In microwave engineering some of the main challenges are size reduction and design flexibility. These are key aspects in communication devices and, as a result, many efforts have been made in this direction. A clear example of that are the so-called transmission lines based on metamaterials. Such artificial lines exhibit controllable characteristics, are electrically small and provide new functionalities. However, due to their complexity, metamaterial transmission lines usually require a cumbersome design process, based on the experience of the designers. In last decades, several optimization techniques based on Space Mapping (SM), which combine the accuracy of the electromagnetic simulators with the speed of circuit simulators, have been reported. This reduces design time and provides the ability to automate the design process. For this reason, these techniques are good candidates to deal with complex problems such as the design of metamaterial transmission lines. Thus, the main objective of the work compiled in this thesis is to develop a new tool for the automated synthesis of such structures from the knowledge of the reactive elements of its equivalent circuit. Specifically, it deals with the automatic synthesis of transmission lines loaded with Complementary Split Ring Resonators (CSRRs) by using the technique known as Aggressive Space Mapping (ASM). Different strategies for the development of the ASM algorithm and its improvements are provided, including a technique to determine whether for a given set of circuit parameters that meet specifications the structure can be synthesized or not, and the reduction of the convergence time. Moreover, the ASM algorithm has been applied to the design of several microwave devices, such as Wi-Fi filters and dual-band power dividers for GSM applications, among others.
Synthesis of microwave circuits based on metamaterials using Aggressive Space Mapping algorithms.
Selga Ruiz, J. (Author). 8 Nov 2013
Student thesis: Doctoral thesis
Student thesis: Doctoral thesis