Moment expansion and nonuniform FFT applied to antenna reflection parameter characterization using a FDTD/WP-PML algorithm

This paper presents the results of the application of a moment expansion and a nonuniform FFT technique together with a FDTD algorithm in order to determinate the return loss parameter of printed antennas. The impedance characterization of wideband printed antennas with lossy substrates is introduced by means of an approach based on FDTD method and the WP-PML absorbing boundary condition. It was used a simple voltage source model where an excitation plane with an Gaussian vertical electrical field was imposed to a rectangular area just below the structure to be analyzed. Results obtained for the return loss of a multiband and an UWB printed antenna are compared to those determined from conventional FFT based methods available in the scientific literature as well as measurements previously done, in order to show the applicability of the methodology that has been developed herein. The results obtained for return loss parameter showed good agreements between the techniques proposed by this work and the results previous done.