Toshimitsu Matsuyoshi

An analysis of the performance of a handset diversity antenna influenced by head, hand and shoulder effects at 900 MHz

The purpose of this work is to make a wire-grid analysis of a diversity antenna comprising a whip antenna and a built-in planar inverted F antenna (PIFA) to include the electromagnetic effects of a human operator and to evaluate the diversity performance with regard to the head-to-radio separation under various incident radio wave environments. Investigations are also made on the power absorbed in the head, hand and shoulder, on the power loss due to impedance mismatch, and on the dissipated power in a non-excited element when the head-to-radio separation is changed. From the results, a mechanism for changing radiation efficiency is explained.

A high-precision real human phantom for EM evaluation of handheld terminals in a talk situation

To determine the effective performance of a handheld cellular radio antenna, it is essential to evaluate the electromagnetic (EM) interaction between the antenna and the human body. This paper presents a high-precision human phantom with a very realistic shape that represents a man holding a handheld terminal while talking. The shape and the size of the phantom are based on statistical data obtained by precisely measuring various parts of the human body. A function of the phantom is that the handheld terminal can be arbitrarily moved in the x-y-z direction, and thus one can evaluate the change in the antenna characteristics by changing the position between the antenna and the phantom.

Dipole antenna radiation characteristics influenced by shoulder and head effects

This paper presents effects of the shoulder on the radiation characteristics of a half wavelength dipole antenna located near the human head. The wire-grid method was used in the analysis. The calculated results were confirmed by experiments using a homogeneous human phantom. The wire-grid analysis also yielded radiation efficiency and mean effective gain characteristic results in a multiple radio wave environment regarding antenna polarization and antenna-head distance.