ADJOINT BASED EVOLUTIONARY OPTIMIZATION OF ANTENNAS

Abstract

<p>This thesis proposes a novel evolutionary approach in antenna design optimization. In this approach using the adjoint sensitivity, readily available in electromagnetic simulation software, a gradient-based optimization process is implemented. In this method coordinates of some control points are used as the optimization variables, and the antenna structure evolves through the optimization process to satisfy the appropriate constraints. This method has been illustrated by design of a number of microstrip antennas.</p> <p>In the next step this method has been modified using constraints on angles between some hypothetical lines in the antenna structure to keep the antenna structure physical during the optimization process.</p> <p>Also a new optimization problem has been defined to reduce the spacing between antenna elements in an antenna array for MIMO systems. The initial antenna structure to solve this problem is one of the antenna structures designed previously in this work. A 1 by 2 and a 1 by 3 antenna array for MIMO systems have been designed using this method and measurement of the fabricated antenna verifies the simulation results.</p>