Aplicación de pantallas magnéticas a la reducción de tamaño de un sistema multiantena

Abstract

In this project, the advantages and disadvantages provided by the inclusion of magnetic screens to decouple the different antennas that integrate a multi-antenna system will be studied. Metamaterials are introduced, being some of their possible uses and some applications (according to referenced papers) will be exposed. Specifically, a type of metamaterials will be explained: magnetic screens. The tools used for the design and simulation of multi-antenna structures involving these artificial materials will be commented. A multi-antenna system design based onm etamaterial separators will be designed in order to reduce the size of the multi-antenna structure keeping the isolation level between antenna elements. Firstly, a unit cell to be used in the magnetic screen will be analysed and designed. Next, a monopole will be tuned at an operating frequency of 2.45GHz. Secondly, two multi-antenna systems will be designed, a first having two monopoles and another one with four monopoles. These designs will be compared with the performance of: 1) a conventional system where the decoupling is achieved by the separating the antennas; 2) a system where the decoupling is achieved by the inclusion of a metal screen; and 3) a system that includes an artificial magnetic screen (metamaterial) composed with a periodic arrangement of a pre-designed unit cell. The parameters evaluated for comparison between the three types of decoupling systems are: reflection coefficient, isolation, and radiation pattern, all of them at frequency of 2.45 GHz because this frequency corresponds to a free band in the National Frequency Table and consequently this system may be used in Wi-Fi systems. The electrical sizes of the final designs having the artificial magnetic screen are compared with the multi-antenna systems without isolating screens.