Broad-band simultaneous measurement of complex permittivity and permeability using a coaxial discontinuity

A technique for simultaneously measuring the real and imaginary parts of both the permittivity and the permeability of a given material is discussed. A gap in a coaxial line is filled with the material under test. Complex permittivity and permeability are computed from the S-parameter (S₁₁ and S₂₁) measurement made on the gap, taking into account higher-order modes excited at the discontinuity. Measured ε_r and μ_r data for several materials are presented from 45 MHz up to 18 GHz. This technique shows good agreement between calculated and generally accepted values