single layer of simple phase gradient metasurface and a microstrip array antenna with integrated phase gradient metasurface function to achieve continuous two-dimensional beam control.

[0007] To solve the above-mentioned technical problems, the present invention provides a microstrip array antenna, comprising a radiating layer, a phase gradient metasurface layer, and a driving device; The radiating layer includes a first dielectric substrate, a rectangular array of microstrip patch antenna elements disposed on the first dielectric substrate, and a feed network disposed on the first dielectric substrate; the electromagnetic waves emitted by the microstrip patch antenna elements in each column have the same phase, and the electromagnetic waves emitted by the microstrip patch antenna elements in each row have different phases, forming a phase gradient along the arrangement direction. The phase gradient metasurface layer includes a second dielectric substrate that is parallel to and directly opposite the top of the first dielectric substrate. Metal structural units are arranged in a rectangular array on the second dielectric substrate. The metal structural units in each column have the same phase shift for transmitted electromagnetic waves, and the metal structural units in each row have different phase shifts for transmitted electromagnetic waves, and form the same phase gradient as the microstrip patch antenna unit along the arrangement direction. The driving device is used to drive the radiating layer and the phase gradient metasurface layer to rotate around the same axis, so that the microstrip array antenna can perform continuous two-dimensional beam scanning.

[0008] Preferably, there is an air gap between the first dielectric substrate and the second dielectric substrate, typically 2~10mm. The microstrip patch antenna element array is disposed on the top surface of the first dielectric substrate.

[0009] In the aforementioned microstrip array antenna, by ensuring that the emitted electromagnetic waves of the microstrip patch antenna elements in each column have the same phase, and that the emitted electromagnetic waves of the microstrip patch antenna elements in each row have different phases and form a phase gradient along the arrangement direction, the radiating layer forms a phase gradient metasurface with radiation function. This enables the microstrip array antenna to have phase gradient capability, thus becoming one of the two phase gradient metasurfaces in a typical planar Risley prism. Reducing one phase gradient metasurface not only reduces loss and improves antenna gain, but also reduces antenna profile.

[0010] As an improvement to the microstrip array antenna of the present invention, the microstrip patch antenna unit has the same structural dimensions and orientation on the first dielectric substrate; the phase of the feed network signal received by the microstrip patch antenna unit in each column is the same, and the phase of the feed network signal received by the microstrip patch antenna unit in each row varies gradient along the arrangement direction.

[0011] Preferably, the phase of the microstrip patch antenna element is arranged by using a passive phase shifter.

[0012] As another improvement to the microstrip array antenna of the present invention, the microstrip patch antenna units have the same structural dimensions, the microstrip patch antenna units in each column are all oriented in the same direction on the first dielectric substrate, and the orientation of the microstrip patch antenna units in each row on the first dielectric substrate varies with gradient along the arrangement direction.

[0013] Preferably, the microstrip patch antenna element achieves azimuth change by rotating around an axis that bypasses the center and is perpendicular to the top surface of the first dielectric substrate.

[0014] As another improvement to the microstrip array antenna of the present invention, the microstrip patch antenna elements are all oriented in the same direction on the first dielectric substrate, the structural dimensions of the microstrip patch antenna elements in each column are all the same, and the structural dimensions of the microstrip patch antenna elements in each row change continuously along the arrangement direction.

[0015] As another improvement to the microstrip array antenna of the present invention, the phase difference of the metal structure units in each row is a constant value. Preferably, the phase difference of the microstrip patch antenna units in each row is a constant value, and is the same as that of the metal structure units, which is 90°.

[0016] As another improvement of the microstrip array antenna of the present invention, the first dielectric substrate is in the shape of a circular plate, and the microstrip patch antenna elements are arranged in a rectangular array along the X and Y directions, forming a row along the X direction and a column along the Y direction; the center of the first dielectric substrate coincides with the center of the microstrip patch antenna element array.

[0017] Preferably, the outermost two rows and two columns each have six of the microstrip patch antenna elements.

[0018] Furthermore, the second dielectric substrate is in the shape of a circular plate, and the metal structural units are arranged in a rectangular array along the X and Y directions, forming rows along the X direction and columns along the Y direction; the center of the second dielectric substrate coincides with the center of the array of metal structural units.

[0019] As an improvement to the microstrip array antenna of the present invention, the microstrip patch antenna unit includes a first square frame, wherein each side strip of the first square frame has a first notch of the same width at its midpoint; a second square frame is concentrically arranged inside the first square frame and has four parallel sides, wherein a second notch is provided at each of two opposite corners of the second square frame, the second notch being an isosceles right triangle, and the two sides being located on the outer sides of the two side strips of the second square frame; a bar is provided inside the second square frame, the bar extending from the midpoint of the inner side of one side strip of the second square frame to the center of the second square frame.

[0020] The four side strips of the second square frame are arranged parallel to one side strip of the first square frame, respectively.

[0021] As another improvement to the microstrip array antenna of the present invention, a ground plane is provided in the middle of the first dielectric substrate, the ground plane dividing the first dielectric substrate into two layers: an upper dielectric substrate and a lower dielectric substrate. The feed network is provided on the bottom surface of the lower dielectric substrate. The first dielectric substrate is provided with a first via at each of the microstrip patch antenna elements. The first via is filled with conductive material for connecting the feed network and the corresponding microstrip patch antenna element.

[0022] As another improvement to the microstrip array antenna of the present invention, the metal structure unit includes an upper patch disposed on the upper surface of the second dielectric substrate, a lower patch disposed on the lower surface of the second dielectric substrate corresponding to the upper patch, and a metallized via connecting the upper patch and the lower patch, the metallized via penetrating the second dielectric substrate.

[0023] Furthermore, the upper patch and the lower patch have the same structural dimensions and are arranged opposite each other. The upper patch includes a cross strip, and each of the four regions divided by the cross strip is provided with an annular strip. The structural dimensions of the cross strip in each row of metal structural units change continuously along the arrangement direction. A connection point is provided at an equal distance from the center on each of the four sides of the cross strip. The connection point is connected to the corresponding connection point on the lower metal patch through the metallized via.

[0024] To address the aforementioned technical problems, the present invention provides a two-dimensional beam control method based on the microstrip array antenna, comprising the following steps: Step 1: Specify the target azimuth and target elevation angles for the beam; Step 2: Control the rotation of the radiating layer and the phase gradient metasurface layer respectively, so that the arrangement direction of the microstrip patch antenna elements on the radiating layer and the arrangement direction of the metal structure elements on the phase gradient metasurface layer are both aligned with the target azimuth direction and towards the target azimuth direction: the phase shift of each row of microstrip patch antenna elements and the phase shift of the metal structure elements are both increasing. Step 3: Control the radiation layer and the phase gradient metasurface layer to rotate simultaneously in opposite directions at the same speed, so that the elevation angle changes continuously, thereby enabling the beam to have the target elevation angle.

[0025] In summary, by employing this microstrip array antenna and two-dimensional beam control method, and through structural improvements to the original microstrip array and phase-gradient metasurface, the microstrip array antenna can radiate plane waves as a basic antenna while also functioning as a phase-gradient metasurface. Continuous two-dimensional beam control can be achieved with only one additional layer of phase-gradient metasurface, reducing the antenna's profile. Furthermore, the design is simple, cost-effective, and consumes little power. This provides a feasible solution for designing low-profile antennas that require generating arbitrary radiated beams in antenna applications, demonstrating strong practical applicability. Attached Figure Description

[0026] In the attached diagram: Figure 1 This is a schematic diagram of a planar Risley prism structure.

[0027] Figure 2 This is an overall structural diagram of the microstrip array antenna of the present invention.

[0028] Figure 3 This is a cross-sectional view of the microstrip array antenna of the present invention.

[0029] Figure 4 This is a structural diagram of the microstrip patch antenna element array of the microstrip array antenna of the present invention.

[0030] Figure 5 This is a cross-sectional view of the microstrip patch antenna element of the microstrip array antenna of the present invention.

[0031] Figure 6 This is a structural diagram of the microstrip patch antenna element of the microstrip array antenna of the present invention.

[0032] Figure 7 This is a schematic diagram illustrating how the phase gradient of the microstrip array antenna of the present invention is achieved by changing the structural dimensions of the microstrip patch antenna elements.

[0033] Figure 8 This is a structural diagram of the metal structure unit array of the microstrip array antenna of the present invention.

[0034] Figure 9 This is a diagram of the upper patch structure of the microstrip array antenna of the present invention.

[0035] Figure 10 This is a cross-sectional view of the metal structure unit of the microstrip array antenna of the present invention.

[0036] Figure 11 This is a simulated 3D stereo radiation pattern of the microstrip array antenna of the present invention when the zeta is 0°.

[0037] Figure 12 This is a simulated elevation angle versus gain relationship diagram for the microstrip array antenna of this invention when zeta is 0°.

[0038] Figure 13 This is a simulated 3D stereo radiation pattern of the microstrip array antenna of the present invention when the zeta is 30°.

[0039] Figure 14 This is a simulated elevation angle versus gain relationship diagram for the microstrip array antenna of this invention when the zeta is 30°.

[0040] Figure 15 This is a simulated 3D stereo radiation pattern of the microstrip array antenna of the present invention when the zeta is 60°.

[0041] Figure 16 This is a simulated elevation angle versus gain relationship diagram for the microstrip array antenna of this invention when the zeta is 60°.

[0042] Figure 17 This is a simulated 3D stereo radiation pattern of the microstrip array antenna of the present invention when the zeta is 90°.

[0043] Figure 18 This is a simulated elevation angle versus gain relationship diagram for the microstrip array antenna of this invention when the zeta is 90°.

[0044] Figure 19 This is a simulated 3D stereoscopic radiation pattern of the microstrip array antenna of the present invention when the zeta is 120°.

[0045] Figure 20 This is a simulated elevation angle versus gain relationship diagram for the microstrip array antenna of this invention when the zeta is 120°.

[0046] Figure 21 This is a simulated 3D stereo radiation pattern of the microstrip array antenna of the present invention when the zeta is 150°.

[0047] Figure 22 This is a simulated elevation angle versus gain relationship diagram for the microstrip array antenna of this invention when the zeta is 150°.

[0048] Figure 23 This is a simulated 3D stereo radiation pattern of the microstrip array antenna of the present invention when the zeta is 180°.

[0049] Figure 24 This is a simulated elevation angle versus gain relationship diagram for the microstrip array antenna of this invention when the zeta is 180°.

[0050] Explanation of reference numerals in the attached figures: 1. Radiation layer; 11. First dielectric substrate; 111. Ground plane; 112. Upper dielectric substrate; 113. Lower dielectric substrate; 114. First via; 12. Microstrip patch antenna element; 121. First square frame; 122. First notch; 123. Second square frame; 124. Second notch; 125. Strip; 13. Feed network; 2. Phase gradient metasurface layer; 21. Second dielectric substrate; 22. Metal structure unit; 221. Upper patch; 201. Cross strip; 202. Ring strip; 222. Lower patch; 223. Metallized via; 3. Driving device. Detailed Implementation

[0051] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions of the embodiments are for the purpose of helping to understand the present invention, but do not constitute a limitation thereof.

[0052] Figure 2-10 A microstrip array antenna of the present invention is shown. For example... Figure 2 and Figure 3 As shown, the microstrip array antenna includes a radiating layer 1, a phase gradient metasurface layer 2, and a driving device 3. The radiating layer 1 includes a first dielectric substrate 11, a plurality of microstrip patch antenna elements 12 arranged in a rectangular array on the first dielectric substrate 11, and a feed network 13 arranged on the first dielectric substrate 11. The electromagnetic waves emitted by the microstrip patch antenna elements 12 in each column have the same phase, and the electromagnetic waves emitted by the microstrip patch antenna elements 12 in each row have different phases, forming a phase gradient along the arrangement direction. The phase gradient metasurface layer 2 includes a second dielectric substrate 21 parallel to and facing the top of the first dielectric substrate 11. Metal structural elements 22 are arranged in a rectangular array on the second dielectric substrate 21. The metal structural elements 22 in each column have the same phase shift, and the metal structural elements 22 in each row have different phase shifts, forming the same phase gradient as the microstrip patch antenna elements 12 along the arrangement direction. The driving device 3 is used to drive the radiating layer 1 and the phase gradient metasurface layer 2 to rotate around the same axis, so that the microstrip array antenna can perform continuous two-dimensional beam scanning.

[0053] Optionally, the microstrip patch antenna unit 12 is arranged in a rectangular array on the top surface of the first dielectric substrate 11.

[0054] To form a phase gradient metasurface with radiation function on the first dielectric substrate 11, the following three methods can be used, including but not limited to: ① The microstrip array antenna is formed by arranging the phase-shifted feed signals of the feed network 13. The microstrip patch antenna elements 12 have the same structural dimensions and orientation on the first dielectric substrate 11; the phase of the feed network 13 signals received by the microstrip patch antenna elements 12 in each row is the same, and the phase of the feed network 13 signals received by the microstrip patch antenna elements 12 in each row varies with a gradient along the arrangement direction. The structural dimensions of the microstrip patch antenna elements 12 refer to their shape and size.

[0055] Optionally, the phase of the microstrip patch antenna elements can be arranged using passive phase shifters. Passive phase shifters are inserted into the feed network 13 of the microstrip array antenna, making the feed network a phase gradient feed network 13. The radiating layer 1 of this microstrip array antenna also becomes a phase gradient radiating layer 1. Taking a 64-element microstrip array antenna as an example, in the feed network 13, a 1-to-4 power divider is used to split the signal into four equal-amplitude, in-phase signals. Then, passive phase shifters of 90 degrees, 180 degrees, or 270 degrees are inserted into three of these split signals, respectively. No passive phase shifter is inserted into the fourth split signal. Each split signal is then further divided into 16 equal-amplitude, in-phase signals. The elements are arranged according to a pattern: the antenna elements in each column have the same phase, and the phase of the antenna elements in each row varies gradient along the arrangement direction, thus forming phase gradients of 0 degrees, 90 degrees, 180 degrees, and 270 degrees.

[0056] ② It is formed by arranging microstrip patch antenna elements 12 in different orientations. The microstrip patch antenna elements 12 have the same structural dimensions, and the orientation of the microstrip patch antenna elements 12 in each column on the first dielectric substrate 11 is the same. The orientation of the microstrip patch antenna elements 12 in each row on the top surface of the first dielectric substrate 11 varies gradually along the arrangement direction.

[0057] Optional, such as Figure 4 As shown, the microstrip patch antenna element 12 achieves azimuth change by rotating along an axis located at the center and perpendicular to the surface of the first dielectric substrate 11. By rotating the microstrip patch antenna element 12, the rotation angle of each column is the same, while the rotation angle of each row varies, giving the radiating layer 1 the ability to have a phase gradient. This makes it one of the two phase gradient metasurfaces in a typical planar Risleyprism, reducing one phase gradient metasurface, which not only reduces loss and improves antenna gain but also reduces antenna profile.

[0058] ③ It is formed by arranging the microstrip patch antenna elements 12 according to their size and shape. The microstrip patch antenna elements 12 are all oriented identically on the top surface of the first dielectric substrate 11, and the structural dimensions of the microstrip patch antenna elements 12 in each column are all identical. The structural dimensions of the microstrip patch antenna elements 12 in each row change continuously along the arrangement direction. Optionally, such as... Figure 7As shown, the phase gradient radiation layer 1 is composed of four microstrip patch antenna elements 12 with different shapes and structures.

[0059] Optionally, the phase difference of the metal structural units 22 in each row is a fixed value. The phase difference of the microstrip patch antenna units 12 in each row is also a fixed value. These can all be set to 90°.

[0060] Optional, such as Figure 4 As shown, the first dielectric substrate 11 is in the shape of a circular plate, with rectangular arrays arranged along the X and Y directions on the top surface, forming rows along the X direction and columns along the Y direction; the center of the top surface of the first dielectric substrate 11 coincides with the center of the microstrip patch antenna element 12 array.

[0061] Optional, such as Figure 8 As shown, the second dielectric substrate 21 is in the shape of a circular plate, with a rectangular array arranged along the X and Y directions on the top surface, forming a row along the X direction and a column along the Y direction; the center of the top surface of the second dielectric substrate 21 coincides with the center of the array of metal structural units 22.

[0062] Optionally, the first dielectric substrate 11 and the second dielectric substrate 21 have the same radius, the number of microstrip patch antenna elements 12 and metal structure elements 22 are the same, and the spacing of each row and column of the rectangular array is the same, so that by rotating the first dielectric substrate 11 and the second dielectric substrate 21, the center of each antenna element 12 can be vertically aligned with the center of a metal structure element 22 at the same time.

[0063] In addition, the structural dimensions and orientation of each metal structural unit 22 on the top surface of the second dielectric substrate 21 are the same.

[0064] Optional, such as Figure 6 As shown, the microstrip patch antenna unit 12 includes a first square frame 121, and each side strip of the first square frame 121 has a first notch 122 of the same width at its midpoint. A second square frame 123 is concentrically arranged inside the first square frame 121 with its four sides parallel to each other. A second notch 124 is provided at each of the two opposite corners of the second square frame 123. The second notch 124 is in the shape of an isosceles right triangle, and its two sides are located on the outer sides of the two side strips of the second square frame 123. A bar 125 is provided inside the second square frame 123. The bar 125 extends from the midpoint of the inner side of one side strip of the second square frame 123 to the center of the second square frame 123.

[0065] The four side strips of the second square frame 123 are arranged parallel to one side strip of the first square frame 121, respectively.

[0066] Optional, such as Figure 3 and Figure 5As shown, a ground plane 111 is provided in the middle of the first dielectric substrate 11, dividing the first dielectric substrate 11 into two layers: an upper dielectric substrate 112 and a lower dielectric substrate 113. A feed network 13 is provided on the bottom surface of the lower dielectric substrate 113. A first via 114 is provided at each microstrip patch antenna element 12 on the first dielectric substrate 11. The first via 114 is filled with conductive material to connect the feed network 13 to the corresponding microstrip patch antenna element 12. The microstrip patch antenna element 12 is printed on the surface of the upper dielectric substrate 112. Alternatively, the microstrip patch antenna element 12 can also be fed through coupling slots.

[0067] The feed network 13 can be powered using a rotatable SMA connector to excite the antenna. The feed point is at the center of the first dielectric substrate 11. The signal is divided into multiple equal parts by the feed network 13. The first via 114 is a cylindrical through-hole with its axis perpendicular to the surface of the first dielectric substrate 11. The through-hole is filled with a metal material such as tin to regulate the propagation characteristics of electromagnetic waves and accurately transmit these signals to each microstrip patch antenna element 12.

[0068] Optional, such as Figure 3 and Figure 10 As shown, the metal structure unit 22 includes an upper patch 221 disposed on the upper surface of the second dielectric substrate 21, a lower patch 222 disposed on the lower surface of the second dielectric substrate 21 corresponding to the upper patch 221, and a metallized via 223 that connects the upper patch 221 and the lower patch 222, the metallized via 223 penetrating the second dielectric substrate 21. The upper patch 221 and the lower patch 222 are respectively printed facing each other on the upper and lower surfaces of the second dielectric substrate 21.

[0069] Optional, such as Figure 9 As shown, the upper patch 221 and the lower patch 222 have the same structural dimensions and are positioned opposite each other. The upper patch 221 includes a cross bar 201. Each of the four regions divided by the cross bar 201 has an annular bar 202. The structural dimensions of the cross bar 201 in each row of metal structural units 22 change continuously along the arrangement direction. A connection point is provided at an equal distance from the center on each of the four sides of the cross bar 201. The connection points are connected to the corresponding connection points on the lower metal patch through metallized vias 223.

[0070] Each metal structural unit 22 has an upper patch 221 or a lower patch 222 consisting of a cross bar 201 and four annular bars 202. Metallized vias 223 are located on the four branches of the cross bar 201, equidistant from the center. The phase shift of the metal structural unit 22 is adjusted by changing the length of the branches of the cross bar 201. Optionally, the metallized vias 223 have a structure similar to the first via 114, consisting of through-holes filled with conductive material.

[0071] The driving device 3 includes a rotating shaft that supports the radiating layer 1 and the phase gradient metasurface layer 2. The axis of the rotating shaft passes through the center of the respective arrays of the microstrip patch antenna unit 12 and the metal structure unit 22, and is perpendicular to the upper surface of the supporting radiating layer 1 and the phase gradient metasurface layer 2. It also includes two sets of motors and linear gear structures, which drive the rotation from the side edges of the first dielectric substrate 11 and the second dielectric substrate 21, respectively.

[0072] The purpose of two-dimensional beam control is to enable the beam to be pointed at any specified azimuth and elevation angle. In use, firstly, the rotating radiating layer 1 and the phase gradient metasurface layer 2 are controlled separately, so that the gradient directions (X-axis direction) of both are aligned with the target azimuth direction of the beam, thus achieving azimuth control. Then, the radiating layer 1 and the phase gradient metasurface layer 2 are controlled to rotate simultaneously in opposite directions at the same speed. This keeps the center of the angle between their gradient directions (X-axis direction) in the target azimuth direction, ensuring that the azimuth of the beam remains constant while the elevation angle of the beam continuously changes to reach the target elevation angle, achieving continuous two-dimensional beam control.

[0073] A wedge prism is composed of a medium with a wedge-shaped thickness. When electromagnetic waves pass through a wedge prism, the thicker areas of the prism experience a greater delay, resulting in a larger phase shift, while the thinner areas experience a smaller delay and also a smaller phase shift. This causes the electromagnetic wave to be deflected in the direction of the larger phase shift. Risley-prism, based on this principle, consists of a pair of wedge prisms. By rotating each wedge prism around its axis, the combined thickness of the prisms is changed, thus controlling the direction of propagation of the transmitted electromagnetic wave beam.

[0074] As described above, controlling the beam propagation direction is essentially controlling the phase of the beam as it travels along the corresponding path. Although a planar phase-gradient metasurface is planar, it still exhibits a phase gradient for transmitted electromagnetic waves, much like the thickness of a wedge prism medium. Planar Risley-prism uses a pair of planar phase-gradient metasurfaces instead of a pair of wedge prisms to achieve control over the beam propagation direction.

[0075] The following uses a specific design structure and Electronics Desktop 2023R1 (formerly HFSS) simulation software to simulate the designed antenna, thereby illustrating the correctness of the present invention.

[0076] like Figure 4As shown, eight rows and eight columns of microstrip patch antenna elements 12 are arranged in a rectangular array along the X and Y directions on the top surface of the first dielectric substrate 11. The outermost two rows and two columns each have six microstrip patch antenna elements 12. The microstrip patch antenna elements 12 are rotated 90 degrees sequentially along the x-axis to form a phase gradient arrangement of 0°, 90°, 180°, 270°, 0°, 90°, 180°, 270°, while the y-axis orientation remains unchanged, forming a phase gradient metasurface. Both the upper dielectric substrate 112 and the lower dielectric substrate 113 are made of Rogers RT5880 with a thickness of 1 mm.

[0077] like Figure 6 As shown, the dimensions of the microstrip patch antenna element 12 are: p=5mm, w=0.9mm, w1=3.5mm, w2=2.5mm, w3=1.7mm, w4=3mm, g=0.36mm, t=0.68mm.

[0078] like Figure 8 As shown, eight rows and eight columns of metal structural units 22 are arranged in a rectangular array along the X and Y directions on the top surface of the second dielectric substrate 21. The outermost two rows and two columns each have six metal structural units 22. By adjusting the length of the crossbars 201 in the metal structural units 22 along the x-axis, the phase shift of the array units in the x-axis direction is arranged according to a phase gradient of 0°, 90°, 180°, 270°, 0°, 90°, 180°, 270°, while remaining unchanged along the y-axis, forming a phase gradient metasurface. The second dielectric substrate 21 uses Rogers RT5880 with a thickness of 1.6 mm. The two bars of the crossbars 201 are arranged along the X and Y directions respectively, and the annular bars 202 are evenly distributed at the four corners of the crossbars 201.

[0079] like Figure 9 As shown, the dimensions of the metal structural unit 22 are as follows: the dimensions of the cross bar 201 are: p=5mm, w=0.3mm, L1=2.4 / 3.79 / 4.08 / 4.5mm corresponding to phase gradients of 0°, 90°, 180°, and 270° respectively, V=1.1mm, R=0.1mm; the dimensions of the ring bar 202 are: the distance between the center of the ring and the center of the cross is 1.2mm in both the X and Y directions, the ring width is the same as that of the cross bar 201, w=0.3mm; the inner radius is 0.8mm.

[0080] The array spacing of the microstrip patch antenna element 12 and the metal structure element 22, i.e. the distance between the centers of two adjacent elements, is p=5mm, so that the upper and lower elements can be completely aligned and overlapped during rotation.

[0081] According to the traditional Risley prisms principle, rotating two phase gradient metasurfaces so that their phase gradient directions coincide and the relative angle between them is 180° results in mutual compensation of the integrated phase gradients, leading to an azimuth angle of 90 degrees and an elevation angle of 0 degrees for the antenna beam. Rotating one of the phase gradient metasurfaces by an angle of zeta changes the relative angle between the two metasurfaces to 180° + zeta. The midpoint of this relative angle is the azimuth direction (180 + zeta) / 2. As zeta increases, the integrated phase gradient gradually increases, and the beam elevation angle gradually increases. When zeta = 180°, the integrated phase gradient reaches its maximum, and the beam elevation angle also reaches its maximum.

[0082] like Figure 11-24 The image shows the simulated radiation pattern of the antenna under different beam states at a frequency of 30 GHz. The values ​​of zeta are 0°, 30°, 60°, 90°, 120°, 150°, and 180°. It was observed that the azimuth angles of the radiation pattern are located at 90°, 105°, 120°, 135°, 150°, 165°, and 180°, respectively, while the elevation angle is controlled from 0° to 70° as the rotation angle increases. This demonstrates that the antenna designed in this invention has continuous two-dimensional beam control capability.

[0083] The 3D stereo radiation pattern shows the relationship between sky gain and azimuth and elevation angles; the darker the color, the higher the gain. Decimal numbers in the pattern represent gain (in dB), while other numbers represent angles.

[0084] The graph showing the relationship between elevation angle and gain has elevation angle on the horizontal axis (in degrees) and antenna gain on the vertical axis (in dB).

[0085] The above correspondence can be seen from the 3D stereo radiation pattern and the relationship between pitch angle and gain for each zeta value.

[0086] To address the aforementioned technical problems, the present invention provides a two-dimensional beam control method based on the microstrip array antenna, comprising the following steps: Step 1: Specify the target azimuth and elevation angles for the beam. Specify these angles according to actual needs; in the example above, the azimuth angle can be 0°-360°, and the elevation angle can be 0°-75°.

[0087] Step 2: Control the rotation of the radiating layer 1 and the phase gradient metasurface layer 2 respectively, so that the arrangement direction of the microstrip patch antenna elements 12 on the radiating layer 1 and the arrangement direction of the metal structure elements 22 on the phase gradient metasurface layer 2 are both aligned with the target azimuth direction and towards the target azimuth direction: the phase shift of each row of microstrip patch antenna elements 12 and the phase shift of the metal structure elements 22 are both increasing.

[0088] At this point, the beam's elevation angle is at its maximum. Note that the phase shift of each row of microstrip patch antenna elements 12 is increasing, meaning that along the arrangement direction, the phase shift of each element gradually increases within one phase shift cycle from 0° to 360°, and also gradually increases in subsequent phase shift cycles.

[0089] Step 3: Control the radiation layer 1 and the phase gradient metasurface layer 2 to rotate simultaneously in opposite directions at the same speed. This keeps the center direction of the angle between the phase shift increasing direction of each row of units in the target azimuth direction, that is, keeps the phase angle of the beam at the target azimuth angle, and makes the elevation angle continuously change, up to 0°, so that the beam can have the target elevation angle.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A microstrip array antenna, characterized in that, It includes a radiation layer (1), a phase gradient metasurface layer (2), and a driving device (3); The radiating layer (1) includes a first dielectric substrate (11), a plurality of microstrip patch antenna elements (12) arranged in a rectangular array on the first dielectric substrate (11), and a feed network (13) arranged on the first dielectric substrate (11); the electromagnetic waves emitted by the microstrip patch antenna elements (12) in each column have the same phase, and the electromagnetic waves emitted by the microstrip patch antenna elements (12) in each row have different phases and form a phase gradient along the arrangement direction; The phase gradient metasurface layer (2) includes a second dielectric substrate (21) parallel to and directly opposite the top of the first dielectric substrate (11). The second dielectric substrate (21) is provided with a rectangular array of metal structural units (22). The metal structural units (22) in each column have the same phase shift for transmitted electromagnetic waves, and the metal structural units (22) in each row have different phase shifts for transmitted electromagnetic waves, and form the same phase gradient as the microstrip patch antenna unit (12) along the arrangement direction. The driving device (3) is used to drive the radiation layer (1) and the phase gradient metasurface layer (2) to rotate around the same axis respectively, so that the microstrip array antenna can perform continuous two-dimensional beam scanning; The microstrip patch antenna unit (12) includes a first square frame (121), and each of the side strips of the first square frame (121) has a first notch (122) of the same width at the midpoint of each side strip; a second square frame (123) is arranged concentrically inside the first square frame (121) and with its four sides parallel to each other. A second notch (124) is provided at each of the two opposite corners of the second square frame (123). The second notch (124) is an isosceles right triangle, and its two sides are located on the outer sides of the two side strips of the second square frame (123); a strip (125) is provided inside the second square frame (123), and the strip (125) extends from the midpoint of the inner side of one side strip of the second square frame (123) to the center of the second square frame (123).

2. A microstrip array antenna according to claim 1, characterized in that, The microstrip patch antenna unit (12) has the same structural dimensions and orientation on the first dielectric substrate (11); the phase of the signal from the feed network (13) received by the microstrip patch antenna unit (12) in each column is the same, and the phase of the signal from the feed network (13) received by the microstrip patch antenna unit (12) in each row varies with gradient along the arrangement direction.

3. A microstrip array antenna according to claim 1, characterized in that, The microstrip patch antenna units (12) have the same structural dimensions. The orientation of the microstrip patch antenna units (12) in each column on the first dielectric substrate (11) is the same. The orientation of the microstrip patch antenna units (12) in each row on the first dielectric substrate (11) varies with gradient along the arrangement direction.

4. A microstrip array antenna according to claim 1, characterized in that, The microstrip patch antenna units (12) are all in the same orientation on the first dielectric substrate (11), and the structural dimensions of the microstrip patch antenna units (12) in each column are all the same. The structural dimensions of the microstrip patch antenna units (12) in each row change continuously along the arrangement direction.

5. A microstrip array antenna according to claim 1, characterized in that, The phase difference between adjacent metal structural units (22) in each row is a constant value.

6. A microstrip array antenna according to claim 1, characterized in that, The first dielectric substrate (11) is in the shape of a circular plate. The microstrip patch antenna units (12) are arranged in a rectangular array along the X and Y directions, forming a row along the X direction and a column along the Y direction. The center of the first dielectric substrate (11) coincides with the center of the array of microstrip patch antenna units (12).

7. A microstrip array antenna according to claim 1, characterized in that, The first dielectric substrate (11) has a ground plane (111) in the middle, which divides the first dielectric substrate (11) into two layers: an upper dielectric substrate (112) and a lower dielectric substrate (113). The feed network (13) is provided on the bottom surface of the lower dielectric substrate (113). The first dielectric substrate (11) has a first via (114) at each of the microstrip patch antenna units (12). The first via (114) is filled with conductive material to connect the feed network (13) with the corresponding microstrip patch antenna unit (12).

8. A microstrip array antenna according to claim 1, characterized in that, The metal structure unit (22) includes an upper patch (221) disposed on the upper surface of the second dielectric substrate (21), a lower patch (222) disposed on the lower surface of the second dielectric substrate (21) corresponding to the upper patch (221), and a metallized via (223) connecting the upper patch (221) and the lower patch (222), wherein the metallized via (223) penetrates the second dielectric substrate (21).

9. A two-dimensional beam control method based on the microstrip array antenna according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Specify the target azimuth and target elevation angles for the beam; Step 2: Control the rotation of the radiation layer (1) and the phase gradient metasurface layer (2) respectively, so that the arrangement direction of the microstrip patch antenna elements (12) on the radiation layer (1) and the arrangement direction of the metal structure elements (22) on the phase gradient metasurface layer (2) are both aligned with the direction of the target azimuth angle and towards the target azimuth angle direction: the phase shift of each row of microstrip patch antenna elements (12) and the phase shift of the metal structure elements (22) are both increasing; Step 3: Control the radiation layer (1) and the phase gradient metasurface layer (2) to rotate simultaneously in opposite directions at the same speed, so that the pitch angle changes continuously, thereby enabling the beam to have the target pitch angle.

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