Determination of Mn-Zn ferrites’ dimension-independent complex permeability and permittivity
Date of Issue2008
School of Electrical and Electronic Engineering
In this thesis, three currently available field-circuit coupled methods to determine the Mn-Zn ferrites’ dimension-independent, or intrinsic, complex permeability and permittivity are reviewed. The application criterion, the accuracy and the computational efficiency of the methods are compared. A few mathematical measures are taken to improve the currently available methods. Furthermore, to avoid the stray capacitance between the coils in the wire wound ferrite core inductor in the measurements, a set of short-ended coaxial test fixture is designed and manufactured. Experimental results of different field-circuit coupled methods are compared up to 10 MHz. Two new field-circuit coupled methods derivative from the currently available field-circuit coupled methods are proposed. The two methods determine the two intrinsic values from the impedances of two ferrite core capacitors and two ferrite core inductors respectively. Since the two methods need only one kind of test fixtures, the measurement process is simplified in terms of the number of test fixtures used. Experimental results of the two methods are given. Advantages and limitations of the two methods are disclosed.
DRNTU::Engineering::Electrical and electronic engineering::Electronic apparatus and materials