Low-profile reconfigurable transmission array antenna and beam regulation and control method

Abstract

The invention relates to a low-profile reconfigurable transmission array antenna and a wave beam regulation and control method, and the low-profile reconfigurable transmission array antenna comprises a ridge gap waveguide feed source array, a reconfigurable transmission array loaded with a variable capacitance diode, and a logic voltage control module. The reconfigurable transmission array placed in a radiation near-field region of the feed source array is excited, and the distance between the space feed source and the reconfigurable transmission array is shortened to 1 / 4 of the focal length, so that the profile height of the reconfigurable transmission array antenna is effectively reduced. In the wave beam regulation and control process, the phase distribution of the reconfigurable transmission array is changed through the logic voltage module, and single-wave-beam + / -75-degree * + / -75-degree ultra-wide-angle two-dimensional scanning and multi-wave-beam simultaneous flexible and controllable wave beam number and wave beam direction can be realized respectively. The antenna has the advantages of low profile, low power consumption, wide beam scanning coverage, high beam regulation and control flexibility and the like, and has important application prospects in the fields of wireless communication, radar detection and the like.

Description

Technical Field

[0001] The present application relates to the field of phased array antennas, and in particular, to a low-profile reconfigurable transmission array antenna and a beam control method. Background Art

[0002] At present, the spectrum resources in the microwave band are being exhausted. The world is stepping up the development of spectrum resources in the millimeter wave and terahertz bands, and is committed to building a 6G integrated space-ground communication network. Phased array antennas, as the core equipment for acquiring electromagnetic information in integrated communication networks, are known as the "clairvoyance" and "wind-hearing" of communication systems. Reconfigurable transmission array antennas are composed of a planarized reconfigurable transmission array and a spatial feed placed behind it. They are one of the most popular types of phased array antennas in recent years. Unlike traditional phased arrays, each antenna unit must be connected to an RF channel composed of a power amplifier, phase shifter, and attenuator. The reconfigurable transmission array antenna combines the advantages of patch array planarization and electromagnetic lens spatial feeding. It only needs a single-channel large power amplifier to connect the feed antenna to illuminate the reconfigurable transmission array radiation panel, and rely on the spatial phase modulation capability of the reconfigurable transmission array itself to achieve the deflection control of the outgoing beam. Compared with traditional phased arrays, reconfigurable transmission array antennas greatly reduce the number of RF channels, simplify the system architecture, and save phased array costs and power consumption. In the millimeter wave and terahertz frequency bands where traditional phased arrays face technical bottlenecks and cost and power consumption constraints, reconfigurable transmission array antennas are a very promising phased array solution.

[0003] In recent years, reconfigurable transmission array antennas and their beam steering technology have been widely studied. Reconfigurable transmission array antennas are developing towards low profile, low cost and multi-polarization. Although some progress has been made, reconfigurable transmission arrays that have multiple performances at the same time, such as low profile, wide scanning coverage, and multi-beam independent steering, still face many problems.

[0004] First, in the early research of reconfigurable transmission arrays, a single horn antenna was mostly used as the feed source. In order to ensure that each transmission unit is fully illuminated, a single horn feed source is usually placed at the focus of the transmission array. The ratio of the focal length F to the diameter D of the transmission array, that is, F / D, is often set to 0.5 to 1.2. In addition, the height of the horn itself causes the profile of the entire reconfigurable transmission array antenna to be too high, which restricts its application in compact spaces. In recent years, there are two main technical means to achieve low-profile reconfigurable transmission arrays. One is the folded transmission array technology, which can shorten the profile of the reconfigurable transmission array based on horn feeding by one third through an additional polarization rotation surface; the other is the planar standard array feeding technology, which uses a half-wavelength spacing microstrip patch array or substrate integrated waveguide slot array instead of a horn feed source. Although the profile is reduced, the dielectric substrate and microstrip feeding network have large losses, which will sacrifice the beam gain of the reconfigurable transmission array.

[0005] Secondly, similar to traditional active phased arrays, existing reconfigurable transmission array antennas also face the problem of rapid roll-off of beam gain as the scanning angle increases, resulting in limited scanning angles and insufficient gain of large-angle pointing beams. In existing literature, the gain loss at a maximum beam pointing angle of 60° reaches 5 to 6 dB. In this case, in order to ensure that the gain at the maximum angle meets the communication or detection requirements, it is often necessary to increase the transmission power or use a larger aperture transmission array, which undoubtedly increases the antenna cost and power consumption.

[0006] Finally, in terms of realizing multi-beam control, the reconfigurable transmission array antenna mostly draws on the principle of lens bias feeding to form multiple fixed beams. It does not have the independent control characteristics of each beam, and is limited by the limited phase modulation capability of the reconfigurable transmission array itself, and the sidelobe level of the multi-beam is relatively high. Summary of the invention

[0007] In order to overcome at least one deficiency in the prior art, the present application provides a low-profile reconfigurable transmission array antenna and a beam steering method.

[0008] In a first aspect, a low-profile reconfigurable transmission array antenna is provided, comprising: a reconfigurable transmission array, a ridge gap waveguide feed array, a bracket, a logic voltage control module, and an electrical connector; the reconfigurable transmission array and the ridge gap waveguide feed array are arranged in an upper and lower spacing and fixedly connected by the bracket; the logic voltage control module is fixedly installed directly above the reconfigurable transmission array through the electrical connector.

[0009] In one embodiment, the reconfigurable transmission array includes a plurality of transmission units arranged in a two-dimensional periodic manner, and the transmission units are loaded with varactor diodes; the side length of the transmission unit is less than half the wavelength of the working center frequency of the reconfigurable transmission array; and the logic voltage control module provides a DC voltage to the transmission unit, so that the transmission unit has a 180° continuous phase modulation capability.

[0010] In one embodiment, the transmission unit includes an upper antenna structure layer, a first dielectric layer, an upper metal ground layer, a second dielectric layer, a DC bias circuit layer, a third dielectric layer, a lower metal ground layer, a fourth dielectric layer, and a lower antenna structure layer, which are stacked in sequence;

[0011] The upper antenna structure layer is laid on the upper surface of the first dielectric layer, the upper metal ground layer is laid on the upper surface of the second dielectric layer, the DC bias circuit layer and the lower metal ground layer are laid on the upper surface and lower surface of the third dielectric layer respectively, and the lower antenna structure layer is laid on the lower surface of the fourth dielectric layer;

[0012] The transmission unit also includes a feeding through hole, a grounding through hole and a buried through hole. The feeding through hole and the grounding through hole penetrate the upper antenna structure layer and the lower antenna structure layer, and the buried through hole penetrates the upper metal layer and the lower metal ground layer.

[0013] In one embodiment, the upper antenna structure layer includes two upper polygonal metal patches with concave and convex grooves and a first varactor diode; the two upper polygonal metal patches have the same structure, wherein the upper polygonal metal patch on the left is recorded as the upper left metal patch, and the upper polygonal metal patch on the right is recorded as the upper right metal patch; the upper left metal patch and the upper right metal patch are symmetrically laid on the upper surface of the first dielectric layer; the first varactor diode is welded at the exact center of the upper surface of the first dielectric layer, the cathode of the first varactor diode is connected to the upper left metal patch, and the anode of the first varactor diode is connected to the upper right metal patch.

[0014] In one embodiment, the lower antenna structure layer includes two lower polygonal metal patches with concave and convex grooves and a second varactor diode; the two lower polygonal metal patches have the same structure, wherein the lower polygonal metal patch on the left is recorded as the lower left metal patch, and the lower polygonal metal patch on the right is recorded as the lower right metal patch;

[0015] The lower left metal patch and the lower right metal patch are symmetrically laid on the upper surface of the fourth dielectric layer; the second varactor is welded at the exact center of the lower surface of the fourth dielectric layer, the cathode of the second varactor is connected to the lower left metal patch, and the anode of the second varactor is connected to the lower right metal patch.

[0016] In one embodiment, the DC bias circuit layer is an L-shaped DC wire, the first branch of the L-shaped DC wire is a straight line parallel to the edge of the third medium, and is arranged directly below the outer edge of the upper left metal patch, and the end of the first branch is connected to the logic voltage control module; the end of the second branch of the L-shaped DC wire is connected to the first branch, and the other end of the second branch contacts the pad of the feeding through hole, and is connected to the cathode of the first varactor diode of the upper antenna structure layer and the cathode of the second varactor diode of the lower antenna structure layer through the feeding through hole;

[0017] The anode of the first variable capacitance diode of the upper antenna structure layer is connected to the upper metal layer through a grounding through hole, and the anode of the second variable capacitance diode of the lower antenna structure layer is connected to the lower metal layer through a grounding through hole.

[0018] In one embodiment, the buried via is located at the center of the transmission unit, the inner wall of the buried via is metallized, and the center is filled with air or dielectric; the buried via, the upper metal layer and the lower metal layer together form an "I"-shaped metal isolation cavity, so that the transmitted electromagnetic wave is transmitted along the upper antenna structure layer and the buried via to the lower antenna structure layer.

[0019] In one embodiment, a ridge gap waveguide feed source array includes a metal base plate and a metal cover plate, which are placed vertically opposite to each other with air gaps. A ridge gap waveguide power division network is engraved on the metal base plate, and a standard waveguide transition structure is provided. Four rectangular radiation slots are provided on the metal cover plate.

[0020] The ridge gap waveguide power division network includes a plurality of periodically arranged metal pins, a primary T-shaped metal ridge and two secondary T-shaped metal ridges, wherein the two secondary T-shaped metal ridges have four branches, and a metal block is arranged at the end of each branch;

[0021] After the RF signal is input from the standard waveguide transition structure, it is divided into four paths along the ridge gap waveguide power division network and transmitted to four metal blocks with equal amplitude and phase, and then radiated from four rectangular radiation gaps through the coupling effect.

[0022] In one embodiment, a distance between two adjacent rectangular radiation slots among the four rectangular radiation slots is greater than a half wavelength of an operating center frequency of the reconfigurable transmission array.

[0023] In one embodiment, the vertical distance between the reconfigurable transmission array and the ridge gap waveguide feed array is H, the focal length of the reconfigurable transmission array is F, and the ratio of H to F does not exceed 1 / 3.

[0024] In one embodiment, the central area of ​​the logic voltage control module is a windowed hollow area, and the area of ​​the windowed hollow area is the area occupied by all transmission units in the reconfigurable transmission array.

[0025] In a second aspect, a beam steering method is provided, the method being based on the above-mentioned low-profile reconfigurable transmission array antenna, comprising:

[0026] Set the beam steering mode of the low-profile reconfigurable transmission array antenna, including the number of beams and beam direction;

[0027] Calculate the target phase state of each transmission element of the low-profile reconfigurable transmission array antenna under the set beam steering mode;

[0028] The target phase state of each transmission unit is transmitted to the logic voltage control module, and the logic voltage control module controls each transmission unit to be in the target phase state, so that the outgoing beam of the low-profile reconfigurable transmission array antenna reaches the set beam control mode.

[0029] In one embodiment, the target phase state of each transmission unit of the low-profile reconfigurable transmission array antenna in the set beam steering mode is calculated using the following formula:

[0030]

[0031] in, is the target phase state of the transmission unit in the mth row and nth column under Q different beams, is the continuous target phase state of the transmission unit in the mth row and nth column under Q different beams, q is the beam index, Q is the number of beams, is the continuous target phase state of the qth beam corresponding to the transmission unit in the mth row and nth column; k0 is the free space wave number, θ0 and denote the elevation angle and azimuth angle of the qth beam, respectively, (x m ,y n ) is the coordinate position of the transmission unit at the mth row and nth column, is the phase distribution generated by the transmission unit in the mth row and nth column of the feed array, i is an integer greater than or equal to 0, δ1 and δ2 are two phase control factors, and their values ​​are random numbers between 0 and 2π.

[0032] Compared with the prior art, this application has the following beneficial effects:

[0033] 1. This application integrates the design of the feed array and the reconfigurable transmission array, as well as the logic voltage control module with a hollow center. Compared with the existing transmission array that uses a single horn feed and the logic voltage control module and the transmission array are connected by wiring, this application uses a planar feed array to feed the reconfigurable transmission array at a close distance, effectively reducing the height of the feed source and shortening the distance between the feed source and the reconfigurable transmission array to 1 / 4 of the focal length. In addition, the logic voltage control module and the reconfigurable transmission array adopt a cable-free plug-in connection, which further reduces the spatial volume of the antenna system, which is conducive to the realization of a highly integrated, low-profile reconfigurable transmission array antenna.

[0034] 2. This application uses a pure metal ridge gap waveguide power division network, which has lower loss than the existing dielectric substrate microstrip power division network. In addition, the radiation gap spacing of the ridge gap waveguide feed array is greater than half a wavelength. Compared with the standard array with half a wavelength spacing, it can generate an incident field distribution of aspherical waves on the surface of the reconfigurable transmission array. Compared with the traditional phased array, it helps to expand the scanning angle of the phased array and improve the rapid roll-off of the beam gain during the scanning process.

[0035] 3. This application effectively solves the problems of large-angle beam pattern distortion and large gain loss in existing phased arrays, and achieves ultra-wide angle coverage of ±75°×±75° with single-beam two-dimensional scanning, and the gain loss does not exceed 3dB in the entire coverage range. Compared with most existing phased arrays that can only cover a scanning range of ±60°×±60° and a gain loss of more than 5dB, the beam control technical indicators of this application have obvious advantages.

[0036] 4. This application is based on the phase complex superposition method to achieve flexible and controllable simultaneous multi-beam number and beam direction, and introduces an additional dual phase control factor to further reduce the sidelobe level of the multi-beam and improve the isolation between beams. Compared with the existing fixed multi-beam technology, this application helps to use fewer flexible beams to achieve wide-area anti-interference communication coverage. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present application may be better understood by referring to the following description given in conjunction with the accompanying drawings, which together with the following detailed description are included in this specification and form a part of this specification. In the drawings:

[0038] Figure 1 An overall schematic block diagram of a low-profile reconfigurable transmission array antenna is shown;

[0039] Figure 2 shows a schematic structural diagram of a transmission unit;

[0040] Figure 3 The cross-sectional structure of the transmission unit and the schematic diagram of electromagnetic wave transmission are shown;

[0041] Figure 4 A schematic diagram showing key dimension parameters of the upper antenna structure layer is shown;

[0042] Figure 5 The transmission amplitude and transmission phase modulation result diagram of the transmission unit are shown;

[0043] Figure 6 A schematic diagram of the structure of a ridge gap waveguide feed array is shown;

[0044] Figure 7 A schematic diagram showing key dimension parameters of a ridge gap waveguide transmission line is shown;

[0045] Figure 8 A schematic diagram showing key dimension parameters of a T-type waveguide power splitter network in a ridge gap waveguide feed array is shown;

[0046] Fig. 9 A schematic diagram showing the key size parameters of the power splitter network end and the radiation slot in the ridge gap waveguide feed array is shown;

[0047] Fig.10 A schematic diagram showing the simulation and measured reflection coefficient results of a ridge gap waveguide feed array is shown;

[0048] Fig.11 A schematic diagram showing the single beam scanning results of the low-profile reconfigurable transmission array antenna is shown;

[0049] Fig.12 A schematic diagram of the multi-beam control results of the low-profile reconfigurable transmission array antenna is shown;

[0050] Fig.13 The comparison results of the multi-beam radiation patterns before and after the phase control factor is introduced into the low-profile reconfigurable transmission array antenna and the comparison results of the target phase state are shown.

[0051] Reference numerals:

[0052] 1—reconfigurable transmission array, 2—ridge gap waveguide feed array, 3—bracket, 4—logic voltage control module, 5—electrical connector, 6—upper polygonal metal patch, 7—first dielectric layer, 8—first varactor diode, 9—upper metal ground layer, 10—second dielectric layer, 11—DC bias line layer, 12—third dielectric layer, 13—lower metal ground layer, 14—fourth dielectric layer, 15—lower polygonal metal patch, 16—second varactor diode, 17—feeding via, 18—ground via, 19—buried via, 20—metal cover, 21—rectangular radiation slot, 22—metal bottom plate, 23—standard waveguide transition structure, 24—metal pin, 25—primary T-shaped metal ridge, 26—secondary T-shaped metal ridge, 27—screw interface, 28—metal block. DETAILED DESCRIPTION

[0053] The exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual embodiments are described in the specification. However, it should be understood that many implementation-specific decisions can be made in the process of developing any such actual embodiments in order to achieve the specific goals of the developer, and these decisions may vary from embodiment to embodiment.

[0054] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure closely related to the scheme according to the present application is shown in the drawings, while other details that are not closely related to the present application are omitted.

[0055] It should be understood that the present application is not limited to the described implementation forms due to the following description with reference to the accompanying drawings. In this article, where feasible, the embodiments can be combined with each other, features between different embodiments can be replaced or borrowed, and one or more features can be omitted in one embodiment.

[0056] One of the core ideas of this application is to use a planar ridge gap waveguide feed array to feed a reconfigurable transmission array with continuous 180° phase modulation capability in a short-range distributed manner, which effectively reduces the profile of the reconfigurable transmission array antenna. The pure metal ridge gap waveguide power division network also helps to reduce the loss of the feed array. After optimizing the design of the ridge gap waveguide feed array and the reconfigurable transmission array unit, combined with the beam control optimization theory, the two-dimensional scanning range of the reconfigurable transmission array antenna beam is expanded to 150°×150°, realizing simultaneous multi-beam with adjustable sidelobe levels.

[0057] Figure 1 The overall schematic block diagram of the low-profile reconfigurable transmission array antenna is shown in FIG. Figure 1A low-profile reconfigurable transmission array antenna comprises: a reconfigurable transmission array 1, a ridge gap waveguide feed array 2, a bracket 3, a logic voltage control module 4, and an electrical connector 5; the reconfigurable transmission array 1 and the ridge gap waveguide feed array 2 are arranged in an upper and lower interval and fixedly connected by the bracket 3; the logic voltage control module 4 is fixedly installed directly above the reconfigurable transmission array 1 through the electrical connector 5.

[0058] Specifically, the vertical distance between the reconfigurable transmission array 1 and the ridge gap waveguide feed array 2 is H, the focal length of the reconfigurable transmission array 1 is F, and the ratio of H to F does not exceed 1 / 3.

[0059] Specifically, the bracket 3 can be made of resin material.

[0060] The above embodiment integrates the design of the feed array and the reconfigurable transmission array, as well as the logic voltage control module with a hollow center. Compared with the existing transmission array that uses a single horn feed and the logic voltage control module and the transmission array are connected by a cable, the present application uses a planar feed array to feed the reconfigurable transmission array at a close distance, effectively reducing the height of the feed source and shortening the distance between the feed source and the reconfigurable transmission array to 1 / 4 of the focal length. In addition, the logic voltage control module and the reconfigurable transmission array adopt a cable-free plug-in connection, which further reduces the spatial volume of the antenna system, which is conducive to the realization of a highly integrated, low-profile reconfigurable transmission array antenna.

[0061] In one embodiment, the reconfigurable transmission array 1 includes a plurality of transmission units arranged in a two-dimensional periodic manner, and the transmission units are loaded with varactor diodes; the side length of the transmission unit is less than half the wavelength of the working center frequency of the reconfigurable transmission array 1; the logic voltage control module 4 provides a DC voltage to the transmission unit, so that the transmission unit has a 180° continuous phase modulation capability.

[0062] Figure 2 FIG. 4 shows a schematic diagram of the structure of the transmission unit, see Figure 2 The transmission unit includes an upper antenna structure layer, a first dielectric layer 7, an upper metal ground layer 9, a second dielectric layer 10, a DC bias circuit layer 11, a third dielectric layer 12, a lower metal ground layer 13, a fourth dielectric layer 14, and a lower antenna structure layer, which are stacked in sequence;

[0063] The upper antenna structure layer is laid on the upper surface of the first dielectric layer 7, the upper metal ground layer 9 is laid on the upper surface of the second dielectric layer 10, the DC bias circuit layer 11 and the lower metal ground layer 13 are laid on the upper surface and lower surface of the third dielectric layer 12 respectively, and the lower antenna structure layer is laid on the lower surface of the fourth dielectric layer 14;

[0064] The transmission unit further includes a feeding through hole 17 , a grounding through hole 18 and a buried via 19 . The feeding through hole 17 and the grounding through hole 18 penetrate the upper antenna structure layer and the lower antenna structure layer, and the buried via 19 penetrates the upper metal layer 9 and the lower metal ground layer 13 .

[0065] In one embodiment, see Figure 2 The upper antenna structure layer includes two upper polygonal metal patches 6 with concave and convex grooves and a first varactor diode 8; the two upper polygonal metal patches 6 have the same structure, wherein the upper polygonal metal patch on the left is recorded as the upper left metal patch, and the upper polygonal metal patch on the right is recorded as the upper right metal patch; the upper left metal patch and the upper right metal patch are symmetrically laid on the upper surface of the first dielectric layer 7; the first varactor diode 8 is welded at the center of the upper surface of the first dielectric layer 7, the cathode of the first varactor diode 8 is connected to the upper left metal patch, and the anode of the first varactor diode 8 is connected to the upper right metal patch.

[0066] In one embodiment, see Figure 2 , the lower antenna structure layer includes two lower polygonal metal patches 15 with concave and convex grooves and a second varactor diode 16; the two lower polygonal metal patches 15 have the same structure, wherein the lower polygonal metal patch on the left is recorded as the lower left metal patch, and the lower polygonal metal patch on the right is recorded as the lower right metal patch;

[0067] The lower left metal patch and the lower right metal patch are symmetrically laid on the upper surface of the fourth dielectric layer 14; the second varactor diode 16 is welded at the center of the lower surface of the fourth dielectric layer 14, the cathode of the second varactor diode 16 is connected to the lower left metal patch, and the anode of the second varactor diode 16 is connected to the lower right metal patch.

[0068] In one embodiment, see Figure 2 , the DC bias circuit layer 11 is an L-shaped DC wire, the first branch of the L-shaped DC wire is a straight line parallel to the edge of the third medium 13, and is arranged just below the outer edge of the upper left metal patch, and the end of the first branch is connected to the logic voltage control module 4; the end of the second branch of the L-shaped DC wire is connected to the first branch, and the other end of the second branch is in contact with the pad of the feeding through hole 17, and is connected to the cathode of the first varactor diode 8 of the upper antenna structure layer and the cathode of the second varactor diode 16 of the lower antenna structure layer through the feeding through hole 17;

[0069] The anode of the first varactor diode 8 of the upper antenna structure layer is connected to the upper metal layer 9 through the grounding via 18 , and the anode of the second varactor diode 16 of the lower antenna structure layer is connected to the lower metal layer 13 through the grounding via 18 .

[0070] Figure 3 The cross-sectional structure of the transmission unit and the schematic diagram of electromagnetic wave transmission are shown in FIG. Figure 3The buried hole 19 is located at the center of the transmission unit. The inner wall of the buried hole 19 is metallized, and the center is filled with air or dielectric. The buried hole 19, the upper metal layer 9 and the lower metal layer 13 together form an "I"-shaped metal isolation cavity, so that the transmitted electromagnetic wave is transmitted along the upper antenna structure layer and the buried hole 19 to the lower antenna structure layer, and the RF electromagnetic wave energy will not be leaked to the DC bias line layer 11, so that the DC and the transmitted electromagnetic wave are effectively isolated. The advantage of this structural design is that due to the isolation of the electromagnetic wave and the DC layer, when the number of reconfigurable transmission array units increases, in order to increase the wiring space, only the number of DC layers needs to be increased, and the impact on the performance of the transmission unit can be ignored, which makes it easy to achieve large-scale aperture expansion.

[0071] The phase modulation principle of the transmission unit is: different DC bias voltages provided by the logic voltage module can change the junction capacitance of the two varactor diodes 8 and 16 at the same time, causing the change of the equivalent impedance of the transmission unit, thereby changing the transmission amplitude and phase of the electromagnetic wave transmitted by the unit. The goal of phase modulation is to have the transmission phase of the transmission unit have the ability to continuously change from 0° to 180° within the working frequency band within 3dB of the transmission amplitude loss.

[0072] In order to further illustrate the phase modulation principle of the transmission unit, an example is now provided. Figure 4 The schematic diagram of the key dimension parameters of the upper antenna structure layer is shown. The side length p of the transmission unit is selected to be 4.7mm. All dielectric layers are selected from the Taikangli high-frequency board TSM-DS3 substrate, where the thickness of the first dielectric layer 7 and the fourth dielectric layer 14 is 0.254mm, and the thickness of the first dielectric layer 7 and the fourth dielectric layer 14 is 0.127mm. The other key dimensions are l=3.72mm, l1=l2=l3=0.42mm, w=1.505mm, w1=0.71mm, w2=1.42mm, w3=0.71mm, d1=0.3mm, d2=0.51mm. The size of the varactor diode is 160um×60um, the equivalent resistance is 1Ω, and the junction capacitance varies from 30fF to 150fF. The transmission unit structure is fully simulated by the electromagnetic simulation software CST to obtain the changes in the transmission amplitude and transmission phase of the transmission unit. Figure 5 The transmission amplitude and transmission phase modulation result diagram of the transmission unit are shown, wherein (a) is the transmission amplitude result diagram of the transmission unit, and (b) is the transmission phase modulation result diagram of the transmission unit. Figure 5 It can be seen that when the junction capacitance of the varactor diode drops from 107fF to 31.5fF, the passband moves to the right, and the passband center frequency gradually increases from 25.5GHz to 31GHz. The maximum amplitude in the entire simulation frequency band is -0.98dB, minus 3dB, that is, when the amplitude loss in the passband does not exceed 4dB, Figure 5In the frequency range of 26.5-29.5 GHz where the shaded part of (b) is located, the transmission phase changes by 180°, indicating that by changing the DC voltage of the varactor diode, the transmission unit can achieve 180° phase modulation within 3 dB of passband amplitude loss. This result meets the expected phase modulation target.

[0073] Figure 6 shows a schematic diagram of the structure of the ridge gap waveguide feed array, see Figure 6 The ridge gap waveguide feed source array 2 includes a metal base plate 22 and a metal cover plate 20, which are placed vertically opposite to each other with air gaps, and are fixed by screw interfaces 27 at the edges; a ridge gap waveguide power division network is engraved on the metal base plate 22, and a standard waveguide transition structure 23 is provided, and four rectangular radiation slots 21 are provided on the metal cover plate 20;

[0074] The ridge gap waveguide power division network includes a plurality of periodically arranged metal pins 24, a primary T-shaped metal ridge 25 and two secondary T-shaped metal ridges 26, the two secondary T-shaped metal ridges 26 have four branches, and a metal block 28 is disposed at the end of each branch;

[0075] The metal cover plate 20 and the ridge gap waveguide power division network form an electromagnetic bandgap structure, so that after the RF signal is input from the standard waveguide transition structure 23, it is divided into four equal-amplitude and in-phase transmissions along the ridge gap waveguide power division network to four metal blocks 28, and then radiated from four rectangular radiation slots 21 through the coupling effect. Each rectangular radiation slot 21 represents a feed source, and the four rectangular radiation slots 21 together constitute a feed source array.

[0076] In order to further explain the working principle of the ridge gap waveguide feed array and the structure of each part thereof, an example is now provided. According to the working principle of the electromagnetic bandgap structure, the electromagnetic wave is only transmitted along the ridge gap waveguide power division network of the ridge gap waveguide feed array.

[0077] Figure 7 A schematic diagram of the key dimensional parameters of the ridge gap waveguide transmission line is shown. The side length a=1.0mm and the height h=2.68mm of the metal pin 24 correspond to 1 / 4λ0 of 28GHz, where λ0 is the free space wavelength of 28GHz. The periodic distribution spacing of the metal pins is 2.5mm, and the air gap g=0.1mm between the metal cover plate 20 and the pins 24. A metal ridge is added to the pin structure to form a ridge gap waveguide. In order to facilitate impedance matching with the standard waveguide transition structure 23, the impedance of the ridge waveguide is set to 110Ω in the 26.5-29.5GHz frequency band, and the slot width w is obtained after optimization. g =5.0mm, ridge width w r =2.0mm, ridge height h r =1.8mm.

[0078] by Figure 7 The ridge waveguide shown is the main waveguide, and a three-port "T" type power splitter network is designed. The model is established in the full-wave simulation software ANSYS EM Suite 2019. Figure 8 The schematic diagram of the key dimension parameters of the T-type waveguide power splitter network in the ridge gap waveguide feed array shows that the T-type power splitter network consists of a main waveguide with an impedance of 110Ω and a length of l m =2.0mm, width w m =1.8mm trapezoidal impedance change section transitions to two sub-waveguides with the same impedance of 110Ω, where slots are cut at the T-junction and the bend to achieve broadband matching. The width of the triangular slot cut at the T-junction is w q and depth l q The diameter of the groove at the bend is 2.0 mm and 0.42 mm respectively. e =0.3mm, and the values ​​of the spacings e1 and e2 between the metal pins around the slot are 0.42mm and 1.42mm respectively.

[0079] Will Figure 8 The designed T-type power division network is replicated and cascaded to form a 2×2 ridge gap waveguide power division network with the same structure of the first-level T-type metal ridge 25 and the second-level T-type metal ridge 26 as the core. Fig. 9 A schematic diagram of key size parameters of the power splitter network end and the radiation slot in the ridge gap waveguide feed array is shown. Metal blocks 28 are added to the four branch ends of the T-shaped metal ridge 26 to couple energy to the four rectangular radiation slots 21 of the metal cover 20, and then the energy is smoothly radiated from the ridge waveguide feed array.

[0080] Furthermore, a distance d between two adjacent rectangular radiation slots 21 among the four rectangular radiation slots 21 is greater than a half wavelength of the working center frequency of the reconfigurable transmission array.

[0081] This embodiment uses a pure metal ridge gap waveguide power division network, which has lower loss than the existing dielectric substrate microstrip power division network. In addition, the radiation gap spacing of the ridge gap waveguide feed array is greater than half a wavelength, which can generate an incident field distribution of aspheric waves on the surface of the reconfigurable transmission array compared to the standard array with half a wavelength spacing. Compared with the traditional phased array, it helps to expand the scanning angle of the phased array and improve the rapid roll-off of the beam gain during the scanning process.

[0082] Here, the theoretical calculation model of the reconfigurable transmission array antenna is established based on the preset vertical distance H between the reconfigurable transmission array and the ridge gap waveguide feed array. According to the transmission array beam scanning theory and optimization algorithm, the gain loss of a single beam in the theoretical model of the reconfigurable transmission array antenna is calculated when it scans to the maximum angle. The spacing d is continuously optimized with the minimum gain loss as the optimization goal to obtain the optimal value of d.

[0083] According to the optimal value of the distance d between two adjacent rectangular radiation slots calculated by the ideal model, the ridge gap waveguide feed array 2 is optimized. The core design is to adjust the number of metal pins in the ridge gap waveguide power division network and the length of the secondary "T"-shaped metal ridge, so that the center distance between two adjacent metal blocks at the ends of the four branches of the secondary "T"-shaped metal ridge is the optimal value of d, and then further optimize the length, width and height of the metal blocks and the rectangular radiation slots, so that the impedance matching bandwidth of the ridge gap waveguide feed array covers the working frequency band of the reconfigurable transmission array.

[0084] Furthermore, the central area of ​​the logic voltage control module 4 is a windowed hollow area, and the area of ​​the windowed hollow area is the area occupied by all the transmission units in the reconfigurable transmission array 1 .

[0085] Furthermore, the low-profile reconfigurable transmission array antenna can achieve single-beam and multi-beam independent control. Single-beam independent control means that there is only a single beam at the same time, and at different times, a single beam can achieve a two-dimensional beam scanning range of ±75°×±75° in the azimuth and elevation directions. Ultra-wide angle scanning coverage, and the beam gain loss does not exceed 3dB in the entire scanning range; multi-beam independent control means that multiple beams are formed at the same time, and the number of beams and the direction of each beam can be set independently, up to 4 beams can be formed at the same time, and the beam pointing can be arbitrarily specified between ±60°×±60°.

[0086] Based on the foregoing embodiments, the present application further provides a beam steering method, including:

[0087] Step 1: Set the beam control mode of the low-profile reconfigurable transmission array antenna, including the number of beams and the beam direction.

[0088] Here, the planar near field at a distance H in front of the ridge gap waveguide feed array 2 is obtained by full-wave simulation or actual testing, and is used as the incident field distribution of the reconfigurable transmission array 1, replacing the incident field distribution with the ideal point source as the feed source in the ideal model. Then, the beam control mode of the reconfigurable transmission array antenna is set, including the number of beams and the beam direction.

[0089] Step 2, calculating the target phase state of each transmission unit of the low-profile reconfigurable transmission array antenna in the set beam steering mode;

[0090] Here, it is assumed that the direction of the qth beam is Then the coordinate position of the mth row and nth column is (x m ,y n ) of the transmission unit of the continuous target phase state The calculation formula is as follows:

[0091]

[0092] If there are Q directional beams in total, the target phases required by each beam are superimposed to obtain the continuous target phase state under Q beams. It is expressed as follows:

[0093]

[0094] Since the transmission unit only has 180° continuous phase modulation capability, the above continuous target phase Quantize according to the following formula to obtain the actual quantized target phase state

[0095]

[0096]

[0097] in, is the target phase state of the transmission unit in the mth row and nth column under Q different beams, is the continuous target phase state of the transmission unit in the mth row and nth column under Q different beams, q is the beam index, Q is the number of beams, is the continuous target phase state of the qth beam corresponding to the transmission unit in the mth row and nth column; k0 is the free space wave number, θ0 and denote the elevation angle and azimuth angle of the qth beam, respectively, (x m ,y n ) is the coordinate position of the transmission unit at the mth row and nth column, is the phase distribution generated by the transmission unit in the mth row and nth column of the feed array, i is an integer greater than or equal to 0, δ1 and δ2 are two phase control factors, which are random numbers between 0 and 2π. The final values ​​are obtained through optimization and are used to optimize the sidelobe levels of single beam and multi-beam, respectively.

[0098] Step 3: transmit the target phase state of each transmission unit to the logic voltage control module, and the logic voltage control module controls each transmission unit to be in the target phase state, so that the outgoing beam of the low-profile reconfigurable transmission array antenna reaches the set beam control mode.

[0099] This embodiment is based on the phase complex superposition method to achieve flexible and controllable simultaneous multi-beam number and beam direction, and introduces an additional dual phase control factor to further reduce the sidelobe level of the multi-beam and improve the isolation between beams. Compared with the existing fixed multi-beam technology, this embodiment helps to use fewer flexible beams to achieve wide-area anti-interference communication coverage.

[0100] According to the design example of the reconfigurable transmission array and the implementation steps of the beam steering method described above, the effectiveness of the beam steering method is further demonstrated in detail below through the simulation experiment results of the embodiment of the present invention.

[0101] Assume that the central operating frequency of the antenna in the embodiment of the present application is 28 GHz, and the reconfigurable transmission array 1 includes 16×16 transmission units with a spacing p of 4.7 mm. Then the side length D of the reconfigurable transmission array 1 is 75.2 mm, corresponding to 7λ0 at 28 GHz. In addition, assume that the vertical distance H between the reconfigurable transmission array 1 and the ridge gap waveguide feed array 2 is one-fourth of the focal length F, that is, 18.8 mm, corresponding to 1.75λ0 at 28 GHz. Taking the gain loss of a single beam scanned to 75° not exceeding 3 dB as the optimization goal, the Monte Carlo algorithm is used to optimize the optimal distance d between the four gaps of the ridge gap waveguide feed array 2 to be 40.1 mm, corresponding to 3.74λ0 at 28 GHz. The length l of the end metal block 28 of the T-type power splitter network of the ridge gap waveguide feed array is then optimized. t 、Width t The width-to-length ratio w of the radiation slot 21 is 5.0 mm, 0.8 mm, and 2.68 mm, respectively. s / l s = 0.5, the best match. s and w s The results of the simulated and measured reflection coefficient s11 in the embodiment of the ridge gap waveguide feed array 2 are finally obtained. Fig.10 The simulation and measured reflection coefficient results of the ridge gap waveguide feed array are shown in Figure 2. 11 The results are in good agreement, S 11 The bandwidth below -10dB ranges from 26.23 to 29.91GHz, with a relative bandwidth of 10.3%, which completely covers the operating frequency band of the reconfigurable transmission array.

[0102] Fig.11 The schematic diagram of the single beam scanning result of the low-profile reconfigurable transmission array antenna shows that when a single beam is scanned from -75° to 75°, the maximum gain loss is 2.97 dB. Due to the symmetry of the antenna structure, ±75° beam scanning can also be achieved in another dimension. Therefore, the single beam scanning coverage of the low-profile reconfigurable transmission array antenna in the present invention is ±75°×±75°, and the maximum gain loss does not exceed 3 dB.

[0103] Fig.12A schematic diagram of the multi-beam control results of the low-profile reconfigurable transmission array antenna is shown, where the number of beams in (a) and (b) is 2 and points in different directions, the number of beams in (c) and (d) is 3 and points in different directions, and the number of beams in (e) and (f) is 4 and points in different directions, which fully demonstrates the effectiveness of the multi-beam independent control method based on the low-profile reconfigurable transmission array antenna in the present invention.

[0104] Take the case where there are two beams at the same time as an example. Fig.13 The comparison results of the multi-beam radiation pattern and the target phase state comparison results of the low-profile reconfigurable transmission array antenna before and after the phase control factor is introduced are shown, where (a) is the comparison result of the multi-beam radiation pattern before and after the phase control factor is introduced, (b) is the target phase state diagram before the phase control factor is introduced, and (c) is the target phase state diagram after the phase control factor is introduced. From (a), it can be seen that when the phase control factor is not introduced, the peak sidelobe level of the beam is -6.65dB, and after the phase control factor is introduced, the peak sidelobe level is reduced to -10.98dB. Before and after the phase control factor is introduced, the target phase state of some transmission units in the reconfigurable transmission array changes, proving the dual non-zero values ​​of δ1 and δ2. This embodiment fully demonstrates that the introduction of phase control factors δ1 and δ2 has a significant effect on reducing the multi-beam sidelobe level.

[0105] The above are only various implementations of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A low-profile reconfigurable transmission array antenna, characterized in that: include: A reconfigurable transmission array (1), a ridge gap waveguide feed array (2), a bracket (3), a logic voltage control module (4), and an electrical connector (5); the reconfigurable transmission array (1) and the ridge gap waveguide feed array (2) are arranged vertically and spaced apart, and are fixedly connected via the bracket (3); the logic voltage control module (4) is fixedly mounted directly above the reconfigurable transmission array (1) via the electrical connector (5).

2. The low-profile reconfigurable transmission array antenna according to claim 1, characterized in that: The reconfigurable transmission array (1) comprises a plurality of transmission units arranged in a two-dimensional periodic manner, wherein the transmission units are loaded with variable capacitance diodes; the side length of the transmission unit is less than half the wavelength of the working center frequency of the reconfigurable transmission array (1); and the logic voltage control module (4) provides a direct current voltage for the transmission unit, so that the transmission unit has a 180° continuous phase modulation capability.

3. The low-profile reconfigurable transmission array antenna according to claim 2, characterized in that: The transmission unit comprises an upper antenna structure layer, a first dielectric layer (7), an upper metal ground layer (9), a second dielectric layer (10), a DC bias circuit layer (11), a third dielectric layer (12), a lower metal ground layer (13), a fourth dielectric layer (14), and a lower antenna structure layer, which are stacked in sequence; The upper antenna structure layer is laid on the upper surface of the first dielectric layer (7), the upper metal ground layer (9) is laid on the upper surface of the second dielectric layer (10), the DC bias circuit layer (11) and the lower metal ground layer (13) are laid on the upper surface and lower surface of the third dielectric layer (12) respectively, and the lower antenna structure layer is laid on the lower surface of the fourth dielectric layer (14); The transmission unit further comprises a feeding through hole (17), a grounding through hole (18) and a buried hole (19); the feeding through hole (17) and the grounding through hole (18) penetrate the upper antenna structure layer and the lower antenna structure layer; and the buried hole (19) penetrates the upper metal ground layer (9) and the lower metal ground layer (13).

4. The low-profile reconfigurable transmission array antenna according to claim 3, characterized in that: The upper antenna structure layer comprises two upper polygonal metal patches (6) with concave and convex grooves and a first varactor (8); the two upper polygonal metal patches (6) have the same structure, wherein the upper polygonal metal patch on the left is recorded as the upper left metal patch, and the upper polygonal metal patch on the right is recorded as the upper right metal patch; the upper left metal patch and the upper right metal patch are symmetrically laid on the upper surface of the first dielectric layer (7); the first varactor (8) is welded at the exact center of the upper surface of the first dielectric layer (7), the cathode of the first varactor (8) is connected to the upper left metal patch, and the anode of the first varactor (8) is connected to the upper right metal patch.

5. The low-profile reconfigurable transmission array antenna according to claim 3, characterized in that: The lower antenna structure layer comprises two lower polygonal metal patches (15) with concave and convex grooves and a second variable capacitance diode (16); the two lower polygonal metal patches (15) have the same structure, wherein the lower polygonal metal patch on the left is recorded as the lower left metal patch, and the lower polygonal metal patch on the right is recorded as the lower right metal patch; The lower left metal patch and the lower right metal patch are symmetrically laid on the upper surface of the fourth dielectric layer (14); the second varactor diode (16) is welded at the exact center of the lower surface of the fourth dielectric layer (14), the cathode of the second varactor diode (16) is connected to the lower left metal patch, and the anode of the second varactor diode (16) is connected to the lower right metal patch.

6. The low-profile reconfigurable transmission array antenna according to claim 3, characterized in that: The DC bias circuit layer (11) is an L-shaped DC conductor, the first branch of the L-shaped DC conductor is a straight line parallel to the edge of the third medium (13), and is arranged directly below the outer edge of the upper left metal patch, and the end of the first branch is connected to the logic voltage control module (4); the end of the second branch of the L-shaped DC conductor is connected to the first branch, and the other end of the second branch contacts the pad of the feeding through hole (17), and is connected to the cathode of the first varactor diode (8) of the upper antenna structure layer and the cathode of the second varactor diode (16) of the lower antenna structure layer through the feeding through hole (17); The positive electrode of the first variable capacitance diode (8) of the upper antenna structure layer is connected to the upper metal layer (9) through the grounding through hole (18), and the positive electrode of the second variable capacitance diode (16) of the lower antenna structure layer is connected to the lower metal layer (13) through the grounding through hole (18).

7. The low-profile reconfigurable transmission array antenna according to claim 3, characterized in that: The buried hole (19) is located at the center of the transmission unit, the inner wall of the buried hole (19) is metallized, and the center is filled with air or dielectric; the buried hole (19), the upper metal layer (9) and the lower metal layer (13) together form an "I"-shaped metal isolation cavity, so that the transmitted electromagnetic wave is transmitted along the upper antenna structure layer and the buried hole (19) to the lower antenna structure layer.

8. The low-profile reconfigurable transmission array antenna according to claim 1, characterized in that: The ridge gap waveguide feed source array (2) comprises a metal base plate (22) and a metal cover plate (20), wherein the metal base plate (22) and the metal cover plate (20) are placed vertically opposite to each other and have air gaps; a ridge gap waveguide power division network is engraved on the metal base plate (22) and a standard waveguide transition structure (23) is provided; and four rectangular radiation slots (21) are provided on the metal cover plate (20); The ridge gap waveguide power division network comprises a plurality of periodically arranged metal pins (24), a primary T-shaped metal ridge (25) and two secondary T-shaped metal ridges (26), wherein the two secondary T-shaped metal ridges (26) have four branches, and a metal block (28) is disposed at the end of each branch; After the radio frequency signal is input from the standard waveguide transition structure (23), it is divided into four paths along the ridge gap waveguide power division network and transmitted to four metal blocks (28) with equal amplitude and phase, and then radiated from the four rectangular radiation slots (21) through the coupling effect.

9. The low-profile reconfigurable transmission array antenna according to claim 8, characterized in that: The distance between two adjacent rectangular radiation slots (21) of the four rectangular radiation slots (21) is greater than half the wavelength of the working center frequency of the reconfigurable transmission array (1).

10. The low-profile reconfigurable transmission array antenna according to claim 1, characterized in that: The vertical distance between the reconfigurable transmission array (1) and the ridge gap waveguide feed source array (2) is H, the focal length of the reconfigurable transmission array (1) is F, and the ratio of H to F does not exceed 1 / 3.

11. The low-profile reconfigurable transmission array antenna according to claim 1, characterized in that: The central area of ​​the logic voltage control module (4) is a windowed hollow area, and the area of ​​the windowed hollow area is the area occupied by all transmission units in the reconfigurable transmission array (1).

12. A beam steering method, the method being based on the low-profile reconfigurable transmission array antenna according to any one of claims 1 to 11, characterized in that: include: Set the beam steering mode of the low-profile reconfigurable transmission array antenna, including the number of beams and beam direction; Calculating a target phase state of each transmission unit of the low-profile reconfigurable transmission array antenna in a set beam steering mode; The target phase state of each transmission unit is transmitted to a logic voltage control module, and the logic voltage control module controls each transmission unit to be in a target phase state, so that the outgoing beam of the low-profile reconfigurable transmission array antenna reaches a set beam control mode.

13. The method according to claim 12, characterized in that in, The target phase state of each transmission unit of the low-profile reconfigurable transmission array antenna in the set beam steering mode is calculated using the following formula: in, is the target phase state of the transmission unit in the mth row and nth column under Q different beams, is the continuous target phase state of the transmission unit in the mth row and nth column under Q different beams, q is the beam index, Q is the number of beams, is the continuous target phase state of the qth beam corresponding to the transmission unit in the mth row and nth column; k0 is the free space wave number, θ0 and denote the elevation angle and azimuth angle of the qth beam, respectively, (x m ,y n ) is the coordinate position of the transmission unit at the mth row and nth column, is the phase distribution generated by the transmission unit in the mth row and nth column of the feed array, i is an integer greater than or equal to 0, δ1 and δ2 are two phase control factors, and their values ​​are random numbers between 0 and 2π.

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