Volumetric Method of Moments

Abstract

In this thesis a Volumetric Method of Moments (V-MoM) is developed to analyse accurately, and ease the design of small size lens antennas, and to estimate the power emitted by warm bodies constituted by realistic materials, and having arbitrary geometries. hanks to the application of the volume equivalence theorem and the use of a structured mesh, this method can be used in a design loop efficiently, since different geometries can be simulated with the same
evaluation of the projections, and the specific material arrangements are added at a negligible cost. Therefore, at every design iteration, differently from other integral equation methods, only the linear system has to be solved. Moreover, thanks to the use of a uniform sampling, a convolutional structure is obtained, implying that only a reduced number of projections are sufficient to characterize the entire matrix, reducing significantly the memory requirements, and allowing the solution of large scale systems. The linear system is then solved with an iterative solver, that, thanks to the convolutional properties, can be accelerated by fast matrix-vector products by using Fast Fourier Transform (FFT). The method is validated by studying the field scattered by a homogeneous and multilayer dielectric sphere, proving an accuracy within the discretization
tolerance, and the capability of handling inhomogeneous structures.
A Graphical User Interface (GUI) based on the presented method has been developed, with the aim of easing and assisting the user experience on the electromagnetic analysis. The GUI allows to simulate complex
geometries combining elementary shapes, characterized by arbitrary materials, and excited by either plane waves or discrete ports. The solution can be post-processed in terms near-fields, far-fields, and network quantities. A representation in terms of impressed currents and incident voltage has been formulated to represent the incoherent radiometric sources in the V-MoM, used to analyse the power emitted by lossy semiconductors, characterized by a Drude’s dispersion for the conductivity. An experimental setup to verify the numerical and analytical model is then designed