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Sangmu Lee,Yoon-Myoung Gimm,Changsoo Eun 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4
In this paper, an electromagnetic induction on a telecommunication line by the distribution line of a power provision system or a feeder line of an electrified railway system has been verified through experiments. The basic cause of induction occurrence by these practical power provision systems is the returning current through the earth. This principle has been confirmed by the experiments documented in this paper which implemented these mechanisms to incur an induction. Experimental methods were used to produce the returning current through the earth. The experiment to find a relationship between inducing strength and the distance between the two phase lines in a power provision line has also been included to confirm that, when the distance is enlarged, the induction effect increases as the crossnullification effect of magnetic fluxes decreases. An experiment for the existence of a shielding effect by another conduction length material has been addedas a protection measure against the induction.
Ki-Chai Kim,Byung-Doo Cho,Tae-Hong Kim,Jong-Moon Lee,Soon-Ik Jeon,Jeong-Ki Pack 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4
This paper presents a tumor detection system for breast cancer that utilizes two-dimensional (2D) image reconstruction with microwave tomographic imaging. The breast cancer detection system under development consists of 16 transmit/receive antennas, and the microwave tomography system operates at 900 MHz. To solve a 2D inverse scattering problem, the method of moments (MoM) is employed for forward problem solving, and the simplex method employed as an optimization algorithm. The results of the reconstructed image show that the method accurately shows the position of a breast tumor.
Yoshio Nikawa,Akira Ishikawa 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4
Recent development of magnetic resonance imaging (MRI) equipment enables interventional radiology (IVR) as diagnosis and treatment under MRI usage. In this paper, a new methodology for magnetic resonance (MR) scanner to apply not only diagnostic equipment but for treatment one is discussed. The temperature measuring procedure under MR is to measure phase shift of T₁, which is the longitudinal relaxation time of proton, for the position inside a sample material with the application of pulsed RF for heating inside the sample as artificial dielectrics. The result shows the possibility to apply MR as temperature measuring equipment and as a heating equipment for applying such as hyperthermia heating modality.
Sangmu Lee,Munhwan Choi,Pyung-Dong Cho,Changsoo Eun,Yoon-Myoung Gimm 한국전자파학회JEES 2009 Journal of Electromagnetic Engineering and Science Vol.9 No.4
The measurements were performed to verify experimentally that the voltage arising on a telecommunication line by a power line is due to the induction phenomena because there has been an opinion that the arising voltage on a telecommunication line is not by induction, but by other causality. The voltage appeared on the telecommunication line by way of an electric field or magnetic field generated by the source apparatus that had been artificially made to provide intentional constant high-voltage or current in ELF, that is, 60 ㎐ as an emulated commercial power.
Design of Resonator-Coupled Wireless Power Transfer System by Use of BPF Theory
Ikuo Awai,Tetsuya Ishida 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4
A wireless power transfer system based on magnetically coupled two resonators is analysed using the filter theory. Design equations for each lumped parameter circuit components are derived. As a result, change of coupling coefficient between the resonators and/or change of load resistance are easily responded. Effect of circuit loss to the design theory is also addressed. After designing a power transfer system, a real system is constructed using spiral and loop coils. Dependence of circuit elements on their dimensions is measured in advance and used to cope with the designed element values. Simulated response by use of designed element values and measured result are compared, indicating the validity of the theory.
Beam Efficiency of Wireless Power Transmission via Radio Waves from Short Range to Long Range
Naoki Shinohara 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4
Wireless power transmission (WPT) is useful technology in near future. There are some kinds of the WPT technologies, WPT via radio waves, resonance coupling, and inductive. Especially the WPT via radio waves is used for multi-purposes from short range to long range application. However, unfortunately it is misunderstood that it is low efficiency and low power. In this paper, I show the theory of beam efficiency between transmitting antennas and receiving antennas and also show some high efficient applications of the WPT via radio waves. Especially, I pick up a wireless power charging system of an electric vehicle and show the experimental results. I show difference between the theory of beam efficiency and the experimental results of short range WPT. I indicate that reasons of poor beam efficiency in the experiment are (1) change of impedance caused by mutual coupling between transmitting antennas and receiving antennas, (2) oblique direction of microwave power to receiving antennas caused by short distance.
Soil Moisture Measurement of Bare and Vegetated Surfaces by X-band Radars
Yisok Oh,Soon-Gu Kwon,Ji-Hwan Hwang 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4
The radar backscatter from various earth surfaces is sensitive to the frequency of the incident wave. This study examined the radar sensitivities for surface parameters such as soil moisture content and surface roughness of both bare and vegetated surfaces at X-band. Because L-band frequencies are often used for sensing the surface parameters, the sensitivities of X-band are also compared with those of the L-band. The sensitivities of the X-band radar backscatter were examined with respect to soil moisture content and surface roughness of rough bare soil surfaces. These sensitivities were also examined using the same parameters for vegetated surfaces for various vegetation densities and incidence angles. Use of the X-band radar for soil moisture detection was as effective as L-band radar for bare soil surfaces. For vegetated surfaces, the soil moisture could be detected using an X-band radar at lower incidence angles, where the upper limit of the incidence angles was dependent on vegetation density.
An Implantable Antenna for Wireless Body Area Network Application
Uisheon Kim,Jaehoon Choi 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4
In this paper, an implantable planar inverted-F antenna (PIFA) for an artificial cardiac pacemaker is proposed. The antenna has a simple structure with a low profile and is placed on the top side of the pacemaker. The dimensions of the pacemaker system, including the antenna element, are 42×43.6×11 ㎜. When the antenna is embedded in pig tissue, its S₁₁ value is ?10.94 ㏈ at 403 ㎒ and the ?10 ㏈ impedance bandwidth of the antenna is 6 ㎒ (399~406 ㎒). The proposed PIFA in tissue has a peak gain of ?20.19 ㏈i and a radiation efficiency of 1.12 % at 403 ㎒. When the proposed antenna is placed in a flat phantom, its specific absorption ratio (SAR) value is 0.038 W/㎏ (1 g tissue). Performances of the proposed PIFA is sufficient to operate at the MICS band (402 ~ 405 ㎒).
Taiji Sakai,Kanako Wake,Soichi Watanabe,Osamu Hashimoto 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4
This study proposes a temperature compensation method of the complex permittivities of biological tissues and organs. The method is based on the temperature dependence of the Debye model of water, which has been thoroughly investigated. This method was applied to measured data at room temperature for whole blood, kidney cortex, bile, liver, and heart muscle. It is shown that our method can compensate for the Cole-Cole model using measured data at 20 ℃, given the Cole-Cole model based on measured data at 35 ℃, with a root-mean-squared deviation of 3~11 % and 2~6 % for the real and imaginary parts of the complex permittivities, respectively, among the measured tissues.