Multi-band 5G millimeter wave antenna unit and antenna array based on HFSS optimization

Abstract

The invention relates to a multi-band 5G millimeter wave antenna unit based on HFSS optimization. The antenna unit comprises a dielectric block, a microstrip line, a dielectric substrate and a floor covering the upper portion of the dielectric substrate. A coupling gap is etched in the floor, the dielectric block is fixed on the coupling gap, and the microstrip line extends from one end of the bottom of the dielectric substrate to the coupling gap and is coupled with the dielectric block through the coupling gap. According to the method, antenna design simulation is carried out based on HFSS software, the software adopts a finite element method, the calculation result is accurate and reliable, and the method is an industrial standard recognized by the industry for three-dimensional electromagnetic field design and analysis. By using the HFSS, various antennas can be simulated, analyzed and optimized, and various performances of the antennas, including two-dimensional and three-dimensional far-field and near-field radiation patterns, directivity coefficients of the antennas, gains, axial ratios, half-power lobe widths, input impedance, voltage standing-wave ratios, S parameters, current distribution characteristics and the like, can be accurately calculated.

Description

Technical Field

[0001] The present invention relates to the field of antennas, and particularly to a multi-band 5G millimeter-wave antenna unit and antenna array optimized based on HFSS. Background Art

[0002] 5G millimeter-wave antenna technology is a key component of 5G communication technology, and the development of its background technology and application prospects have attracted much attention. Millimeter waves refer to electromagnetic waves with wavelengths between 1 millimeter and 10 millimeters, and the frequency range is approximately between 30 GHz and 300 GHz. Due to the high-frequency characteristics of millimeter waves, they can provide extremely high data transmission rates, which is crucial for meeting the requirements of 5G networks for high speed, large bandwidth, and low latency.

[0003] In a wireless communication system, an antenna is an indispensable front-end component, and its performance directly affects the information transmission quality of the communication system. With the increasing congestion in the application of microwave low-frequency bands, spectrum resources have become scarce. Millimeter waves, due to their advantages such as high speed and low latency, have become potential application bands in 5G mobile communication. When designing millimeter-wave antennas, improving antenna gain and obtaining as wide an antenna bandwidth as possible have become the main concerns. Substrate integrated waveguide technology has been widely used in millimeter-wave antennas due to its advantages such as easy integration and low loss.

[0004] The development of 5G millimeter-wave antenna technology, especially in the design of array antennas, faces challenges in reducing mutual influence, decoupling, and decorrelation. These problems involve mutual interference between different functional modules and different frequency bands, as well as mutual coupling and channel isolation of antennas in MIMO systems. To solve these problems, researchers have proposed various technical solutions, including metamaterial technology, substrate or package integrated antennas, and electromagnetic lens technology.

[0005] Metamaterial technology has achieved success in 3G and 4G, realizing miniaturization, low profile, high gain, and wide frequency bands of antennas. Substrate or package integrated antennas are mainly applied to high-frequency bands, that is, millimeter-wave bands, by integrating antennas with substrates or smaller packages to reduce losses and improve integration. Electromagnetic lens technology uses dielectrics to focus high-frequency beams to improve antenna performance, reduce costs and complexity, increase radiation efficiency, and enhance the filtering characteristics of antenna arrays.

[0006] With the advancement of 5G technology, millimeter-wave antenna technology is also constantly progressing. For example, AiP (Antenna in Package) technology conforms to the trend of increasing integration of silicon-based semiconductor processes, taking into account antenna performance, cost, and volume, representing the technological upgrade direction of 5G millimeter-wave band terminal antennas. In addition, the application scenarios of millimeter waves are also constantly expanding, including large backhaul, hotspot coverage, industrial applications, new services, and fixed wireless broadband access (FWA), etc.

[0007] With the continuous progress of technology and the expansion of application scenarios, millimeter-wave antenna technology will play an increasingly important role in 5G communication. During the antenna design process, simulation must be carried out to ensure the reliability of various parameter performances. However, the reliability of the performance parameters of antenna elements designed based on traditional simulation software is often very low. Summary of the Invention

[0008] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a multi-band 5G millimeter-wave antenna element and antenna array optimized based on HFSS.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A multi-band 5G millimeter-wave antenna element optimized based on HFSS, the antenna element includes:

[0011] Dielectric block;

[0012] Microstrip line;

[0013] Dielectric substrate;

[0014] And a ground plane covering the upper part of the dielectric substrate;

[0015] A coupling slot is etched on the ground plane, the dielectric block is fixed above the coupling slot, the microstrip line extends from one end of the bottom of the dielectric substrate towards the coupling slot, and is coupled to the dielectric block through the coupling slot.

[0016] In this solution, antenna design simulation is carried out based on HFSS software. HFSS software is a full-wave three-dimensional electromagnetic simulation software developed by Ansoft Corporation in the United States. This software uses the finite element method, and the calculation results are accurate and reliable. It is the recognized industrial standard for three-dimensional electromagnetic field design and analysis in the industry. Using HFSS, various antennas can be simulated, analyzed, and optimized, and various performances of the antenna can be accurately calculated, including two-dimensional and three-dimensional far-field and near-field radiation patterns, antenna directivity coefficient, gain, axial ratio, half-power beamwidth, input impedance, voltage standing wave ratio, S parameters, and current distribution characteristics, etc.

[0017] Furthermore, the dielectric block is made of TP material with a dielectric constant of 4.4 and a loss tangent of 0.001.

[0018] Furthermore, the dielectric substrate is made of Rogers 4003 material, and its dielectric constant and loss tangent are 3.55 and 0.0027 respectively.

[0019] Further, the dielectric block is fixed directly above the coupling slot and completely covers it. This design can reduce the interference of the coupling slot to the overall antenna unit, and at the same time improve the coupling strength between the dielectric block and the microstrip line.

[0020] Further, the dielectric substrate is provided with a through hole on each side of the microstrip line.

[0021] Further, it further includes a second ground plane. The second ground plane is connected to the first end of the microstrip line through the through hole. The second end of the microstrip line extends towards the coupling slot and is coupled to the dielectric block through the coupling slot.

[0022] For the convenience of processing and testing, an SSMP millimeter-wave connector is used. Thus, the ground plane is introduced to the other side of the dielectric substrate through two metallized through holes to form a second ground plane, which facilitates the mounting of the millimeter-wave connector on the second ground plane. Using this feeding structure, except for the relatively narrower bandwidth, it has little impact on other performances. Although the bandwidth is narrowed, it can still cover the required frequency band.

[0023] Further, the first end of the microstrip line is aligned with the end face of the dielectric substrate to form an excitation port.

[0024] A multi-band 5G millimeter-wave antenna array optimized based on HFSS, the antenna array includes:

[0025] At least one column of antenna arrays;

[0026] The antenna array is composed of a plurality of the antenna units, and the spacing between adjacent antenna units in the antenna array is 5 mm - 6 mm.

[0027] Further, each column of the antenna arrays can be arranged in different spatial dimensions to form a complete multi-dimensional antenna array.

[0028] Further, the spacing between adjacent antenna units in the antenna array is 5.5 mm.

[0029] The beneficial effects of the present invention are:

[0030] This millimeter-wave array antenna supports 5G n257 (26.5 GHz - 29.5 GHz) and n258 (24.25 GHz - 27.5 GHz) frequency bands, can realize the beamforming function with a scanning angle greater than 160°, supports beam scanning in three dimensions, and is suitable for use in different terminals. Description of the Drawings

[0031] Figure 1 It is a schematic structural diagram of an antenna unit according to an embodiment of the present invention;

[0032] Figure 2Schematic diagram of the structure of a dielectric substrate according to an embodiment of the present invention;

[0033] Figure 3 Planar schematic diagram according to an embodiment of the present invention;

[0034] Figure 4 Schematic diagram of the structure of an antenna array according to an embodiment of the present invention;

[0035] Figure 5 Simulation diagram of the radiation direction of an antenna unit according to an embodiment of the present invention;

[0036] Figure 6 Distribution diagram of the electric field vector of an antenna unit at 26 GHz according to an embodiment of the present invention;

[0037] Figure 7 Simulation results of the Z - parameter and return loss of an antenna unit according to an embodiment of the present invention;

[0038] Figure 8 Result of the real part of the Z - parameter of an antenna unit varying with the DRAx direction according to an embodiment of the present invention;

[0039] Figure 9 Radiation pattern of an antenna unit at 28 GHz according to an embodiment of the present invention;

[0040] Figure 10 Schematic diagram of the Active S - parameter of an antenna array according to an embodiment of the present invention;

[0041] Figure 11 Schematic diagram of the isolation degree of an antenna array unit according to an embodiment of the present invention;

[0042] Figure 12 Impedance matching situation of the optimized unit S - parameter according to an embodiment of the present invention;

[0043] Figure 13 Schematic diagram of the beam scanning performance of an antenna array according to an embodiment of the present invention;

[0044] Figure 14 Schematic diagram of the scanning performance of an antenna array in the Z - direction according to an embodiment of the present invention. Detailed implementation manners

[0045] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following.

[0046] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application with reference to the accompanying drawings. A lot of specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0047] In the description of the present application, it should be understood that if terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0048] In addition, if terms such as "first" and "second" appear, these terms are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0049] In the present application, unless otherwise clearly specified and limited, if terms such as "install", "connect", "couple", "fix", etc. appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0050] In this application, unless otherwise clearly specified and defined, when a first feature is described as being "on" or "under" a second feature or the like, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower horizontal height than the second feature.

[0051] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If present, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in this application are only for the purpose of illustration and do not represent the only implementation.

[0052] Referring Figure 1 and Figure 2 As shown, a multi-band 5G millimeter-wave antenna unit optimized based on HFSS, the antenna unit includes: a dielectric block 102, a microstrip line 104, a dielectric substrate, and a ground plane 101 covering the upper part of the dielectric substrate. A coupling slot 106 is etched on the ground plane 101, the dielectric block 102 is fixed above the coupling slot 106, the microstrip line 104 extends from one end of the bottom of the dielectric substrate towards the coupling slot 106, and is coupled to the dielectric block 102 through the coupling slot 106. The dielectric substrate is made of Rogers 4003 material, and its dielectric constant and loss tangent are 3.55 and 0.0027 respectively. The bottom of the 15mm*19mm dielectric substrate is the microstrip line 104 structure, and the upper part of the dielectric substrate is the ground plane 101 structure. At the same time, a 3.5mm*0.2mm coupling slot 106 is etched on the ground plane 101. A TP material with a dielectric constant of 4.4 and a loss tangent of 0.001 is used as the DR structure. The DR is a dielectric block 102 with a size of 4mm*4.6mm*2mm, located directly above the coupling slot 106.

[0053] Referring Figure 3 As shown, optionally, in some embodiments, a through hole 103 is opened on each side of the microstrip line 104 on the dielectric substrate. Because the processing problem needs to be considered, the ground plane 101 needs to be enlarged based on the above model, and the influence of the connector needs to be considered. The main difference from the previous model is the size of the ground plane 101, and two fixing holes are etched on the dielectric substrate to facilitate connecting the SMA connector for testing.

[0054] Optionally, in some embodiments, it further includes a second floor, which is connected to the first end of the microstrip line 104 through a through hole 103. The second end of the microstrip line 104 extends towards the coupling gap 106 and is coupled to the dielectric block 102 through the coupling gap 106.

[0055] Optionally, in some embodiments, the first end of the microstrip line 104 is aligned with the end face of the dielectric substrate to form an excitation port. The antenna is excited at the port, and the energy is transmitted through the microstrip line 104 to the coupling gap 106, and the coupling gap 106 couples the energy to the dielectric block 102.

[0056] Reference Figure 4 As shown, a multi-band 5G millimeter-wave antenna array optimized based on HFSS, the antenna array includes at least one column of antenna arrays, and the spacing between adjacent antenna elements in the antenna array is 5 mm - 6 mm. Optionally, in some embodiments, each column of antenna arrays can be arranged in different spatial dimensions to form a complete multi-dimensional antenna array. Optionally, in some embodiments, the spacing between adjacent antenna elements in the antenna array is 5.5 mm.

[0057] Reference Figure 4 As shown, on the basis of unit design, the antenna unit is extended to an array, and a 16-element antenna array is designed with an array element spacing of 5.5 mm. Each port of the array element is fed with equal amplitude and in-phase, and the maximum gain of the antenna can reach 18 dBi. There are slight column lobes and mild asymmetry in the E-plane radiation pattern of the antenna, which is mainly caused by the asymmetric feeding and the asymmetry of the floor 101.

[0058] The antenna simulation based on HFSS is as follows:

[0059] For this antenna structure, the -10 dB impedance bandwidth is 23.29–30.04 GHz, which can cover the required frequency band. Figure 5 The radiation directions of the antenna at 27 GHz in the E-plane ( Figure 5 left) and H-plane ( Figure 5 right) are given.

[0060] The antenna is excited at the port, and the energy is transmitted through the microstrip line 104 to the coupling gap 106. The coupling gap 106 couples the energy to the dielectric block 102, thereby exciting the TE 111 mode of the dielectric block 102 (denoted as DRA in the following simulation). The field distribution of this mode is as Figure 6 shown, where Figure 6 the displayed is the electric field vector distribution at 26 GHz.

[0061] The simulation results of the Z-parameters and return loss of the antenna are as Figure 7As shown, the -10 dB impedance bandwidth is 23.19 GHz – 33.21 GHz, and the absolute bandwidth is 35.5%.

[0062] To facilitate the analysis of the principle of this antenna and study the origin of each mode, next, the dimensions of the DRA in the x, y, and z directions and the dimensions of the coupling slot in the x and y directions are changed to observe the mode changes. The comprehensive analysis leads to the following conclusions:

[0063] From the results of the real part of the Z parameter varying with the DRA in the x direction, it is found that in addition to affecting the magnitude of the real part of each mode, it mainly affects the frequency points of the middle mode;

[0064] From the results of the real part of the Z parameter varying with the DRA in the y direction, it is found that in addition to affecting the magnitude of the real part of each mode, it mainly affects the frequency points of the middle mode;

[0065] From the results of the real part of the Z parameter varying with the DRA in the z direction, it is found that in addition to affecting the magnitude of the real part of each mode, it mainly affects the frequency points of the middle mode;

[0066] From the results of the real part of the Z parameter varying with the coupling slot in the x direction, it is found that in addition to affecting the magnitude of the real part of each mode, it mainly affects the frequency points of the last mode, and has the greatest impact on the last mode;

[0067] From the results of the real part of the Z parameter varying with the coupling slot in the y direction, it is found that in addition to affecting the magnitude of the real part of the first two modes, it mainly affects the frequency points of the last mode, and has the greatest impact on the last mode;

[0068] From the results of the real part of the Z parameter varying with the microstrip line in the x direction, it is found that it mainly affects the magnitude and frequency points of the real part of these three modes and has a great impact on the matching of the three modes.

[0069] Figure 8 Exemplarily, the results of the real part of the Z parameter varying with the DRA in the x direction are given.

[0070] Within this matching bandwidth, there are multiple modes in the antenna, and these modes all have an end-fire radiation pattern. Due to the feed imbalance and the asymmetry of the ground plane 101, it may cause a certain degree of pattern distortion and asymmetry, especially in the non-symmetric plane (E-plane). Taking the radiation pattern at 28 GHz as an example, as Figure 9 shown ( Figure 9 the left is the E-plane, Figure 9On the right is the H plane). It can be seen from the simulation results that when the size of the floor 101 is symmetric about the dielectric block 102, the antenna radiation pattern has good symmetry at the same time. If the size of the antenna floor 101 is relatively small, the maximum gain of the antenna will be relatively high. However, considering issues such as processing and welding joints, we have to enlarge the size of the floor 101 in the E plane. Enlarging the floor 101 will destroy the original symmetry of the pattern and cause the antenna gain to decrease. In order to ensure that the unit gain meets the requirements, on the premise of meeting the needs of processing and welding, the size of the floor 101 is reduced as much as possible. Finally, the maximum gain within the bandwidth can reach 7.5 dBi.

[0071] The antenna array simulation is as follows:

[0072] Based on the unit design, the unit is extended to an array, and an array of 16 units is designed. As Figure 4 shown, the array element spacing is 5.5 mm. Each port of the array element is fed with equal amplitude and in-phase. Its Active S parameters and element isolation are as Figure 10 and Figure 11 shown.

[0073] Compared with the antenna element, the maximum gain of the antenna array can reach 18 dBi. There are slight side lobes and mild asymmetry in the antenna E-plane radiation pattern, which are mainly caused by asymmetric feeding and the asymmetry of the floor 101.

[0074] For the convenience of processing and testing, SSMP millimeter-wave connectors are used, so the design is optimized. As Figure 2 shown, the floor 101 is introduced to the other side of the dielectric substrate through two metallized vias 103, which is convenient for mounting the millimeter-wave connector on the floor 101 shown in orange. From the simulation results, using this feeding structure has little impact on other performances except that the bandwidth becomes relatively narrow. Although the bandwidth becomes narrow, it can still cover the required frequency band. The impedance matching of the unit S parameters after optimization is as Figure 12 shown.

[0075] After optimization, the maximum gain of the array antenna can reach 16 dBi. There are slight side lobes and mild asymmetry in the antenna E-plane radiation pattern, which are mainly caused by asymmetric feeding and the asymmetry of the floor 101. The H plane has relatively good symmetry.

[0076] In order to study the influence of the element spacing on the antenna isolation, Active S parameters, radiation pattern, and gain, next, the element spacing is modified to 5 mm and 6 mm respectively, and the simulation results are checked.

[0077] It is found through analysis that: 1. The closer the antenna element spacing is, the worse the isolation between elements will be; 2. The pattern variation within the bandwidth is small, and it has an end-fire radiation pattern; 3. The maximum gain of the antenna can reach over 16 dBi; 4. Due to the reason of feed imbalance, the symmetry of the E-plane pattern is relatively poor.

[0078] By forming an antenna array with antenna elements, the antenna gain can be increased to over 16 dBi, but its beamwidth becomes very narrow. To ensure a certain antenna coverage range, by controlling the feed phase magnitude of each element, the beam can be directed to the position we want to achieve wide-range signal communication. The beam scanning performance of the array is as Figure 13 shown. Figure 13 The scanning performance at 29.5 GHz is given. At 29.5 GHz, the maximum scanning angle of the antenna is ±65°, and the maximum gain can reach 16.7 dBi.

[0079] The beam scanning performance of the millimeter-wave phased array in three dimensions realizes beam scanning within the range of ±80°, and the maximum antenna gain reaches over 16 dBi. On this basis, the antenna array in a single dimension is extended to three dimensions, and the beam scanning performance in three dimensions is as Figure 14 (Exemplarily, the scanning performance in the positive Z direction is given) shown.

[0080] After testing a single millimeter-wave antenna element, open the remaining 15 channels to test the performance of the entire millimeter-wave array. The antenna installation settings are still as Figure 4 shown. Since this antenna array has a total of 4 beam states, which are 0°, 33°, 51°, and 101° respectively, and the element amplitudes are equal-amplitude, and the corresponding adjacent element phase differences are 0°, 60°, 120°, and 180° respectively. Therefore, when testing different beam states, only the element phase difference needs to be changed. It should be noted that the gain of the 5G beamforming instrument is 17 dB. Therefore, the gain of the array obtained from the test results needs to subtract this value to obtain the true gain level.

[0081] Change the corresponding adjacent element phase differences to 0°, 60°, 120°, and 180° respectively. The test operation is the same as the above test steps. After setting the frequency sweep and scanning settings, the test can be started and wait for the test results.

[0082] The above is only the preferred implementation manner of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as an exclusion of other embodiments, but can be used in various other combinations, modifications, and environments, and can be changed within the scope of the concept described herein through the above teachings or the technology or knowledge in related fields. And any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should fall within the protection scope of the appended claims of the present invention.

Claims

1. A multi-band 5G millimeter wave antenna unit based on HFSS optimization, characterized in that: The antenna unit comprises: Dielectric block; Microstrip line; dielectric substrate; and a floor covering the upper portion of the dielectric substrate; A coupling slot is etched on the floor, the dielectric block is fixed on the coupling slot, the microstrip line extends from one end of the bottom of the dielectric substrate to the coupling slot, and is coupled with the dielectric block through the coupling slot.

2. The multi-band 5G millimeter wave antenna unit based on HFSS optimization according to claim 1, characterized in that: The dielectric block is made of TP material with a dielectric constant of 4.4 and a loss tangent of 0.

001.

3. The multi-band 5G millimeter wave antenna unit based on HFSS optimization according to claim 1, characterized in that: The dielectric substrate is made of Rogers 4003 material, and its dielectric constant and loss tangent are 3.55 and 0.0027 respectively.

4. The multi-band 5G millimeter wave antenna unit based on HFSS optimization according to claim 1, characterized in that: The dielectric block is fixed just above the coupling gap and completely covers it.

5. The multi-band 5G millimeter wave antenna unit based on HFSS optimization according to claim 1, characterized in that: The dielectric substrate has a through hole on both sides of the microstrip line.

6. The multi-band 5G millimeter wave antenna unit based on HFSS optimization according to claim 5, characterized in that: The second floor is connected to the first end of the microstrip line through the through hole, and the second end of the microstrip line extends to the coupling slot and is coupled to the dielectric block through the coupling slot.

7. The multi-band 5G millimeter wave antenna unit based on HFSS optimization according to claim 6, characterized in that: The first end of the microstrip line is aligned with the end surface of the dielectric substrate to form an excitation port.

8. A multi-band 5G millimeter wave antenna array based on HFSS optimization, characterized in that: The antenna array comprises: at least one antenna array; The antenna array is composed of a plurality of antenna units as described in any one of claims 1 to 7, and the spacing between adjacent antenna units in the antenna array is 5 mm to 6 mm.

9. The multi-band 5G millimeter wave antenna array based on HFSS optimization according to claim 8, characterized in that: Each column of the antenna array may be arranged in different spatial dimensions to form a complete multi-dimensional antenna array.

10. The multi-band 5G millimeter wave antenna array based on HFSS optimization according to claim 8, characterized in that: The spacing between adjacent antenna units in the antenna array is 5.5 mm.

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