WO2014177005A1

WO2014177005A1 - Antenna and terminal

Info

Publication number: WO2014177005A1
Application number: PCT/CN2014/076063
Authority: WO
Inventors: 李群
Original assignee: 中兴通讯股份有限公司
Priority date: 2013-09-23
Filing date: 2014-04-23
Publication date: 2014-11-06
Also published as: CN104466356A

Abstract

Disclosed are an antenna and a terminal. An antenna body of an antenna comprises a first antenna radiation supporting arm, a second antenna radiation supporting arm, a first feeding part and a first grounding part, wherein the first antenna radiation supporting arm is connected to one end of the second antenna radiation supporting arm in parallel to form a common end, and the first feeding part and the first grounding part are connected to the common end. The antenna body also comprises a third antenna radiation supporting arm which is led out from the common end and is set to shunt a current flowing through the first feeding part. Because the third antenna radiation supporting arm shunts the current which is concentratedly flowing through the first feeding part, the peak value of the current on a mainboard can be correspondingly reduced, and then an SAR of the antenna is reduced; and at the same time, an entire current intensity of the antenna cannot be reduced, so that the total radiation power of the antenna can be ensured. Therefore, the antenna provided in the present invention can reduce the SAR thereof while ensuring that the antenna has a very good radiation performance, thereby improving the degree of satisfaction of the user experience to a certain extent.

Description

The present invention relates to the field of communications, and in particular to an antenna and a terminal. Background Art A specific absorption rate (SAR) is generally called an absorption ratio or an absorption ratio, and refers to an electromagnetic wave energy absorption ratio of a mobile terminal. The specific meaning is: Under the action of external electromagnetic field, the inductive electromagnetic field will be generated in the human body. Since all organs of the human body are consuming medium, the electromagnetic field in the body will generate an induced current, which causes the human body to absorb and dissipate electromagnetic energy. SAR is often used to characterize this physical process. The meaning of SAR is the electromagnetic power absorbed or consumed by human tissue per unit mass, in units of W/kg, or mw/g. The expression is:

SAR= o |ΕΪ| ² /2 where Ei is the effective value of the electric field strength in the cell tissue, expressed in V/m; σ is the electrical conductivity of the human tissue, expressed in S/m; P is the tissue density of the human body, in kg/ m ³ . Said. The SAR in human tissue is proportional to the square of the electric field strength in the tissue, and is determined by the parameters of the incident electromagnetic field (such as frequency, intensity, direction, and source of the electromagnetic field), the relative position of the target, and the typical tissue of the exposed human body. Genetic characteristics, ground effects, and environmental impacts of exposure are determined. At present, many countries and regions have established safety standards for human exposure to electromagnetic waves. At present, there are two internationally accepted standards, one is less than 2.0w/kg per 10 grams of European standards, and one is less than 1.6mw/g per gram of American standard. It is precisely because of the mutual constraint relationship between SAR and TRP (Total Radio Power) that the current mobile terminal has a low SAR value under the condition of ensuring high required transmission power. At present, the commonly used methods for reducing SAR are as follows:

(1) Directly reduce the transmit power; this method is the most direct and effective, but it is difficult to guarantee the TRP requirements, the TRP is too low, and the communication quality is reduced, so it is difficult to achieve both.

(2) At the beginning of the design, the position of the antenna is away from the direction of the human head. This method can also reduce the absorption of electromagnetic waves by the human body. However, the current development trend of mobile terminals is that the thickness is getting thinner and thinner, and the functions are more and more, and the antenna space is coming. The smaller, the harder it is to ensure a greater distance from the head. (3) The absorbing material is attached to the hot spot of the current near the antenna. Due to the limited design of the mobile terminal, there is often no space reserved for the absorbing material in the hot spot, and the reliability of this method is poor. . It can be seen that, up to now, there is still no better solution that can reduce the SAR of the antenna and reliably guarantee its TRP. SUMMARY OF THE INVENTION The main technical problem to be solved by the embodiments of the present invention is to provide an antenna and a terminal, which can reduce the SAR of the terminal antenna while ensuring the performance of the terminal antenna. To solve the above technical problem, an embodiment of the present invention provides an antenna, including an antenna body, where the antenna body includes a first antenna radiation arm, a second antenna radiation arm, a first power feeding portion, and a first ground portion. The first antenna radiating arm and one end of the second antenna radiating arm are connected in parallel to form a common end, and the first feeding portion and the first ground portion are connected to the common end; the antenna body further includes The common terminal leads to a third antenna radiating arm that is shunted by a current flowing through the first power feeder. In an embodiment of the present invention, the antenna further includes a main board, a radio frequency circuit module disposed on the main board, and a second power feeding part and a second grounding part disposed on the main board, A power feeding portion and the first ground portion are respectively connected to the second power feeding portion and the second ground portion, and the second power feeding portion is connected to the radio frequency circuit module. In an embodiment of the invention, the antenna further includes a matching circuit module, and the second power feeding unit is connected to the radio frequency circuit module through the matching circuit module. In an embodiment of the invention, the third antenna radiating arm is led out from a side of the common end away from the first antenna radiating arm. In an embodiment of the invention, the first power feeding portion is connected to a region of the common end adjacent to the third antenna radiation arm. In an embodiment of the invention, the third antenna radiating arm extends from an end of the common end to a position where the first feeding portion on the common end is located. In an embodiment of the invention, a gap width between the third antenna radiation arm and the common end is greater than or equal to 0.2 mm and less than or equal to 1 mm. In an embodiment of the invention, the trace length of the third antenna radiating arm is less than a quarter wavelength of the center frequency of the preset frequency band. In an embodiment of the present invention, a trace length of the first antenna radiating arm is smaller than a trace length of the second antenna radiating arm, and the first antenna radiating arm and the second The gap width between the antenna radiating arms is greater than or equal to 0.3 mm and less than or equal to 0.8 mm. In order to solve the above problem, an embodiment of the present invention further provides a terminal, where the terminal includes an antenna as described above. The antenna of the antenna and the antenna body of the terminal provided by the embodiment of the present invention includes a first antenna radiating arm, a second antenna radiating arm, a first feeding portion, and a first grounding portion; One end of the radiating arm and the second antenna radiating arm are connected in parallel to form a common end, and the first feeding portion is connected to the common end of the first grounding portion; the antenna body further includes an outlet from the common end, and is disposed to flow through the first feeding a third antenna radiating arm that is shunted by the current; since the current flowing through the first power feeding portion is shunted by the third antenna radiating arm, the peak value of the current on the main board can be correspondingly reduced, thereby reducing the antenna SAR; At the same time, it does not reduce the overall current intensity of the antenna, thus ensuring the total radiated power of the antenna. It can be seen that the antenna provided by the embodiment of the present invention can reduce the SAR of the antenna while ensuring good radiation performance of the antenna, and also improves the satisfaction of the user experience to a certain extent. 1 is a schematic structural view of an antenna according to a second embodiment of the present invention; FIG. 2 is a schematic structural view of an antenna body according to a second embodiment of the present invention; FIG. 3 is a schematic diagram of a SAR test hotspot of an antenna according to Embodiment 2 of the present invention; FIG. 5 is a schematic diagram of a radiation apple of a conventional antenna; FIG. 6 is a schematic diagram of a radiation apple of an antenna according to Embodiment 2 of the present invention. The SAR value of the existing terminal antenna is large, mainly because the current of the high frequency part of the antenna is concentrated when the current on the antenna radiator is collected to the power feeding part (ie, the signal feeding point), and the corresponding current on the main board is Will produce a large peak, This results in a larger SAR value for the antenna. In this regard, the embodiment of the present invention additionally adds a third antenna radiating arm to the radiating body of the antenna, and is configured to shunt the current flowing through the feeding portion, thereby reducing the peak generated by the current on the main board, thereby reducing the SAR of the antenna; The antenna's radiated power is not lost. The embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Embodiment 1 The antenna device in this embodiment can be applied to any communication terminal that requires an antenna, for example, to a mobile communication terminal such as a mobile phone or an IPAD, and can also be applied to other fixed terminals that require an antenna. The antenna in this embodiment includes an antenna body, a main board, and a radio frequency module. The antenna body includes an antenna radiating body and a first feeding portion (ie, a signal feeding point) and a first ground portion (ie, a ground feeding point) disposed on the antenna radiating body. Correspondingly, a second feeding portion and a second grounding portion respectively connected to the first feeding portion and the first grounding portion are disposed on the main board, and the antenna radiating body passes through the first feeding portion and the first ground portion respectively The motherboard is connected. In this embodiment, in order to better adjust the impedance of each band, a matching circuit module may be disposed for the antenna, and the first feeding portion of the antenna body is connected to the radiation module through the matching circuit; and the impedance of each band is adjusted by the matching circuit module. The band can have a better matching output for optimal radiation. In this embodiment, the antenna radiating body includes a first antenna radiating arm and a second antenna radiating arm; and the first antenna radiating arm and the second antenna radiating arm are connected in parallel to form a common end, and the common end is used as a common end. One unit is connected to the first feeding portion and the first ground portion; the other ends of the first antenna radiating arm and the second antenna radiating arm respectively extend in the same direction, and extend corresponding lengths and corresponding bends After that, an antenna of a corresponding type is formed. In this embodiment, the type may be selected according to a specific application scenario, for example, a G-type antenna or the like may be selected. In this embodiment, the antenna radiating body further includes a third antenna radiating arm that is branched from the common end and configured to shunt the current flowing through the first feeding portion; that is, the third antenna first radiating arm may be To some extent, the current of the antenna high-frequency radiator is equalized, thereby reducing the current peak of the approach area on the main board and reducing the SAR value of the antenna. At the same time, it does not affect the overall current of the antenna, and can ensure the radiation performance of the antenna. In this embodiment, a third antenna radiating arm may be disposed from a side of the common end remotely of the first antenna radiating arm and/or the second antenna radiating arm. And for better tuning, the first feed portion may be further disposed adjacent to the third antenna radiation arm, that is, the first feed portion is coupled to the region of the common end adjacent to the third antenna radiation arm. At the same time, the third antenna radiating arm extends from the common end to the position where the first feeding portion on the common end is located. In this embodiment, the width of the gap between the third antenna radiating arm and the common end and the length of the third antenna radiating arm may affect the position of the resonant frequency point, and thus may be according to specific application scenarios and specific The frequency band to be tuned specifically sets the width of the gap between the third antenna radiating arm and the common end and the length of the third antenna radiating arm. For example, the gap width between the third antenna radiation arm and the common end may be set to be greater than or equal to 0.2 mm, or equal to 1.0 mm, and may be specifically set to 0.2 mm, 0.4 mm, 0.5 mm, 0.8 mm, and 1.0. Mm and so on. The length of the third antenna radiating arm can theoretically be set to a quarter wavelength of the center frequency of the preset frequency band; the preset frequency band here is a specific frequency band to be tuned; but limited to the structural shape of the attached antenna Limit, the trace of the third antenna radiating arm is generally smaller than a quarter wavelength of the center frequency of the preset frequency band, and because the gap between the third radiating arm and the common end exists, the third radiating arm and the There is a coupling effect between the common ends, which affects the resonant length of the third radiating arm. Since the degree of coupling effect cannot be estimated, the length of the third radiating arm needs to be confirmed according to the actual structural pattern attached to the antenna. For example, the present embodiment mainly solves the SAR problem of the WCDMA 1900 frequency band, so the trace length of the third radiating arm can be set to about 15 mm. In this embodiment, the length of the first antenna radiating arm is smaller than the length of the second antenna radiating arm, and the first antenna radiating arm is mainly configured to generate a resonance of a higher frequency band, and the second antenna radiating arm It can be set to generate a resonance of a low frequency band. Correspondingly, the length of the trace of the first antenna radiation arm can be set to be a quarter wavelength of the center point of the first preset frequency band, and the first preset frequency band can be For the high frequency band, for example, it can be set to a frequency band of 1710 MHz to 2700 MHz or 1850 MHz to 1920 MHz. The length of the second antenna radiation arm can be set to be a quarter wavelength of the center point of the second preset frequency band; the second preset frequency band at this time can be the second highest frequency band and the low frequency band, for example, it can be set to 824 MHz. To the frequency band of 960MHZ. The width and length of the gap between the first antenna radiating arm and the second antenna radiating arm may also change the resonant frequency. In this example, the gap width between the first antenna radiating arm and the second antenna radiating arm is set. It is 0.3 mm or more and 0.8 mm or less.

Embodiment 2 Hereinafter, in order to better understand the present invention, the present invention will be further described by taking a specific antenna as an example with reference to the accompanying drawings. The antenna provided by the embodiment of the present invention can be applied to various communication terminals, such as various mobile communication terminals such as a mobile phone and an IPAD. In the following, in order to better understand the embodiments of the present invention, an embodiment of the present invention will be further described by taking a specific antenna as an example. Referring to FIG. 1 , the antenna in this embodiment includes an antenna body 1 , a matching circuit 4 , a radio frequency module 5 , and a main board 6 . The antenna body 1 is connected to the main board 6 through the first power feeding portion 3 and the first ground portion 2 (this figure does not show the corresponding second feeding portion and the second ground portion on the main board), and the matching circuit 4 is disposed at The first feeding portion 3 and the radio frequency module 5 are arranged to assist the tuning of the antenna body 1. The matching circuit 4 may specifically be a PI type matching circuit, a T type matching circuit, or the like. In this embodiment, the first power feeding portion 3 and the second grounding portion 2 of the antenna body 1 are respectively connected to the edge of the main board 6; as shown in FIG. 2, the antenna body 1 further includes a first antenna radiating arm 11 and a a two-antenna radiating arm 12 and a third antenna radiating arm 7; one ends of the first antenna radiating arm 11 and the second antenna radiating arm 12 are connected in parallel to form a common end 9, and the common end 9 as a whole and the first feeding portion 3 is connected to the first grounding portion 2, and the other ends of the first antenna radiating arm 11 and the second antenna radiating arm 12 are drawn from one side of the common end 9 (left side shown in FIG. 2) along one direction. . In FIG. 2, the first power feeding portion 3 is located on the right side of the common terminal 9, the first grounding portion 2 is located on the left side of the common terminal 9, and the third antenna radiation arm 7 is remote from the common terminal 9 away from the first antenna radiation arm. 11 and one side (i.e., the right side) of the second antenna radiating arm 12 are taken out and extended toward a position toward the first feeding portion 3 to form a third antenna radiating arm. The width of the gap between the third antenna radiating arm 7 and the common end 9 and the length of the third antenna radiating arm can be selected according to a specific application scenario. At the same time, the width of the gap between the first antenna radiating arm 11 and the second antenna radiating arm 12 can also be set according to a specific application scenario; the specific setting manner is not described herein again. In this embodiment, the first antenna radiating arm 11 and the third antenna radiating arm 7 can be tuned to the high frequency band to be covered, mainly radiating energy of the high frequency portion; and the second antenna radiating arm 12 is tuned to enable The antenna is tuned to the low frequency band that needs to be covered, mainly radiating low frequency part of the energy. Since the antenna generally has a high head SAR problem in the high frequency PCS and AWS bands, the antenna body shown in FIG. 2 is taken as an example. For the transmitting portion of the W1900 band, the resonance is generated in the band 1850 MHz to 1920 MHz. When the gap width between the third antenna radiation arm 7 and the common end 9 is set to about 0.5 mm, the length of the trace of the third antenna radiation arm 7 is set and correspondingly generated, so that the resonance frequency is generated in the PCS emission band. . In the following table, Table 2 shows the comparison data of the radiated power TRP of the antenna shown in Figure 2 in this application scenario; Table 1 shows the comparative data of the radiated power TRP of the existing antenna in this application scenario. table

Figure 3 and Figure 4 are schematic diagrams showing the near-field electric field distribution of the antenna when measuring SAR, showing the electric field intensity distribution state of the radiation when the signal input is OdB, wherein the darker the color, the weaker the electric field strength, the more the color The shallower is the stronger the electric field strength, the specific electric field strength value can be seen in the left color histogram; the specific test values are calculated by the instrument and software. According to the data of the above two tables and combined with FIG. 3, the TRP value of the antenna in this embodiment is 20.58 dB on average, and the SAR value is only 0.97 mw/g; and the data according to Table 1 above is combined with the figure. 4 It can be known that the existing antenna has an average TRP value of 19.41 dB, and its SAR value is It reached 1 mw/g. It can be seen that the antenna in this embodiment has a better TRP and a lower SAR value. Please refer to FIG. 5 , which shows a 3D radiation apple diagram of the existing antenna, which has relatively strong radiation in all directions; see FIG. 6 , which shows the antenna in the embodiment. According to the figure, it can be seen that the antenna in the embodiment also changes the radiation pattern of the antenna at the same time, so that the radiation in the direction of the terminal near the head (XZ direction) is reduced, and the far field is also reduced. Electromagnetic radiation absorption. Because the position of the signal feeding point and the ground feeding point of the antenna shown in this embodiment is close to the left position at the bottom of the mobile terminal, and the position of the antenna signal feeding point is often the position with the strongest surface current of the antenna, which is also the near field. The strongest position of radiation. Correspondingly, in a certain direction of the far field, a strong electric field radiation point is generated. The specific angle of this direction is related to the feeding position of the antenna and the shape of the main board (length to width ratio) and the layout of each module of the terminal. When the application environment is unchanged, only changing the routing mode of the antenna body will change the direction of the maximum radiation intensity of the entire terminal, and the antenna of the present example distributes the current intensity of the antenna body by adding a third radiating arm. The effect of radiation in the far field is that the maximum radiation intensity of the electric field is not as strong as that of a conventional antenna, but it has better radiation in a wider radiation direction, that is, although the radiation peak is reduced, the average value of the overall radiation Not reduced. This changes the radiation pattern in disguise, and finally the 3D radiation apple map shown in Fig. 6 is obtained.

The above is a further detailed description of the present invention in conjunction with the specific embodiments. It is not intended that the specific embodiments of the invention are limited to the description. It will be apparent to those skilled in the art that the present invention may be practiced without departing from the spirit and scope of the invention. Industrial Applicability As described above, an antenna and a terminal provided by the embodiments of the present invention have the following beneficial effects: while ensuring good radiation performance of the antenna, the SAR can be reduced, and the user experience is also improved to some extent. Satisfaction.

Claims

An antenna includes an antenna body, the antenna body including a first antenna radiating arm, a second antenna radiating arm, a first feeding portion, and a first ground portion; the first antenna radiating arm and One end of the second antenna radiation arm is connected in parallel to form a common end, and the first power feeding portion and the first ground portion are connected to the common end; the antenna body further includes a convection current from the common end. A third antenna radiating arm that is shunted by the current of the first power feeder. The antenna according to claim 1, wherein the antenna further includes a main board, a radio frequency circuit module disposed on the main board, and a second power feeding portion and a second ground portion disposed on the main board, The first power feeding portion and the first ground portion are respectively connected to the second power feeding portion and the second ground portion, and the second power feeding portion is connected to the radio frequency circuit module. The antenna device according to claim 2, wherein the antenna further comprises a matching circuit module, and the second feeding portion is connected to the radio frequency circuit module through the matching circuit module. The antenna according to claim 1, wherein said third antenna radiating arm is led out from a side of said common end remote from said first antenna radiating arm. The antenna according to claim 4, wherein said first power feeding portion is connected to a region of said common end adjacent to said third antenna radiation arm. The antenna according to claim 5, wherein an end from which the third antenna radiating arm is led out from the common end extends to a position where the first power feeding portion on the common end is located. The antenna according to any one of claims 1 to 6, wherein a gap width between the third antenna radiating arm and the common end is 0.2 mm or more and 1 mm or less. The antenna according to any one of claims 1 to 6, wherein a length of a trace of the third antenna radiating arm is smaller than a quarter wavelength of a center frequency of the preset frequency band. The antenna according to any one of claims 1 to 6, wherein a length of a trace of the first antenna radiating arm is smaller than a length of a trace of the second antenna radiating arm, the first antenna radiating branch The gap width between the arm and the second antenna radiation arm is greater than or equal to 0.3 mm and less than or equal to 0.8 mm. A terminal comprising the antenna of any one of claims 1-9.