Sistema de array circular para un radar secundario en banda L: Diseño de los elementos radiantes

Abstract

The following Degree Thesis seeks to design the radiating elements of electronically steerable antenna in a circular array, which is able to electronically change the pointing direction with the aim to locate targets within in an area. This antenna will be implemented on a radar in order to build identification friend-or-foe (IFF) system. The same antenna will be used in both transmission and reception. In transmission, it uses two channels, which are mandatory fot the Mode S Interrogation of the system. These channels are called SUM channel and OMNIDIRECTIONAL channel. On the other hand, in reception it uses three channels, which are the two mentioned above and the DIFERENCE channel. At the beginning. An introduction to these systems have been made. A selection of commercial elements is shown and the specification that the radiant element must meet are studied. Afterwards, diferents options of elements that could constitute the circular array are discussed: The slot antenna and the patch antenna. The radiant elements are designed, and the necessary simulations such as bandwidth, impedance, polarization, directivity and their farfield, in order to fulfill more precisely the main requirements. Finally a structure that allows the parallel feeding between two elements is designed with a final quarter wave transformer that allows the impendance control at the end of the network, in this case, a coaxial line impedance.