Implementação de uma antena ressoadora magneto-dielétrica cilíndrica baseada na matriz YIG para o controle dos modos de propagação HEM11δ, TE01δ e TM01δ.

Abstract

The magneto-dielectric resonator antennas (MDRA, magnetic dielectric resonant antennas) have been investigated by several researchers for their varied characteristics and applications. Among these characteristics, high dielectric and magnetic constant, fundamental for the miniaturization of resonator antennas, low dielectric losses compared to metallic materials, ease in the excitation aiming the generation of modes of propagation and selective magnetization. This work presents the results of the study of an MDRA with cylindrical geometry, based on the matrix (Yttrium Iron Garnet, YIG), aiming to control the HEM11δ, TE01δ and TM01δ propagation modes, which can be controlled individually on the same antenna, or excite each port independently at the same time or not, allowing to excite one mode at a time on each port. Analytical results are presented from the mathematical equations available in the specialized literature, numerical results obtained using the CST Studio software and experimental results show a very good agreement among them. The designs of three MDRAs are presented, all fed by microstrip line with 50 Ω input impedance. The first antenna generates the measured frequency from 5.78 GHz to the HEM11δ mode, the second antenna excites the HEM11δ, TE01δ modes for measured frequencies 5.78 GHz and 6.75 GHz, respectively, and the third antenna generates modes HEM11δ, TE01δ and TM01δ for the simulated frequencies 5.75 GHz, 6.86 GHz and 8.37 GHz, independently controlled. The antennas were manufactured from a low cost FR4 fiberglass substrate and have a common ground plane. The magneto-dielectric resonator is manufactured using the magnetic ceramic material originated from the ferrites (Yttrium Iron Garnet, YIG) of composition Y3Fe2(FeO4)3 or Y3Fe5O12, which is positioned on the dielectric substrate. The scattering parameters S were analyzed in the frequency bands from 4.9 GHz to 9.5 GHz, with results within the expected range. The 2-D and 3-D irradiation diagrams are also presented. Three MDRAs were designed and analyzed numerically, making it possible to manufacture and measure the three proposed MDRAs. The mode control was obtained from the second and third projected antenna, being possible to excite the HEM11δ, TE01δ and TM01δ modes and to control them independently. Results were also obtained regarding the effect of the magnetic field of the second antenna, an important characteristic in the selectivity of magnetization, which can be controlled electronically. Therefore, MDCRA presented characteristics of miniaturization, modes of propagation and frequency individually controlled, with potential for application in wireless communication systems.