Antena de microfita multimodo (TM03/TM11) com ganho e largura de banda aprimorados para 5G em 3,5 GHz

Abstract

This work presents the design, analysis, and experimental validation of a microstrip antenna developed for operation in the 3.5 GHz band for fifth-generation (5G) wireless communication systems. The proposed antenna is based on the controlled combination of higher-order resonant modes in a rectangular patch modified by metallic shorting vias, enabling the simultaneous excitation of the TM03-like and TM11-like modes. The introduction of these vias alters the electromagnetic boundary conditions of the resonant cavity, bringing two resonances closer together and producing a dual-resonance response responsible for bandwidth enhancement. Initially, a reference antenna operating in the fundamental TM10 mode was analyzed based on the cavity model and full-wave electromagnetic simulations performed in Ansys HFSS. Then, the structure was redesigned for the target frequency range through the systematic adjustment of its geometric parameters, with special emphasis on the W/L ratio, identified as the key variable for controlling the frequency spacing between the excited resonant modes. The simulated results showed a 14.65% fractional impedance bandwidth for the criterion |S11| ≤ −10 dB, covering the frequency range from 3.29 to 3.81 GHz, with realized gain varying from 7.21 to 9.56 dBi and reaching a peak value of 9.62 dBi. The experimental validation of the fabricated prototype, in terms of |S11|, showed good agreement with the numerical predictions, yielding a measured bandwidth of 16.03%, from 3.27 to 3.84 GHz. In addition, the simulated radiation patterns exhibited stable behavior over the operating band, with predominantly broadside radiation and no significant sidelobes. The obtained results demonstrate that the adopted modal-combination strategy is an efficient approach for developing microstrip antennas with enhanced bandwidth, relatively high gain, and simple geometry, thus properly meeting the operational requirements of the 3.5 GHz 5G band.