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ABSTRACT: In this paper, the induced current in PEC wire which touched semi-infinite ground plane was calculated. In the calculation, SIBC was used to model semi-infinite ground plane. The result is good agreement with PML result. Therefore the proposed method is effective to model PEC wire which touched semi-infinite ground plane.
Antennas and Propagation Society International Symposium (APSURSI), 2010 IEEE; 08/2010
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ABSTRACT: Until now, our group have proposed an 8-shaped loop antenna, which can realize the localized EMF exposure inside 4-, 8-, and 12-week-old rats' brain in 1.5 GHz band. However, in juvenile rats, which is younger than 4-weekold, the localized exposure within the rats' brain using this antenna is difficult. Therefore, in this paper, the 8-shaped loop antenna with a 0.3625lambda H-shaped director is proposed, to achieve the localized exposure within the juvenile rats' brain in 1.5 GHz band. At first, the SAR in the 1-week-old rat is calculated using the FDTD method. As a result, the localized exposure within the rat using the antenna with director is 1.75 times higher than that without the director. In addition, the temperature-rise distribution within the rat phantom, which is exposed to the antenna with the director, is measured using the thermographic technique. As a result, the validity of the antenna with the director is confirmed.
Microwave Conference, 2007. APMC 2007. Asia-Pacific; 01/2008
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ABSTRACT: We developed a new exposure system to irradiate microwaves locally on a rabbit eye using a small coaxial-to-waveguide adapter filled with low-loss dielectric material as an antenna. A numerical rabbit model was also developed using X-ray computer tomography images, and the specific absorption rates (SARs) in the rabbit, especially in the eye, were analyzed with the finite-difference time-domain method. The temperature elevation in the exposed eye was also evaluated by solving a bioheat equation. Our exposure system can generate incident power density of 15 mW/cm<sup>2</sup> at the surface of a rabbit eye with input power of 1 W. When the incident power density on the rabbit eye is 300 mW/cm<sup>2 </sup>, average SAR over the exposed eye and the whole body were approximately 108 and 1.8 W/kg, respectively. The exposure system can realize localized exposure to the eye with the ratio of exposed-eye averaged SAR to the whole-body averaged SAR was 60. The developed exposure system can achieve high-intensity exposure such as the threshold of cataracts, i.e., the eye-averaged SAR over 100 W/kg or the lens temperature over 41 degC with the incident power density of 300mW/cm<sup>2</sup> without significant whole-body thermal stresses
IEEE Transactions on Microwave Theory and Techniques 04/2007; · 1.85 Impact Factor
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ABSTRACT: We developed an exposure system for an animal bioassay to evaluate possible health effects by the exposure with 1.5-GHz-band personal digital cellular system used in Japanese telecommunications. For large-scale and long-term study, i.e., 500 rats were employed for two years, the exposure system was designed to simultaneously expose 100 rats and to easily maintain. The specific absorption rate (SAR) inside the rat was evaluated with numerical simulation using anatomical rat models and was validated by comparing it with experimental dosimetry using phantom models. Variation and uncertainty of the SAR in the rat for each exposure was also statistically investigated using logged data, which had been acquired in the exposure system during the animal bioassay. We confirmed that the desired exposure (a SAR averaged over a brain of 2 W/kg for the high-dose group and 0.67 W/kg for the low-dose group and a SAR average over a whole body of less than 0.4 W/kg) had been fairly achieved during the exposure period of two years. A relatively large variation of the SAR was found in the male high-dose group
IEEE Transactions on Microwave Theory and Techniques 03/2007; · 1.85 Impact Factor
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ABSTRACT: Advantages of the use of directional antenna patterns for portable
telephones are demonstrated. They contribute to (1) reduction of power
absorption into the head, (2) reduction of multipath interference, and
(3) power saving and increase of battery lifetime. The paper compares
directional and omni-directional antennas with the human head existing
near them, in terms of radiation patterns and absorbed power. It is
pointed out that overall radiation patterns are more or less directive
for both types of patterns, while power absorption into the head is much
smaller for directional antenna
Universal Personal Communications. 1995. Record., 1995 Fourth IEEE International Conference on; 12/1995
