Permeability evaluation of ferrite pastes, epoxies, and substratesover a wide range of frequencies

Two accurate methods for determining the magnetic constants of ferrite pastes, epoxies, and substrates are proposed. The first method is used for low-to-mid frequencies (DC-100 MHz) and is based on current images. The permeability is calculated from measurements of the inductance of thick-film spiral inductors printed on the magnetic material under investigation. The second technique is a frequency-domain coaxial cavity method and is used for the mid-to-high frequency range (50 MHz-2 GHz). The complex permeability is calculated using this method