Measurement of linewidth of single crystal ferrites by monitoring the reflected wave in short-circuited transmission line

Abstract

A method is described for measuring the linewidth of single crystal ferrite spheres, based on monitoring the reflected wave in a short-circuited transmission line. The ferrite sample is at the short circuit, or a half wavelength from it. An equation is given for the normalized equivalent resistance of a ferrite sphere at resonance, and a comparison made between theory and experiment. At <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</tex> band, resonance curves of undercoupled spheres are relatively free of distortion. However, at frequencies of 2 GHz and lower, resonance curves are often distorted. Moreover, it is frequently possible to obtain a discrete number of different resonant curves at a given frequency. Data are given on errors due to nonideal microwave components. A method of displaying a resonance curve on an oscilloscope, using swept fields, is described.