For studying the harmful influences of a portable transmitter on the human eyeball, this letter examines numerically the specific absorption rate (SAR) using the sphere model exposed to the near-fields of a half-wavelength dipole antenna. The SAR's inside the eyeball due to the 1.5 GHz near-field exposure are calculated in relation to the antenna location.

This letter presents a new method for estimating discontact rate using the impulsive responses in VHF band to the noise currents flowing through the pantograph of an electric car. Numerical computation to confirm the validity of the method above is also given.

In this paper, we report the calculations of the quantum efficiencies of new types of photodiodes that have the ability to demultiplex the incident light beam into two or three independent outputs according to its wavelength, and determine the diode parameters that give maximum efficiency and low crosstalk. Two types of diodes were fabricated with LPE grown InGaAsP/InP quaternary system which is one of the most useful materials in the 1.01.7 µm low-loss spectral window of optical fiber. One diode divides the input light beam into two outputs and the other does in three outputs. The experimentally obtained spectral responses of the diodes were in good agreement with the calculated ones. The fabricated diodes exhibited nearly 100% internal quantum efficiency and crosstalks of 34 dB at λ1.0 µm and below 50 dB at λ1.35 µm, respectively, where the efficiencies of two outputs take their maximum values.

This paper presents a relationship between the near-field shielding effectiveness (SE) and the far-field SE of an infinite planar shield for dipole fields. The penetration fields through the shield and the near-field SE are deduced analytically from an explicit integral expression based on certain assumptions. They further give us approximate formulas for the near-field SE. The near-field SE depends on not only wavelength and material used, but also on the distance r from a source to an observation point through the shield, the source type (magnetic dipole or electric dipole) and the orientation (vertical or horizontal to the shield face) in general. The results we obtained are as follows. The near-field SE for magnetic dipole fields vertical to the shield face is the same as that horizontal to the shield face, and their absolute values equal that of the far-field SE multiplied by k0r/3 (k0 is the wave number). The near-field SE for electric dipole fields vertical to the shield face doubles that horizontal to the shield face, and the absolute value of the latter equals that of the far-fields SE divided by k0r. The validity of the assumptions used to obtain the approximate formulas are examined. The range of r (an application range), over which the difference between the approximate value and the true value is under 1 dB, is determined, where the former value is calculated by the approximate formula of the SE and the latter value is etsimated by direct integration of the related integral expression. For instance, an application range of the approximate formula for magnetic dipole fields vertical to the shield face is from larger one of 50δ and 33µrδ to 0. 11λ0, where µr is specific permeability, δ is skin depth of the shielding material used and λ0 is wavelength in the free space.

For investigating the validity of the two exclusion criteria in the ANSI safety guide revised in 1982, this paper examines numerically the specific absorption rate (SAR) in the lossy sphere simulating a human head exposed to the microwave near-fields due to a half wavelength dipole antenna. The SAR patterns on the spherical surface are calculated with respect to the antenna input powers and the frequencies.

In 1985, Kues et al. (Bioelectromagnetics, 6, pp.177-188, 1985) reported that corneal endothelial abnormalities were observed after a 4-hour exposure of anesthetized monkey eyes to 2.45GHz CW. We have traced their experimental study without anesthetization. Although we irradiated with power density exceeding the threshold of 30mW/cm2 obtained by them, we could not observe the same abnormalities as they did.

This paper surveys the researches on biological and electeromagnetic environments in RF (radio frequency) and microwave regions in Japan. Publicized research reports on biological objectives, evaluation of exposure rate, electromagnetic environments and guideline for the protection from radio wave nuisances are briefly introduced. Some researches on the evaluation of the exposure rate caused by the near field effect of portable radio transceiver are reviewed. Radio frequency exposer protection guidelines in Japan are also described.