JP5598893B2 - Humanoid phantom - Google Patents

Description

  The present invention relates to an experimental human body phantom related to electromagnetic waves.

  Wireless communication terminals such as mobile phones transmit and receive electromagnetic waves related to communication using their antennas. Since these terminals and antennas are used close to the human body, radiation of electromagnetic waves is caused by the interaction between the human body and the antenna. It will affect the direction and strength. Therefore, conventionally, it is necessary to conduct experiments and tests for grasping and analyzing the effects and effects of such electromagnetic waves. In these experiments and tests, a phantom that simulates the human body is used instead of the human body.

Such an experimental human body phantom is formed of a material having a dielectric constant similar to that of a human body using a resin material or a liquid. For example, in the solid phantom described in Patent Document 1, a conductive fiber is used as a resin. It is possible to adjust the dielectric constant of the phantom itself with this conductive material.
Patent No. 3663264

  However, the conventional human body phantom is formed of a homogeneous and solid resin material or liquid, and is configured to simulate at least the upper body part of the human body, so that its weight is heavy, for example, having a weight of 20 kg to 30 kg. become. Such a heavy human phantom is difficult to move and handle.

  Further, when an experiment is performed using this heavy phantom, it is inconvenient because an expensive and rigid heavy support positioner must be used when acquiring a radiation pattern in three dimensions.

  Furthermore, since the conventional liquid type phantom contains a lot of moisture, its characteristics may change over time.

  An object of the present invention is to provide a human body-type phantom that eliminates such drawbacks of the prior art and is light in weight and has little change in temporal characteristics while having the same electrical characteristics as those of the human body.

For the present invention to solve the above problems, is molded with at least a portion of the torso, the torso phantom for use in experiments on electromagnetic waves, at least for a portion of this phantom torso of the part A radio wave absorber formed to cover the surface of the humanoid mimetic body including a hollow humanoid mimetic body having an outer shell and having a hollow inside, and an absorbing material having electrical loss characteristics Including
A part of the phantom is formed by forming a plurality of layers including a first layer made of the humanoid mimetic body and a second layer made of the radio wave absorber ,
This wave absorber is characterized in that the impedance viewed from the outside in the phantom to have a set dielectric constant and thickness to be similar to the human body.

  According to the human body phantom of the present invention, at least part of the human body phantom, for example, the head, is formed so that the human body imitation has a predetermined thickness from the outer shell of the human body to the inside, and further the radio wave absorber Are formed so as to have a predetermined thickness inward from the inner surface of the humanoid mimetic body, and include a first layer made of the humanoid mimetic body and a second layer made of a radio wave absorber By being configured in layers, the weight can be significantly reduced while the electrical characteristics seen from the outside are equal to those of the human body.

  Further, since the human body phantom of the present invention is configured to be very lightweight, the setup measurement time can be shortened and can be supported by using an inexpensive positioner.

  Furthermore, in the experiment relating to the interaction between the human body and the antenna, it is necessary to manufacture a plurality of phantoms having different characteristics for each frequency of the electromagnetic wave to be tested. According to the human body phantom of the present invention, It is only necessary to manufacture the same body, and it is only necessary to attach a radio wave absorber having characteristics of each frequency to the human body-like body, so that convenience in manufacturing can be achieved.

  Embodiments of a human body phantom according to the present invention will now be described in detail with reference to the accompanying drawings. For example, as shown in FIGS. 1 and 2, the human body phantom 10 of the present embodiment has an inner surface at least one of the head 22 and the chest 24 with respect to the hollow human body-shaped simulated body 12. It is formed so as to be covered with the radio wave absorber 14. Note that portions not directly related to understanding the present invention are not shown and redundant description is avoided.

  The human body phantom 10 is used in a simulation or experiment for grasping the influence of electromagnetic waves due to the interaction between a human body and an antenna. For example, assuming that a base station installed in a mobile phone network and a mobile phone, which is a user terminal, are connected for communication and radio waves related to communication are emitted from the antenna of the base station to the mobile phone. A simulation or experiment is performed with the body phantom 10 having a mobile phone.

  As shown in FIG. 3, the human body phantom 10 may be a simulation of the upper body of a human body having a head 22, a chest 24 and left and right arms 26. Further, the human body phantom 10 may be configured such that the head 22, the chest 24, and the left and right arms 26 are detachable, and each part may be configured to be movable like a human body. The arm 26 may be configured to be able to hold a wireless communication terminal 28 such as a mobile phone.

  In this embodiment, FIGS. 1 and 2 are cross-sectional views from the front of the head 22 and chest 24 of the human body phantom 10, respectively. The human body phantom 10 of the present embodiment may be configured by a hollow body in which one of the head 22 and the chest 24 has the radio wave absorber 14, but both the head 22 and the chest 24 are formed of this hollow body. You may comprise, and it is good also considering another part as a hollow body.

  Furthermore, the human body phantom 10 of the present embodiment is configured to cover the inner surface of the human body type pseudo body 12 with the radio wave absorber 14, but is configured to cover the outer surface with the radio wave absorber 14. May be.

  The human body model 12 is a model of a human body, and is formed of a model having a predetermined thickness inward from the outer shell of the human body and having a cavity 16 inside.

  The human body model 12 may be formed of a synthetic resin material such as nylon, polypropylene, or urethane foam, that is, plastic, or may be formed of other non-metallic materials. The human body model body 12 can be integrally formed by, for example, a mold.

  In the present embodiment, the human body type pseudo body 12 may be formed with a predetermined thickness from the outer shell being uniform, and as shown in FIGS. 1 and 2, the predetermined thickness from the outer shell is formed. May not be uniform. The humanoid mimetic 12 may be appropriately formed so as to easily form an internal cavity and have a predetermined thickness from the outer shell.

  The radio wave absorber 14 has a property of absorbing radio waves and is provided on the inner surface or the outer surface of the humanoid body 12 having a cavity. The radio wave absorber 14 of the present embodiment is configured to have a predetermined thickness from the inner surface of the human body type pseudo body 12 to the inner side, and may be, for example, a radio wave absorbing sheet that is attached to the inner surface.

  The radio wave absorber 14 is formed of a material having electrical loss characteristics, and includes, for example, a carbon-based material such as carbon black or carbon fiber, or a conductive material such as ferrite powder. Good. For example, the radio wave absorber 14 may be configured by dispersing and mixing carbon particles in a foamed urethane foam.

  The radio wave absorber 14 is made of only at least one kind of solid dielectric material, and is lighter than a liquid material having similar properties. For example, ferrite powder, Rochelle salt, titanium oxide, or barium titanate. It is produced by solidifying a dielectric material such as. For example, the radio wave absorber 14 may be solidified by mixing solid dielectric materials such as particles or powders with a predetermined liquid.

  Also, when using the radio wave absorber 14 made of only a solid dielectric material in this way, for example, a core is formed of a dielectric material having a relatively large amount of carbon, and this core is replaced with the cavity 16 inside the phantom. The human body phantom 10 may be formed. In that case, the radio wave absorber 14 disposed around the core is formed of a dielectric material having a smaller amount of carbon than the core.

  In the present embodiment, the radio wave absorber 14 may be formed by adjusting the thickness from the surface of the human body type pseudo body 12 so that the electrical characteristics of the phantom 10 are equal to the electrical characteristics of the human body.

  By the way, considering the standard by IEEE (Institute of Electrical and Electronic Engineers) 1528, the impedance Zc obtained from the electrical constant of the human body can be considered as an electrical loss necessary for the human body phantom. A transmission line model in the case where a plane wave is incident from a wave source sufficiently far away from a human body phantom having a property of impedance Zc and formed of a homogeneous and solid resin material is, for example, as shown in FIG. The electric loss of the radio wave can be measured by simulation using this model.

  In FIG. 4, the spatial impedance in the air is indicated by impedance Zo, and it is assumed that the homogeneous model is at infinity in the negative direction with respect to Z = 0, that is, the right side of the dotted line indicated by Z = 0 in FIG. Assume that it is a humanoid phantom, and the left side is a free space such as the outside atmosphere.

  On the other hand, the human body phantom 10 in the present embodiment can be assumed as a model in which the radio wave absorber 14 is disposed between the external free space and the internal cavity region. The transmission line model is shown in FIG. Can be expressed as shown. In the model of FIG. 5, the electrical loss due to the radio wave absorber 14 is indicated by impedance Zs, and the thickness of the radio wave absorber 14 is indicated by t. The impedance Zs of the radio wave absorber 14 changes according to the thickness t.

  In FIG. 5, it is assumed that the radio wave absorber 14 is up to z = t with z = 0 as a reference. That is, the left side of the dotted line indicated by z = t in FIG. 5 is an external free space, and the right side is a human body shape. A phantom is assumed to be an internal cavity region on the right side of the dotted line indicated by z = 0. Here, the impedance of the human body phantom on the right side of the dotted line of z = t is indicated by impedance Zt.

  For example, in this embodiment, the impedance Zs and the thickness t are adjusted so that the electrical loss by the radio wave absorber model in FIG. 5 is equal to the electrical loss by the homogeneous model in FIG. It is preferable to use the radio wave absorber 14 from which a characteristic value is obtained. For example, a radio wave absorber 14 having a complex relative dielectric constant of 1 [GHz] and a thickness of 9.0 [mm] can be realized.

  Since the human body phantom 10 is formed according to the frequency of the radio wave to be tested, in this embodiment, the thickness of the radio wave absorber 14 is changed, or a carbon-based material or a conductive material mixed in the radio wave absorber 14 is used. The human body phantom 10 corresponding to each frequency can be formed by changing the content rate.

  Further, when analyzing the characteristics of the human body phantom, for example, assuming that there is a mobile phone antenna in the vicinity of the human body, as shown in FIG. 6, it is separated from the head 52 of the human body phantom by a predetermined distance d. It is possible to perform analysis by arranging a dipole antenna 54 at a certain position. Here, the human body phantom 10 of this embodiment provided with the radio wave absorber 14, that is, the analysis result when using the radio wave absorption model, and the human body phantom formed of a homogeneous and solid resin material, that is, the homogeneous model The analysis result when using is compared as follows. In these analysis models, a sphere with a diameter of 100 mm configured in the same manner as each human body phantom is used as the head 52.

  Here, when the ratio between the incident wave and the reflected wave related to the antenna 54, that is, the amount of reflection, is measured according to the change in the distance d, the measurement result is represented as a graph shown in FIG. In the graph of FIG. 7, the vertical axis indicates the reflected power amount S11 [dB], and the horizontal axis indicates the distance d / λ. In addition, in the graph of FIG. 7, the analysis result when the radio wave absorption model including the 4.2 mm-thick wave absorber 14 is used is indicated by a solid line, and the radio wave absorption model including the 9.0 mm-thick wave absorber 14 is illustrated. The analysis result when using is shown by a broken line, and the analysis result when using a homogeneous model is shown by a long broken line.

  In these analytical models, the incident surface may not be flat, and if the distance d is reduced to about 0.25λ, the difference in reflection between the case using the radio wave absorption model and the case using the homogeneous model becomes significant. Become. When this distance d is large, it is hardly affected by the thickness of the radio wave absorber 14. Therefore, in the human body phantom 10 of this embodiment, the values of the respective reflection amounts approach even when the distance d is a close distance. The thickness of the radio wave absorber 14 can be determined. For example, by setting the thickness of the radio wave absorber 14 to 4.2 mm, the amount of each reflection can be made substantially equal.

  Further, in the analysis model shown in FIG. 6, when the upper and left directions on the paper are the x direction and the y direction, respectively, and the direction from the paper to the front is the z direction, the radiation patterns of the respective analysis models are shown in FIGS. As shown in FIG. 8 to 11, the radiation pattern of the radio wave absorption model is indicated by a solid line, the radiation pattern of the homogeneous model is indicated by a broken line, and the radiation pattern when the human body phantom is not used is indicated by a one-point difference line.

  The radiation patterns in FIGS. 8 and 9 show the main polarization and cross polarization intensities [dB] at each phase in the xy plane of each model when the distance d = 0.05λ is set, respectively. 11 radiation patterns indicate the intensity [dB] of the main polarization and the cross polarization in each phase of the yz plane of each model when the distance d = 0.05λ is set.

  Thus, even when the antenna is close to the human body phantom, it can be seen that the same radiation pattern can be obtained when the radio wave absorption model is used and when the homogeneous model is used.

  In another embodiment, the human body phantom 10 of the present invention has a radio wave absorber 34 composed of a plurality of layers 38 and 40 of absorbing materials having different dielectric constants, as shown in FIGS. It may be configured.

  In this embodiment, the head 30 of the human body phantom 10 includes a hollow pseudo body 32 of the head 30 and a radio wave absorber 34. In this embodiment, an example of the head 30 of the human body phantom 10 will be described, but the chest, arms, and other parts may be configured to have a plurality of layers of radio wave absorbers.

  The radio wave absorber 34 may be layered from outside to inside or in the opposite direction, and may be laminated from the inner surface of the pseudo body 32 of the head 30 toward the center of the head 30.

  The multiple layers 38 and 40 constituting the radio wave absorber 34 may be made of the same absorbing material, that is, the same dielectric material, but may be made of different dielectric materials. The dielectric constant of each layer 38 or 40 in the radio wave absorber 34 can be adjusted according to the quality or quantity of the dielectric material constituting each layer 38 or 40. For example, the dielectric constant can be adjusted by containing a large amount of carbon. A high layer is formed, and a layer having a low dielectric constant is formed by containing a small amount of carbon.

  In addition, the radio wave absorber 34 may be configured such that each layer 38 or 40 is arranged according to the dielectric constant.For example, a layer having a higher dielectric constant is arranged on the inner side, and a layer having a lower dielectric constant is provided. Each layer is preferably laminated in order of the dielectric constant so as to be arranged on the outside.

  By the way, it is desirable that the human body phantom 10 is commonly used corresponding to each frequency without being influenced by the frequency of the electromagnetic wave to be tested, but may be prepared for each frequency. Therefore, when generating the human body phantom 10 corresponding to the frequency of the electromagnetic wave to be tested, the dielectric constant of the radio wave absorber 34 suitable for the test of the target electromagnetic wave is determined in advance according to this frequency, and the determination In order to realize the above-described dielectric constant, the number of layers constituting the radio wave absorber 34 and the dielectric constant of each layer may be determined in advance. The human body phantom 10 of this embodiment may be formed based on these determination results.

  For example, when generating a human body phantom 10 for testing an electromagnetic wave having a frequency of 800 MHz, a radio wave absorber 34 formed of a single layer of dielectric material 42 may be used as shown in FIGS. it can.

  When the human body phantom 10 intended for testing electromagnetic waves having a frequency of 2000 MHz is generated, a radio wave absorber formed by laminating two layers of dielectric materials 38 and 40 as shown in FIGS. 34 can be used. In this radio wave absorber 34, the dielectric materials 38 and 40 have different dielectric constants, and the dielectric material 40 having a relatively high dielectric constant is disposed on the inner side of the dielectric material 38 having a relatively low dielectric constant, thereby absorbing the radio wave. A body 34 is formed.

  Thus, in the human body phantom 10 of this embodiment, the radio wave absorber 34 has a larger number of layers when the frequency of the target electromagnetic wave is higher, and a smaller number of layers when the frequency is lower, It is good to form with the number of layers suitable for the experiment of object electromagnetic waves.

It is front sectional drawing which shows one Example of the head of the human body type phantom which concerns on this invention. It is front sectional drawing which shows one Example of the chest of the human body type phantom which concerns on this invention. It is a schematic diagram which shows the usage example of the human body type phantom of the Example shown in FIG. 1 and / or FIG. It is a schematic diagram which shows the transmission line model by a homogeneous human body type phantom. It is a schematic diagram which shows the transmission line model by the human body type phantom shown in FIG. It is a schematic diagram which shows the analysis model which analyzes the characteristic of a human body type phantom. It is a graph which shows the analysis result of the analysis model in FIG. 7 is a graph showing a radiation pattern of the main polarization in the xy plane in the analysis model in FIG. 6. It is a graph which shows the radiation pattern of the cross polarization of the xy plane in the analysis model in FIG. It is a graph which shows the radiation pattern of the main polarization of the yz plane in the analysis model in FIG. It is a graph which shows the radiation pattern of the cross polarization of the yz plane in the analysis model in FIG. It is front sectional drawing which shows the other Example of the head of the human body type phantom which concerns on this invention. FIG. 13 is an upper sectional view of the head of a human body type phantom of another embodiment shown in FIG. 12 as viewed from above. It is front sectional drawing which shows the other Example of the head of the human body type phantom which concerns on this invention. FIG. 15 is an upper cross-sectional view of the head of a human body phantom according to another embodiment shown in FIG. 14 as viewed from above.

Explanation of symbols

10 Humanoid phantom
12 Humanoid mimetic
14 Electromagnetic wave absorber
16 cavity
22 head
24 chest
26 arms

Claims (11)

In a human body phantom that is molded to have at least a part of a human body and is used for an experiment relating to electromagnetic waves, the phantom is:
At least a part of the phantom forms a human body-shaped outer shell of the part, and a hollow body-shaped mimetic body having a cavity inside,
Absorbing material only only contains at least one or more solids having the electrical loss characteristics, laminated toward the center of the phantom layer of the plurality of the absorbent materials having different dielectric constants from the inner surface of the person type mimetic And a radio wave absorber formed to cover the inner surface of the humanoid mimetic body,
A part of the phantom is formed by forming a plurality of layers including a first layer made of the human body-like mimetic and a second layer made of the radio wave absorber,
The human body type phantom, wherein the radio wave absorber has a dielectric constant and a thickness set so that an impedance viewed from the outside of the phantom is similar to that of a human body.   2. The human body phantom according to claim 1, wherein the radio wave absorber is formed to have a predetermined thickness from an inner surface in a hollow region of the human body pseudo body.   The human body phantom according to claim 1, wherein the radio wave absorber is formed to have a predetermined thickness from an outer surface of the human body pseudo body.   2. The human body phantom according to claim 1, wherein the phantom is configured to simulate an upper body part of a human body, and at least a head of the upper body part is configured of the human body type body and the radio wave absorber. A humanoid phantom characterized by   2. The human body phantom according to claim 1, wherein the phantom is configured to simulate an upper body part of a human body, and at least a chest part of the upper body part includes the human body type body and the radio wave absorber. Characteristic human phantom.   The human body phantom according to claim 1, wherein the phantom is configured by adjusting the content of the absorbing material and shaping the radio wave absorber according to the frequency of the electromagnetic wave to be tested. A humanoid phantom.   The human body phantom according to claim 1, wherein the absorbing material is a carbon-based material.   2. The human body phantom according to claim 1, wherein the radio wave absorber is formed by applying carbon particles as the absorbing material and dispersing and mixing the carbon particles in a foamed urethane foam. Body phantom.   The human body type phantom according to claim 1, wherein the radio wave absorber is a radio wave absorption sheet attached to the human body type pseudo body. 2. The human body phantom according to claim 1 , wherein the radio wave absorber is formed by laminating layers of the plurality of absorbing materials in the order of the respective dielectric constants. 2. The human body phantom according to claim 1 , wherein the radio wave absorber is formed by laminating the absorbing material in a number of layers suitable for the experiment according to the frequency of the electromagnetic wave to be tested. Humanoid phantom.

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