Jörn Weber

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Intraocular distances can be measured by echography. In this determination the velocity of sound in the various media is assumed to be constant and equal to the velocity found by in vitro measurements. However, interindividual variability causes an inaccurate determination of these distances. We present a method to determine the velocity of ultrasound in(More)
The optical properties of silicon oxynitride films deposited by reactive dc magnetron sputtered films have been investigated. In particular the absorption characteristics of silicon nitride thin films in the visible spectrum and their optical bandgap were analyzed with regard to their composition and deposition properties. It can be shown that there is a(More)
The concave part of Hertel's exophthalmometer which contacts the orbita functions like an inclined plane. Therefore, the measurement is sensitive against tilting and changing of the basic distance. We modified this contact surface into a right angle. The tangents at the contact points form a common line at right angles to the measurement direction.(More)
We propose and evaluate an antenna array consisting of three, quarter-wavelength spaced, monopoles and a passive network. The latter decouples and matches the antenna array to prevent gain reduction. At the same time, it forms orthogonal radiation patterns, which divide the space into three different sections. By using a geometry-based channel model, the(More)
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