Design and analysis of logarithmic axicons at millimeter wavelengths

Extension of depth of field (DOF) has many practical applications. Logarithmic axicons have been introduced into optics to extend DOF, and investigated intensively on the basis of scalar approximate theory. Logarithmic axicons, which are suited for imaging systems in millimeter range, are designed in this paper. The analysis of their properties has been carried out by rigorous electromagnetic computational method. Numerical results demonstrate that the designed logarithmic axicons have a much larger DOF, when compared with the classical axicons.