Design and implementation of metamaterial and metamaterial - inspired microwave components

Abstract

In this thesis, we present the research conducted during the three years of PhD program. Will be presented the design, implementation and the experimental results of several devices that find application in microwave communication and test field. First, I present a new possibility for waveguide bending based on metamaterials inspired structures. In particular, we have studied designed and experimentally verified structures able to transmit efficiently energy through subwavelength slides. The physical insight of this approach relies in the fact that the bifilar line is almost insensitive to bending, and, thus, the system turns out to be robust against the arbitrary position of the two connected waveguide segments. The efficient mode conversion is achieved using the connected bi omega particle able to convert waveguide modes in voltage and current that can be transmitted using bifilar structures. Then, I have studied the state of art of the carpet cloak and proposed a new carpet device able to overcome the throwbacks of the common methods. Starting from transmission-line cloaking concepts and Van-Atta retroreflector antenna connection proposed a full passive antenna based carpet device able to mimic reflection from a ground plane even in presence of a large bump over a wide angular band and with a flexible frequency band correlated to the design of antennas implied in the structure. To experimentally characterize the proposed carpet device, I have composed a measurement setup able to propagate a plane wave in 2D domain based on parallel plate s type of reflector with cylindrical symmetry. The proposed structure has been characterized and experimentally verified before to be used in the facility to verify the carpet device. Finally, I have explored the topological phases of matter, in particular the possibility to reproduce the topological insulator behaviour at microwaves using bi-anisotropic structures and I have proposed a new full passive device able to act in the same fascinating way of a non-reciprocal three port device where the signal is route to one port keeping isolated the other one without break the reciprocity of the structure.