Millimeter waves for determination of composition of biodisel fuel

In this paper, we consider the possibility of significantly increasing the measurement accuracy for the content of MDF in fuel practically without adjustment for temperature by measuring the absorption of millimeter waves in a fuel blend. The measurement technique is similar to that applied in measuring moisture in oils [2]. To find out such a possibility, we investigated the dielectric properties of BDF in the frequency range from 80 to 90 GHz. The properties of MDF were investigated earlier in [2]. The real part n of the complex refractive index of BDF at frequency of 81.7 GHz is determined by measuring the reflection coefficient from a metal plate placed in a teflon measurement cell filled with fuel.