N-bit holographic beamforming microstrip antenna unit, antenna and application thereof

Abstract

This invention discloses an N-bit holographic beamforming microstrip antenna element, antenna, and their applications, belonging to the field of wireless communication, where N≥1. The element comprises a first metal layer, a first dielectric substrate, a second metal layer, a second dielectric substrate, a control circuit layer, a third dielectric substrate, and a feed layer stacked sequentially. The first metal layer operates in a resonant state at the target carrier frequency band; the second metal layer serves as a metal ground layer; the control circuit layer is used to transmit control signals; the feed layer includes a bridge and 2 N microstrip lines; the bridge includes 2 N‑1 Each bridge output port is connected to two microstrip lines. The bridge is used to decompose the original feed signal into 2... N‑1 The signal is of constant amplitude; the length l of each microstrip line satisfies: θ and θ represent the signal phase at both ends of the microstrip line, respectively, and λ represents the effective wavelength. This invention can achieve arbitrary N-bit phase modulation, and is low in cost, easy to manufacture, and easy to deploy.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of wireless communication, and more particularly, relates to an N-bit holographic beamforming microstrip antenna unit, an antenna and application thereof. BACKGROUND

[0002] With the continuous growth of mobile users' demand for data, mobile networks have also experienced breakthroughs day by day. Compared with the fourth generation mobile communication technology (4G), the fifth generation mobile communication technology (5G) uses higher frequency electromagnetic waves to transmit information. After the frequency of electromagnetic waves is increased, the penetration ability is weakened, and the diffraction and scattering are not obvious. This leads to network coverage difficulties. One way to solve this problem is to use dynamically adjustable high directivity beams to increase the received signal strength. Currently, there are some technologies that can achieve real-time regulation of electromagnetic waves, such as mechanically rotating directional radiating antennas such as horn antennas, array antennas, or electrically controlled scanning active phased array antennas, i.e., connecting controllable active devices to each unit of the phased array antenna to control the outgoing phase of each unit to achieve electrically controlled scanning to regulate electromagnetic waves. However, the former has slow scanning speed and the mechanical needs regular maintenance, and the latter has a complex system, high cost and difficult maintenance.

[0003] In the long-term evolution of 4G, the cellular technology has reached the theoretical limit of time division multiplexing and frequency division multiplexing. In 5G, many schemes consider using software-driven high directivity antennas to divide the physical space, so that mobile phone users at different locations in the cellular network can share the same frequency at the same time, i.e., to realize multi-user spatial division multiplexing. Spatial division multiplexing relies on multiple-input-multiple-output (MIMO) technology, which transforms a single point-to-point channel into multiple parallel channels through the transmission and reception of multiple antennas at the transmitting end and the receiving end, and processes multiple base station antennas and terminal antennas to form a multiple parallel communication system. The spectral efficiency mainly depends on the number of parallel channels, thereby breaking through the limit of the Shannon theorem of point-to-point channels and improving the system capacity and spectral efficiency. However, ordinary MIMO requires complex and high-cost baseband units (BBUs) and a large number of expensive phase shifters, thus having the disadvantages of high cost and high power consumption.

[0004] It is expected that the communication network capacity will increase by a thousand times in the next decade, and ubiquitous wireless connectivity will become a reality, but highly complex networks, high-cost hardware and increasing energy consumption will become key challenges for future wireless communication.

[0005] Holographic Beam Forming (HBF) is a novel dynamic beamforming technology that uses software-defined antennas (SDAs) and employs a minimal C-SWaP (cost, size, weight, and power) architecture. It uses digital circuitry to control the electromagnetic wave phase of each antenna element, forming an ultra-dense array that directs wireless capacity to any location within the cellular coverage area where demand is needed. Figure 1 As shown. This technology is called holographic technology because the element density of the antenna array can far exceed that of ordinary MIMO antenna arrays, enabling miniaturization, easy deployment, low power consumption, and low cost. Holographic beamforming technology is a brand-new wireless communication technology that is expected to solve the technical pain points of high cost and high energy consumption in the post-5G era.

[0006] However, holographic beamforming technology is still in its early stages of research. Domestic research remains at the theoretical modeling level. While holographic beamforming products developed by PitovalCommware have been deployed in outdoor locations such as residential areas and airports, providing signal coverage and filling signal gaps indoors, these antennas are only suitable for millimeter-wave communication and not for domestic use. Furthermore, their internal structure is not publicly available, hindering further research. Additionally, these antennas have low gain (9–11 dBi) and high cost. Summary of the Invention

[0007] To address the shortcomings and improvement needs of existing technologies, this invention provides an N-bit holographic beamforming microstrip antenna unit, antenna, and its application, aiming to solve the problems of high cost and inflexible controllability of existing holographic beamforming antennas.

[0008] To achieve the above objectives, according to one aspect of the present invention, an N-bit holographic beamforming microstrip antenna element is provided, where N is a positive integer greater than or equal to 1. The N-bit holographic beamforming microstrip antenna element includes a first metal layer, a first dielectric substrate, a second metal layer, a second dielectric substrate, a control circuit layer, a third dielectric substrate, and a feed layer stacked sequentially from top to bottom.

[0009] The first metal layer operates in a resonant state at the target carrier frequency band, and is used to radiate effective electromagnetic waves outward.

[0010] The second metal layer serves as the metal substrate, and grooves are engraved on it;

[0011] The control circuit layer is used to transmit control signals;

[0012] The feed layer is used to decompose the original feed signal into 2 N Signals with equal amplitude but different phases are separated from their 2 N Each signal output port outputs;

[0013] The feed layer includes: a bridge and 2 N microstrip lines; the bridge includes 2 N-1 Each bridge output port is connected to two microstrip lines. The bridge is used to decompose the original feed signal into 2... N-1 Bundle equal amplitude signals; 2 N The end of the microstrip line not connected to the bridge forms the 2nd feed layer. N For each signal output port, the length l of each microstrip line satisfies:

[0014] Among them, the control signal is used to indicate the signal selected for output in the feed layer; θ and θ represent the signal phases output from the bridge output port and signal output port connected by the microstrip line, respectively, and λ represents the effective wavelength.

[0015] Furthermore, the 2nd feed layer N 2 signal output ports N In signals with equal amplitude but different phases, the phase difference between adjacent signals is .

[0016] Furthermore, the first metal layer is H-shaped.

[0017] Furthermore, the N-bit holographic beamforming microstrip antenna unit provided by the present invention further includes: 2 N Select one RF switch; 2 N Select one RF switch and 2 N All signal output ports are connected to each other, used to control signals from 2 N The signal output ports output 2 N Select the target phase signal from signals with equal amplitude but different phases.

[0018] Furthermore, the first metal layer, the first dielectric substrate, the second metal layer, the second dielectric substrate, the control circuit layer, the third dielectric substrate, and the power supply layer are all fabricated using printed circuit boards.

[0019] According to another aspect of the present invention, a holographic beamforming microstrip antenna is provided, comprising: a holographic MIMO array composed of the above-described N-bit holographic beamforming microstrip antenna elements provided by the present invention.

[0020] Furthermore, in the MIMO array, the thickness of the first dielectric substrate in the N-bit holographic beamforming microstrip antenna unit is 2% to 5% of the wavelength.

[0021] According to another aspect of the present invention, the application of the above-mentioned holographic beamforming microstrip antenna in a wireless communication system is provided, wherein the holographic beamforming microstrip antenna is used to realize beam-oriented transmission of a target carrier frequency band; the target carrier frequency band is a Sub-6G high-frequency band, a millimeter-wave band, a 6G band, or a WLAN band.

[0022] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0023] (1) The N-bit holographic beamforming microstrip antenna element provided by this invention has a feed layer constructed with bridges and microstrip lines to create paths of different lengths, leading out 2 N One port can decompose the original feed signal into 2 N Signals with equal amplitude but different phases are respectively from 2 N With multiple output ports, arbitrary N-bit phase modulation can be achieved. Specifically, the decomposition of the original signal by the feed layer can be divided into two stages. First, the original feed signal is decomposed into 2... N-1 A beam of equal amplitude signal is generated, and then these two signals are coupled together by a microstrip line of a specific length. N-1 The equal-amplitude beam signal is further decomposed into 2 N By feeding signals with different phases, the bridge structure is small in size, and the microstrip line allows for flexible phase control. Therefore, the feed layer can be miniaturized to the greatest extent possible while achieving phase control. Furthermore, the N-bit holographic beamforming microstrip antenna element provided by this invention has a simple stacked structure, similar to existing antenna element structures. It is low-cost, easy to manufacture, and can be applied to Sub-6G high-frequency bands, millimeter-wave bands, 6G bands, WLAN bands, and other frequency bands through parameter optimization. In summary, the N-bit holographic beamforming microstrip antenna element provided by this invention can achieve arbitrary N-bit phase control, and is low-cost, easy to manufacture, and easy to deploy.

[0024] (2) In the preferred embodiment of the N-bit holographic beamforming microstrip antenna unit provided by the present invention, the first metal layer is H-shaped, which is beneficial to optimizing the antenna radiation performance.

[0025] (3) The holographic beamforming microstrip antenna provided by the application, wherein the holographic MIMO array is composed of the N-bit holographic beamforming microstrip antenna unit provided by the application, and small size, easy deployment, low power consumption and low cost can be achieved. In the preferred scheme, the thickness of the first dielectric substrate of the unit in the array is relatively thick, specifically 2% to 5% of the wavelength length, so that the energy storage in the cavity is increased, the antenna Q value is reduced, and the bandwidth is effectively improved. Experiments show that the working bandwidth of the N-bit holographic beamforming microstrip antenna unit provided by the application is more than 200 MHz, which exceeds the bandwidth of a general microstrip antenna. At the same time, since the unit provided by the application is used to form the holographic MIMO array in the holographic beamforming antenna array, beamforming is realized through algorithm control, which can effectively alleviate the decrease of directivity gain caused by the increase of the thickness of the first dielectric substrate while improving the bandwidth. In a super-dense array, the number of units is large, and the decrease of the directivity gain can also be effectively compensated. Overall, the holographic beamforming microstrip antenna provided by the application has a large bandwidth while ensuring the directivity gain. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a schematic diagram of an existing holographic beamforming antenna system.

[0027] Figure 2 It is a schematic diagram of the holographic beamforming microstrip antenna unit provided by embodiment 1 of the application.

[0028] Figure 3 It is a schematic diagram of the laminated structure of the holographic beamforming microstrip antenna unit provided by embodiment 1 of the application.

[0029] Figure 4 It is a top view of the holographic beamforming microstrip antenna unit provided by embodiment 1 of the application.

[0030] Figure 5 It is a schematic diagram of the feeding layer of the holographic beamforming microstrip antenna unit provided by embodiment 1 of the application.

[0031] Figure 6 It is the S11 parameter of the feeding layer of the holographic beamforming microstrip antenna unit provided by embodiment 1 of the application.

[0032] Figure 7 It is a four-port phase diagram of the holographic beamforming microstrip antenna unit provided by embodiment 1 of the application.

[0033] Figure 8 It is the S11 parameter of the feeding layer of the holographic beamforming microstrip antenna unit provided by embodiment 2 of the application.

[0034] Figure 9The S11 parameter of the feed layer of the holographic beamforming microstrip antenna unit provided in Embodiment 3 of the present application;

[0035] In all the drawings, the same reference signs are used to denote the same elements or structures, wherein:

[0036] 1 - first metal layer, 2 - first dielectric substrate, 3 - second metal layer, 4 - second dielectric substrate, 5 - control circuit layer, 6 - third dielectric substrate, 7 - feed layer. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0038] In the present application, the terms "first", "second" and the like (if any) in the present application and the drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0039] In order to solve the problems of high cost and inability to flexibly control the existing holographic beamforming antenna, the present application provides an N-bit holographic beamforming microstrip antenna unit, an antenna and an application thereof, the overall idea of which is to improve the feed layer in the existing laminated microstrip antenna unit so that it can realize the regulation of any N-bit phase, and has the characteristics of miniaturization, low cost and easy processing. Through parameter optimization, it can be applied to Sub-6G high frequency band, millimeter wave frequency band, 6G frequency band, WLAN frequency band and other frequency bands. On this basis, further improvement is made to the structure of the radiation layer to improve the working bandwidth.

[0040] Considering that in the holographic beamforming antenna, when N-bit phase regulation is realized, the antenna unit needs to specifically output 2 N The ability to beam different phase information, the adjacent phase difference is generally And in the holographic beamforming antenna, two bits (i.e. N = 2) four-phase control is commonly used, and the adjacent phase difference is 90°. In the case of setting the original feed signal phase to 0°, an optional phase shift scheme is 0°, 90°, 180°, 270°, which can correspond to 00, 01, 10, 11 four-bit digital signals respectively. For ease of description, without loss of generality, in the following embodiments, the phase shift scheme is taken as an example for description.

[0041] The following is an embodiment.

[0042] Embodiment 1:

[0043] An N-bit holographic beamforming microstrip antenna unit, as shown in Figure 2 and Figure 3 , wherein N=2. As shown in Figure 2 and Figure 3 , in this embodiment, the N-bit holographic beamforming microstrip antenna unit comprises, from top to bottom, a first metal layer 1, a first dielectric substrate 2, a second metal layer 3, a second dielectric substrate 4, a control circuit layer 5, a third dielectric substrate 6, and a feed layer 7.

[0044] The N-bit holographic beamforming microstrip antenna unit provided in this embodiment is used to realize functions such as beam directional transmission in the Sub-6G frequency band (i.e., the 5G frequency band).

[0045] In this embodiment, the first metal layer 1 works in a resonant state of a target carrier frequency band, and is used to radiate effective electromagnetic waves outward; the first metal layer 1 is similar to the radiation patch of a common microstrip antenna. According to the equivalent circuit theory, the resonant frequency L represents the equivalent inductance, and C represents the equivalent capacitance; changing the shape and size of the first metal layer 1 will affect its equivalent capacitance and equivalent inductance, and thus affect the structure resonant frequency; therefore, the structure and size of the first metal layer 1 are designed accordingly, so that it can work in a resonant state of a specific carrier frequency band and radiate effective electromagnetic waves outward. Considering that the typical communication frequency in the Sub-6G frequency band is 2.6 GHz, in this embodiment, the metal layer 1 specifically works in a resonant state of 2.6 GHz.

[0046] As shown in Figure 2 and Figure 4 , in this embodiment, the first metal layer 1 is specifically in the form of H, which helps to optimize the antenna radiation performance and also helps to improve the performance such as bandwidth. Alternatively, in this embodiment, the H-shaped structure of the first metal layer 1 is formed by removing two square slots in the middle of the square structure, and some basic antenna sizes can be obtained by calculation using the knowledge of transmission line theory and antenna theory. Alternatively, as shown in Figure 4 , in this embodiment, the length of the first metal layer 1 is L=52.6 mm, the width is W=34.2 mm, the thickness is 35 μm, and the side length of the square slot removed in the middle is a=14 mm. This size is verified by using the parameter scanning function of the HFSS software on the basis of theoretical calculation, and can make the unit performance relatively excellent. It should be noted that the parameters here are only exemplary descriptions and should not be understood as the only limitation of the present application.

[0047] In the embodiment, the second metal layer 3 is a metal ground layer, and a groove is engraved on the second metal layer 3, so as to realize aperture coupling feed of the metal patch on the first metal layer 1 by the feed layer 7; and the thickness of the second metal layer 3 is 35 μm.

[0048] The feed layer 7 is used for decomposing the original feed signal into two N equal-amplitude and different-phase signals and outputting the two equal-amplitude and different-phase signals from two signal output ports, respectively. N The feed layer 7 comprises a bridge and two microstrip lines. N The bridge comprises two bridge output ports, and each bridge output port is connected with the two microstrip lines. N-1 The bridge is used for decomposing the original feed signal into two N-1 equal-amplitude signals, and the two equal-amplitude signals can include signals with the same phase. N-1 The two microstrip lines are connected with the two bridge output ports, respectively. N The two ends of the two microstrip lines not connected with the bridge constitute two signal output ports of the feed layer. N The length l of each microstrip line satisfies: wherein, and θ respectively represent the phase of the signal output from the bridge output port and the signal output port, and λ represents the effective wavelength.

[0049] The control circuit layer 5 is used for transmitting a control signal.

[0050] In the embodiment, the antenna unit is specifically used for decomposing the original feed signal into four equal-amplitude and different-phase signals, outputting the four equal-amplitude and different-phase signals from four signal output ports, respectively, and the phases of the four equal-amplitude and different-phase signals are 0°, 90°, 180° and 270°, respectively. In order to facilitate phase selection, the N-bit holographic beamforming microstrip antenna unit provided in the embodiment further comprises a four-to-one radio frequency switch chip, the four-to-one radio frequency switch chip is connected with the four signal output ports of the feed layer 7, and by changing the control signal of the switch, a signal with a specified target phase can be selected from the four signals and output, so as to realize two-bit phase control. Alternatively, in the embodiment, the four-to-one radio frequency switch chip is specifically a micro-electro-mechanical system switch (MEMS Switch), and in some other embodiments of the application, a field effect transistor switch, a PIN diode or the like can also be used.

[0051] In order to realize the above phase control scheme, as shown in Figure 5 In the embodiment, the bridge structure in the feed layer 7 is specifically a 3dB bridge, the 3dB bridge can divide one input signal into two equal-amplitude and 90°-phase-difference signals, and the two bridge output ports are respectively connected with the two microstrip lines. After the length of the microstrip line is set, the two signals split from the signal output from the same bridge output port have a half effective wavelength difference in the path from the bridge output port to the input port of the radio frequency switch, so that the two signals output from the same bridge output port have a phase difference of 180° after being output through the two microstrip lines connected thereto, thereby obtaining equal-amplitude signals with phases of 0°, 90°, 180° and 270°.

[0052] In this embodiment, the thickness of the feed layer 7 is specifically 35 μm.

[0053] It is easy to understand that the above 3dB bridge structure is only the preferred structure of the embodiment and should not be understood as the only limitation of the application. Other bridge structures that can split the original feed signal into two equal-amplitude signals, such as 180-degree bridge, ring bridge, lange bridge, etc., can also be used in the application. When the number of bits corresponding to the controllable phase changes, the structure of the bridge in the feed layer 7 and the number and length of the microstrip lines are adjusted accordingly. For example, when 3-bit phase control is implemented, the bridge structure in the feed layer 7 needs to split the original feed signal into four equal-amplitude signals. At this time, the bridge structure can be composed of three 3dB bridge structures connected in a tree shape, or other bridge structures can be used. The four equal-amplitude signals output by the bridge structure are output through eight microstrip lines, and the phase difference of the eight equal-amplitude signals is . In the case of a determined bridge structure, the phase of the signals at both ends of each microstrip line is known, and the length of each microstrip line can be determined according to .

[0054] The feed layer 7 of the embodiment is composed of a bridge and microstrip lines to form paths of different lengths, thereby achieving 2-bit phase control. Since the bridge structure is small in size and the microstrip line can achieve flexible phase control, the feed layer 7 can be miniaturized to the greatest extent while achieving phase control. In addition, the structure of the embodiment is a simple laminated structure similar to the existing antenna unit structure, which is low in cost and easy to process.

[0055] In this embodiment, the first dielectric substrate 2, the second dielectric substrate 4, and the third dielectric substrate 6 serve to isolate the propagating feed signal. Optionally, in this embodiment, the first dielectric substrate 2 is made of F4B material (a high-frequency substrate made of polytetrafluoroethylene-based materials), with a dielectric constant of 2.55, a dielectric loss tangent of 0.0015, and a thickness of 3 mm. Compared to the conventionally selected factory nominal value, the thickness is set to be thicker in this example, specifically 2.6% of the operating wavelength, which can achieve good bandwidth performance and antenna radiation performance. Since the unit provided in this embodiment will be used to form a holographic MIMO array in a holographic beamforming antenna array, the problem of reduced antenna directivity gain due to the increased thickness of the first dielectric substrate can be compensated by appropriately increasing the number of units in the antenna array and using an algorithm to adjust the phase of each unit to achieve beamforming. The second dielectric substrate 4 and the third dielectric substrate 6 are both made of FR-4 material, with a dielectric constant of 4.8, a dielectric loss tangent of 0.025, and a thickness of 0.5 mm.

[0056] Similarly, the material of the aforementioned dielectric substrate was determined through calculations based on transmission line theory and antenna theory, and verified using the parameter scanning function of HFSS software. It should be noted that the parameters of the dielectric substrate described above are only preferred parameters and should not be construed as the sole limitation of this invention. When the operating bandwidth meets the requirements, the thickness of the first dielectric substrate can also be set using conventional methods, i.e., selecting the standard board thickness (nominal value from 0.8mm to 1.6mm) commonly used in PCB manufacturing.

[0057] In this embodiment, each layer is made of printed circuit boards.

[0058] Based on the relative permittivity and resonant frequency of the dielectric substrate, the width of the impedance matching feed line in the feed layer 7 can be further determined. Specifically, for example... Figure 5 As shown, in this embodiment, the widths of each trace are b = 1.395 mm, c = 2.46 mm, and d = 0.28 mm.

[0059] It is easy to understand that in practical applications, when the resonant frequency changes within the Sub-6G frequency band, the parameters of each layer can be calculated using transmission line theory and antenna theory, and then verified using the parameter scanning function of HFSS software.

[0060] The following simulation tests of the unit performance provided in this embodiment are performed using HFSS software. The control circuit layer is a reserved space for array design and does not need to be used in the unit performance simulation. For the bridge feed layer, there are two input ports in the simulation, which are completely equivalent. They can be selected according to requirements, or one can be deleted in the actual product to simplify the circuit.

[0061] Figure 6S11 parameters of the bottom layer feed end are shown. The simulation result shows that the holographic beamforming antenna array unit has a bandwidth of about 200 MHz around the frequency point of 2.6 GHz, and has a small reflection loss at the frequency point of 2.6 GHz. It is shown that the embodiment has a large bandwidth on the basis of realizing 2-bit phase control.

[0062] The simulation result of the polarization pattern of the antenna unit shows that the gain in the electromagnetic wave emission direction is 5.1 dB, and the direction performance is good.

[0063] Figure 7 The phase pattern of the four signal output ports in the feed layer is shown. The simulation result shows that the four ports have good 90° phase difference characteristics at the frequency point of 2.6 GHz. In the actual chip, the four ports are input into the radio frequency switch chip for digital selection control, so as to realize phase control.

[0064] Embodiment 2:

[0065] An N-bit holographic beamforming microstrip antenna unit is used to realize functions such as beam directional transmission in the millimeter wave frequency band. Considering that the typical communication frequency in the millimeter wave frequency band is 28 GHz, in this embodiment, the first metal layer works in the resonant state at 28 GHz.

[0066] This embodiment is similar to the above-mentioned embodiment 1, and the difference is that the parameters of the laminated structure are slightly different to adapt to the resonant frequency. Specifically, in this embodiment, the length of the first metal layer is L=2.1 mm, the width is W=5 mm, and the side length of the square slot in the middle is a=14 mm.

[0067] It is easy to understand that in actual application, when the resonant frequency changes in the millimeter wave frequency band, the parameters of the transmission line theory and the related knowledge of the antenna theory are calculated, and the parameter scanning function of the HFSS software is verified to determine.

[0068] The unit performance provided by this embodiment is simulated and tested by using the HFSS software. The S11 parameters of the bottom layer feed end are shown. Figure 8 The simulation result shows that the holographic beamforming antenna array unit has a bandwidth of 2.2 GHz around the frequency point of 28 GHz, accounting for about 7.86% of the frequency point of 28 GHz. It is shown that it has a large working bandwidth while realizing 2-bit phase control.

[0069] Embodiment 3:

[0070] An N-bit holographic beamforming microstrip antenna unit is used to realize functions such as beam directional transmission in a WLAN frequency band, and considering that the typical communication frequency in the WLAN frequency band is 5.8 GHz, in the embodiment, the first metal layer specifically works in a resonant state at 5.8 GHz.

[0071] The embodiment is similar to the above-mentioned embodiment 1, and the difference is that the parameters of the laminated structure are slightly different to adapt to the resonant frequency. Specifically, in the embodiment, the length of the first metal layer is L = 12.8 mm, the width is W = 21.9 mm, and the side length of the square slot in the middle is a = 3.2 mm.

[0072] It is easy to understand that in actual application, when the resonant frequency changes in the millimeter wave frequency band range, the parameters of the transmission line theory and the antenna theory related knowledge are calculated, and the parameter scanning function of the HFSS software is verified to determine.

[0073] The unit performance provided by the embodiment is simulated and tested by using the HFSS software, and the S11 parameter of the bottom feed end is as shown in Figure 9 The simulation result shows that the holographic beamforming antenna array unit has a frequency point of 0.78 GHz around 5.8 GHz, accounting for about 13.45% of the frequency point 5.8 GHz, which means that it has a large working bandwidth while realizing 2-bit phase control.

[0074] Embodiment 4:

[0075] A holographic beamforming microstrip antenna includes a holographic MIMO array composed of the N-bit holographic beamforming microstrip antenna unit provided by any one of the above-mentioned embodiments 1-3, and the array structure can refer to the structure shown in Figure 1 .

[0076] It is easy to understand that in order to ensure the signal transmission efficiency, the period of the holographic beamforming microstrip antenna, that is, the distance between the units in the array, is the half wavelength distance at the resonant frequency; for example, when the unit is the unit provided by the above-mentioned embodiment 1, the period of the holographic beamforming microstrip antenna on the holographic MIMO array is 57.69 mm (half wavelength distance at 2.6 GHz frequency).

[0077] Since the antenna unit provided by the above-mentioned embodiments 1-3 can realize arbitrary N-bit phase control, and the working bandwidth of each unit is large, the holographic beamforming antenna provided by the embodiment has low cost, easy processing, easy deployment, and at the same time has large gain and bandwidth.

[0078] Embodiment 5:

[0079] The holographic beamforming microstrip antenna is applied to a wireless communication system, and is used to realize beam directional transmission of a target carrier frequency band; the target carrier frequency band is a Sub-6G high frequency band, a millimeter wave frequency band or a WLAN frequency band.

[0080] It is easy to understand that the application can be applied to the required target frequency band by theoretical calculation and simulation optimization of specific parameters to achieve a high bandwidth result, and the phase control method using the combination of the electric bridge and the microstrip line can also design the parameters of the electric bridge and the microstrip line according to the target frequency band to realize the phase controllability of the antenna unit under the target frequency band, so that the holographic beamforming microstrip antenna unit and the antenna provided by the application can also be applied to the beam directional transmission of the future 6G frequency band after corresponding parameter design.

[0081] It is easy for those skilled in the art to understand that the above only describes the preferred embodiments of the application and is not intended to limit the application, and any modification, equivalent replacement and improvement made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A N Bit holographic beamforming microstrip antenna unit characterized in that, N is a positive integer greater than or equal to 1, and the N The bit holographic beamforming microstrip antenna unit comprises, from top to bottom, a first metal layer, a first dielectric substrate, a second metal layer, a second dielectric substrate, a control circuit layer, a third dielectric substrate, and a feeding layer. The first metal layer works in a resonant state of a target carrier frequency band, and is used for radiating effective electromagnetic waves outwardly; The second metal layer is a metal ground layer, and a groove is engraved on the second metal layer; The control circuit layer is used for transmitting control signals; The feed layer is used to decompose the original feed signal into 2 N signals with equal amplitudes and different phases and output from 2 N signal output ports respectively; The feeding layer comprises: an electrical bridge and 2 N microstrip lines; the electrical bridge comprises 2 N-1 electrical bridge output ports, and each electrical bridge output port is connected with two microstrip lines, the electrical bridge is used for decomposing an original feeding signal into 2 N-1 equal-amplitude signals; the ends of the 2 N microstrip lines not connected with the electrical bridge constitute 2 N signal output ports of the feeding layer, and the lengths of the microstrip lines satisfy: l ;​ The control signal is used for indicating the selected output signal in the feed layer. Phi and Theta respectively represent the phase of the signal output by the bridge output port and the signal output port connected by the microstrip line, Lambda represents the effective wavelength.

2. The method of claim 1, wherein the at least one of the plurality of data streams is transmitted using a plurality of subcarriers. N Bit holographic beamforming microstrip antenna unit characterized in that, The 2 N signal output ports of the feed layer output 2 N signals with equal amplitudes and different phases, and the adjacent phase difference is .

3. The method of claim 1 or 2, wherein the first and second sets of parameters are determined based on a first and second set of channel state information, respectively. N Bit holographic beamforming microstrip antenna unit characterized in that, The first metal layer is in an H shape.

4. The method of claim 1 or 2, wherein the first and second sets of parameters are determined based on a first and second set of channel state information, respectively. N Bit holographic beamforming microstrip antenna unit characterized in that, Further comprising: 2 N Select one radio frequency switch; the 2 N Select one RF switch and 2 N All signal output ports are connected to each other, for use in accordance with the control signal from 2 N The two signal output ports output 2 N Select the target phase signal from signals with equal amplitude but different phases.

5. The method of claim 1 or 2, wherein the first and second sets of bits are the same. N Bit holographic beamforming microstrip antenna unit characterized in that, The first metal layer, the first dielectric substrate, the second metal layer, the second dielectric substrate, the control circuit layer, the third dielectric substrate and the feed layer are all made of printed circuit boards.

6. A holographic beamforming microstrip antenna, characterized by Comprising: The method according to any one of claims 1 to 5 N Holographic MIMO array of bit holographic beamforming microstrip antenna elements.

7. The holographic beamforming microstrip antenna of claim 6, wherein, In the MIMO array, N The thickness of the first dielectric substrate in the bit holographic beamforming microstrip antenna unit is 2%~5% of the wavelength length.

8. Use of the holographic beam-forming microstrip antenna according to claim 6 or 7 in a wireless communication system, characterized in that, The holographic beamforming microstrip antenna is used for realizing beam directional transmission of a target carrier frequency band; the target carrier frequency band is a Sub-6G high frequency band, a millimeter wave frequency band, a 6G frequency band or a WLAN frequency band.

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