Analysis and design of innovative antenna systems for telecommunications and health applications

In this thesis the study of different innovative antenna systems is presented. The antenna designs that have been analyzed and that are described in this thesis can be divided in three main groups based on their application: phased-array antennas working on surfaces that change shape in time, millimeter-wave antennas for skin cancer diagnosis, and gaseous plasma antennas for satellite communications. As far as the first topic is concerned, the research activity presented in this thesis focuses on the study of the strengths and limitations of a specific pattern recovery technique: the projection method. This technique has been adopted to retrieve the radiation properties of linear and planar arrays placed on surfaces whose shape changes in time according to different geometrical deformation; moreover, its effectiveness was assessed for both broadside and beam steering arrays, leading to a novel and simpler formulation of this pattern recovery technique for arrays whose beam is tilted towards different directions. The results have been obtained both through full-wave numerical simulations in CST Microwave Studio and through measurements performed in collaboration with the North Dakota State University (NDSU), Fargo, North Dakota, USA. Regarding skin cancer diagnosis, a novel substrate integrated waveguide probe for early-stage skin cancer detection has been designed as well: this probe is cheap and easy to fabricate and can achieve high accuracy in detecting small early-stage skin cancer, thus providing a tool with the potential of being adopted as a real aid for skin cancer diagnosis. The probe has been tested both through full-wave numerical simulations and through measurements on a skin phantom realized at The University of Queensland with the support of the Microwave Team. The study about gaseous plasma antennas for satellite communications has been mainly numerical. Different designs have been conceived with the aim of exploiting the advantages of using plasma elements while at the same time avoiding the limitations related to this novel technology. A practical implementation of these designs is now the subject of a collaboration with CISAS B. Colombo, an aerospace research center of the University of Padova