Detailed Description
In order to describe the technical contents, the achieved objects and effects of the present invention in detail, the following description will be made with reference to the embodiments in conjunction with the accompanying drawings.
The most critical concept of the invention is as follows: the radiator structure of the antenna unit comprises a single-stage antenna and a loop antenna which is formed by encircling the single-stage antenna and connecting the single-stage antenna with a PCB board, and each radiator generates a mutually independent resonance, so that the antenna has double resonances and meets the frequency band requirements of 37GHz and 39GHz 5G millimeter waves which are newly defined by FCC.
Technical term explanation related to the invention:
referring to fig. 1, the present invention provides a dual-frequency array antenna for fifth-generation wireless communication, where an antenna unit of the dual-frequency array antenna includes a first antenna radiator and a second antenna radiator disposed on a surface of a stereo antenna carrier;
the first antenna radiator is a monopole antenna; the second antenna radiator is a loop antenna which is arranged around the first antenna radiator and is connected with the ground of the PCB.
As can be seen from the above description, the invention has the beneficial effects that: the antenna unit of the invention is directly fed by a monopole antenna with the working frequency of 1/4 wavelength formed by a first antenna radiator, and a resonance point with the frequency of 36-40GHz is generated; the first antenna radiator is surrounded and connected with the ground of the PCB to form a loop antenna with the working frequency of 1 wavelength, and another resonance point with the frequency of 36-40GHz can be generated; the lengths of the first antenna radiator and the second antenna radiator are adjusted so that the resonance frequency generated by the first antenna radiator is larger or smaller than the resonance frequency generated by the second antenna radiator, and therefore the antenna comprises two 5G frequency bands of 37GHz and 39GHz which are newly defined by FCC; and has the characteristics of small size, large bandwidth, high gain and efficiency, good directivity and stable performance.
Further, the second antenna radiator is connected with the ground of the PCB through a via hole on the PCB.
As can be seen from the above description, the second antenna radiator on the surface of the three-dimensional antenna carrier cannot form a complete loop by itself, and the two end points of the second antenna radiator are connected to the ground through the via hole on the PCB board to form a complete loop, thereby forming a loop antenna with an operating frequency of 1 wavelength and generating a resonance point with a frequency in the range of 36-40 GHz.
Referring to fig. 2, further, the three-dimensional antenna carrier is connected with the PCB board through a bonding pad; the bonding pad is connected with two end points of the second radiator antenna, and the via hole is arranged on the bonding pad.
As can be seen from the above description, the pad connection manner not only can improve the connection stability between the three-dimensional antenna carrier and the PCB board, but also is easy to install; but also facilitates the ground connection of the second radiator antenna to the PCB.
Further, a first bonding pad and a second bonding pad are respectively arranged on the bottom surface of the three-dimensional antenna carrier corresponding to the two end points of the second antenna radiator; the upper surface of the PCB is provided with a third bonding pad and a fourth bonding pad corresponding to the first bonding pad and the second bonding pad respectively; the two end points are respectively correspondingly connected with the first bonding pad and the second bonding pad, the first bonding pad and the second bonding pad are correspondingly connected with the third bonding pad and the fourth bonding pad respectively.
As can be seen from the above description, the carrier and the upper surface of the PCB board are firmly connected by welding the four pads, so that the carrier is not easy to fall off; meanwhile, the carrier is convenient to install; further, the stability of the connection of the second radiator and the PCB is also ensured.
Further, a fifth bonding pad connected with the bottom surface of the three-dimensional antenna carrier is arranged corresponding to the feeding point of the first antenna radiator; and a sixth bonding pad connected with the fifth bonding pad is arranged on the upper surface of the PCB corresponding to the fifth bonding pad.
As can be seen from the above description, the arrangement of the fifth bonding pad can not only ensure stable feed connection of the first antenna radiator; but also can further promote the connection stability between the carrier and the PCB.
Further, the three-dimensional antenna carrier is rectangular three-dimensional ceramic; the second antenna radiator is arranged along the ridge line of the rectangular three-dimensional ceramic.
As can be seen from the above description, the three-dimensional antenna carrier is rectangular, and has good stability; and the arrangement of the radiators is convenient. The second antenna radiator is designed to be arranged along the ridge line of the carrier, so that the production is convenient, and the second antenna radiator is not easy to fall off; the overlapping of the radiators can be effectively prevented, and the radiators are guaranteed to have good working performance; and is more beautiful.
Since the size of the antenna radiator (antenna element) is determined by the dielectric constant of the antenna carrier, the larger the dielectric constant of the carrier, the shorter the wavelength and thus the overall size of the antenna can be reduced. The carrier is made of ceramic material, and has ideal dielectric constant, so that the sizes of the single-stage (monopole) antenna with 1/4 wavelength and the annular (loop) antenna with one wavelength required by the carrier are also reduced, the whole size of an antenna monomer is reduced, the whole size of an array antenna is reduced, and the carrier is better suitable for miniature communication equipment.
Further, the first antenna radiator is arranged on one side face of the rectangular solid ceramic; the second antenna radiators are distributed on the side face, the upper surface of the rectangular three-dimensional ceramic and the side face adjacent to the side face.
As can be seen from the above description, the arrangement of the first antenna radiator and the second antenna radiator not only ensures that the first antenna radiator and the second antenna radiator form a desired resonance point; and is not easy to fall off.
Referring to fig. 3, further, the antenna further includes a feed network, where more than two antenna units are connected to the feed network; the distance between each antenna unit is between 1/2 and 1 wavelength of the working frequency of the dual-frequency array antenna.
Further, the feed network is formed by mutually cascading 2n-1 power distributors; the number of the antenna monomers is 2 n; and n is a positive integer.
Further, the feed network comprises 2 n-1T-shaped network nodes, and each T-shaped network node comprises an impedance converter with 1/4 wavelength relative to the central working frequency of the dual-frequency array antenna.
From the above description, it will be appreciated that the microstrip line feed network in parallel is used in the example of the present invention, although other forms of feed networks, such as series or series-parallel hybrid, may be used. The dual-frequency array antenna can overcome the problems of high 5G frequency, large loss in air and short transmission distance, ensure that the transmission distance reaches the standard, and increase the gain of the antenna so as to meet the requirement of long-distance transmission communication.
Example 1
Referring to fig. 1, 3 and 5, the present embodiment provides a dual-frequency array antenna for fifth-generation wireless communication, which can simultaneously include large bandwidths of two frequency bands of 37GHz and 39GHz, and has the advantages of high gain and radiation efficiency, good directivity, and the like, and can provide a millimeter wave antenna array system for future 5G communication for mobile devices.
The dual-frequency array antenna comprises a plurality of antenna monomers 1 and a feed network 2, wherein the antenna monomers 1 are connected with the feed network 2. Each antenna unit 1 comprises a three-dimensional antenna carrier 4 and a PCB 7; the surface of the three-dimensional antenna carrier 4 is provided with a first antenna radiator 5 and a second antenna radiator 6 in a surrounding mode, different resonance points are respectively generated, and the double-frequency characteristic is achieved. Each resonance point is created by a different antenna branch, in particular:
the first antenna radiator 5 is a monopole antenna with a working frequency of 1/4 wavelength, the feeding point of the monopole antenna is connected with the upper surface of the PCB 7, and a resonance point with an antenna frequency of 36-40GHz range is formed by directly feeding the first antenna radiator, that is, the first antenna radiator 5 itself is used as all antenna branches to generate the resonance point.
The second antenna radiator 6 is connected with the ground of the PCB 7 through two end points thereof to form a ring-shaped loop, and the working frequency of the ring-shaped loop is one wavelength; the second antenna radiator 6 surrounds the first antenna radiator 5 therein, and a coupling relationship is obtained, whereby the second antenna radiator 6 forms another resonance point having an antenna frequency in the range of about 36-40GHz by coupling with the first antenna radiator 5.
Preferably, the first antenna radiator 5 and the second antenna radiator 6 may be respectively formed into two resonance points having frequencies of about 39GHz and about 36GHz by adjusting the dimensions, and of course, may be interchanged and adjusted by adjusting the dimensions.
The antenna unit 1 formed by the structure has the characteristics of double frequencies as can be seen from the return loss diagram of the antenna unit in fig. 4, and the working frequency band of the antenna is expanded to 37GHz and 39GHz, so that the antenna unit 1 can be well suitable for communication of millimeter wave frequency band of a 5G antenna in the future.
It should be noted that, the feeding network 2 in this embodiment may be in a form of series connection, parallel connection or a form of series-parallel connection; either a microstrip line based feed network or a substrate integrated waveguide type of form.
Referring to fig. 3, preferably, the feeding network 2 is a parallel microstrip feeding network, and is formed by cascading 2n-1 power splitters, and includes 2 n-1T-shaped network nodes 3, where each T-shaped network node 3 includes an impedance converter with 1/4 wavelength of the working frequency of the corresponding antenna, and the characteristic impedance of other microstrip lines can be set to be 50 ohms. The number of the antenna monomers 1 is 2n, and the distance between each antenna monomer 1 is 1/2 to 1 wavelength of the working frequency of the antenna center.
Referring to fig. 5, in order to provide a return loss diagram of a dual-frequency array antenna with 8 antenna elements 1, the return loss of the feed network 2 in this embodiment is about-28 dB, which well meets the requirements of the antenna array; the distance between each antenna element 1 of the antenna array is about 0.65 wavelength.
Example two
Referring to fig. 2, the present embodiment further expands the structure of the dual-band antenna unit based on the first embodiment.
Specifically, the bottom surface of the three-dimensional antenna carrier 4 of the antenna unit 1 is provided with a first bonding pad 11 and a second bonding pad 12 corresponding to two end points of the second antenna radiator 6. The PCB 7 comprises a PCB substrate 8 and a PCB floor 9; a third bonding pad 13 and a fourth bonding pad 14 are respectively arranged on the upper surface (the PCB substrate 8) of the PCB 7 corresponding to the first bonding pad 11 and the second bonding pad 12, and are connected with the PCB floor 9 through a via hole 10; the two end points of the second antenna radiator 6 are respectively and correspondingly connected with the first bonding pad 11 and the second bonding pad 12, and the first bonding pad 11 and the second bonding pad 12 are respectively and correspondingly connected with the third bonding pad 13 and the fourth bonding pad 14.
The solid antenna carrier 4 and the PCB 7 are firmly connected through four bonding pads; meanwhile, the second antenna radiator 6 can also be connected with the ground of the PCB board 7 by means of a bonding pad, thereby forming a loop. Specifically, the third bonding pad 13 and the fourth bonding pad 14 on the PCB 7 are provided with vias 10 that are in communication with the ground, and preferably, the number of the vias 10 is more than two; the two end points of the second antenna radiator 6 can be connected with the ground of the PCB board through bonding pads to form a loop antenna.
Further, a fifth bonding pad 15 connected with the bottom surface of the stereo antenna carrier 4 is arranged corresponding to a feeding point 17 of the first antenna radiator 5, a sixth bonding pad 16 connected with the fifth bonding pad 15 is arranged corresponding to the upper surface of the PCB 7, and the first antenna radiator 5 is directly fed through an array feeding point 19 to obtain the second resonance of the antenna.
Preferably, the first pad 11, the second pad 12, the third pad 13, the fourth pad 14, the fifth pad 15, and the sixth pad 16 are elongated.
In the embodiment, the arrangement of the bonding pads not only can ensure the stable connection between the carrier and the PCB 7; but also provides a channel for the connection of the second antenna radiator 6 to the PCB board 7 and feeds the first antenna radiator 5 directly.
Example III
The present embodiment further expands the structure of the dual-band antenna unit on the basis of the first embodiment and the second embodiment.
Specifically, the stereo antenna carrier 4 may be a rectangular stereo structure (a cube structure or a cuboid structure), or may be a cylindrical stereo structure such as a cylinder; the material can be ceramic or other materials with good dielectric constants. In this embodiment, the three-dimensional antenna carrier 4 is rectangular three-dimensional ceramic.
Since the size of the antenna radiator is determined by the dielectric constant epsilon of the antenna carrierr The larger the dielectric constant of the carrier, the shorter the wavelength is determined. In this embodiment, since dielectric constant ε is usedr The dielectric constant of the ceramic material of 8.0 is large, so that the size of the antenna radiator can be reduced, the size of the antenna unit can be reduced, the whole size of the obtained array antenna can be reduced, and the antenna can be better suitable for microminiature equipment.
Preferably, the length, width and height of the rectangular three-dimensional ceramic are respectively 0.9mm, 0.75mm and 0.9mm, but the rectangular three-dimensional ceramic is not limited to the length, and the required dual-frequency resonance can be obtained by properly adjusting the size of the radiator and changing the dielectric constants of the carrier, for example, ceramic materials with different dielectric constants are adopted for simple adjustment.
It should be noted that, the rectangular three-dimensional ceramic can be directly welded with the PCB board through the bonding pad, so that firm connection is ensured, and the rectangular three-dimensional ceramic is easy to install. Different from the existing antenna form of PATCH (PATCH), namely, the PATCH is manufactured on a multi-layer PCB board, so that the antenna design lacks flexibility, when the theoretically designed antenna is inconsistent with the actual design (the situation often occurs, because the environment around the antenna cannot be considered in the theoretical design), the whole PCB board has to be manufactured again, and the PATCH type ceramic antenna does not need to be manufactured again on the PCB board, and only the rectangular three-dimensional ceramic itself is modified appropriately. In addition, the area or size of the patch antenna on the surface of the PCB is far larger than that of the three-dimensional antenna in the invention, so the antenna array based on the patch antenna occupies a larger area on the PCB. The stereoscopic antenna of the present invention is more suitable for use in a handheld device than a patch-based antenna because of the limited space available in the handheld device.
Further, the arrangement of the first antenna radiator 5 and the second antenna radiator 6 on the rectangular solid ceramic may be:
the first antenna radiator 5 as a monopole antenna is vertically arranged on the side of the rectangular solid ceramic, the feed end of which is connected with the PCB board 7, and the other end of the suspended arrangement can be located in the side, extended to the upper surface of the rectangular solid ceramic, or extended to the other side opposite to the side depending on the required frequency range. In this embodiment, the first antenna radiator 5 is vertically disposed at a middle position of a side surface of the rectangular solid ceramic, and the suspension end and the feeding end thereof are both located in the side surface.
The second antenna radiator 6 is arranged along the ridge line 18 of the rectangular solid ceramic, and surrounds the first antenna radiator 5. Preferably, one end of the second antenna radiator 6 extends from the side surface of the first antenna radiator 5 to the upper surface along the ridge line 18, and then extends to the top point around the three edges of the upper surface, and then extends downwards from the ridge line on the adjacent surface of the side surface and shared with the side surface to the PCB; the second antenna radiator 6 is distributed on the side surface, the upper surface of the rectangular solid ceramic and the side surface adjacent to the side surface to form a convex shape.
The first antenna radiator 5 and the second antenna radiator 6 of the above-described structure provided on the rectangular solid ceramic of the above-described size can generate a first resonance point of 39.544GHz by the first antenna radiator 5; another resonance point with the frequency of 36.005GHz is generated by the second antenna radiator 6, so that the array antenna obtains two frequency bands of 37GHz and 39GHz simultaneously. It should be noted that, the resonance points obtained by the radiators of the present embodiment are only a specific embodiment, and the resonance generated by the first antenna radiator 5 and the second antenna radiator 6 can be interchanged and adjusted by adjusting the dimensions.
Referring to fig. 4, the array antenna of the present embodiment may include two frequency bands of 37GHz and 39GHz (i.e., 37GHz-40 GHz). FIG. 6 is a graph of maximum gain for an antenna array, the gain for the antenna array being greater than 12.9dB over the range of 37-40 GHz; the gain of the antenna will increase as the number of antenna elements included in the antenna array increases. Fig. 7 shows a three-dimensional radiation pattern of the antenna array at a frequency of 40GHz, and it can be seen that the antenna array system has a good radiation directivity, and that the maximum is distributed in the whole YZ plane, that is, the antenna system can be used to receive and transmit 5G signals at any angle in the YZ plane, which is just suitable for the application of the handheld device, that is, the 5G signals can be received at one side of the screen but at the back of the device. In addition, the antenna array has higher radiation efficiency, and the radiation efficiency of the antenna array is more than-1.0 dB in the working frequency band. Figures 8-10 are two-dimensional radiation patterns at frequencies of 37GHz, 38.5GHz and 40GHz, respectively, from which it can be seen that the antenna array has a relatively uniform directivity at each frequency point. In addition, the antenna array can be extended to other 5G working frequency bands, such as 28GHz or 60 GHz.
In summary, the dual-frequency array antenna for fifth-generation wireless communication provided by the invention not only has dual resonance, but also can contain two large bandwidth frequency bands of 37GHz and 39 GHz; the gain and efficiency are high, and the directivity is good; furthermore, the installation between the device and the PCB is simple and firm; still further, the carrier of ceramic material makes the antenna have small characteristics. In addition, as with other antenna array designs, the antenna array based on the three-dimensional antenna unit provided by the invention can control the beam direction of the antenna array by adding the phase adjuster into the feed network, thereby realizing the beam forming and the beam scanning of the antenna array.
The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent changes made by the specification and drawings of the present invention, or direct or indirect application in the relevant art, are included in the scope of the present invention.