JP3993557B2 - Electromagnetic field distribution simulation method and apparatus - Google Patents

Description

  The present invention relates to an electromagnetic field distribution simulation method and apparatus for simulating electromagnetic field distribution of electromagnetic waves such as microwaves.

  In general, electromagnetic waves follow Maxwell's equations. Solving this Maxwell equation can obtain the electromagnetic field distribution of the electromagnetic wave, but it is difficult to solve it analytically and is currently being numerically calculated by various approximations.

  Further, in microwave power transmission in which the electric power stored in the power generation satellite is transmitted by microwaves, it is necessary to calculate a long distance exceeding 500 km, and the calculation time becomes enormous.

  In particular, in microwave power transmission, an ionosphere is interposed in the middle. In this ionosphere, it is known that an electrostatic plasma wave is generated when a microwave passes. The simulation considering the influence of this electrostatic plasma wave is even more difficult.

As a method of simulating in consideration of the influence of the ionosphere, there is an FDTD (Finite Difference Time Domain) method that directly solves an electromagnetic field (for example, see Non-Patent Document 1).
IEICE Transactions B-II Vol. J78-B-II No. 3 pages 119-129

  However, in the FDTD method, the calculation amount is enormous and the calculation time is long, and the calculation can be performed only in an area of about several kilometers at most.

  On the other hand, as a simulation method with a short calculation time, there are a ray tracing method for performing geometric approximation and a full wave method for solving a matrix composed of boundary conditions of electromagnetic fields by dividing a propagation path into multiple layers. . However, since these simulation methods basically handle a single plane wave, the interaction between the plane waves is not taken into consideration. Therefore, with these methods, an electromagnetic field distribution, that is, a profile of electromagnetic waves in a plane orthogonal to the propagation direction cannot be obtained.

  In view of the above problems, an object of the present invention is to provide a simulation method and apparatus capable of obtaining an electromagnetic field distribution of electromagnetic waves in a practical calculation time.

  In order to solve the above problems, the present invention employs the following means.

The simulation method of the present invention is an electromagnetic field distribution simulation method for simulating an electromagnetic field distribution of electromagnetic waves in a plane perpendicular to the propagation direction between a transmitter and a receiver by a computer ,
A constant frequency of electromagnetic waves, to ignore the change in the frequency components of the electromagnetic wave is focused on a change in its envelope,
The computer solves by the beam propagation method using the Maxwell equation approximated under the conditions: and obtains the electromagnetic field distribution.

  An electromagnetic field distribution (profile) in a plane perpendicular to the propagation direction is important for devices that transmit or receive electromagnetic waves. When approximating the Maxwell equation that is based on this electromagnetic field distribution, the change of the electromagnetic wave frequency (for example, 5.8 GHz) is ignored, and only the envelope of the electric field vector that gently changes in the propagation direction is focused. As a result, the calculation time is greatly reduced.

  Further, since the beam propagation method is used, the dielectric constant is taken into consideration. Here, the beam propagation method refers to a method of sequentially performing beam propagation analysis using a calculation formula relating electromagnetic field distributions before and after a minute propagation section.

  The electromagnetic wave distribution simulation of the present invention is not intended for limited interpretation, but is particularly suitable for simulation of radio waves, more specifically, microwaves. This is because in the case of microwaves, since the frequency is as high as several GHz, there is less loss compared to low frequencies, so the fluctuation of the electric field of the high frequency component is ignored, and only gentle changes in the envelope (envelope) are handled. This is because even if the value is added, the calculation accuracy is hardly affected.

  Maxwell's equations can be obtained by reducing the divergence of the electric field to zero, considering only the linear component of the polarization vector, that is, the component proportional to the electric field, or ignoring the second derivative term in the propagation direction of the electric field vector. May be further approximated.

  The electromagnetic field distribution simulation method of the present invention is characterized in that an ionosphere is interposed in the propagation path of the electromagnetic wave.

  Even in the simulation over a long distance that the ionosphere is interposed, as described above, “the frequency of the electromagnetic wave is constant, the change in the frequency component of the electromagnetic wave is ignored, and the change in the envelope is focused” Therefore, the calculation amount is largely omitted, and the electromagnetic field distribution can be obtained in a practical time.

  In addition, since the dielectric constant is taken into account by using the “beam propagation method”, even if an ionosphere is present, a highly accurate simulation result considering the ionosphere can be obtained.

Further, the computer is, ionosphere interposed propagation path of the electromagnetic wave, magnetism, by the environmental characteristic data of the atmosphere or the like, retrieve by referring to the environmental factor database in which the environmental characteristic data has been stored, the environmental characteristic data Is used for electromagnetic field distribution simulation to determine the influence of the global environment .

  By referring to a standard database and automatically capturing environmental characteristic data and reflecting it in the simulation, the accuracy of the simulation can be improved.

  Further, the electromagnetic field distribution simulation method of the present invention obtains the electromagnetic field distribution at the first propagation position by numerical calculation, and obtains the electromagnetic field distribution at the second propagation position in the next step. The state of space division at the second propagation position is determined based on the electromagnetic field distribution obtained at the first propagation position, with the number of space divisions and the number of space divisions at the second propagation position being substantially the same. It is characterized by changing.

  Since the number of space divisions at the first propagation position and the number of space divisions at the second propagation position remain substantially the same, the state of space division at the second propagation position is changed (remeshed). The calculation time at is a fixed time. That is, since the calculation time does not become longer or shorter for each propagation position, the calculation time as a whole is reduced.

  Since the space division state at the second propagation position is changed (remeshed) based on the electromagnetic field distribution obtained at the first propagation position, the space division setting is not changed even if the electromagnetic field distribution changes. It is possible to prevent deterioration of calculation accuracy depending on the manner.

Further, the electromagnetic field distribution simulation method of the present invention is a method of finely dividing a space at a position where the electric field strength of the electromagnetic wave is large in the electromagnetic field distribution obtained at the first propagation position, and a space at a position where the electric field strength of the electromagnetic wave is small. Is roughly divided.

  In the electromagnetic field distribution, the position where the value is large increases the accuracy by finely dividing the space. On the other hand, since the position having a small value has a relatively small influence on the calculation result, the space is roughly divided.

The present invention also provides an electromagnetic field distribution simulation program that includes the numerical calculation program of the beam propagation method and that executes the above-described electromagnetic field distribution simulation method and that can be executed by a computer .

The present invention also provides an electromagnetic field distribution simulation apparatus comprising a computer that executes the above-described electromagnetic field distribution simulation program .

  The present invention also provides a design method for a transmitter / receiver for designing a transmitter and / or a receiver using the electromagnetic field distribution simulation method.

  The size and shape of the transmitter and receiver can be determined according to the electromagnetic field distribution obtained by the electromagnetic field simulation method according to the present invention. For example, if the electromagnetic field distribution of the electromagnetic wave reaching the receiver is obtained, a receiver having a necessary and sufficient size can be designed.

  Moreover, you may manufacture a transmitter and / or a receiver based on the design method of the said transmitter / receiver. Thereby, a transmitter and a receiver having a size and shape corresponding to the electromagnetic field distribution are provided.

  The present invention also provides a transmitter / receiver control device for controlling a transmitter and / or a receiver based on an electromagnetic field distribution obtained by the electromagnetic wave distribution simulation method.

  By controlling the positions and orientations of the transmitter and receiver by the control device, the optimal arrangement of the transmitter and receiver can be realized according to the environment that changes from moment to moment.

  Moreover, this invention provides the electromagnetic wave transmission / reception system provided with the transmitter, the receiver, the said electromagnetic field distribution simulation apparatus, and the control apparatus of the said transmitter / receiver.

  By combining these, an electromagnetic wave transmission / reception system optimized at each time is provided.

  When approximating Maxwell's equations that underlie the electromagnetic field distribution, the change in the frequency of the electromagnetic wave is ignored and only the electric field vector that changes slowly in the propagation direction is considered, so the calculation time can be greatly reduced. it can.

  In addition, since the beam propagation method is used, the dielectric constant is taken into consideration, and an accurate electromagnetic field distribution can be obtained.

  In addition, even in simulations over long distances where the ionosphere is present, it is assumed that the frequency component of the electromagnetic wave is ignored and the amplitude of the electric field vector that changes in the propagation direction is focused. Is greatly omitted, and the electromagnetic field distribution can be obtained in a practical time.

  Further, since the dielectric constant is taken into account by using the beam propagation method, a highly accurate simulation result considering the ionosphere can be obtained even if the ionosphere is present.

  In addition, the environmental characteristic data is automatically taken in with reference to a standard database provided generally and reflected in the simulation, so that the accuracy of the simulation can be improved.

  In addition, since the number of space divisions at the first propagation position and the number of space divisions at the second propagation position remain substantially the same, the state of the space division at the second propagation position is changed. Since the calculation time is a fixed time and the calculation time does not become longer or shorter for each propagation position, the calculation time as a whole can be reduced.

  Since the space division state at the second propagation position is changed based on the electromagnetic field distribution obtained at the first propagation position, even if the electromagnetic field distribution changes, the calculation is performed according to the setting method of the space division. The accuracy can be increased.

  In addition, since the position where the value is large in the electromagnetic field distribution is finely divided, the calculation accuracy can be prevented from being deteriorated. On the other hand, since the position having a small value has relatively little influence on the calculation result, the number of space divisions as a whole can be made constant by roughly dividing the space.

Further, by using the electromagnetic field distribution obtained by the electromagnetic field simulation method according to the present invention, the size and shape of the transmitter and the receiver can be determined.
Further, the position and orientation of the transmitter and the receiver are controlled by the transmitter and receiver control device that controls the transmitter and / or the receiver based on the electromagnetic field distribution obtained by the electromagnetic wave distribution simulation method according to the present invention. By controlling the above, it is possible to realize an optimal arrangement of the transmitter and the receiver according to the environment that changes every moment.

[First embodiment]
Below, 1st embodiment of this invention is described.

  First, a simulation method using a beam propagation method according to the present invention will be described with reference to FIG.

  Maxwell's equations that explain the electromagnetic phenomenon in a unified manner are expressed as the following equation when expressed in a differential form (S1).

式および（２）式から磁束ベクトルＢを代数的に消去すると、下式が得られる（Ｓ２）。

When the magnetic flux vector B is algebraically eliminated from the equations and (2), the following equation is obtained (S2).

上記（８）式の左辺を変形すると、下式が得られる。

When the left side of the above equation (8) is deformed, the following equation is obtained.

ここで、電界の発散がゼロ（Ｓ３）、すなわち、

Here, the divergence of the electric field is zero (S3), that is,

を仮定すると、下式が得られる。

Assuming that, the following equation is obtained.

ここで、分極ベクトルＰを、電界の強さに比例する線形項Ｐ_Ｌと、電界の強さに比例しない非線形項Ｐ_ＮＬとに分解して記述すると、

Here, the polarization vector P is described by being decomposed into a linear term P _L proportional to the electric field strength and a nonlinear term P _NL not proportional to the electric field strength.

となる。ここで、非線形項Ｐ_ＮＬを無視し、

It becomes. Here, the nonlinear term P _NL is ignored,

と記述すると、下式が得られる（Ｓ４）。

The following formula is obtained (S4).

ここで、電磁波の伝播方向をｚ軸に選ぶ。そして、電界ベクトルＥは、電磁波の周波数に相当する角周波数ωで変化する成分と、緩やかに変化する成分（包絡線）との積の形で記述すると下式のようになる（Ｓ５）。

Here, the propagation direction of the electromagnetic wave is selected on the z axis. When the electric field vector E is described in the form of a product of a component that changes at an angular frequency ω corresponding to the frequency of the electromagnetic wave and a slowly changing component (envelope), the following expression is obtained (S5).

そして、次のような仮定をする（Ｓ６）。

Then, the following assumption is made (S6).

上記１の条件は、電界ベクトルＥの振幅が時間に依存しないこと、すなわち電磁波の周波数での変化を無視することを意味する。

The above condition 1 means that the amplitude of the electric field vector E does not depend on time, that is, the change in the frequency of the electromagnetic wave is ignored.

The above condition 2 means that the rate of change (second derivative) in the propagation direction of the amplitude E ₀ of the electric field vector E is negligibly small compared to the slope (first derivative) in the propagation direction.

  When the above assumptions 1 and 2 are introduced, the following equation is obtained.

上式を変形すると、

Transforming the above equation,

となる。

It becomes.

  Also,

とすると、下式が得られる（Ｓ７）。

Then, the following formula is obtained (S7).

上式がビーム伝播法の基礎方程式である。この式では、電界の三成分は互いに独立であり、各成分の混合は生じない。これは媒質が等方的と仮定した結果である。ただし、誘電率がテンソルで与えられた場合は、独立ではなくなる。

The above equation is the basic equation of the beam propagation method. In this equation, the three components of the electric field are independent of each other and no mixing of the components occurs. This is a result of assuming that the medium is isotropic. However, when the dielectric constant is given by a tensor, it is not independent.

  As can be seen from the equation (18), all information on the medium through which the electromagnetic wave propagates is reflected in the refractive index n and thus the dielectric constant. Therefore, as will be described later, even when the ionosphere is present, simulation can be performed with sufficient accuracy.

  Equation (18) is solved by numerical calculation (S8). Specifically, an initial distribution is given in a certain plane, and a change in the electric field is obtained while the plane is advanced in a direction perpendicular to the plane. For example, the electric field distribution radiated from the antenna (transmitter) is given to the z = 0 plane, and the state of the electric field spread and attenuation is calculated as it propagates in the z-axis direction.

  The steady state analysis is performed assuming that the initial distribution of the electric field does not change with time. This is because, since the analysis target is a situation where the radiated electromagnetic wave is sufficiently long in the propagation direction with respect to the wavelength of the electromagnetic wave, the phenomenon can be sufficiently understood by steady analysis.

  For the calculation grid (mesh), the following means were adopted in order to reduce the amount of calculation. That is, when electromagnetic waves are emitted as a beam, the electric field strength (or energy) is concentrated at the center of the beam at the beginning, but the beam diameter increases as it propagates. In the initial state where the electric field strength is concentrated at the center, it is necessary to provide a fine mesh at the center (adopting a non-uniform mesh). As the beam diameter increases, a portion with a strong electric field strength appears also in the region outside the center, and it is necessary to give a fine mesh to this portion. In order to realize this, the calculation is advanced by appropriately adjusting the mesh interval while monitoring the beam expansion (while grasping each step) (adopting remeshing).

  Specifically, the electric field intensity distribution (electromagnetic field distribution) of the beam in the previous step (first propagation position) is monitored, and a fine mesh is applied to the inner part of the half-value width of this electric field intensity distribution (the electric field intensity is strong). And a coarse mesh is given to the portion outside the half width (the portion where the electric field strength is weak).

  At this time, the total number of meshes (space division number) is constant. By doing so, the calculation amount becomes the same in each step, and the calculation amount is suppressed. At the same time, since a non-uniform mesh is employed, accuracy degradation can be prevented.

  As a method for solving the z direction, which is the propagation direction of the electromagnetic wave, an alternate direction implicit method, which is one of implicit methods, was used. This method is characterized in that it can efficiently solve elliptical or parabolic partial differential equations.

As described above, according to the simulation method in the present embodiment, the change in the frequency of the electromagnetic wave is ignored, and only the electric field vector that gently changes in the propagation direction is focused. The Rukoto. (See S6)
Further, since the beam propagation method is used, the dielectric constant is taken into consideration. That is, as apparent from the equation (18), the refractive index n is taken into account in the beam propagation method. The dielectric constant is reflected through the refractive index n.

  Moreover, since the divergence of the electric field is zero (S3) and the Maxwell equation is approximated, the amount of calculation can be reduced. Furthermore, only the component proportional to the magnitude of the electric field, that is, the linear term, is considered in the polarization vector (S4), and the second derivative term in the propagation direction of the electric field vector is ignored (S6) to further approximate the Maxwell equation. As a result, the amount of calculation can be greatly reduced.

  Since remeshing is performed with the number of meshes in each calculation step being substantially the same, the calculation time in each calculation step is set to a fixed time, and the overall calculation time can be shortened.

  Since the remeshing is performed based on the electromagnetic field distribution obtained in the previous calculation step, a mesh suitable for the electromagnetic field distribution can be set.

Further, when re-meshing, the accuracy can be improved by finely dividing the space at a position where the value of the electromagnetic field distribution is large. On the other hand, the position where the value of the electromagnetic field distribution is small has a relatively small influence on the calculation result, so that the amount of calculation can be reduced by roughly dividing the space.
[Second Embodiment]
Next, a second embodiment in which the beam propagation method described above is applied to microwave power transmission will be described with reference to FIG.

  In the present embodiment, microwaves having a frequency of 5.8 GHz are taken as an example of electromagnetic waves. However, the simulation method according to the present invention can be applied even to electromagnetic waves having other frequencies.

  However, in the case of a microwave, since it becomes a high frequency of several GHz, there is little loss compared with a low frequency. Therefore, there is an advantage that even if the assumption (see S6 in FIG. 1) of ignoring the fluctuation of the electric field of the high frequency component as described in the first embodiment is added, the calculation accuracy is hardly affected.

  FIG. 2 is a diagram showing a simulation model for performing microwave power transmission between an array antenna (transmitter) 5 and a power receiving antenna (receiver) 7 arranged with the ionosphere 1 interposed therebetween.

  The ionosphere 1 is composed of a D layer, an E layer, an F1 layer, and an F2 layer, and exists at a height of 60 km, 90 km, 130 km, and 210 km from the ground, respectively. It is known that when a microwave passes through this ionosphere, a part of the microwave is converted into an electrostatic plasma wave.

  Below the ionosphere 1, a mesosphere 2, a stratosphere 3, and a troposphere 4 are located.

  The array antenna 5 is an antenna that employs a phased array system and transmits microwaves.

  The power receiving antenna 7 is installed on the ground facing the array antenna 5 and receives microwaves.

The electromagnetic field distribution simulation method according to the present embodiment simulates the electric field strength distribution (electromagnetic field distribution) of the microwaves transmitted between the array antenna 5 and the power receiving antenna 7 as follows. (Hereinafter, the electric field intensity distribution of the microwave is referred to as “beam profile”.)
A microwave beam profile on the surface of the array antenna 5 is given as one of the input conditions 9. Specifically, the beam profile is defined by giving the phase of each array of the array antenna 5. This provides an initial beam profile 15 as shown in FIG. The diameter of the initial beam profile is about 500 m, for example.

  The beam profile is a distribution in a plane perpendicular to the microwave propagation direction. Specifically, when the propagation direction of the microwave is taken on the z axis, it means an electric field strength distribution in the xy plane.

  Then, the propagation path condition is given as one of the input conditions 9.

  Next, the date is specified as one of the input conditions. Thereby, an environmental factor database (standard database) 11 in which environmental characteristic data such as ionosphere, magnetism, and atmosphere are stored is referred to, and influences of the global environment such as ionosphere, geomagnetism, and atmospheric model are determined.

As the environmental factor database 11, there is a public database shown in FIG. Here, IRI (International Reference Ionosphere) is the international ionosphere standard, IGRF (International
Geomagnetic Reference Field) means the international standard geomagnetic field model, and COSPAR (Committee on Space Research) means the Space Research Committee.

  In order to consider the weather and the like, a scattering model 13 due to rain / snow / fine particles is introduced.

  Under the above input condition 9, microwave propagation analysis (electromagnetic field distribution simulation) 14 is performed by the beam propagation method described in the first embodiment. The microwave propagation analysis 14 simulates a beam profile from the array antenna 5 to the power receiving antenna 7 through the ionosphere 1 as shown by a frame in FIG.

  An output beam profile 17 in the power receiving antenna 7 is obtained by the microwave propagation analysis 14. From this output beam profile 17, the power receiving antenna surface beam pattern 19 is known. Thereby, the directivity and attenuation amount of the microwave beam can be evaluated.

  Based on this result, a phased array control indicator 21 for controlling the phase of the array antenna 5 is obtained and reflected in the beam pattern as the input condition 9.

  In FIG. 3, the calculation accuracy of the simulation result obtained by the microwave propagation analysis in this embodiment is examined.

  The horizontal axis in the figure indicates the radius of the beam at the power receiving antenna 7 located 570 km away from the array antenna (transmitter) 5. The vertical axis represents the error when evaluated in decibel values.

  Each value in the figure is obtained by subtracting the value in the state without loss without the ionosphere from the value in the state with loss through the ionosphere.

  It can be seen from FIG. 3 that the value up to a radius of 1000 m almost coincides with the theoretical value. Deviation from the theoretical value occurs from around the radius of 1200 m. However, considering the beam electric field intensity at this position, it can be said that the error is about 1% at most, so that it can be sufficiently approximated.

  FIG. 4 examines the accuracy of microwave propagation analysis when changes in the global environment are taken into account.

  4A shows the electric field strength in the y direction, and FIG. 4B shows the electric field strength in the z direction.

  The horizontal axis indicates the radius of the microwave beam as in FIG.

  The solid line represents winter daytime (12 o'clock on December 20), the dotted line represents winter nighttime (1 o'clock on December 20), and the broken line represents summer daytime (12:00 on June 20).

  It is known that the electron density of the ionosphere changes depending on the season and day and night, and the electron density is higher in winter than in summer and day in the night.

  As can be seen from FIGS. 4A and 4B, the electric field strength decreases in the order of daytime in winter, daytime in summer, and nighttime in winter, and shows a value corresponding to the difference in electron density. From this, it can be seen that the microwave propagation analysis in the present embodiment has sufficient accuracy.

  FIG. 5 examines the accuracy of microwave propagation analysis from the polarization of the microwave.

  The horizontal axis indicates the radius of the microwave beam as in FIG.

  The vertical axis represents the Faraday rotation angle.

  In the figure, as analysis results, both the data calculated from the real part and the data calculated from the imaginary part are shown.

  From FIG. 5, it can be seen that the result of the microwave propagation analysis is almost equal to the theoretical value (−0.0604 °) within a radius of 1000 m. Although it deviates from the theoretical value within a radius of 1000 m or more, it can be evaluated that it has sufficient accuracy considering that the electric field strength at this position is small. In addition, although it has shifted | deviated largely in the place over a radius of 1000 m, this seems to have come out by the error by switching of a mesh.

  From the figure, it can be said that the influence of the electrostatic plasma wave in the ionosphere 1 is simulated by the microwave propagation analysis, and the polarization can be sufficiently predicted by the microwave propagation analysis according to the present embodiment.

  FIG. 6 shows the performance improvement when the microwave propagation analysis is performed by parallel calculation.

  The horizontal axis indicates the number of CPUs of computers to be parallelized, and the vertical axis indicates the degree of performance improvement. Ideally, as indicated by the dotted line, the performance is improved in proportion to the number of CPUs, but this is difficult in practice. In the case of this embodiment, when the number of CPUs is 8, the ability of about 75% is exhibited with respect to the ideal performance, and it can be evaluated that the parallel performance is sufficient.

  As the CPU, Intel's Itanium was used. The clock frequency is 800 MHz. A 24 gigabyte memory was used.

As for the processing speed, in the case of this embodiment, when the propagation distance of 570 km is calculated, the calculation is completed in about two days if four CPUs are used. In light of the fact that it takes one week or more to solve several tens of meters in the case of the FDTD method shown in the prior art, it can be said that this embodiment has a very significant effect.
[Third embodiment]
FIG. 7 shows an embodiment using the above-described microwave propagation analysis (electromagnetic field distribution simulation) as a design tool for a power transmission / reception antenna.

  This figure is the same as FIG. 2 showing the second embodiment. That is, the microwave propagation analysis 14, the environmental factor database 11, and the scattering model 13 due to rain / snow / fine particles are the same as in the first embodiment.

  In the present embodiment, the orbit analysis 26 of the power generation satellite is performed with reference to the environmental factor database 11, and this result is set as one of the input conditions 9. Thus, the microwave propagation analysis 14 predicts the characteristics of the microwave such as the path, loss, and polarization.

  Based on this result, the power transmission antenna capabilities such as directivity and power, and the specifications of the power receiving antenna such as size and shape are designed.

As described above, when the power transmission / reception antenna is designed, if this simulation method is used, a power transmission / reception antenna suitable for environmental conditions can be provided.
[Fourth embodiment]
FIG. 8 shows an embodiment relating to a microwave power transmission and reception system using the above-described microwave propagation analysis (electromagnetic field distribution simulation).

  This figure is the same as FIG. 2 showing the second embodiment. That is, the microwave propagation analysis 14, the environmental factor database 11, and the scattering model 13 due to rain / snow / fine particles are the same as in the first embodiment.

  The microwave power transmission / reception system executes power transmission / reception antennas 23 and 24 installed in an actual site, a control unit (not shown) for controlling these antennas 23 and 24, and a program for performing microwave propagation analysis 14. A microwave distribution simulation device (not shown).

  The program for performing the microwave propagation analysis 14 includes the numerical calculation program for the beam propagation method according to the present invention described in the first embodiment.

  The microwave distribution simulation apparatus that has executed the program obtains a beam profile 17 in the power receiving antenna 7 on the simulation, and evaluates the directivity and attenuation of the microwave beam based on the result. And this evaluation result is transmitted to the control part (not shown) of the power transmission antenna 23 and the power receiving antenna 24. FIG. Based on the transmission result, the control unit controls the power transmitting and receiving antennas 23 and 24.

  The microwave power transmitting and receiving system according to the present embodiment adjusts the position and orientation of the power transmitting and receiving antennas 23 and 24 installed on the site online by performing such control, thereby realizing optimum power transmission efficiency. be able to.

It is the flowchart which showed the simulation method concerning 1st embodiment of this invention. It is the figure which showed the microwave propagation analysis concerning 2nd embodiment of this invention. It is the figure which showed the calculation accuracy of the simulation result. It is the figure which showed the calculation accuracy of the simulation result. It is the figure which showed the calculation accuracy of the simulation result. It is the figure which showed the performance improvement at the time of performing a microwave propagation analysis by parallel calculation. It is the figure which showed the design method using the microwave propagation analysis concerning 3rd embodiment of this invention. It is the figure which showed the microwave power transmission / reception system concerning 4th embodiment of this invention.

Explanation of symbols

1 Ionosphere 5 Array antenna (transmitter)
7 Power receiving antenna (receiver)
15 Initial beam profile (electromagnetic field distribution)
17 Output beam profile (electromagnetic field distribution)

Claims (8)

In the electromagnetic field distribution simulation method for simulating the electromagnetic field distribution of electromagnetic waves in a plane orthogonal to the propagation direction between the transmitter and receiver by a computer ,
A constant frequency of electromagnetic waves, to ignore the change in the frequency components of the electromagnetic wave is focused on a change in its envelope,
Using the Maxwell equation approximated under the condition of
An ionosphere is interposed between the transmitter and the receiver,
The computer, ionosphere interposed propagation path of the electromagnetic wave, magnetic, environmental characteristics data of the air or the like, by retrieve by referring to the environmental factor database in which the environmental characteristic data is stored, the electromagnetic the environmental characteristic data Use the field distribution simulation to determine the impact of the global environment ,
When obtaining the electromagnetic field distribution at the first propagation position by numerical calculation, and obtaining the electromagnetic field distribution at the second propagation position in the next step,
The second propagation position based on the electromagnetic field distribution obtained at the first propagation position while keeping the number of space divisions at the first propagation position and the number of space divisions at the second propagation position substantially the same. A method for simulating electromagnetic field distribution, wherein the state of space division is changed. 2. The electromagnetic field distribution obtained at the first propagation position, wherein a space at a position where the electric field strength of the electromagnetic wave is large is finely divided, and a space at a position where the electric field strength of the electromagnetic wave is small is roughly divided. 2. The electromagnetic field distribution simulation method according to 1. An electromagnetic field distribution simulation program comprising a numerical calculation program for the beam propagation method and executing the electromagnetic field distribution simulation method according to claim 1 , wherein the program is executable by a computer . An electromagnetic field distribution simulation apparatus comprising a computer that executes the electromagnetic field distribution simulation program according to claim 3 .   A transmitter / receiver design method, wherein the transmitter / receiver is designed using the electromagnetic field distribution simulation method according to claim 1.   A transducer manufacturing method for manufacturing a transmitter and / or a receiver based on the transmitter / receiver design method according to claim 5.   3. A transmitter / receiver control device that controls a transmitter and / or a receiver based on an electromagnetic field distribution obtained by the electromagnetic wave distribution simulation method according to claim 1 or 2.   An electromagnetic wave transmission / reception system comprising: a transmitter; a receiver; an electromagnetic field distribution simulation apparatus according to claim 3; and a transmitter / receiver control apparatus according to claim 7.

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