CN112751162B

CN112751162B - Mobile terminal

Info

Publication number: CN112751162B
Application number: CN201911065561.9A
Authority: CN
Inventors: 孙乔; 李堃; 卢亮; 叶茂; 王尚; 呼延思雷
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2022-04-22
Anticipated expiration: 2039-10-31
Also published as: CN114824754A; CN112751162A; CN114824754B; WO2021082912A1

Abstract

The application relates to a mobile terminal, which comprises an antenna unit and a floor, wherein the antenna unit comprises a feed device and a radiating body, two ends of the radiating body are open, the feed device is electrically connected to the radiating body, the floor comprises a first edge and a second edge which are adjacent, the intersection of the first edge and the second edge is a datum point, the position where the feed device is connected with the radiating body is a feed point, a region with smaller current is arranged on the floor, in the extending direction of the first edge, the distance between the boundary of the area with small current and the reference point is less than or equal to 0.3 times of the length of the first edge, in the extending direction of the second side, the distance between the boundary of the current smaller region and the reference point is less than or equal to 0.3 time of the length of the second side, the feeding point is arranged in the current smaller region, the feeding device feeds power to excite current on the floor and generate low-frequency resonance on the radiator, and the length of the radiator is less than or equal to one sixteenth of the wavelength of the low-frequency resonance. The present application realizes miniaturization of an antenna device.

Description

Mobile terminal

Technical Field

The application relates to the technical field of antennas applied in mobile terminals.

Background

In recent years, the development trend of mobile phone ID is large screen occupation ratio and multiple cameras, which causes the antenna headroom to be greatly reduced, and the antenna layout space is more and more limited. Meanwhile, many new communication specifications, such as sub-6G, dual low frequency and the like, need to be arranged in the mobile phone. The antenna scheme in the industry at present occupies the largest space in the design of the antenna, because the radiation wavelength of the low frequency is the longest and the required radiator length is the largest.

The miniaturization of the antenna is also more and more demanding, and especially in the low frequency band, how to make the antenna with the same performance by using a smaller radiator becomes a difficult problem.

Disclosure of Invention

The application provides a mobile terminal, and an antenna unit in the mobile terminal has the advantage of miniaturization in a low-frequency band.

In a first aspect, the present application provides a mobile terminal comprising an antenna unit and a floor. The antenna unit includes a feeding device and a radiator, both ends of the radiator are open-circuited, and specifically, the radiator includes a first open end, a second open end, and a body extending between the first open end and the second open end. The feeding device is electrically connected to the radiator, and the connection between the feeding device and the radiator may be a direct connection having an actual connection relationship, or may be a coupling manner to implement feeding. The floor comprises a first edge and a second edge which are adjacent, the intersection of the first edge and the second edge is a reference point, a current smaller area is arranged on the floor, the current smaller area extends along the first edge to the middle area of the first edge by taking the reference point as an origin, and extends along the second edge to the middle area of the second edge by taking the reference point as an origin, the current smaller area is an area between the first edge and the second edge, in the extending direction of the first edge, the distance between the boundary of the current smaller area and the reference point is less than or equal to 0.3 times of the length of the first edge, in the extending direction of the second edge, the distance between the boundary of the current smaller area and the reference point is less than or equal to 0.3 times of the length of the second edge, and the position where the feeding device is connected with the radiator is a feeding point, the feeding point is located in the region of small current. Specifically, the current smaller region may be a rectangular region formed between the first side and the second side, or a sector region or a triangular region. In other words, in the extending direction of the first side, the distance between the feeding point and the reference point is equal to or less than 0.3 times the length of the first side, and in the extending direction of the second side, the distance between the feeding point and the reference point is equal to or less than 0.3 times the length of the second side. The feeder is used for feeding so as to excite current on the floor and generate low-frequency resonance on the radiator, the current distribution on the floor tends to be large in the middle and small in the two ends on the first edge and the second edge, the length of the radiator is less than or equal to one sixteenth of the wavelength of the low-frequency resonance, and the length of the radiator refers to the size of extension of the main body between the first open end and the second open end.

This application mobile terminal's floor can be for the metal center in the mobile terminal, lid, the ground plane or the complete machine of circuit board behind the metal, when regard mobile terminal whole as the floor, the benchmark is the long limit of mobile terminal and minor face intersection, if the intersection is the arc, then the benchmark is the mid point of arc.

The feed point of the antenna unit may be directly electrically connected to the radiator through a spring, a probe (or a thimble), a screw, or the like, or may be connected to the feeder through a coupling manner.

This application sets up the irradiator into both ends and opens a way to set up the feed position of irradiator the less region of electric current on the floor, the less regional setting of electric current needs to satisfy: in the extending direction of the first edge, the distance between the feeding point and the reference point is less than or equal to 0.3 time of the side length of the first edge, and in the extending direction of the second edge, the distance between the feeding point and the reference point is less than or equal to 0.3 time of the side length of the second edge.

In a possible embodiment, the feeding device includes a feeding port and a capacitor, and the capacitor may be a lumped capacitor or a coupling capacitor. The capacitor is connected in series between the feed port and the feed point, and the feed port is electrically connected with a feed network in the mobile terminal. In this embodiment, the feeding means corresponds to the capacitive excitation means, and the capacitive excitation means may be a capacitor, i.e. feeding through one capacitor. The supply means may also comprise a circuit arrangement of a plurality of capacitors and/or inductors connected in parallel or in series.

The radiator in the antenna unit may be a metal frame of the mobile terminal, or may be a structure formed inside a housing of the mobile terminal by laser integral molding, or the radiator may be an all-metal antenna structure, for example, a steel sheet structure is used as the radiator, and the radiator is fixed inside the mobile terminal. The shape of the radiator can be a straight strip, and can also be L-shaped, arc-shaped, irregular shape and the like. The length direction of the radiator is the direction in which the body thereof extends, and the length of the radiator is the dimension of the extending path between the first open end and the second open end, that is, the extending dimension of the radiator on the extending path of the body.

The position of the feeding point may be at the first open end, or the second open end, or any position between the first open end and the second open end. In the present application, the position of the feed point is set in an area with a relatively small current on the floor, which is called as a current small point, where the current small point refers to a position with a relatively minimum current on the floor, and theoretically, the current small point may be a current zero point, so that a common mode ultra short antenna mode (CMSA common mode ultra short antenna mode) mode is constructed. The low frequency resonance generated on the radiator refers to the frequency band of 704MHz-960 MHz.

In particular, the feeding device is electrically connected to a radio frequency circuit (i.e., a feeding network) within the mobile terminal, which provides signals to the feeding device to effect feeding. When the feeder feeds power, current is excited on the floor, and the current distribution on the floor is in a large current area and a small current area.

In one embodiment, the floor panel is rectangular, the first side is a long side, the second side is a short side, and a distance between the feeding point and the reference point in an extending direction of the second side is less than or equal to 0.25 times of the length of the second side.

Particularly, the floor includes adjacent long limit and minor face, the long limit with current distribution on the minor face position all is the little trend in big both ends in the middle of, the electric current dot is located the long limit with the intersection of minor face. For example, in one possible embodiment, the floor board has a rectangular shape, and includes adjacent long sides and short sides, the central area of the long sides and the short sides is an area where the current is larger on the floor board, and the edge positions of the long sides and the short sides, i.e., the intersection area of the long sides and the short sides, are areas where the current is small, and the current small point in this application refers to the position of the edge of the long sides and the short sides. Taking the mobile terminal as a mobile phone as an example, if the floor is a middle frame or a metal cover plate of the mobile terminal, the antenna units are disposed at four corners of the mobile terminal.

In one embodiment, the radiator is arranged parallel to the long side, and "arranged parallel to the long side" may be understood as that the radiator has the same or similar extension tendency as that of the long side. A gap is formed between the radiator and the long edge. In particular, the radiator may have a straight bar shape, and the radiator may be parallel to the long side.

In one embodiment, the antenna unit further includes a parasitic radiator, a gap is formed between one end of the parasitic radiator and the first open end, an end of the parasitic radiator away from the first open end is grounded, the feeding device feeds power to excite the radiator and the parasitic radiator to form a first resonant mode, a second resonant mode and a third resonant mode, the first resonant mode is the low-frequency resonance, the second resonant mode is a quarter-wavelength mode of the radiator, and the third resonant mode is a quarter-wavelength mode of the parasitic radiator. In other words, in the second resonant mode, the electrical length of the radiator is a quarter wavelength, and in the third resonant mode, the electrical length of the parasitic radiator is a quarter wavelength.

The first resonant mode is a CMSA mode, the second resonant mode is an IFA mode, and the third resonant mode is a parasitic mode. The second resonance mode and the third resonance mode cover the N77/N78/N79 frequency band.

In one embodiment, the floor is rectangular, the radiator of the antenna unit is disposed opposite to a long side of the floor, and a ground terminal of the parasitic radiator is electrically connected to a short side of the floor.

Specifically, the parasitic radiator is L-shaped or arc-shaped.

In one embodiment, the antenna unit further includes a switch, one end of the switch is electrically connected to the radiator, and the other end of the switch is grounded, and the switch is used for switching different low-frequency resonances. For example, the antenna needs to cover two low frequency bands, i.e., LTEB5 and LTEB8, the initial state of the antenna is in the LTEB5 band, a proper inductive element may be disposed on the branch where the switch is located, and when the path with the inductive element is turned on, the antenna is switched to the LTEB8 band. The proper inductance element is subjected to simulation test, and when the frequency band of the antenna is adjusted to the LTEB8 frequency band, the inductance value of the inductance element can be adjusted through adjusting the size of the inductance value.

Specifically, one end of the switch is grounded, and the other end is electrically connected to the first open end, or a position between the first open end and the feeding device, or a position between the first open end and the second open end.

The antenna unit can cover the resonance of N77, N78, N79 frequency band under the second resonance mode and the third resonance mode, and when the switch switches different low-frequency resonances, the switch has no influence on the frequency bands of the second resonance mode and the third resonance mode.

In one embodiment, the number of the antenna units is two, and the floor comprises a first corner and a second corner which are adjacently arranged, wherein one of the antenna units is arranged at the position of the first corner, and the other antenna unit is arranged at the position of the second corner. In another embodiment, the number of the antenna units is two, and the floor comprises a first corner and a second corner arranged diagonally, wherein one of the antenna units is disposed at the position of the first corner and the other antenna unit is disposed at the position of the second corner. It can be seen that the present application can implement MIMO antenna functions of multiple inputs and multiple outputs. In one embodiment, the floor is rectangular, and the present embodiment includes three antenna element arrangements, namely, two antenna elements disposed at both ends of the long side of the floor, two antenna elements disposed at both ends of the short side of the floor, and two antenna elements disposed at both ends of the diagonal of the floor.

Of course, the number of the antenna units can be three or four. In one embodiment, the number of the antenna units is four, the floor includes a middle corner, the four corners are all areas with small current, and the four antenna units are arranged at the positions of the four corners in a one-to-one correspondence manner.

The isolation between each antenna unit is below-13 dB, and the antenna has good signal transmitting and receiving performance.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present application, the drawings required to be used in the embodiments or the background art of the present application will be described below.

Fig. 1 is a schematic diagram of an antenna unit applied in a mobile terminal according to an embodiment of the present application, where the number of the antenna unit is one;

fig. 2 is a schematic diagram of an antenna unit applied in a mobile terminal according to an embodiment of the present application, where the number of the antenna units is four, and the antenna units are arranged at four corners of a floor.

Fig. 3 is a schematic diagram of an antenna unit applied in a mobile terminal according to an embodiment of the present application, where the number of the antenna units is two and the antenna units are arranged at opposite corners of a floor.

Fig. 4 is a schematic diagram of an antenna unit applied in a mobile terminal according to an embodiment of the present application, where the number of the antenna units is two, and the antenna units are disposed at two ends of a long side of a floor.

Fig. 5A is a schematic diagram of an antenna unit in a mobile terminal according to an embodiment of the present application;

FIG. 5B is a schematic diagram of current distribution across a floor in a mobile terminal according to one embodiment of the present application;

FIG. 5C is a schematic illustration of a distribution of small areas of current on a floor within a mobile terminal according to one embodiment of the present application;

fig. 5D is a schematic diagram illustrating a positional relationship between a feeding device and a radiator and a floor in a mobile terminal according to an embodiment of the present disclosure;

fig. 6 is a schematic diagram of an antenna provided in another embodiment of the present application;

fig. 7 is a graph of S-parameter for the antenna provided by the present application in a first resonant mode, a second resonant mode, and a third resonant mode;

fig. 8 is a current distribution diagram of an antenna provided by the present application in a first resonant mode;

fig. 9 is a current distribution diagram of the antenna provided by the present application in a second resonant mode;

fig. 10 is a current distribution diagram of the antenna provided by the present application in a third resonant mode;

FIG. 11 is a graph of S parameters of a low frequency signal of the antenna in a state of switching different low frequency by switching the switch;

FIG. 12 is a graph of S parameters of NR frequency bands at different low frequency states switched by switching;

FIG. 13 is a graph of the radiation efficiency of the antenna in switching different low frequency states;

FIG. 14 is a graph of the system efficiency of the antenna in switching different low frequency states;

FIG. 15 is a graph of the efficiency of an NR band antenna in switching between different low frequency states;

FIG. 16 is a schematic diagram of a two antenna element modulo edge layout;

fig. 17 is a diagram of S parameters for a two antenna element layout at the lateral edges;

fig. 18 is a schematic diagram of a diagonal layout of two antenna elements;

FIG. 19 is a graph of S parameters for a two antenna diagonal layout;

fig. 20 is a schematic diagram of a two antenna element longitudinal edge layout;

fig. 21 is a diagram of S parameters for a two antenna element longitudinal edge layout;

FIG. 22 is a schematic diagram of a four antenna layout;

fig. 23 is an S parameter diagram for a four antenna layout.

Detailed Description

The embodiments of the present application will be described below with reference to the drawings.

Fig. 1 to 4 are schematic diagrams of an antenna 10 applied in a mobile terminal 100. The mobile terminal 100 may be a mobile phone, a tablet, or other terminal device. The mobile terminal 100 is internally provided with the radio frequency circuit 101, and the radio frequency circuit 101 may be arranged on a main board in the mobile terminal or may be arranged inside the mobile terminal as a separate chip. The rf circuit 101 is used to provide rf signals to the antenna 10 as a power supply.

The antenna 10 includes an antenna unit 11 and a floor 12. The floor 12 may be a metal bezel, a metal back cover, a ground plane for a circuit board, or the entire machine within the mobile terminal 100. The number of the antenna elements 11 may be one, two, or more than two (e.g., three, four). In the embodiment shown in fig. 1, the number of the antenna units 11 is one, and the antenna units are disposed in the upper right corner of the floor 12 in the mobile terminal 100, and the radio frequency circuit 101 is electrically connected to the antenna units. As shown in fig. 2, the number of the antenna units 11 is four, and the antenna units are respectively distributed at four corners of the floor 12, and the rf circuit 101 is electrically connected to the four antenna units 11. As shown in fig. 3, the number of the antenna units 11 is two, and the two antenna units 11 are respectively located at opposite corners of the floor 12, that is, corresponding to the upper right corner and the lower left corner in fig. 3, and the radio frequency circuit 101 is electrically connected to the two antenna units 11. As shown in fig. 4, the number of the antenna units 11 is two, and the two antenna units 11 are respectively located at two ends of a long side of the floor 12, that is, corresponding to the upper right corner and the lower right corner in fig. 4, and the radio frequency circuit 101 is electrically connected to the two antenna units 11, in this embodiment, the two antenna units 11 may also be located at two ends of a short side of the floor 12 (located at the top or the bottom of the mobile terminal 100), or located at two ends of another long side.

In the embodiment of the present application, the mobile terminal 100 is taken as an example of a mobile phone, and as the function of the mobile phone is diversified, there are many requirements for the arrangement of the antenna in the mobile phone, and as the requirement for large screen occupation of the mobile phone is increased, the arrangement space of the antenna in the mobile phone is more and more limited, especially for a low-frequency antenna, the space occupied by the frequency antenna is the largest, because the radiation wavelength of the low frequency is the longest and the length of the required radiator is the largest. The antenna 10 provided by the application can realize a miniaturized low-frequency antenna, and the antenna 10 provided by the application can realize the common body (integration) of the low-frequency antenna and the sub-6G frequency band antenna, so that the sub-6G frequency band antenna is not influenced during low-frequency switching. The low frequency resonance refers to the frequency band of 704MHz-960 MHz. The sub-6G frequency bands comprise 800MHz, 900MHz, 1.8GHz, 2.1GHz, 3.5GHz and 4.9GHz, and the high-speed movement in the medium and high-speed movement is supported, so that the integration is facilitated, and the number of the antennas is reduced.

In one embodiment, the present application provides a mobile terminal, as shown in fig. 5A, an antenna 10 in the mobile terminal includes a floor 12 and an antenna unit 11, which may also be understood as a mobile terminal including a floor and an antenna unit, where the floor may be regarded as a component in the mobile terminal or as a part of the antenna. The present embodiment schematically shows one antenna unit 11, and the number of the antenna units 11 may be two or more, and may be distributed at different corners of the floor 12. The antenna unit 11 includes a feeding device S and a radiator R, two ends of the radiator R are in an open circuit state, the feeding device S is electrically connected to the radiator R, and the connection between the feeding device S and the radiator R may be a direct connection having an actual connection relationship, or may be a coupling manner to implement feeding. The feeding device S is electrically connected to the rf circuit 101 (see fig. 1) in the mobile terminal 100 to receive the rf signal and realize feeding.

As shown in fig. 5A, 5B, 5C, and 5D, the feeding device S is electrically connected to the radiator R. The floor 12 includes a first side 121 and a second side 122 that are adjacent to each other, where a junction of the first side 121 and the second side 122 is a reference point B, a position where the feeding device is connected to the radiator is a feeding point a, and a distance between the feeding point a and the reference point B is equal to or less than 0.3 times of a length of the first side 121 in an extending direction of the first side 121, and a distance between the feeding point a and the reference point B is equal to or less than 0.3 times of a length of the second side in an extending direction of the second side 122. In other words, the floor 12 is provided with a current-reduced area 120, the current-reduced area 120 extends along the first edge 121 toward the middle area of the first edge 121 with the reference point B as the origin, and extends along the second edge 122 toward the middle area of the second edge 122, in the extending direction of the first edge 121, the distance between the boundary of the current smaller region 120 and the reference point B is equal to or less than 0.3 times the side length of the first edge 121, in the extending direction of the second side 122, the distance between the boundary of the current smaller region 120 and the reference point B is not more than 0.3 times the side length of the second side 122, when the floor is rectangular, the first side is a long side, the second side is a short side, in the extending direction of the second side, the distance between the boundary of the current smaller region 120 and the reference point B is equal to or less than 0.25 times the side length of the second side 122. The current smaller region 120 is a region between the first side 121 and the second side 122, and specifically, the current smaller region 120 may be a rectangular region formed between the first side 121 and the second side 122, or a fan-shaped region or a triangular region.

As can be seen, when the floor 12 is rectangular, the reference points B are four in number and are located at the four corners of the floor, and correspondingly, the current smaller areas 120 are also four in number and are distributed at the four corners of the floor.

When the mobile terminal is taken as a floor as a whole, the reference point is the intersection of the long side and the short side of the mobile terminal, and if the intersection is an arc, the reference point is the middle point of the arc.

The feeding device is used for feeding to excite current on the floor and generate low-frequency resonance on the radiator, and the length of the radiator is less than or equal to one sixteenth of the wavelength of the low-frequency resonance.

Specifically, the feeding device S receives a radio frequency signal of a radio frequency circuit and feeds the radio frequency signal so as to excite a current on the floor 12, as shown in fig. 5A, the current distribution on the floor 12 includes a region with a large current and a region with a small current, in the figure, a broken line outside the long side and the short side indicates the current distribution, a position in the middle of the long side and the short side, a region Imax indicated by an indicator line with an arrow at both ends is a region with a maximum current, that is, a region with a large current in the middle of the long side and the short side, and a region with a small current in the both ends (edges), that is: the current distribution on the long side and the short side of the floor 12 is a trend with a large middle and small ends, fig. 5A, 5B, and 5C only schematically show the current distribution trend at the position of one long side and one short side of the floor 12, and in practical application, the other long side and the other short side also have such current distribution trends: the middle part is large and the two ends are small. That is, the four sides of the floor 12 have similar current distributions, i.e., the current distributions on the pair of long sides of the floor 12 are nearly the same, and the current distributions on the pair of short sides on the floor are also nearly the same. The area of lower current 120 on the floor 12 is located close to the intersection of the long and short sides, i.e. the edge of the long and short sides.

As shown in fig. 5B, the floor panel 12 has a rectangular shape, and the current is distributed along the long and short sides, and the larger black circle in the figure indicates that the current is large, and the smaller black circle indicates that the current is small.

As shown in fig. 5C, the intersection of the long side and the short side on the floor is a reference point, and the position of the reference point has the smallest current, and may be, for example, a current zero point. In the direction in which the long side extends, the region at a distance X2 from the reference point is a position where the feeding device S and the feeding point a of the radiator R are disposed, and X2 is 0 or more and 0.3 times or less the long side length. In the direction in which the short sides extend, the region at a distance of X1 from the reference point is the position where the feeding device S and the feeding point a of the radiator R are disposed, and X1 is 0 or more and 0.25 times or less the side length of the short sides. In fig. 5C, only schematically, the areas of X1 and X2 are shown at two datum positions, respectively, and in practice, four datum positions of the floor, each having areas marked by X1 and X2 on either side of the datum position.

Specifically, the feeding device S may be a capacitive excitation device, as shown in fig. 5D, the feeding device S includes a feeding port P and a capacitor C, i.e., feeding is performed through a capacitor C, and the circuit structure is a capacitor; the supply means S may also comprise a circuit arrangement of a plurality of capacitors and/or inductors connected in parallel or in series. The feeding port P is electrically connected to the rf circuit 101 in the mobile terminal 100, the capacitor C is electrically connected to the radiator through a conductive wire, and a position where the capacitor C is connected to the radiator R is a feeding point a.

Referring to fig. 5D, the floor 12 includes a first edge 121 and a second edge 122 adjacent to each other, and only a portion of the first edge 121 and a portion of the second edge 122 are shown in fig. 5D for clarity of showing the specific structure of the power feeding device S. The intersection of the first side 121 and the second side 122 is a reference point B, the position where the feeding device S is connected to the radiator R is a feeding point a, in the extending direction of the first side 121, a distance L1 between the feeding point a and the reference point B is less than or equal to 0.3 times the length of the first side 121, and in the extending direction of the second side 122, a distance L2 between the feeding point a and the reference point B is less than or equal to 0.3 times the length of the second side 122. Specifically, when the floor panel 12 has a rectangular shape, the first side 121 is a long side, the second side 122 is a short side, and the distance L2 between the feeding point a and the reference point B in the extending direction of the second side 122 is equal to or less than 0.25 times the length of the second side.

The radiator R may be a metal frame of the mobile terminal 100, or may be a structure integrally formed inside a housing of the mobile terminal by laser, or may be an all-metal antenna structure, for example, a steel sheet structure is used as the radiator and fixed inside the mobile terminal. Referring to fig. 5A, the radiator R includes a first open end 112, a second open end 114, and a main body 116 extending between the first open end 112 and the second open end 114, and the shape of the radiator R may be a straight bar, or may be an L-shape, an arc, an irregular shape, or the like. The length direction of the radiator R is the direction in which the body 116 thereof extends, and the length of the radiator R is the dimension of the extending path between the first open end 112 and the second open end 114, that is, the extending dimension of the radiator R on the extending path of the body 116.

The present application achieves that the length of the radiator R, which refers to the dimension of extension of the body 116 between the first open end 112 and the second open end 114, is less than or equal to one sixteenth of the wavelength of the low frequency resonance.

A gap is formed between the radiator R and the floor 12, that is, the radiator R is not grounded, and there is no direct electrical connection between the radiator R and the floor 12.

Specifically, the first open end 112, the second open end 114, and the body 116 are collinear, i.e.: the radiator R is in a straight strip shape, the radiator R can be parallel to the long side, and the shape of the radiator R can also be in other shapes such as irregular bending and extending shape, regular winding shape (for example, wave shape, zigzag shape), arc shape and the like.

The position where the power feeding device S is connected to the floor 12 is a current small point on the floor 12. The feeding means S feed is able to generate a low frequency resonance (704 MHz-960 MHz band) on the radiator R. The length of the radiator R is less than or equal to one sixteenth of the wavelength of the low-frequency resonance, and no current zero point exists on the radiator R. In the present embodiment, the length of the radiator R is 17 mm.

The size of the radiation antenna R can be changed according to different environments, but the size of the radiation antenna R is less than or equal to one sixteenth wavelength of the low-frequency resonance frequency, and the miniaturization of the low-frequency antenna is realized. The term "different environment" as used herein mainly refers to the effect of antenna clearance, and the larger the antenna clearance, the longer the required size, but the smaller the size of the radiator R, no matter how the clearance environment changes, the less the size of the radiator R is equal to or less than one sixteenth wavelength.

In the present application, the radiator R is designed to be open-circuited at two ends, and the connection between the feeding device S and the radiator R, that is, the position of the feeding point, is set in an area (referred to as a current small point) with a small current on the floor 12, so that a common mode ultra short antenna mode (CMSA) mode can be generated. The feeding device S excites a current on the floor 12 and generates a low-frequency resonance on the radiator R, and the length of the radiator R can be equal to or less than one sixteenth of the wavelength of the low-frequency resonance, thereby realizing miniaturization of the antenna of a low-frequency band and facilitating layout of the antenna unit 11 in the mobile terminal 100.

In another embodiment, the present application provides a schematic diagram of a low frequency antenna (LB) integrated with a sub-6G antenna. In addition to the embodiment shown in fig. 5A, the antenna unit further includes a parasitic radiator, as shown in fig. 6, the antenna unit 11 includes a radiator R1 and a parasitic radiator R2, the structure of the radiator R1 is the same as that of the radiator in the embodiment shown in fig. 5A, and the radiator R1 also includes a first open end 112, a second open end 114, and a main body 116. One end of parasitic radiator R2 with form slot 111 between the first open circuit end 112, parasitic radiator R2 is kept away from the one end ground of first open circuit end 112, feeder S feed can encourage radiator R1 with parasitic radiator R2 forms first resonant mode, second resonant mode and third resonant mode, first resonant mode is low frequency resonance (704 MHz-960 MHz frequency channel), the second resonant mode is radiator R1 'S quarter wavelength mode, the third resonant mode is parasitic radiator R2' S quarter wavelength mode. The first resonance mode is a CMSA mode, the second resonance mode is an IFA (i.e., Inverted-F antenna) mode, and the third resonance mode is a parasitic mode. The second resonance mode and the third resonance mode cover N77 (3300 MHz-4200 MHz)/N78 (3300 MHz-3800 MHz)/N79 (4400 MHz-5000 MHz) frequency band.

In this embodiment, the radiator R1 of the antenna unit 11 is disposed opposite to the long side of the floor 12, and the ground of the parasitic radiator R2 is electrically connected to the short side of the floor 12. Specifically, the parasitic radiator R2 has an L shape or an arc shape, and the parasitic radiator R2 may have another irregular shape or a regular meandering shape (e.g., a wave shape or a zigzag shape).

In the present embodiment, both the radiator R1 and the parasitic radiator R2 have a stripe structure extending with a constant width. The width of the parasitic radiator R2 is the same as the width of the radiator R1, the width of the parasitic radiator R2 is the dimension perpendicular to the extending direction thereof, and the width of the radiator R1 also refers to the dimension perpendicular to the extending direction thereof. The radiator R1 and the parasitic radiator R2 may be of a metal sheet structure, a metal microstrip line structure printed on a circuit board, or a metal layer structure formed integrally by laser on an insulating substrate, where the insulating substrate may be a housing of a mobile terminal or an internal support.

The antenna unit 11 further includes a switch 117, one end of the switch 117 is electrically connected to the radiator R, and the other end of the switch 117 is grounded, that is, electrically connected to the floor 12. The switch 117 is used to switch different low frequency resonances. For example, the antenna 10 needs to cover two low frequency bands, i.e., LTEB5 (e.g., 824-. When the frequency band of the antenna 10 is adjusted to the LTEB8 frequency band through simulation tests, the inductance value of the inductance element can be adjusted by adjusting the magnitude of the inductance value to further adjust the frequency band of the antenna 10.

Specifically, one end of the switch 117 is grounded, and the other end is electrically connected to the first open end 112, or a position between the first open end 112 and the power feeding device S, or a position between the first open end 112 and the second open end 114.

The antenna unit 11 can cover the resonances of the N77, N78, and N79 frequency bands in the second resonance mode and the third resonance mode, and when the switch 117 switches different low-frequency resonances, there is no influence on the frequency bands of the second resonance mode and the third resonance mode.

Fig. 7 is a graph showing S-parameter curves in the first, second, and third resonance modes, with frequency on the horizontal axis in units: GHz, vertical axis S11 parameter, unit: dB. The S11 parameter is one of S parameters, which represents the input reflection coefficient, and the larger the value, the more energy reflected by the antenna itself, and thus the worse the efficiency of the antenna.

As can be seen from FIG. 7, the input return loss of the antenna in the first resonance mode is between-20 dBA and-22 dBA, the return loss of the antenna in the second resonance mode is between-16 dBA and-18 dBA, and the return loss of the antenna in the third resonance mode is between-24 dBA and-25 dBA, which indicates that the antenna has good resonance performance, and when the antenna is used as a single-port circuit, the reflection of a port is small, the impedance of the antenna is closer to the center of a 50OHM impedance, and the impedance matching characteristic of the antenna is good.

Fig. 8 shows a current distribution diagram in the first resonance mode, in which an arrow indicating line upward on the right side of the radiator R1 indicates the flow direction of current. The current on radiator R1 flows from second open end 114 to first open end 112 with no current zero on radiator R1. Since there is no current zero on radiator R1. The mode of resonance is therefore certainly less than a quarter wavelength and the mode of the antenna 10 should be less than a sixteenth wavelength in view of the length of the antenna 10 and the frequencies supported.

Fig. 9 shows a current distribution diagram in the second resonance mode, in which an arrow indicating line upward on the right side of the radiator R1 indicates the flow direction of current. The current on the radiator R1 flows from the second open end 114 to the first open end 112, the second open end 114 is a current zero point, and the circle below the upward arrow indicates the current zero point. This pattern is a quarter wavelength pattern for radiator R1, which is an IFA antenna pattern.

Fig. 10 is a current distribution diagram in the third resonant mode, in which the current in the parasitic radiator R2 flows from a position adjacent to the first open end 112 of the radiator R1 to the ground end of the parasitic radiator R2, and an arrow line above the parasitic radiator R2 indicates the flow direction of the current. The position on the parasitic radiator R2 adjacent to the first open end of the radiator is the current zero point, and the circle below the arrowed indicator line represents the current zero point. This mode is a quarter wave mode of the parasitic radiator R2.

Different low-frequency frequencies can be switched by setting the switch 117, and fig. 11 is an S parameter diagram of a low-frequency signal of the antenna in a state of switching the different low-frequency frequencies. The S11 values for 8 different low frequency frequencies are shown. The frequency band of 704-960MHz can be covered by switching. Fig. 12 is a graph showing the S parameters of the NR frequency bands in the low frequency switching state, and it can be seen that the NR frequency bands are substantially unchanged in the low frequency switching state. The coverage of the NR frequency band can not be influenced by the switching of the low-frequency resonance, and the simultaneous coverage of the low-frequency band and the NR frequency band can be realized, so that the antenna has the advantage of miniaturization, and the performance of the antenna in each frequency band is ensured.

Fig. 13 and 14 show the efficiency of low frequency in different switching states, the efficiency is basically unchanged during the switching process, and the simulation efficiency is basically about-6 dB. Fig. 13 is a graph of the radiation efficiency of the antenna in the state of switching different low-frequency frequencies, and fig. 14 is a graph of the system efficiency of the antenna in the state of switching different low-frequency frequencies. System efficiency = radiant efficiency-reflection efficiency, reflection efficiency being related to the S parameter, the deeper the S parameter, the smaller the reflection efficiency, the closer the system efficiency is to the radiant efficiency. The shallower the S parameter, the greater the reflection efficiency, and the greater the difference between the system efficiency and the radiation efficiency. The theoretical maximum value of the system efficiency is the radiation efficiency, which represents the maximum radiation capability of an antenna structure.

Fig. 15 is a graph showing the efficiency of the NR band in switching different low frequency states, and it can be seen that the NR band is substantially unchanged in the low frequency switching state.

The number of the antenna elements 11 in the antenna 10 provided by the present application may be one, or may also be two, three, four, and so on.

The floor 12 includes four corners, and the positions of the four corners are all current small points. When the number of the antenna units 11 is two, the two antenna units are respectively disposed at two adjacent corners, or the two antenna units are respectively disposed at two diagonally disposed corners.

As shown in fig. 16, the two antenna units 11 are distributed at two ends of the short side of the floor 12, and this layout is a modular edge layout, and when the antenna unit is applied in a mobile terminal, the two antenna units 11 can be arranged at two corner positions of the top of the mobile terminal.

FIG. 17 is a graph of S parameters for two antenna elements laid out laterally, with the worst LB isolation being-13 dB and the isolation of the NR bands being better than-18 dB.

As shown in fig. 18, two antenna units 11 are distributed at diagonal positions on the floor 12, and this layout is a diagonal layout.

FIG. 19 is a graph of S parameters for a diagonal layout of two antennas, with the worst LB isolation of-15 dB and better isolation in the NR band than-20 dB.

As shown in fig. 20, two antenna elements 11 are distributed at both ends of the long side of the floor 12, and this layout is a vertical side layout.

FIG. 21 is a graph of S parameters for two antenna longitudinal edge layouts, with the worst LB isolation being-20 dB and the isolation of the NR band being better than-20 dB.

As shown in fig. 22, four antenna units 11 are distributed at four corners of the floor 12, and this layout is a four-antenna layout. Taking the mobile terminal as a mobile phone as an example, if the floor is a middle frame or a metal cover plate of the mobile terminal, the antenna units are disposed at four corners of the mobile terminal.

FIG. 23 is a graph of S parameters for a four antenna layout, with the worst LB isolation being-13 dB and the isolation in the NR band being better than-13 dB.

The present embodiment can realize a MIMO antenna function of multiple input multiple output. The isolation between each antenna unit is below-13 dB, and the antenna has good signal transmitting and receiving performance.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A mobile terminal is characterized in that the mobile terminal comprises an antenna unit and a floor, the antenna unit comprises a feeding device and a radiator, two ends of the radiator are in an open circuit state, the feeding device is electrically connected to the radiator, the floor comprises a first side and a second side which are adjacent, the intersection of the first side and the second side is a reference point, the current at the position of the reference point on the floor is minimum, a region with smaller current is arranged on the floor, the region with smaller current takes the reference point as an original point and extends along the first side to the middle region of the first side, the region with smaller current extends from the reference point as an original point to the middle region of the second side along the second side, the region with smaller current is a region between the first side and the second side, and in the extending direction of the first side, the distance between the boundary of the region with smaller current and the reference point is less than or equal to 0.3 times of the side length of the first side, in the extending direction of the second edge, the distance between the boundary of the region with smaller current and the reference point is less than or equal to 0.3 time of the length of the second edge, the position where the feeding device is connected with the radiator is a feeding point, the feeding point is located in the region with smaller current, the feeding device is used for feeding so as to excite current on the floor and generate low-frequency resonance on the radiator, and the length of the radiator is less than or equal to one sixteenth of the wavelength of the low-frequency resonance.

2. The mobile terminal of claim 1, wherein the floor has a rectangular shape, the first side is a long side, the second side is a short side, and a distance between a boundary of the current reduction region and the reference point in an extending direction of the second side is equal to or less than 0.25 times the length of the second side.

3. The mobile terminal of claim 2, wherein the feeding means comprises a feeding port and a capacitance connected in series between the feeding port and the feeding point, the feeding port being electrically connected to a feeding network within the mobile terminal.

4. The mobile terminal of claim 3, wherein the radiator includes a first open end and a second open end, the antenna unit further includes a parasitic radiator, a slot is formed between one end of the parasitic radiator and the first open end, an end of the parasitic radiator away from the first open end is grounded, the feeding device is capable of exciting the radiator and the parasitic radiator to form a first resonant mode, a second resonant mode, and a third resonant mode, and the first resonant mode is the low frequency resonance.

5. The mobile terminal of claim 4, wherein the second resonant mode is a quarter-wavelength mode of the radiator and the third resonant mode is a quarter-wavelength mode of the parasitic radiator.

6. The mobile terminal of claim 5, wherein the radiator of the antenna unit is disposed opposite the first side, and a ground terminal of the parasitic radiator is electrically connected to the second side.

7. The mobile terminal of claim 6, wherein the parasitic radiator is L-shaped or arc-shaped.

8. The mobile terminal of claim 5, wherein the antenna unit further comprises a switch, one end of the switch is electrically connected to the radiator, the other end of the switch is grounded, and the switch is used for switching different low frequency resonances.

9. The mobile terminal of any of claims 1-8, wherein the number of antenna elements is two, and the floor comprises a first corner and a second corner disposed adjacent to each other, wherein one of the antenna elements is disposed at the first corner and the other antenna element is disposed at the second corner.

10. The mobile terminal of any of claims 1-8, wherein the number of antenna elements is two, and the floor comprises a first corner and a second corner arranged diagonally, wherein one of the antenna elements is disposed at the position of the first corner and the other antenna element is disposed at the position of the second corner.

11. The mobile terminal of any of claims 1-8, wherein the number of antenna elements is four, the floor includes four corners, and four of the antenna elements are disposed at the positions of the four corners in a one-to-one correspondence.