This article presents the design of 4x4 patch antenna array for 5G applications that provides a reasonable bandwidth around 28 GHz. The main element of this arrangement is a rectangular patch antenna designed on the Rogers RT / Duroid 5880 substrate, which is simulated and optimized using an commercially available electromagnetic simulation software.

In this work, we propose and analyze a thermally tunable metasurface based on indium antimonide (InSb), designed to operate in the terahertz (THz) frequency range. The metasurface exhibits dual functionalities: single-band perfect absorption and efficient polarization conversion, enabled by the temperature-dependent permittivity of InSb. At approximately 280 K, InSb transitions into a metallic state, enabling the metasurface to achieve near-unity absorptance (100%) at 0.408 THz under normal incidence, independent of polarization. Conversely, when InSb behaves as a dielectric at 200 K, the metasurface operates as an efficient polarization converter. By exploiting structural anisotropy, it achieves a polarization conversion ratio exceeding 85% over the frequency range from 0.56 to 0.93 THz, while maintaining stable performance for incident angles up to 45°. Parametric analyses show that the resonance frequency and absorption intensity can be effectively tuned by varying the InSb square size and the silica (SiO₂) layer thickness, achieving maximum absorptance at a SiO₂ thickness of 16 μm. The proposed tunable metasurface offers significant potential for applications in THz sensing, imaging, filtering, and wavefront engineering.

This study presents a quasi-transparent circularly polarized patch antenna integrated to a solar cell using metamaterial. The disadvantages and challenges related to patch antennas and solar cell integration are point out. Then, in order to compensate these detriments to antenna performance metamaterials with reactive impedance surface (RIS) are proposed. A report of the benefits introduced by these elements is shown. Finally, in order to accomplish quasi- transparency, the antenna is meshed adding slots where the currents densities are insignificant. A final prototype with a meshing that do not influence the antenna parameters was achieved and their features are presented.

In this work, an ultra-bandwidth antenna (UWB) is proposed for applications in ground penetrating radar (GPR). A novel Vivaldi antipodal antenna (AVA) with elliptical slot at the edges (ESE) made with FR4 is presented. The antenna was optimized by adjusting the geometry of the tapers and modifying the shape of the balun, with these modifications a lower cutoff frequency (LCF) around 1.5 GHz is achieved. Results from reflection coefficients, radiation pattern and gain are presented. The overall design and electromagnetic simulation of the antenna are made with a a commercially avalaible simulator.

In the this contribution, a Multi-Objective Genetic Algorithm (MOGA) was implemented to analyze, design and optimize several Antipodal Vivaldi Antennas (AVA) that are being used on Ground Penetration Radars (GPR) applications. This algorithm was implemented and used as an optimization tool in a commercial available software. Directivity, lower cutoff frequency (LCF), bandwidth and cross-polarization were the objectives to be optimized. For the use of the MOGA, the 3D model of the antenna is built in the simulator. Some of its parameters are defined as variables, as the dimensions and shape of the antenna (Individual) depend on the value that its parameters (Genes) take. This work proves to be simple and time saving tool to optimize parameters in a geometry changing system as GPR.

In this paper, three Vivaldi antenna are introduced to compare their performance. As base for our study an ordinary Vivaldi antenna is designed. Then defected ground structures (DGS) are employed to extend the low-end bandwidth limitation and improve the radiation characteristics at lower frequencies. A prototypes with 4 pairs of DGS placed in the antennas is fabricated and experimentally compared with the ordinary Vivaldi antenna. Reflection coefficient is measured indicating a reasonable agreement with simulations. These results validate the benefits of DGS in Vivaldi antennas to its application for a Ground Penetrating Radar (GPR).