This application claims the priority of Chinese patent application No. 201710261516.5, filed Apr. 20, 2017, which is incorporated by reference in its entirety.
This disclosure relates generally to the technical field of antenna. More specifically, this disclosure relates to the mobile terminal antenna in 28 Gigahertz (GHz) with reconfigurable radiation pattern.
Recently, with the rapid development of wireless communication technology, the fourth generation (4G) network technology (up-link rate of 20 megabits per second (Mbit/s) and down-link rate of 100 Mbit/s) is basically able to meet the needs of a variety of mobile communications services. However, with the rapid development of mobile Internet technology and Internet of things technology, it almost subverts the traditional mobile communication business models. These emerging mobile communication services have provided new demands for the development of mobile communication networks, such as high traffic density, mass connections and ultra-low latency, which have led to the research and development of fifth generation (5G) communication technology. At present, the standardization of 5G mobile communication technology is gradually completed, and the equipment using 5G technology will also be gradually commercial around 2020. The data services of Giga-bit level in 5G will give users a totally new experience.
Through using the millimeter (mm) wave antenna, the problem of narrow bandwidth is solved. Through using the antenna array and beamforming technologies, the problem of attenuation of free space in millimeter wave band is solved. However, the problem of radiation direction in the 5G antenna is still existed. A typical radiation pattern of a 4G antenna which is an omnidirectional antenna. The radiation pattern is approximately circular in the horizontal direction, so it can achieve a full signal coverage of free space in horizontal direction with appropriate gain. A typical radiation pattern of a 5G antenna which is a directional antenna. The signal can only be transmitted and received in specified direction range pointed by terminal antenna. Even if the beam scanning is realized by phase shifter, it can only extend the signal radiation range in the lateral direction of radiation pattern of antenna array, and other directions remain blind spots of signal radiation, therefore it is difficult to achieve omnidirectional radiation characteristic of 4G antennas.
In view of this, the technical problem to be solved of this disclosure is to provide an antenna array with different radiation patterns through switching between different sub-arrays, therefore the 5G terminal antenna with a reconfigurable radiation pattern can be realized.
In order to solve the above technical problems, the technical scheme provided by this disclosure is a 5G terminal antenna with a reconfigurable radiation pattern, which includes two or more antenna sub-arrays with different radiation patterns and a switch that is connected with each antenna sub-array and controls the switching between the different antenna sub-arrays.
This disclosure relates to a 5G terminal antenna in 28 GHz with a reconfigurable radiation pattern. A switching scheme is achieved by switching between two or more different antenna sub-arrays. The different sub-arrays have different radiation patterns with a certain angle, the radiation pattern of the different angles can be realized by switching between the different sub-arrays. By switching between the different sub-arrays, the radiation pattern in the desired directions can be selected, and the signal coverage in hemispherical space over the mobile terminal can be realized.
The described switch can be one of the following low loss switch: a single-pole-double-throw (SPDT) switch, a double-pole-double-throw (DPDT) switch, a single-pole-three-throw (SP3T) switch or a single-pole-three-throw (DP3T) switch, and so on.
Preferably, the two different antenna sub-arrays intersect each other. The antenna array has the advantages of simple structure and small size, and can be positioned at the top, the bottom, the left and the right sides of the hand-held mobile terminal device.
Preferably, the described switch is disposed between the antenna sub-arrays and a radio frequency (RF) frontend module. By accessing the RF frontend module, the antenna array can be used as a transmitting antenna or as a signal receiving antenna within the range of RF signal coverage.
Preferably, the RF frontend module includes a phase shifter. One end of the phase shifter is connected with the signal input port, and the other end is connected with the switch through a transceiver module. A phased array antenna with beam scanning can be formed by using phase shifters. Through changing the amplitude and phase of each antenna element, the beam scanning of each antenna sub-array can be realized. Each antenna sub-array itself can scan from −90 degrees to +90 degrees (Theta planes).
Preferably, the antenna array is composed of a plurality of antenna elements. The antenna element can be one or more of a slot antenna, an electric dipole antenna or a patch antenna. An antenna sub-array is composed of the above mentioned antenna elements. The combination of the radiation patterns of each antenna sub-arrays forms the signal coverage in hemispherical space over the 5G mobile terminal. Considering the radiation pattern after switching which need to realize the signal coverage in hemispherical space over the 5G mobile terminal, in the case of setting two antenna sub-arrays, at least one sub-array can achieve bidirectional radiation. In the case of setting three antenna sub-arrays, each antenna sub-array need to have a better beam width in the specified directions. In the case of setting two antenna sub-arrays, one antenna sub-array need to have a broadside radiation pattern on the top and bottom of the mobile terminal main board and another antenna sub-arrays need to have an end-fire radiation pattern on the end surface of the mobile terminal main board. Through switching between two different antenna sub-arrays, the switching between different radiation patterns can be realized, therefore the reconfigurable radiation pattern of the 5G terminal antenna is realized.
The combination of a slot antenna and an electric dipole antenna has the advantages of simple structure, small size and is convenient to the integrated at the end of the mobile terminal main board. The antenna array consisting of several T slot antenna elements has a bilateral radiation pattern on the top and bottom of the mobile terminal main board. The antenna array consisting of several electric dipole antenna elements has an end-fire radiation pattern at the end surface of the mobile terminal main board. Through switching between two different antenna sub-arrays, the switching between different radiation patterns can be realized, therefore the reconfigurable radiation pattern of the 5G terminal antenna is realized. By switching between the different sub-arrays, the radiation in the desired directions can be selected. Therefore, the problem of the narrow beam coverage of the 5G terminal antenna in millimeter wave band can be solved effectively. So the beam scanning angle can be expanded by combining beam scanning and other methods.
Preferably, the patch antenna includes a printed circuit board (PCB) substrate. A metal sheet is disposed on the top of the PCB substrate and a reference ground is disposed on the bottom of the PCB substrate. The patch antenna also includes a coaxial probe. An inner core at one end of the coaxial probe is connected with the metal sheet, and the other end of the coaxial probe passes through the PCB substrate and serves as a feed point.
As one of the implementation methods, three microstrip patch antenna sub-arrays are arranged on three different planes on the upper, lower and the end of the main board and the signal coverage of the antenna array in three directions is achieved respectively. Through switching between three antenna sub-arrays on different planes, the switching between the upper, lower and the end of the main board can be realized, therefore the reconfigurable radiation pattern of the 5G terminal antenna is realized.
Preferably, the described slot antenna can be one of a T-slot antenna, an I-slot antenna or a co-planar tapered slot antenna. The slot antenna is used to form a bilateral radiation pattern on the top and bottom of the mobile terminal main board.
Preferably, when the slot antenna is a T-slot antenna, which includes a PCB substrate. A metal copper foil is disposed on the top and bottom of the PCB substrate respectively. A T-slot is opened on the metal copper foil. A metal strip is located in the longitudinal gap of the T-slot on the top of the PCB substrate. A feed point is located at the lower end of the metal strip. Several metal vias are evenly distributed around the T-slot on the PCB substrate.
When the slot antenna is an I-slot antenna, which includes a PCB substrate. A metal I-slot passes through the PCB substrate. A metal layer on the PCB substrate is connected with the inner copper plating layer of the metal I-slot. A coaxial probe is used to feed the I-slot and is located in the width direction of the metal I-slot.
When the slot antenna is a co-planar slot antenna, which includes a PCB substrate. A metal copper foil is disposed on the top and bottom of the PCB substrate respectively. Two co-planar tapered slot are opened symmetrically on the metal copper foil. The co-planar slot includes an I-slot, a tapered slot and a rectangular slot. A co-planar waveguide feeder line is located at the symmetrical axis of the co-planar tapered slot and a feed point is located at the end of the co-planar waveguide feeder line.
Preferably, an electric dipole antenna includes an upper conductive module and a lower conductive module. A two-layer substrate is located between the upper conductive module and the lower conductive module. A feeder line is located in the middle of the two-layer substrate. The upper conductive module is connected with the feeder line through a metal via and the lower conductive module is connected with the reference ground.
Preferably, an electric dipole antenna can be one of a surface mount technology (SMT) electric dipole antenna, a printed electric dipole antenna or a metal via electric dipole antenna. The electric dipole antenna has an end-fire radiation pattern at the end surface of the mobile terminal main board.
When the electric dipole antenna is an SMT electric dipole antenna, which includes a symmetrically set of metal block 1 and metal block 2. A metal sheet 1 and a metal sheet 2 are respectively arranged on the opposite surfaces of the metal block 1 and the metal block 2. A two-layer substrate is located between the metal block 1 and the metal block 2. A feeder line is in the middle of the two-layer substrate. The metal sheet 1 is connected with the feeder line through the metal vias 191 and the metal sheet 1 is connected with the reference ground.
When the electric dipole antenna is a printed electric dipole antenna, which includes the first substrate, the second substrate, the third substrate and the fourth substrate. A metal sheet 1 is located at the side of the first substrate. A metal sheet 2 is located on the top of the second substrate and is connected with the metal sheet 1. A metal sheet 3 is located on the bottom of the third substrate. A metal sheet 4 is located at the side of the fourth substrate and is connected with the metal sheet 3. A feeder line is located between the second substrate and the third substrate. The metal sheet 2 is connected with the feeder line through the metal vias 191 and the metal sheet 3 is connected with the reference ground.
When the electric dipole antenna is a metal via electric dipole antenna, which includes the first substrate, the second substrate, the third substrate and the fourth substrate. A metal via 1 and a metal via 2 are located at edge of the first substrate and the fourth substrate respectively. A metal sheet 1 is located on the top of the metal via 1. A metal sheet 2 is located on the bottom of the metal via 1 and is connected with the metal sheet 1 through the metal via 1. A metal sheet 3 is located on the top of the metal via 2. A metal sheet 4 is located on the bottom of the metal via 2 and is connected with the metal sheet 3 through the metal via 2. A feeder line is located between the second substrate and the third substrate. The metal sheet 2 is connected with the feeder line through the metal via 191 and the metal sheet 3 is connected with the reference ground.
There are basically two ways to increase the wireless transmission rate, one is to increase the spectrum efficiency, and the other is to increase the bandwidth of the spectrum, which is particularly more important. Compared with the 100 MHz spectral bandwidth in the band below 3 GHz, the millimeter wave band has the natural advantage of several GHz spectral bandwidth. However, the millimeter wave band attenuates greatly in the air, and the diffraction ability is weaker, so the gain requirement of the antenna is relatively higher. Therefore, this disclosure adopts an antenna array, and each antenna element has its own amplitude and phase. By effectively controlling the amplitude and phase of each antenna element, the emitted electromagnetic waves from each antenna element cancel or reinforce each other. The limited energy is concentrated to be transmitted in a beam, and the energy transmission density is obviously enhanced, which can compensate for the fast attenuation spectrum characteristic of the millimeter wave.
The 5G terminal antenna solves the problem of narrow band width by adopting the millimeter wave antenna. Through the antenna array and beam forming technology, the problem of fast attenuation is solved, and the beam scanning is realized by using phase shifters to control the phase of the antenna elements.
Compared with the existing technologies, this disclosure has the following advantages, this disclosure proposes an antenna system with a reconfigurable radiation pattern characteristic for the fifth generation (5G) mobile terminal, which includes two or more antenna sub-arrays. A switch is disposed between the plurality of antenna sub-arrays and the RF front-end module. By switching between the different sub-arrays, the radiation in the desired direction can be selected. Therefore, the problem of the beam coverage and beam scanning blind spot of 5G terminal antenna in millimeter wave band can be solved effectively. Through expanding the scanning angle of the beam scanning, the scheme of 5G terminal antenna with a reconfigurable radiation pattern can be realized. The antenna structure of this disclosure makes full use of the space of the PCB board, and has the advantages of miniaturization, simple processing and compact structure, etc.
Embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements.
In order to facilitate the understanding of technical personnel in the field, this disclosure will be described in further detail in conjunction with the accompanying drawings and embodiments.
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The above mentioned two-layer substrate is a multiple layer laminated PCB substrate in the embodiment of this disclosure. Based on the comprehensive consideration of functionality and cost, a two layer laminated PCB substrate with permittivity of 4.4 is adopted. The thickness of PCB is 1 mm and the thickness of the first substrate 11 and the second substrate 12 is 0.5 mm respectively. A T-slot is opened on the metal copper layer on the top and bottom of the two layer laminated PCB substrate and is symmetrical with the metal strip 2. The metal vias 181 are evenly distributed around the T-slot. To ensure the continuity of the reference ground around the T-slot, the metal vias 181 pass through the two layer laminated PCB substrate and are connected with the upper metal copper foil 171 and the lower metal copper foil 172. The distance between the adjacent metal vias of the metal vias 181 should be less than a quarter of waveguide wavelength and the diameter of the metal vias should preferably be less than one eighth of waveguide wavelength.
Within the structure of the electric dipole antenna, the rectangular metal block 8 is located at the edge of the PCB substrates 4 and 5, and the long edge of the metal block 8 is along the length direction of the PCB substrates 4 and 5. The wide edge of the first metal block 13 is along the width direction of the two layer substrates and is parallel with the length direction of the feeder line 192. The first metal sheet 15 and the second metal sheet 16 are symmetrical with the feeder line 192. In order to facilitate SMT process and guarantee the solidity of the SMT, the size of the first metal block 13 shall be smaller than the size of the first metal sheet 15 and the second metal sheet 16. The first metal block 13 is located in the middle of the two T-slot antennas and there is a gap between the first metal block 13 and the transverse slot of the T-slot to reduce the mutual influence between the first metal block 13 and the T-slot antenna.
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The structure of the T-slot antenna in this embodiment is the same as embodiment 1. The electric dipole antenna of this embodiment adopts a metal via electric dipole antenna. The antenna array includes a four layer laminated PCB substrate: a first substrate 21, a second substrate 22, a third substrate 23, and a forth substrate 24. The T-slot is located at the second and the third layer of the four layer laminated PCB substrate. The T-slot is opened on the second and the third layer of the four layer laminated PCB substrate, and the T-slot antenna is fed by a co-planar waveguide (CPW). The electric dipole is composed of two rows of metal vias, which are punched in thickness direction of the first substrate 21 and the fourth substrate 24 of the four layer PCB substrate. The metal vias 25 and the metal vias 26 are disposed at the edges of the first substrate 21 and the fourth substrate 24 to form an electric dipole structure. The metal sheet 251 is located on the top of the metal vias 25. The metal sheet 252 is located on the bottom of the metal vias 25 and is connected with the metal sheet 251 through the metal vias 25. The metal sheet 261 is located on the top of the metal vias 26. The metal sheet 262 is located on the bottom of the metal vias 26 and is connected with the metal sheet 261 through the metal vias 26. The two layer substrate of the T-slot antenna includes the second substrate 22 and the third substrate 23, and same as embodiment 1, the feeder line is located between the second substrate 22 and the third substrate 23. The second metal sheet 252 is connected with the feeder line through the metal vias 27. Same as embodiment 1, the metal copper foil 271 is located on the top of the second substrate 22, and the metal copper foil 272 is located on the bottom of the third substrate 23. There is a gap between the second metal sheet 252 and the metal copper foil 271 on the top of the second substrate 22. The third metal sheet 261 is connected with the metal copper foil 272 on the bottom of the third substrate 23 and is also connected with the reference ground.
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The structure of the T-slot antenna in this embodiment is the same as embodiment 1. The electric dipole antenna of this embodiment adopts a printed electric dipole antenna. The antenna array includes a four layer laminated PCB substrate: the first substrate 31, the second substrate 32, the third substrate 33 and the forth substrate 34. A T-slot is located at the second and the third layer of the four layer laminated PCB substrate. The T-slot is opened on the second and the third layer, and the T-slot antenna is fed by the CPW. The printed electric dipole is realized by attaching the metal sheet to the side of the thickness direction of the upper substrate and the lower substrate by adopting the PCB hemming process. The first metal sheet 35 is located at the side of the first substrate 31. The second metal sheet 36 is located at the upper edge of the second substrate 32 and is connected with the first metal sheet 35. The third metal sheet 38 is located at the lower edge of the third substrate 33. The forth metal sheet 37 is located at the side of the forth substrate 34 and is connected with the third metal sheet 37. There is a gap between the second metal sheet 36 and the metal copper foil on the second substrate 32. The third metal sheet 38 is connected with the metal copper foil on the third substrate 33. A feeder line is located between the second substrate 32 and the third substrate 33. The second metal sheet 36 is connected with the feeder line through the metal vias. The third metal sheet 38 is connected with the reference ground. The electric dipole consists of the first metal sheet 35, the second metal sheet 36, the third metal sheet 38, the forth metal sheet 37, the metal vias and the feeder line. The feeder line is located between the second substrate 32 and the third substrate 33. One end of the feeder line is connected with the metal vias, and the other end of the feeder line is connected with the feed point, therefore the direct feed of the electric dipole antenna is realized.
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This embodiment includes a two-layer substrate: a first substrate 41 and a second substrate 42. The structure of electric dipole antenna is basically the same as the embodiment 1. The difference is that the metal vias 44 are evenly distributed at the both sides of the feeder line 45. The metal vias are connected with the metal copper foil on the top and the bottom of the two layer PCB substrate. The slot antenna adopts an I-slot antenna in this embodiment. The I-slot 43 passes through the two layer substrate and the metal copper foil on the top and the bottom of the two layer substrate. The metal copper foil 431 is located around the I-slot 43 and is connected with the inner surface of the I-slot 43. The I-slot antenna is fed by the coaxial probe 432, which is located at the width direction of the I-slot. The I-slot 43 is filled by air.
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This embodiment includes a four-layer substrate: a first substrate 51, a second substrate 52, a third substrate 53, and a forth substrate 54. The structure of the metal via electric dipole antenna is basically the same as the embodiment 2. The difference is that the metal vias 57 are evenly distributed at the both sides of the feeder line 45. The metal vias 57 is connected with the first metal copper foil 55 on the top of the second substrate 52 and the second metal copper foil 56 on the bottom of the third substrate 53. The metal vias 57 passes through the first metal copper foil 55, the second substrate 52, the third substrate 53 and the second metal copper foil 56. The feeder line is located between the second substrate 52 and the third substrate 53 (not shown in the figure and the structure is similar to the embodiment 2). The slot antenna adopts a co-planar tapered slot antenna, which is also called a complementary dipole antenna. Two symmetrical co-planar slot are opened on the first metal copper foil 55. The co-planar slot includes an I-slot 551, a tapered slot 552, and a rectangular slot 553. The CPW feeder line 554 is located at the symmetrical axis of two co-planar tapered slots. The feed point is located at the end of the CPW feeder line and the co-planar tapered slot is fed by the CPW. The corresponding region of the rectangular slot 553 on the second metal copper foil 56 is a clearance area.
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The substrate 61 in this disclosure is a single layer substrate. Based on the comprehensive consideration of functionality and cost, a PCB substrate with permittivity of 4.4 is adopted. The thickness of PCB is 1 mm. The rectangle metal sheet is located at the center of the PCB substrate. The connection point of the coaxial probe and the rectangular metal sheet is disposed in the length direction of the rectangular metal sheet, and has an equal distance to the both sides of the rectangular metal sheet. The length of the rectangular metal sheet is about λ g/2, and λ g is the wavelength of the electromagnetic wave in the PCB substrate.
The above are the concrete embodiments of the disclosure. The descriptions are very specific and detailed, but it cannot be understood as a limitation of the scope of the disclosure. It should be noted that the ordinary technical staff in the field, without departing from the disclosure concept, also can make some deformation and improvement, these obviously substitute forms belong to the scope of the disclosure.
Number | Date | Country | Kind |
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2017 1 0261516 | Apr 2017 | CN | national |
Number | Name | Date | Kind |
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9001917 | Tzanidis | Apr 2015 | B2 |
9570809 | Ganchrow | Feb 2017 | B2 |
10135149 | Zhou | Nov 2018 | B2 |
20170012359 | Jung | Jan 2017 | A1 |
Number | Date | Country | |
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20180309198 A1 | Oct 2018 | US |