A free space technique for measuring the complex permittivity and permeability in the millimeter wave range

A new technique is presented for measuring the complex permittivity /spl epsiv/=/spl epsiv/´-j/spl epsiv/´´ and permeability /spl mu/=/spl mu/´-j/spl mu/´´ of matter at millimeter wavelengths. A direct transmission path is established between two horn antennas. A planar material sample is inserted into the path between the antennas and the transmission coefficient is measured. Subsequently, the sample is used as a reflector between the transmitting and receiving antennas. The angle of incidence is varied and both the horizontal and the vertical polarization are measured. With glass samples the accuracy of better than 0.04% and 0.5% for /spl epsiv/´ and /spl epsiv/´´, respectively, has been achieved at 94 GHz. The sample preparation is very easy and nondestructive.<>