Precision measurements of dielectric permittivity of common thin film materials at microwave and terahertz frequencies

Two different types of instrumentation have been utilized to characterize thin film samples. New techniques have been developed so that the dielectric permittivity values can be determined accurately at microwave as well as at millimeter wave and terahertz frequencies. A specially designed slotted cavity for X-band microwave measurement has been employed with a vector network analyzer to overcome the phase shift not large enough to evaluate the real part of dielectric permittivity. Also, dispersive Fourier transform spectroscopy (DFTS) with an improved movement step has been implemented to determine the real part of permittivity from about 60 GHz to 1,000 GHz.