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Thank you Mr./Ms. Chairperson. I’m Masahiro Hanazawa from Toyota Central R&D Laboratory.[The chairperson has probably already introduced you and your affiliation. Not required.]
I will talk about the technology of power supply to a moving vehicle.
Recently, the electric vehicle has attracted attention from the viewpoint of environmental protection. However, the energetic density of present batteries is very low compared with gasoline. Moreover, charging time is very long compared with the charging time for gasoline.
Some methods are examined as solutions to this problem.
We have examined a wireless power supply technology that is applicable while a vehicle is moving. The advantages of this power transfer technology are as follows.
The efficiency of wireless electric power transmission is generally low; however, a new method has been proposed by a research group at MIT.
The new method has achieved a high transmission efficiency of 90% or more.  As a result, a number of research groups are currently examining wireless power transfer technology.
Although the resonance method can provide highly effective transmission compared with previous methods, the efficiency can deteriorate sharply if the position of the transmission coil shifts.
Therefore, it is difficult to effectively transmit electric power to a running vehicle using this method.
Moreover, individuals and telecommunications equipment in the immediate vicinity of a running car are adversely affected by the energy transmission.
This diagram shows the proposed power transfer system for a moving vehicle.
This system transmits electric power thorough a capacitor composed of a steel belt in the tire and a metal plate attached to the road.
The power is supplied in differential mode. Therefore, the electromagnetic field leakage is small. Moreover, the infrastructure can be set up at a lower cost than a coil system.
This shows the proposed model and measurement model. In the measurement model, metal plates were arranged above and below the tire, 
and complex impedance was measured. Pieces of styrene foam of different thickness were placed between the upper surface of the tire and metallic plate.
The size of the metal plate is 200 mm by 300 mm.
The measurement frequency was from 10 kHz to 10 MHz.
These figure show the results of the complex impedance measurements. These are the results of the real part and the imaginary part. The vertical axis shows the real part and imaginary part of the impedance, respectively. The horizontal axis show frequency. [It is not recommended to explain what is obvious from the figure.] the imaginary part increases with frequency and decreases with the thickness of the styrene foam.
From these results, the capacitance element is more predominant than the inductance element in the measurement model.
We experimented to simply confirm the existence of the capacitor that could be composed of the tire and metal plate. This is the measurement result for a tire and for a wooden stool.
The gray line shows the results for the stool and metal plates, and these lines shows the results for the tire and metal plates.
From these results, we have assumed that a capacitor exists and is composed of the tire and metal plates.
As shown previously, the real and imaginary part of the complex impedance of the tire is very large. In an actual system, it would be possible to adjust a supply circuit to the impedance.
However, the supply circuit has not yet been designed. Therefore, a 50-ohm matching circuit designed for use with measurement instruments, such as a Vector Network Analyzer, is used.
Many matching circuits have been proposed. As an example, three structures of matching circuits are shown here.
In this study, Matching circuit 3 was selected from the viewpoint of transmission loss.
[Fig. edit: Space numbers and units (1 MHz).]
This figure shows the equivalent circuit model of the proposed method. Generally, vehicles are symmetric; therefore, the centerline of this figure is equivalent ground.
So, the left figure is equivalent to the right figure.
The measurement model  has complex impedance, as previously shown. However, a simple equivalent circuit model is used here, as shown in this figure.
The admittance matrix is represented by the blue box. Parallel capacitance is added to this admittance matrix, so that it becomes this matrix.
This matrix is then changed by the addition of series inductance, and then to an impedance matrix.
The impedance matrix given is changed to an S matrix, which is necessary in order to define the standardization impedance to change the matrix.
In the following, the source impedance and load impedance are used as the standardization impedance Z0
The non-diagonal part of the above-mentioned matrix yields the following:
The electric power transmission coefficient is obtained like this.
The previous condition is considered here.
In order to ensure that the electric power transmission coefficient is 96% or more, it is only necessary to satisfy the following equation:
Electric power can be transmitted even with an element that has a high resistance compared with the source impedance and the load impedance.
Electric power could be effectively transmitted by connecting the tire through a matching circuit.
Next, a 50-ohm matching circuit designed for use with measurement instruments, such as a vector network analyzer (VNA), was used.
As an example, the matched frequency was set to 1 MHz.
In addition, 120 pF and 220 mH were selected as values of C and L that satisfied previous conditions.
The transmission properties were simulated using open-source software. These figure show the simulation results obtained in a Smith chart
and the transmission properties that connect the matching circuit.
At the matched frequency, S11 was confirmed to be approximately -0.1 dB.
[Fig. edits: Space all number and units (220 uH, 120 pF, -0.1 dB).]
Impedance might change if a different tire is used.
Therefore, the transmission characteristics were simulated when the impedance of the tire was changed.
This figure shows the simulation results; each axis shows the amount of change in the real and imaginary parts.
The vertical axis is S21.
From these results, even if the impedance of the tire changes, the amount of change of S21 is small.
Moreover, the matching frequency is not changed for all the results.
[Fig. edits: Space all number and units (700 ohm, 2000 ohm, 1 MHz, 220 uH, 120 pF).]
[Please confirm “Amount of change” and not “Amount of charge” in axis labels.]
These are the measurement results for S11 and S21 of the tire connected to the matching circuits. The x-axis shows the frequency and the y-axis shows S11 and S21. [It is not recommended to explain what is obvious from the figure.]
In this figure, the red line indicates s21 and the blue line shows s11.
S21 is approximately -3 dB at 0.88 MHz. And the transmission loss of the matching circuit is approximately -1.3 dB.
The transmission loss of the tire is estimated to be -1.7 dB from the above-mentioned results.
[Fig. edits: Space all number and units (100 uH, 267 pF).]
Next, we fabricated the other matching circuits, and measured the transmission characteristics, as shown in these figures.
It was confirmed that the transmission frequency is changeable and changes with the constants of the matching circuits. [Is this your intended meaning?]
[Fig. edits: Space all number and units (22 uH, 120 pF, etc.).]
In conclusion, we made a basic examination of a proposed power transfer method for a moving vehicle.
We confirmed the formation of a capacitor and highly effective transmission was confirmed.
Our future work will focus on…
Thank you.