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IEEE Transactions on Microwave Theory and Techniques
Volume 48 Number 8, August 2000

Table of Contents for this issue

Complete paper in PDF format

New Method for Determining the Permeability Tensor of Magnetized Ferrites in a Wide Frequency Range

Patrick Quéffélec, Member, IEEE Marcel Le Floc'h and Philippe Gelin

Page 1344.

Abstract:

To provide a broad-band method for measuring the complex permeability tensor components of magnetized ferrites we have realized a nonreciprocal rectangular waveguide cell. A network analyzer setup is used to measure the scattering parameters of the cell over a wide range of frequencies. The nonreciprocity of the cell permits the determination of the permeability tensor components in a single experimental phase. Complex permittivity and complex components of the permeability tensor are computed from a data-processing program, taking into account higher order modes excited at the cell discontinuities and using a numerical optimization procedure to match calculated and measured values of the S-parameters. We have studied the convergence of the calculated S-parameters as the number of modes taken into account in the calculations. Sensitivity to the input parameters for the optimization algorithm is discussed. A thru-reflect-line calibration in conjunction with a specific sample holder is used to eliminate systematic errors inherent in the S-parameter measurements. Measured complex permeability tensor components data for microwave ferrites are presented at X-band frequencies (8-12 GHz). Experimental results are in good agreement with theoretical results given by the ferromagnetic material theory.

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