Complex permittivity measurements of dielectrics and semiconductors at millimeter waves with high power sources

We present complex dielectric permittivity measurements of various semiconductor and dielectric materials, including highly absorbing substances, in Q-, V- and W-band frequencies. The measurements have been done using broadband quasioptical millimeter wave system with a backward-wave oscillator as a high power source of radiation. Frequency dependencies of real and imaginary parts of dielectric permittivity are calculated from the transmittance spectra. Complex dielectric permittivity data, obtained using both waveguide bridge technique and free space measurements have been compared with previously published results.