Antenna structure and terminal equipment

Abstract

The present application proposes an antenna structure and terminal device, wherein the antenna structure includes: a first dielectric layer, a second dielectric layer, a metal reflective floor, a microstrip line, and a slotted grid antenna array; the slotted grid antenna array is disposed on the first surface of the first dielectric layer; the microstrip line is disposed on the second surface of the first dielectric layer; the metal reflective floor is disposed on the third surface of the second dielectric layer; the microstrip line is a metal strip and includes a signal input end and a feed end; the width of the signal input end is determined by the characteristic impedance of the signal source, and the width of the feed end is determined by the characteristic impedance of the slotted grid antenna array. The present application achieves impedance matching between the signal input end and the signal source, and also achieves impedance matching between the feed end and the slotted grid antenna array, thereby reducing energy loss during signal transmission to the slotted grid antenna array and improving the efficiency of the antenna in transmitting signals.

Description

Technical Field

[0001] The present application relates to the field of antenna technology, and in particular to an antenna structure and a terminal device. Background Art

[0002] Frequency scanning antennas are generally in the form of waveguide slot antenna arrays. Frequency scanning is achieved by introducing slot antenna arrays at appropriate locations in the waveguide. However, the size, weight, and manufacturing cost of waveguide slot antenna arrays make them unsuitable for use in modern millimeter-wave communication systems. Scanning systems using waveguide slot antenna arrays are more cumbersome, limiting their further development. With the advancement of communication technology, including the emergence of 5G (5th Generation Mobile Communication Technology) and 6G (6th Generation Mobile Communication Technology), the requirements for related antennas are becoming increasingly stringent. Summary of the Invention

[0003] The present application aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, the purpose of this application is to provide an antenna structure and a terminal device.

[0005] To achieve the above objectives, the first aspect of the present application provides an antenna structure, comprising:

[0006] a first dielectric layer, a second dielectric layer, a metal reflective floor, a microstrip line, a signal source, and a slotted grid antenna array;

[0007] The slot grid antenna array is arranged on a first surface of the first dielectric layer, where the first surface is a surface away from the second dielectric layer;

[0008] The microstrip line is provided on the second surface of the first dielectric layer, and the second surface is a surface close to the second dielectric layer;

[0009] The metal reflective floor is arranged on the third surface of the second dielectric layer, and the third surface is the surface close to the first dielectric layer;

[0010] The microstrip line is a metal strip, including a signal input end and a feeding end, the signal input end is connected to the signal source, wherein the width of the signal input end is determined by the characteristic impedance of the signal source, and the width of the feeding end is determined by the characteristic impedance of the slot grid antenna array.

[0011] Optionally, the width of the signal input end is greater than the width of the feeding end.

[0012] Optionally, in the microstrip line, the feeding end is used to feed the slot-type grid antenna array.

[0013] Optionally, the slot-type grid antenna array includes a peripheral metal unit and a plurality of metal patches.

[0014] Optionally, the feeding end is located in an area of ​​the positive projection of the metal patch in the slot-type grid antenna array.

[0015] Optionally, the signal source includes: a coaxial cable;

[0016] The coaxial cable comprises an outer conductor and an inner conductor, wherein the inner conductor is connected to the signal input end of the microstrip line;

[0017] The outer conductor is connected to the peripheral metal units of the slot grid antenna array.

[0018] Optionally, it further includes: a dielectric layer connector; a connecting through hole on the first dielectric layer and a connecting through hole on the second dielectric layer;

[0019] The dielectric layer connector connects the first dielectric layer and the second dielectric layer via the connecting through hole;

[0020] The metal reflective floor is connected to the peripheral metal units of the slot-type grid antenna array through the dielectric layer connector.

[0021] Optionally, the metal patch is provided in a metal-free area of ​​the peripheral metal unit;

[0022] The gap between the metal patch and the peripheral metal unit constitutes a radiation unit and a transmission unit.

[0023] Optionally, the length of the radiation unit is the same as the length of the short side of the metal patch, and the length of the transmission unit is the same as the length of the long side of the metal patch, wherein the length of the short side and the length of the long side are determined by the target signal wavelength.

[0024] Optionally, the length of the short side is equal to half the target signal wavelength, and the length of the long side is equal to the target signal wavelength, wherein the target signal wavelength is determined by the target signal center frequency and the dielectric constant of the first dielectric layer.

[0025] A terminal device proposed in the second aspect of the present application includes: an antenna structure proposed in the first aspect of the present application.

[0026] After adopting the above technical solution, the advantages of this application compared with the related art are:

[0027] The width of the signal input end in the microstrip line is set according to the characteristic impedance of the signal source, thereby achieving impedance matching between the signal input end and the signal source; at the same time, the width of the feeding end in the microstrip line is set according to the characteristic impedance of the slot grid antenna array, thereby achieving impedance matching between the feeding end and the slot grid antenna array, reducing the energy loss of the signal during transmission to the slot grid antenna array, and improving the efficiency of the antenna in transmitting signals.

[0028] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0030] Figure 1 This is a side view of an antenna structure provided by an embodiment of the present application;

[0031] Figure 2 This is a schematic diagram of the three-dimensional structure of the antenna proposed in one embodiment of the present application;

[0032] Figure 3 is a top view of a slotted grid antenna array in an antenna structure proposed in one embodiment of the present application;

[0033] Figure 4 2. It is a schematic diagram of the simulation results of the reflection coefficient and antenna gain of the antenna structure proposed in one embodiment of the present application;

[0034] Figure 5 is the normalized frequency pattern of the antenna structure proposed in one embodiment of the present application;

[0035] Main components and numbers: first dielectric layer 110; second dielectric layer 120; metal reflective floor 130; microstrip line 140; signal source 150; slot grid antenna array 160; dielectric layer connector 170; connecting through hole 180; signal input terminal 141; feeding terminal 142; inner conductor 151; outer conductor 152; peripheral metal unit 161; metal patch 162; transmission unit 163; radiation unit 164. DETAILED DESCRIPTION

[0036] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present application and are not to be construed as limiting the present application. On the contrary, the embodiments of the present application include all variations, modifications, and equivalents that fall within the spirit and scope of the appended claims.

[0037] Frequency scanning antennas typically take the form of waveguide slot antenna arrays, which implement frequency scanning functionality by inserting slot antenna arrays at appropriate locations within the waveguide. However, the size, weight, and manufacturing cost of waveguide slot antenna arrays make them unsuitable for use in modern millimeter-wave communication systems. Scanning systems using waveguide slot antenna arrays are also more cumbersome, limiting their further development. Current research on frequency scanning antennas focuses primarily on bandwidth, scanning angle, and array complexity, with limited application in the millimeter-wave band. These antennas are therefore unsuitable for today's mainstream 5G and the upcoming large-scale deployment of 6G communication technologies.

[0038] Related art provides an antenna structure that achieves beam scanning control by using embedded varactor diodes in circular cells. The structure contains multiple reconfigurable units. Sweeping the bias voltage causes a change in the phase constant, thereby achieving fixed-frequency beam scanning. Each reconfigurable unit includes a circular slot on the top plate and a varactor diode switch, a direct current (DC) block, and a radio frequency (RF) block on the back of the structure. The operating frequency is selected to be 28.5 GHz (gigahertz) to support the upcoming 5G millimeter-wave communication system. The antenna's beam achieves a 29° scanning angle by switching between different states at 28.5 GHz. The peak achieved gain and sidelobe level measured at 28.5 GHz are 8.2±0.6 dBi and 5 dB, respectively, and the antenna has an impedance bandwidth of 1.5 GHz. Although this solution operates in the millimeter-wave frequency band and achieves very precise scanning angle control, its structure is relatively complex, requiring the corresponding varactor diode, DC block, and RF block to be embedded in each unit. This leads to very high manufacturing costs and a relatively small scanning angle.

[0039] The application of communication technology in various fields is becoming increasingly widespread and in-depth. The dramatic increase in the number of vehicles, the rapid development of artificial intelligence, the popularization of concepts such as intelligent driving and the Internet of Vehicles (IoV), and the advancement of modern science and technology have led to the rapid development of radar and antenna technologies, which play an irreplaceable role in IoV systems. In IoV systems, because vehicles are constantly in motion, data transmission can only be achieved through wireless technologies. Wireless communication enables inter-vehicle and inter-vehicle communication, allowing users to monitor and control vehicles using terminal devices. As a core component of wireless networks, the importance of antennas is self-evident. Currently, conventional automotive radar antenna systems utilize traditional microstrip antenna arrays or phased arrays. These complex feed network designs, high losses, small scanning angles, and narrow bandwidth make them unsuitable for use in fifth-generation millimeter-wave communication systems.

[0040] An antenna structure is proposed in an embodiment of the present application. Figure 1 This is a side view of an antenna structure provided by an embodiment of the present application. Figure 1 As shown, the antenna structure 100 includes: a first dielectric layer 110 , a second dielectric layer 120 , a metal reflective floor 130 , a microstrip line 140 , a signal source 150 and a slot grid antenna array 160 .

[0041] In the embodiment of the present application, the first dielectric layer 110 and the second dielectric layer 120 both use printed circuit boards (PCBs), and the antenna circuits are engraved on the surface of the dielectric layer with metal, so that the function of the antenna can be realized in a smaller space, that is, the function of receiving and transmitting signals can be realized. The slot-type grid antenna array 160 is printed on the first surface of the first dielectric layer 110, and the metal reflective floor 130 is printed on the third surface of the second dielectric layer 120. The first dielectric layer 110 and the second dielectric layer 120 are parallel to each other, the first surface is the surface of the first dielectric layer 110 away from the second dielectric layer 120, and the second surface is the surface of the first dielectric layer 110 close to the second dielectric layer 120. In the embodiment of the present application, the antenna needs to receive or transmit 5G or 6G high-frequency millimeter wave signals. In the high-frequency circuit, the signal transmission speed is Where k is a constant, c is the speed of light in vacuum, and ε ris the dielectric constant of the dielectric layer. It is easy to see from the formula that a lower dielectric constant value enables the dielectric layer to propagate millimeter wave signals faster when used as an antenna to receive and transmit high-frequency millimeter wave signals, so the first dielectric layer 110 and the second dielectric layer 120 need to use materials with lower dielectric constants. At the same time, the antenna of the present application is a wide-band antenna. For the stability of the antenna, it is necessary to use materials with smaller dielectric loss. Dielectric loss refers to the phenomenon that the dielectric itself heats up due to the consumption of part of the electrical energy in the alternating electric field. The signal attenuates less in a medium with low dielectric loss. The dielectric loss factor (DF) can be used to measure the degree of dielectric loss. The dielectric loss factor is the ratio of the energy lost to the energy not lost when the signal is transmitted in the medium. The smaller the dielectric loss factor, the less dielectric loss the medium has.

[0042] In a possible embodiment, the dielectric layer is made of polytetrafluoroethylene (PTFE) material, has a dielectric constant of 2.1±0.3, a thickness of 0.78±0.2 mm (millimeter), and a dielectric loss factor of 0.0009 at an operating frequency of 10 GHz.

[0043] In another possible embodiment, the dielectric layer is low temperature co-fired ceramic (LTCC), the dielectric constant of which is 2.7±0.2, the thickness of which is 0.87±0.15 mm, and the dielectric loss factor of which is 0.0004 at an operating frequency of 10 GHz.

[0044] The slot grid antenna array 160 is disposed on a first surface of the first dielectric layer 110 , where the first surface is away from the second dielectric layer.

[0045] The slotted grid antenna array 160 is configured to couple and feed the signal source 150 via the microstrip line 140, receiving high-frequency signals transmitted by the signal source 150 and transmitting the high-frequency signals into a nearby space. Coupled feeding refers to the conduction of electrical energy between two non-contacting circuit elements or circuit networks that are located at a certain distance, through coupling, in fields such as communications. This allows one element to receive energy without direct contact with the electrical energy transmission system.

[0046] The metal reflective floor 130 is arranged on the third surface of the second dielectric layer 120. The third surface is the surface of the second dielectric layer 120 close to the first dielectric layer 110. The metal reflective floor 130 serves as the reflective surface of the slot-type grid antenna array 160, and is used to obtain high gain and realize beamforming. In the related art, a complex feeding network is required for the antenna array to obtain high gain and beamforming, and the loss of the antenna and the feeding network causes the actual antenna gain to be not obvious. In the embodiment of the present application, the signal emitted by the signal source 150 is transmitted to the slot-type grid antenna array 160 through the microstrip line 140, and then the signal is sent from the slot-type grid antenna array 160 to the outside world, wherein the signal can be emitted from the first surface in a direction away from the second dielectric layer, or from the second surface in a direction close to the second dielectric layer. This will cause the intensity of the transmitted signal to be weakened, thereby reducing the gain of the antenna to the signal. To focus signal transmission in a specific direction and reduce signal leakage in other directions, the present application utilizes the metal reflective floor 130 to reflect electromagnetic wave signals directed toward the metal reflective floor 130 from the second surface toward the slotted grid antenna array 160, causing them to be transmitted from the first surface in a direction away from the second dielectric layer. Concentrating the signal on the first surface for transmission outward increases the intensity of the emitted high-frequency signal and improves the antenna's signal gain.

[0047] The microstrip line 140 is disposed on the second surface of the first dielectric layer 110, the second surface being a surface adjacent to the second dielectric layer. The microstrip line 140 is a metal strip and includes a signal input end 141 and a feed end 142. The signal input end 141 is connected to the signal source 150. The width of the signal input end 141 is determined by the characteristic impedance of the signal source 150, and the width of the feed end 142 is determined by the characteristic impedance of the slot grid antenna array 160.

[0048] In the embodiment of the present application. In the process of the antenna radiating signals outward, if the signal source 150 directly transmits signals to the slot grid antenna array 160, that is, the feeding process is performed, the position where the signal source 150 feeds the slot grid antenna array 160 is called the feeding point. The signal source 150 has a certain characteristic impedance, and the characteristic impedance is determined by the geometric properties, size, material and other physical properties of the signal source 150; the impedance of the signal source 150 input to the slot grid antenna array 160 is called the input impedance, and the input impedance can be obtained according to the ratio of the voltage and current at the feeding point. The input impedance is related to the structure, material, operating frequency and other factors of the slot grid antenna array 160. The degree of matching between the input impedance and the characteristic impedance can be measured by the reflection coefficient or standing wave ratio of the feeding end. The value range of the standing wave ratio is [1,∞). The smaller the standing wave ratio, the better the impedance matching; the smaller the reflection coefficient, the better the impedance matching. When the input impedance of the slot grid antenna array 160 completely matches the characteristic impedance of the feed point, that is, when the input impedance is equal to the characteristic impedance, the power of the signal transmitted from the signal source 150 to the slot grid antenna array 160 is maximized, and no reflected waves appear at the signal source 150. For the slot grid antenna array 160, if the input impedance differs significantly from the characteristic impedance of the feed point, resulting in a poor match, the radiated power of the slot grid antenna array 160 will decrease, the loss at the signal source 150 will increase, and the power capacity of the signal source 150 will decrease. In severe cases, frequency pulling may occur, i.e., the oscillation frequency changes, causing signal reflections that waste energy and affect the normal operation of the antenna.

[0049] To avoid the above problems, the present application adds a microstrip line 140 between the signal source 150 and the slot grid antenna array 160, so that the signal source 150 indirectly feeds the slot grid antenna array 160. The signal from the signal source 150 is first input into the microstrip line 140 from the signal input terminal 141 (i.e., the signal source feeds the signal input terminal 141 of the microstrip line), and then transmitted to the feeding terminal 142, through which the slot grid antenna array 160 is fed. At this time, the feeding terminal of the microstrip line 140 serves as the feeding point for feeding the slot grid antenna array 160. The width of the signal input terminal 141 on the microstrip line 140 is set according to the characteristic impedance of the signal source 150, so that the characteristic impedance of the signal source 150 and the input impedance of the signal input terminal 141 are equal, that is, matched; the width of the feeding terminal 142 is determined according to the characteristic impedance of the slot grid antenna array 160, so that the input impedance of the slot grid antenna array 160 and the characteristic impedance of the feeding terminal 142 are equal, that is, matched, so as to reduce signal loss.

[0050] Optionally, the feeding end 142 is used to feed the slot grid antenna array 160 .

[0051] In an embodiment of the present application, the microstrip line 140 is a strip-shaped trace attached to the surface of the PCB, which can receive the signal transmitted by the signal source 150, and couple and feed with the slot-type grid antenna array 160 to transmit the received electrical signal to the slot-type grid antenna array 160.

[0052] Optionally, the signal source 150 includes: a coaxial cable

[0053] When the signal source 150 is the coaxial cable, it includes an outer conductor 151 and an inner conductor 152 . The inner conductor 151 is connected to the signal input end 141 of the microstrip line 140 ; ​​the outer conductor 152 is connected to the peripheral metal unit of the slot grid antenna array 160 .

[0054] In an embodiment of the present application, the coaxial cable is an electric wire and a signal transmission line that can be used to transmit analog signals or digital signals. The coaxial cable in the embodiment of the present application is used to transmit high-frequency millimeter wave signals. The coaxial cable includes an outer conductor 151 and an inner conductor 152. The inner conductor is the main path for transmitting electrical signals and is composed of a single strand or multiple strands. The inner conductor 152 in the embodiment of the present application is connected to the microstrip line 140 for transmitting electrical signals. The outer conductor 151, also called a shielding layer, is used to shield external electromagnetic interference or serve as a conductor for a loop. The outer conductor can be composed of a braided mesh and aluminum foil. The outer conductor 152 in the embodiment of the present application is in direct contact with the peripheral metal unit of the slot-type grid antenna array 160.

[0055] In a possible embodiment, the coaxial cable is a standard coaxial cable, and its impedance is 50Ω (ohm) or 70Ω.

[0056] The width of the signal input end 141 is determined by the characteristic impedance of the coaxial cable. In the embodiment of the present application, the electrical signal is input from the inner conductor 151 to the signal input end 141 of the microstrip line 140, transmitted to the feeding end 142 through the microstrip line, and then enters the slot grid antenna array 160 through the feeding end 142. In order to reduce signal reflection, it is necessary to perform impedance matching on the inner conductor 151 of the coaxial cable and the signal input end 141, that is, to adjust the width of the signal input end 141 to change the input impedance of the signal input end 141 so that the characteristic impedance of the signal source 150 and the input impedance of the input end 141 are equal, that is, matched; at the same time, the impedance matching is performed on the feeding end 142 and the slot grid antenna array 160, that is, to adjust the width of the feeding end 142 to change the input impedance of the feeding end 142 so that the input impedance of the slot grid antenna array 160 and the characteristic impedance of the feeding end 142 are equal, that is, matched.

[0057] The characteristic impedance of the two ends of the microstrip line is related to their width, thickness and the dielectric constant of the first dielectric layer 110, and is calculated as follows:

[0058]

[0059] Where Z is the characteristic impedance, ε r is the dielectric constant of the first dielectric layer 110, h is the thickness of the first dielectric layer 110, w is the width of the microstrip line, and t is the thickness of the microstrip line. The constants in the formula are characteristic coefficients determined in related art. As can be seen from the above formula, when the thickness remains unchanged, the characteristic impedance of the signal input terminal 141 or the feeding terminal 142 is inversely proportional to their width, i.e., the larger the width, the smaller the characteristic impedance.

[0060] In the embodiment of this application, the ε r When , h, and t are all determined, the width of the signal input end 141 can be determined according to the characteristic impedance of the coaxial cable inner conductor 151.

[0061] Optionally, the feeding end 142 is located in an area corresponding to the positive projection of the metal patch in the slot grid antenna array 160 in a reference direction, wherein the reference direction of the first dielectric layer 110 points to a position close to the second dielectric layer 120, and the reference direction is perpendicular to the first surface, and the width of the feeding end 142 is determined by the characteristic impedance of the slot grid antenna array 160.

[0062] Similarly, the width of the feeding end 142 can be determined according to the characteristic impedance of the slot grid antenna array 160 .

[0063] Optionally, the width of the signal input end is greater than the width of the feeding end.

[0064] In a possible embodiment, the characteristic impedance of the inner conductor 152 is much smaller than the characteristic impedance of the slot grid antenna array 160 . In order to better perform impedance matching, the width of the signal input end 141 should be greater than the width of the feeding end 142 .

[0065] In a possible embodiment, the width of the signal input end 141 is smaller than the width of the feeding end 142 , and the width of the microstrip line decreases gradually from the signal input end 141 to the feeding end 142 .

[0066] In a possible embodiment, the width of the signal input end 141 is smaller than the width of the feeding end 142 , and the width of the microstrip line decreases in a step-by-step manner from the signal input end 141 to the feeding end 142 .

[0067] The metal patch Figure 2 FIG. 1 is a top view of the slotted grid antenna array 160 in the antenna structure proposed in one embodiment of the present application. Figure 2 As shown, in the embodiment of the present application, the slot-type grid antenna array 160 includes a peripheral metal unit 161 and a plurality of metal patches 162, wherein the specifications of the metal patches are variable.

[0068] Optionally, the metal patch is rectangular in nature, and its specifications include length and width.

[0069] Optionally, the metal patch 162 is disposed in a metal-free area of ​​the peripheral metal unit 161; the metal patches 162 are staggered with each other, and the gaps between the metal patches 162 and the peripheral metal unit 161 constitute a plurality of radiation units 164 and transmission units 163. Figure 2 It can be seen that the length direction of the radiation unit 164 is in the y-axis direction, the length direction of the transmission unit 163 is in the x-axis direction, any two radiation units 164 are parallel to each other, any two transmission units 163 are parallel to each other, and adjacent radiation units 164 and transmission units 163 are perpendicular to each other. Figure 2 It can be seen that any two metal patches 162 do not contact each other, the length directions of any two metal patches 162 are parallel to each other, and the width directions of any two metal patches 162 are parallel to each other.

[0070] In the embodiment of the present application, the feeding end of the microstrip line 140 is located in the area of ​​the orthographic projection of the metal patch 162, that is, directly below the metal patch, and performs contactless feeding of the slot grid antenna array 160, transmitting an electrical signal to the slot grid antenna array 160. The electrical signal is transmitted through the transmission unit 163 and emitted outward through the radiation unit 164.

[0071] Optionally, in the radiation unit 164 and the transmission unit 163 formed by the metal patch 162, the length of the radiation unit 164 is the same as the length of the short side of the metal patch 162, and the length of the transmission unit 163 is the same as the length of the long side of the metal patch 162, wherein the length of the short side and the length of the long side are determined by the target signal wavelength.

[0072] In the embodiment of the present application, the wavelength λ1 of the target signal can be determined according to the dielectric constant of the first dielectric layer 110 , and the calculation method is expressed as follows:

[0073] Where λ0 is the free space wavelength of the electromagnetic wave at the target frequency, ε r is the dielectric constant of the first dielectric layer 110 .

[0074] The length of the short side is equal to half of the target signal wavelength, and the length of the long side is equal to the target signal wavelength, wherein the target signal wavelength is determined by the target signal center frequency and the dielectric constant of the first dielectric layer.

[0075] In the slotted grid antenna array 160, the amplitude of the electric field of the target signal plane electromagnetic wave at each position can be expressed as E=E0×cos(ωt-k1x), where E0 is the electromagnetic wave amplitude, x is the position of the spatial coordinate axis, t is the position of the time coordinate axis, k1 is the propagation coefficient, ω is the angular frequency of the electromagnetic wave, and the amplitude E0 decays with time during the propagation of the electromagnetic wave. Then, E0 is a decreasing function of time t. As time increases, the amplitude E0 decreases, and the energy E0 of the electromagnetic wave decreases. 2It also decreases accordingly. Since E is a cosine function, a radiation unit is set when ωt-k1x=1 to radiate the target signal to the outside world. At this time, the radiated energy is maximum, the attenuation of the target signal is minimum, and the obtained gain is maximum. Therefore, if the length of the radiation unit 164 is approximately half a wavelength at the center frequency of the target signal, and the length of the transmission unit 163 is approximately one wavelength at the center frequency of the target signal. When the target signal is transmitted from one radiation unit to another radiation unit through the transmission unit, the amplitude of the signal is larger, and the signal energy radiated from the radiation unit 164 to the outside world is stronger. The gain obtained by the target signal from the slot-type grid antenna array 160 is larger. Therefore, the shorter the wavelength of the target signal, the shorter the length of the short side, and the shorter the length of the long side.

[0076] In a possible embodiment, the length of the short side of the metal patch 162, that is, the length b of the radiation unit 164 can be set to 0.3λ1, 0.35λ1, or 0.5λ1, etc.; the width d of the radiation unit 164 can be set to 0.33λ1, 0.25λ1, or 0.4λ1, etc.; the length of the long side of the metal patch 162, that is, the length l of the transmission unit 163 can be set to 0.89λ1, 0.9λ1, or 0.95λ1, etc., and the width l of the transmission unit 163 w It can be set to 0.02λ1, 0.028λ1, or 0.032λ1, etc.

[0077] like Figure 1 As shown, optionally, it further includes: a dielectric layer connector 170; a connecting through hole 180 on the first dielectric layer 110 and a connecting through hole 180 on the second dielectric layer 120;

[0078] The dielectric layer connector 170 connects the first dielectric layer 110 and the second dielectric layer 120 through the connecting through hole 180 ; the metal reflective floor 130 is connected to the peripheral metal unit 161 of the slot-type grid antenna array 160 through the dielectric layer connector 170 .

[0079] The first dielectric layer 110 and the second dielectric layer 120 are provided with connecting through holes 180. The dielectric layer connector 170 is connected to the slot grid antenna array 160 on the first surface of the first dielectric layer through the connecting through holes 180 of the first dielectric layer 110, and is connected to the metal reflective floor 130 on the third surface of the second dielectric layer 120 through the connecting through holes 180 of the second dielectric layer 120.

[0080] In the embodiment of the present application, the dielectric layer connector 170 is inserted into the connecting through holes 180 in the first dielectric layer 110 and the second dielectric layer 120 to fix the first dielectric layer and the second dielectric layer and keep their relative positions unchanged.

[0081] In a possible embodiment, there are four dielectric layer connectors 170 in the antenna structure, and there are four connecting through holes 180 in each of the first dielectric layer and the second dielectric layer.

[0082] In a possible embodiment, the dielectric layer connector 170 is a metal cylinder, the height h of the dielectric layer connector 170 can be set to 2.9 mm, 3.0 mm or 3.1 mm, etc., and the bottom diameter r1 can be set to 0.95 mm, 1.0 mm or 1.12 mm, etc.

[0083] In this embodiment of the present application, the outer conductor 152 is connected to the peripheral metal unit 161 of the slot-type mesh antenna array 160 and is connected to the metal reflective floor 130 via the dielectric layer connector 170. Because the outer conductor 152 is grounded, both the peripheral metal unit 161 and the metal reflective floor 130 are grounded. This forms a loop between the metal reflective floor 130 and the slot-type mesh antenna array 160, enhancing anti-interference capabilities and improving the antenna structure's transmission performance.

[0084] In a possible embodiment, in order to optimize the performance of the antenna, the size of each metal patch 162 and the size of the peripheral metal layer are adjusted. Figure 2 The parameter sizes of each are shown in Table 1, where the units of the values ​​are all mm (millimeter):

[0085]

[0086] Table 1

[0087] Wherein, l is the total length of the slot grid antenna array 160 in the x-axis direction, r1 is the diameter of the connecting through hole 180 and the dielectric layer connector 170, h is the height of the dielectric layer connector 170, l1 to l5 are the lengths of the transmission unit 163, l w is the width of the transmission unit 163, feed l The length of the microstrip line 140, w1 is the width of the signal input end 141 in the microstrip line 140, w2 is the width of the feeding end 142 in the microstrip line 140, b1 to b4 are the lengths of the radiation unit 164, and d1 to d3 are the widths of the radiation unit 164.

[0088] In a possible embodiment, the slot-type grid antenna array 160 is an axisymmetric figure, with the straight line L′ in the figure as the axis of symmetry, and the metal patches symmetrical on both sides of the axis of symmetry have the same specifications.

[0089] In the embodiment of the present application, the width of the signal input end in the microstrip line is changed to adjust the characteristic impedance of the signal input end, thereby achieving impedance matching between the signal input end and the signal source. The characteristic impedance of the feeding end is adjusted by changing the width of the feeding end in the microstrip line to achieve impedance matching between the feeding end and the slot grid antenna array, thereby reducing the energy loss of the signal during transmission to the slot grid antenna array and improving the efficiency of the antenna in transmitting the signal.

[0090] By adjusting the side length of the metal patch in the slot grid antenna array, the side lengths of the radiation unit and the transmission unit are changed, and the amplitude of the signal when transmitted to the radiation unit is increased, thereby increasing the energy radiated by the slot grid antenna array.

[0091] Figure 3 This is a schematic diagram of the three-dimensional structure of the antenna proposed in one embodiment of the present application. Figure 3 As shown, the antenna structure includes: a first dielectric layer 110, a second dielectric layer 120, a metal reflective floor 130, a microstrip line 140, a signal source 150, a slot grid antenna array 160, a peripheral metal unit 161, a metal patch 162, a dielectric layer connector 170 and a connecting through hole 180.

[0092] Figure 4 1 is a schematic diagram of the simulation results of the reflection coefficient S11 and antenna gain of the antenna structure proposed in one embodiment of the present application. The parameters of the antenna structure are input into the simulation software and the simulation is performed. Figure 4 As shown, the relationship between the S11 parameter and the gain parameter and the input signal frequency of the slot grid antenna array 160 designed in this application during operation is shown in the figure. Figure 4The horizontal axis represents the signal frequency corresponding to the signal propagating in the slot-type grid antenna array 160, the S11 curve corresponds to the vertical axis on the left, the vertical axis on the left represents the S11 parameter, its unit is dB, and the S11 curve represents the S11 parameter value corresponding to the feeding end 142 at the signal frequency shown on the horizontal axis; the gain curve corresponds to the vertical axis on the right, the vertical axis on the right represents the gain, its unit is dBi, and the gain curve represents the signal gain value corresponding to the slot-type grid antenna array 160 at different signal frequencies. The S11 parameter is the ratio of the reflected wave to the incident wave at the feeding point, and the unit is dB. That is, the larger the S11, the more the target signal is reflected, and the greater the loss of the target signal, which affects the propagation of the signal. When the S11 signal loss is less than a certain threshold, the signal loss is within the acceptable range, and the frequency of the target signal at this time can be regarded as the operating frequency of the antenna structure. This application sets the threshold to -10dB, and the Figure 4 It can be seen that the operating frequency of the antenna structure is 24 GHz to 33 GHz, which fully covers the frequency band used by modern 5G millimeter wave bands. The gain parameter represents the ratio of the power density of the signal generated by the actual antenna and the ideal radiating element at the same point in space under the condition of equal input power. It quantitatively describes the degree to which an antenna concentrates the input power and its unit is dBi. The reference standard of dBi is an omnidirectional antenna. The gain parameter curve shows that the gain value reaches a maximum value of 15.2dBi at 29 GHz and a minimum value of 12.8dBi at 33 GHz, and the gain flatness is 15.2-12.8=2.4dBi.

[0093] Figure 5 is the normalized frequency pattern of the antenna structure proposed in one embodiment of the present application. Figure 4 It can be seen that the operating frequency of the antenna structure is 24GHz to 33GHz. Figure 5 As shown, the direction in which the antenna structure transmits signals at different operating frequencies can be obtained. The direction diagram is a polar coordinate diagram. For a single operating frequency, the transmission angle is the angle corresponding to the point farthest from the coordinate center in the diagram. Figure 5 (a) is the directional pattern at 24 GHz, (b) is the directional pattern at 26 GHz, (c) is the directional pattern at 31 GHz, and (d) is the directional pattern at 33 GHz. Figure 5 It can be seen that the corresponding transmission angle for 24 GHz is 150°; the corresponding transmission angle for 26 GHz is 140°; the corresponding transmission angle for 31 GHz is 105°; and the corresponding transmission angle for 33 GHz is 90°. Therefore, within the operating frequency range (24 GHz to 33 GHz), the antenna structure can transmit signals within a range of 90° to 150°, so the scanning angle of the antenna structure is 150° - 90° = 60°.

[0094] Through the antenna structure provided in this application, the antenna reaches an operating frequency of 24GHz to 33GHz. The center frequency of the antenna is (33+24)÷2=28.5GHz, and the corresponding operating bandwidth is A 60° scanning angle is achieved on the horizontal plane, and the peak gain can reach 15.2dBi, which improves the antenna's scanning angle and transmission bandwidth.

[0095] An embodiment of the present application further provides a terminal device, comprising: the antenna structure as described above.

[0096] In some embodiments, the terminal device may be a mobile phone, a tablet computer, a wearable device, a vehicle-mounted terminal, etc.

[0097] It should be noted that, in the description of this application, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0098] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0099] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0100] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. An antenna structure, characterized in that: include: a first dielectric layer, a second dielectric layer, a metal reflective floor, a microstrip line, a signal source, and a slotted grid antenna array; The slot grid antenna array is arranged on a first surface of the first dielectric layer, where the first surface is a surface away from the second dielectric layer; The microstrip line is provided on the second surface of the first dielectric layer, and the second surface is a surface close to the second dielectric layer; The metal reflective floor is disposed on the third surface of the second dielectric layer, the third surface being close to the first dielectric layer. The metal reflective floor serves as a reflective surface for the slot-type grid antenna array, and is used to obtain high gain and implement beamforming. The metal reflective floor is used to reflect electromagnetic wave signals directed from the second surface toward the metal reflective floor to the slot-type grid antenna array, causing the signals to be emitted from the first surface in a direction away from the second dielectric layer. The microstrip line is a metal strip, including a signal input end and a feeding end, the signal input end is connected to the signal source, wherein the width of the signal input end is determined by the characteristic impedance of the signal source, and the width of the feeding end is determined by the characteristic impedance of the slot grid antenna array.

2. The antenna structure according to claim 1, wherein: The width of the signal input terminal is greater than the width of the feeding terminal.

3. The antenna structure according to claim 1, wherein: In the microstrip line, the feeding end is used to feed the slot-type grid antenna array.

4. The antenna structure according to claim 1, wherein: The slot-type grid antenna array includes a peripheral metal unit and a plurality of metal patches.

5. The antenna structure according to claim 4, characterized in that: The feeding end is located in the area of ​​the orthographic projection of the metal patch in the slot-type grid antenna array.

6. The antenna structure according to claim 4, characterized in that: The signal source includes: a coaxial cable; The coaxial cable comprises an outer conductor and an inner conductor, wherein the inner conductor is connected to the signal input end of the microstrip line; The outer conductor is connected to the peripheral metal units of the slot grid antenna array.

7. The antenna structure according to claim 4, characterized in that: Also includes: Dielectric layer connector; a connecting through hole on the first dielectric layer and a connecting through hole on the second dielectric layer; The dielectric layer connector connects the first dielectric layer and the second dielectric layer via the connecting through hole; The metal reflective floor is connected to the peripheral metal units of the slot-type grid antenna array through the dielectric layer connector.

8. The antenna structure according to claim 4, characterized in that: The metal patch is arranged in a metal-free area in the peripheral metal unit; The gap between the metal patch and the peripheral metal unit constitutes a radiation unit and a transmission unit.

9. The antenna structure according to claim 8, characterized in that: The length of the radiation unit is the same as the length of the short side of the metal patch, and the length of the transmission unit is the same as the length of the long side of the metal patch, wherein the length of the short side and the length of the long side are determined by the target signal wavelength.

10. The antenna structure according to claim 9, characterized in that: The length of the short side is equal to half of the target signal wavelength, and the length of the long side is equal to the target signal wavelength, wherein the target signal wavelength is determined by the target signal center frequency and the dielectric constant of the first dielectric layer.

11. A terminal device, characterized in that: include: The antenna structure according to any one of claims 1 to 10.

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