WO2013182144A1

WO2013182144A1 - Device for reducing electromagnetic radiation specific absorption rate and mobile terminal

Info

Publication number: WO2013182144A1
Application number: PCT/CN2013/079550
Authority: WO
Inventors: 张琦; 张璐
Original assignee: 中兴通讯股份有限公司
Priority date: 2012-10-25
Filing date: 2013-07-17
Publication date: 2013-12-12
Also published as: CN103001005A; CN103001005B

Abstract

A device for reducing an electromagnetic radiation specific absorption rate and a mobile terminal. The device comprises: a retrodirective antenna array device, which is arranged between a mobile terminal display component and a circuit board, and passive connection transmission lines. The retrodirective antenna array device comprises a plurality of antenna element pairs, and in each of the antenna element pairs, two antenna elements are connected through a passive connection transmission line of the same electrical length. When an antenna element receives an incoming wave radiated to a human body, the device and the mobile terminal which comprise another antenna element paired with the foregoing antenna element through the passive connection transmission line can achieve an effect of well reducing an electromagnetic radiation specific absorption rate without lowering communication efficiency.

Description

Device and mobile terminal for reducing electromagnetic radiation specific absorption rate

Technical field

The present invention relates to the field of communications technologies, and in particular, to a device and a mobile terminal for reducing the specific absorption rate of electromagnetic radiation.

Background technique

As mobile terminals become more widely used, the public is increasingly considering the radiation of mobile terminals to the human body. The indicator for measuring the amount of electromagnetic wave energy radiated to the human body is SAR (Specific Absorption Rate), that is, the electromagnetic wave energy absorption ratio of the wireless terminal. The SAR is generally used as a numerical value indicating the degree of harmful effects on the human body caused by electromagnetic waves radiated by the mobile terminal. At present, most of the SAR-reducing technologies reduce the transmission power of mobile terminal antennas, the use of absorbing materials and conductor reflectors, and the application of radiation and absorbing coatings, which reduces communication efficiency.

Summary of the invention

Embodiments of the present invention provide a device and a mobile terminal for reducing the specific absorption rate of electromagnetic radiation, which are used to solve the problem of reducing communication efficiency caused by reducing the specific absorption rate of electromagnetic radiation in the related art.

An embodiment of the present invention provides a device for reducing the specific absorption rate of electromagnetic radiation, comprising: a backtracking antenna array device and a passive connection transmission line disposed in a direction between a display component of the mobile terminal and the circuit board, wherein

The direction backtracking antenna array device includes a plurality of antenna unit pairs, and each antenna unit is connected by a passive connection transmission line of an equal length;

When an antenna unit receives a incoming wave radiating to the human body, the reflected wave is transmitted through the passive connection transmission line.

Optionally, all pairs of antenna elements are of the same type and are symmetric with the geometric center of the passive direction backtracking antenna array. Optionally, the type of the antenna unit is: a second-order Hilbert fractal antenna, a monopole antenna, a meander line antenna, an equiangular spiral antenna, a fractal antenna or a slot antenna.

Optionally, the direction backtracking antenna array has the characteristics of a Van Atta array.

The embodiment of the present invention further provides an apparatus for reducing the electromagnetic radiation specific absorption rate, comprising: an antenna array feeding device and a direction backtracking antenna array device disposed in the middle of the display component of the mobile terminal and the circuit board, wherein

The direction backtracking antenna array device includes a plurality of antenna unit pairs;

The antenna array feeding device is configured to: when an antenna unit receives a incoming wave signal radiated to the human body, generate a reflected wave having the same frequency but opposite direction as the incoming wave signal, and the reflected wave is transmitted through the antenna unit Launched.

Optionally, the antenna array feeding device at least includes: a local oscillator, and a mixer corresponding to each antenna unit, where

All mixers are connected to the local oscillator;

The local oscillator is configured to: output an oscillating signal that generates twice the frequency of the incoming signal to the mixer; an input port of the mixer is configured to: receive an oscillation of twice the frequency of the local wave generated by the local oscillator a signal, the other input port is configured to: receive the incoming wave signal and conjugate the phase of the incoming wave signal; the mixer is configured to: oscillate the frequency of the double-wave signal frequency After the conjugated incoming wave signal is mixed, the reflected wave having the same magnitude but opposite direction as the incoming wave signal is generated, and the reflected wave is emitted.

Optionally, the type of the antenna unit is: a second-order Hilbert fractal antenna, a monopole antenna, a meander line antenna, an equiangular spiral antenna, a fractal antenna or a slot antenna.

Embodiments of the present invention also provide a mobile terminal, including the above apparatus for reducing electromagnetic radiation specific absorption rate.

By using the apparatus and the mobile terminal of the embodiment of the present invention, the effect of better reducing the electromagnetic radiation absorption rate is achieved, and the communication efficiency is not lowered. BRIEF abstract

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing the basic working principle of a Van Atta array of passive direction backtracking antennas according to a first embodiment of the present invention.

2 is a schematic diagram of an antenna unit arrangement based on a Van Atta array according to a first embodiment of the present invention. Fig. 3 is a schematic view showing the arrangement of slot antenna elements based on a Van Atta array according to the first embodiment of the present invention.

4 is a schematic diagram of a device based on a two-dimensional array element of a Van Atta antenna array according to a first embodiment of the present invention.

Figure 5 is a schematic illustration of the principle of implementing active phase conjugation of a retroreflective antenna array in accordance with a second embodiment of the present invention.

Figure 6 is a schematic diagram of active power feeding based on a Van Atta antenna array in accordance with a second embodiment of the present invention.

FIG. 7 is a schematic diagram of an application of a mobile terminal according to a second embodiment of the present invention.

FIG. 8 is another schematic diagram of another application of the mobile terminal according to the second embodiment of the present invention.

Preferred embodiment of the invention

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

An embodiment of the present invention provides an antenna array for reducing the specific absorption rate of electromagnetic radiation and a mobile terminal using the antenna array. The backward direction antenna array can reflect electromagnetic waves along the incoming wave direction, and realize incident waves and reflected waves in the human body. The offset in the direction, thereby reducing the electromagnetic radiation energy radiated to the human body.

In order to achieve the above object, embodiments of the present invention provide both passive and active solutions for reducing electromagnetic wave energy radiated to a human body. Among them, the passive scheme includes a direction backtracking antenna array device and its corresponding passive connection transmission line. The active solution includes a direction backtracking antenna array device and an antenna array feed device. When the mobile terminal antenna radiates electromagnetic waves to the human body, the direction backtracking antenna array can reflect the electromagnetic waves back along the incoming wave direction without any prior information of the incoming wave, thereby reducing the radiation of the mobile terminal to the human body. The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, in which FIG.

First embodiment (passive scheme)

In the passive scheme, a direction backtracking antenna array device and a passive connection transmission line are disposed in the middle of a mobile terminal display component and a printed circuit board (PCB), wherein the direction backtracking antenna array device includes a plurality of antenna unit pairs. And each antenna unit is connected by a passive connection transmission line of an equal length; all antenna unit pairs are of the same type and symmetric with the geometric center of the array; when the antenna unit receives the incoming radiation to the human body, the passive connection transmission line , Go with that day.

The direction backtracking antenna array in the passive scheme has the characteristics of a Van Atta array. As shown in Fig. 1, Fig. 1 is a schematic diagram showing the basic working principle of the Van Atta array of the direction backtracking antenna. The Van Atta antenna array consists of multiple antenna element pairs (equal to the center of the antenna array), and each antenna element is connected by a passive connection transmission line of equal length; if the phase gradient of the antenna array is kept opposite, Get the right phase for the direction backtracking. As shown in Figure 1, the phase difference between the four elements is incremental, and the increase is 0. A pair of antennas with the same distance from the center of the antenna array are connected by an equal-length transmission line, and the phase difference and incidence between the elements at the time of exit. The phase difference generated by the wave between the array elements is the same. When the signal received by each antenna unit is radiated by the antenna unit paired with it, the array automatically realizes the direction of the reflected wave and the direction of the incident wave. The ultimate goal of backtracking.

The Van Atta antenna array can achieve directional backtracking in a wide frequency band, and its bandwidth is limited only by the bandwidth of the array unit. Since the reflected wave is composed of the secondary radiation of the array, the patch of the array element and the scattering of the metal plate, the array has a good reflection waveform only at a certain interval. Therefore, different array spacings can be designed according to different mobile terminals. Fig. 2 is a schematic diagram showing an arrangement of array elements based on a Van Atta antenna array according to a first embodiment of the present invention. In the entire direction back to the antenna array 201, eight antenna elements 202 are hooked.

In order to achieve the operating frequency band of the mobile communication, the antenna unit of the first embodiment of the present invention is designed as a second-order Hilbert fractal antenna. The type of the antenna unit can also be selected as a monopole antenna, a zigzag line antenna, an isometric helical antenna, a fractal antenna or a slot antenna, etc., so that it operates in the mobile communication band. Figure 3 is a schematic diagram of a slot array arrangement based on a Van Atta antenna array according to a first embodiment of the present invention. In implementation, it is also possible to continue to increase the number of antenna elements to enhance the reflection effect.

As shown in FIG. 4, FIG. 4 is a schematic diagram of a device based on a two-dimensional array of Van Atta antenna arrays according to a first embodiment of the present invention. Wherein, in the direction backtracking antenna array device 401, there are two-dimensional antenna units (that is, array units, referred to as array elements) 402, each antenna unit pair is connected through a passive connection line 403, and the antenna unit is of the same type. The antennas, and symmetric about the geometric center of the array, are connected to each other by a passive connection transmission line of equal length.回Returning the antenna with the direction of the passive structure, the antenna unit and the passive connection transmission line can be processed on the FPCB (Flexible Printed Circuit Board) to realize the ultra-thin design of the whole machine.

Second Embodiment (Active Scheme)

The active scheme is to feed the array in a phase conjugate manner. An antenna array feeding device and an active direction backtracking antenna array device are sequentially disposed in the middle of the mobile terminal display component and the PCB circuit board, wherein the active direction backtracking antenna array device is composed of a plurality of antenna unit pairs; when an antenna unit receives When the incoming wave signal is radiated to the human body, a reflected wave having the same frequency but opposite direction to the incoming wave signal is generated by the antenna array feeding device, and the reflected wave is emitted through the antenna unit.

The antenna array feeding device comprises at least: a mixer corresponding to each antenna unit and a local oscillator, wherein all the mixers are connected to the local oscillator; the local oscillator is set to: an oscillating signal that generates twice the frequency of the incoming signal Outputting to the mixer; one input port of the mixer is configured to receive an oscillating signal of twice the frequency of the wave generated by the local oscillator, and the other input port is configured to receive the incoming signal and to the incoming signal The phase is conjugated; the mixer is configured to: mix the oscillating signal of the double-wave signal frequency and the conjugated incoming wave signal to generate the same frequency but the direction of the incoming wave signal The opposite reflected wave, and the reflected wave is emitted.

As shown in FIG. 5, FIG. 5 is a schematic diagram of the principle of implementing active phase conjugate of the backtracking antenna array, that is, using a local oscillator and several mixers to obtain the phase conjugate received by the antenna unit as the transmitting phase, which can be realized. Backtracking direction. Taking the phase of the first array element receiving the incoming wave as the reference, the other array elements are in phase with the first array element, and the conjugate of the phase of each array element is generated by the mixer as the phase of the transmitted wave, which can be realized. Backtracking direction. When the radiation source is far away from the antenna array, the electric wave propagates toward the antenna array, and when it reaches the antenna, it is a plane wave. It is assumed that the phase of the electromagnetic wave reaching the antenna is: θ. , θι , θ ₂ , . . . , Θ _Ν . Where the phase of the received signal of the antenna unit where the reference plane is located is θο, the phase of the received signal of the remaining antenna elements and the phase difference thereof are:

ΔΘ ₂ = θ _{2 -} θο

In order to make the main lobe of the antenna array radiation pattern point to the direction of the incoming wave, the phase of the transmitted signal of each antenna unit can be compensated for this phase difference, which satisfies the requirement of being in phase in the reference plane. For example, the received signals of all antenna elements are phase conjugated. At this time, the phase of the radiation signal becomes: -θ ₀ ,

- θι , -θ ₂ , . . . , -Θ _Ν , where the phase of the antenna element where the reference plane is located is -θο, then the phase difference between the transmitted signal of the antenna unit and the reference unit is:

-Δθι=-θι- ( -θ ₀ ) -Δθ ₂ =−Θ ₂ - ( -θ ₀ )

It can be seen that the phase conjugate of the received signal of the antenna unit acts as the phase of the transmitted signal, which can compensate the phase difference caused by the difference of the position of the antenna unit, and direct the main lobe of the antenna pattern to the direction of the incoming wave, thereby achieving the purpose of backtracking. .

There are two signals at the input end of the mixer, one is the local oscillator signal, one is the received electromagnetic wave signal to the human body, that is, the incoming wave signal, and the output end has the intermediate frequency signal, that is, the reflected wave signal.

The local oscillator generates an oscillating signal at a local frequency, the frequency is 2Fin (Fin is the frequency of the received electromagnetic radiation to the human body), the oscillating signal is input to an input port of the mixer; another signal of the mixer input is received The electromagnetic wave signal radiated to the human body at a frequency of Fin. The IF signal generated by such a mixer is the same as the frequency of the electromagnetic wave radiated to the human body, but the phase is conjugated to cancel. 6 is a schematic diagram of active power feeding based on a Van Atta antenna array according to a second embodiment of the present invention. The antenna array feeding device 601 feeds an antenna unit of an active direction backtracking antenna array device through a feed line 602. Thus, when one of the array antennas receives electromagnetic waves radiating to the human body, the other elements will reflect the electromagnetic waves back in the direction of the incoming wave. At the same time, the active direction backtracking antenna array device and the antenna array feeding device 601 are distributed on both sides of the FPCB, thereby realizing the ultra-thin design of the whole machine.

As shown in FIG. 7 and FIG. 8 , FIG. 7 and FIG. 8 are schematic diagrams of application according to a second embodiment of the present invention. FIG. 7 is a schematic diagram of a touch screen type mobile terminal. The radiating antenna 703 of the mobile terminal is mounted on the mobile terminal PCB circuit board 702. The direction backtracking antenna array device 701 is located on the same side of the mobile terminal LED (Light-Emitting Diode Light Emitting Diode) display component 704, and the antenna array feeding device 705 is located at the mobile terminal LED display component 704 and the direction backtracking antenna. Between the array devices 701. 8 is a schematic diagram of a flip-type mobile terminal, the structure is similar to that of FIG. 7, that is, the radiating antenna 803 of the mobile terminal is mounted on the mobile terminal PCB circuit board 802, and the direction backtracking antenna array device 801 is located at the mobile terminal LED display component 804 (including the display) On the same side of the folded portion below the screen, the antenna array feed 805 is located between the mobile terminal LED display assembly 804 and the direction backtracking antenna array device 801.

The embodiment of the present invention further provides a mobile terminal, where the apparatus for reducing the electromagnetic radiation specific absorption rate described in the first embodiment or the second embodiment is provided in the mobile terminal. For details, refer to the above related description. Let me repeat.

In summary, the embodiment of the present invention provides a device and a mobile terminal for reducing the specific absorption rate of electromagnetic radiation, and has made great progress compared with the related art. Compared with the application of the absorbing material, it is required to apply one layer or even multiple layers, which occupies a large space, and the mobile terminal of the embodiment of the invention occupies a relatively small space. Moreover, since the reflection efficiency of the ordinary reflection plate is low, and even the transmission phenomenon may occur, the embodiment of the present invention is a better choice from the demand of high reflection efficiency; for different mobile terminals, the position and quantity of the sensor are added. There may be differences, which are difficult to implement on a large scale, and the embodiment of the present invention has no such troubles and is easy to implement. In summary, the technical solution of the embodiment of the present invention achieves a better effect of reducing the electromagnetic radiation specific absorption rate compared with the related art, and does not Reduce communication efficiency. The passive scheme helps to save space, and the active scheme improves the radiation performance and communication quality of the terminal antenna through reflected waves.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. Embodiments of the invention are not limited to any particular form of combination of hardware and software.

The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or within the technical scope disclosed by the present invention. Alternatives are intended to be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Industrial applicability

With the apparatus and the mobile terminal of the embodiment of the present invention, the effect of better reducing the electromagnetic radiation than the absorption rate is achieved, and the communication efficiency is not lowered.

Claims

Claim

What is claimed is: 1. A device for reducing the specific absorption rate of electromagnetic radiation, comprising: a backtracking antenna array device and a passive connection transmission line disposed in a direction between a display component of the mobile terminal and the circuit board, wherein

2. Apparatus according to claim 1 wherein all pairs of antenna elements are of the same type and are symmetric with respect to the geometric center of the passive direction backtracking antenna array.

3. The apparatus according to claim 1 or 2, wherein the type of the antenna unit is: a second-order Hilbert fractal antenna, a monopole antenna, a meander line antenna, an equiangular spiral antenna, a fractal antenna or a slot antenna.

4. Apparatus according to claim 1 wherein the directional backtracking antenna array has the characteristics of a Van Atta array.

5. A device for reducing the specific absorption rate of electromagnetic radiation, comprising: an antenna array feeding device and a direction backtracking antenna array device disposed between the display component of the mobile terminal and the circuit board, wherein

The apparatus according to claim 5, wherein the antenna array feeding device comprises: at least: a local oscillator, and a mixer corresponding to each antenna unit, wherein

All mixers are connected to the local oscillator;

The local oscillator is configured to: output an oscillating signal that generates twice the frequency of the incoming signal to the mixer; an input port of the mixer is configured to: receive an oscillation of twice the frequency of the local wave generated by the local oscillator a signal, the other input port is configured to: receive the incoming wave signal and conjugate the phase of the incoming wave signal; the mixer is configured to: oscillate the oscillating signal of the double-wave signal frequency And after the conjugated incoming wave signal is mixed, the reflected wave having the same frequency but opposite direction as the incoming wave signal is generated, and the reflected wave is emitted.

The apparatus according to claim 5 or 6, wherein the type of the antenna unit is: a second-order Hilbert fractal antenna, a monopole antenna, a meander line antenna, an equiangular spiral antenna, a fractal antenna or a slot antenna.

8. Apparatus according to claim 5 wherein the directional backtracking antenna array has the characteristics of a Van Atta array.

A mobile terminal comprising at least the apparatus for reducing the specific absorption rate of electromagnetic radiation according to any one of claims 1 to 8.