Study of Landau-Lifshitz-Looyenga's formula for dielectric correlation between powder and bulk

Landau-Lifshitz-Looyenga's formula for correlation of bulk and powder dielectric parameters has been investigated at microwave and radio frequencies for a number of materials for wide enough experimental conditions of particle size, shape and packing fraction. It has been found that the formula gives good accuracy (about 3%) for dielectric constant determination for particle size not less than 50 μm. For fine powders (particle size less than 30 μm) the deduced dielectric constant is too low by about 3-8%. Dielectric loss determination from the formula is, however, less accurate, the deduced values being always too low by about 10-20%.