Time-domain dielectric constant measurement of thin film in GHz-THz frequency range near the Brewster angle

We present a free-space time-domain method to measure the dielectric property of thin film on substrate in the GHz-THz frequency range. The concept is based on the phase flip of the field wave form for near-Brewster angle reflection. Realizing this concept, we demonstrate the determination of the dielectric constant of a thin polymer film at a few micrometer thickness on the silicon wafer. (C) 1999 American Institute of Physics. [S0003-6951(99)03215-5].