Dielectric Constant and Permeability of Various Ferrites in the Microwave Region

The dielectric constant ε and permeability μ of ferrites have already been studied at audio and high frequency region, but they have scarcely been measured in the microwave region. We have determined ε and μ on various simple polycrystalline specimens of magnesium, copper, cobalt, nickel and manganese ferrites quenched or slow・cooled from high temperatures at the wave-length of 6.6 cm by observing changes in Q-value and frequency shift when a thin disk formed specimen, whose diameter is 20 mm and thickness is 1 mm or 1.5 mm, attached on a supporter, was inserted in the rectangular cavity (TE_ mode) at the positions of the electric and magnetic field maxima, respectively. From these measurements, both real and imaginary part of e and p were determined from the formula which were derived by expanding the field in the cavity by using orthogonal function introduced by Slater