Authors:Mats Gustafsson, Doruk Tayli, Casimir Ehrenborg, Marius Cismasu, Sven Nordebo
Source:FERMAT, Articles, 2016-Vol15-May_Jun-005
Abstract:Antenna current optimization is a tool that offers many possibilities in antenna technology. Optimal currents are determined in the antenna design region and used for physical understanding, as a priori estimates of the possibilities to design antennas, physical bounds and as figures of merits for antenna designs. Antenna current optimization is particularly useful for small antennas and antennas that are constrained by their electrical size. The initial non-convex antenna design optimization problem is reformulated as a convex optimization problem expressed in the currents on the antenna. This convex optimization problem is solved efficiently at a computational cost comparable to a Method of Moments (MoM) solution of the same geometry. In this paper a tutorial description of antenna current optimization is presented. Stored energies and their relation to the impedance matrix in MoM is reviewed. The convex optimization problems are solved using MATLAB and CVX. MoM data is included together with MATLAB and CVX codes to optimize the antenna current for strip dipoles and planar rectangles. Codes and numerical results for maximization of the gain to Q-factor quotient and minimization of the Q-factor for prescribed radiated fields are provided.
Index Terms:Stored energy, Antenna Q, Convex Optimization, Physical bounds, Q-factor, Antenna theory.
View PDF
Antenna Current Optimization using MATLAB and CVX