In this study, the reflection efficiency of a 1-bit 16x16 array switchable reflective electromagnetic surface (SRES) design is evaluated for beam deflector applications. Three design configurations with different deflection angles are analyzed, namely 4-cell-per-supercell, 8-cell-per-supercell, and 16-cell-per-supercell. The unit cell structure of SRES is designed to produce two states with a 180-degrees phase difference, enabling beam deflection functionality. The reflection efficiency is assessed under normal and oblique incident wave scenarios. The results indicate that the reflection efficiency in all configurations remains relatively low, below 50%, primarily due to the dominance of parasitic lobes appearing alongside the anomalous reflection. As the incident angle increases, the parasitic lobes intensify, further reducing the reflection efficiency at the anomalous reflection angle. Among the configurations, the 16-cell-per-supercell configuration achieves the highest efficiency, as it eliminates specular reflection. Furthermore, the effect of varying tilt angles of incident wave polarization is studied in the 4-cell-per-supercell configuration under normal incidence. The highest efficiency is achieved at the tilt angle of 0 degree when the incident wave polarization vector is in parallel with the phase variation orientation.
Global communication services utilize terrestrial communication systems, which apply to urban, suburban, rural, and remote areas. However, terrestrial infrastructure in rural and remote areas often faces challenges, restricting access to telecommunication services. The presence of a high-altitude platform station (HAPS) represents an alternative solution that addresses the challenge of wide-area coverage while supporting operational cost efficiency. HAPS was then used as a base station for international mobile telecommunications (IMT) services known as HIBS. It operates on a 2 GHz cellular frequency and is located at an altitude of 20 km. In this study, the system is designed to serve an area consisting of seven cells, where one cell is located directly under the HAPS as a reference cell, and the remaining six cells are outside cells that can cause interference. Channel capacity and outage probability for 5G services using different numerologies reveal the system’s performance. Simulation results indicate that $\mu=0$ and $\mu=1$ numerology can maintain communication reliability in the planned system.
This paper discusses the utilization of an aperture coupled feeding technique in a filtering antenna (filtenna) with a square spiral resonator radiation element. The proposed filtenna comprises two layers of FR4-epoxy substrate joined together using four nylon spacers and screws in each corner. The groundplane with a rectangular slot aperture is positioned between two substrates, while the feeding line is placed at the bottom side of filtenna. Here, the filter element is formed using interdigital capacitor (IDC) and meandered-inductor (MI) circuits connected to the feeding line. The simulation and measurement results show that the proposed spiral resonator filtenna resonates at the center frequency of 2.45 GHz and has a 40 MHz bandwidth response, with the simulated and measured reflection coefficient (S11) values of –29.85 dB and – 23.71 dB, respectively. Both results demonstrate a similar trend, indicating a good agreement between them. In addition, the proposed spiral resonator filtenna has a directional radiation pattern at the frequency of 2.45 GHz.
Technological development has influenced significant progress across various fields, particularly communication and electronic systems. Communication equipment must demonstrate resistance to electromagnetic (EM) waves, necessitating Electromagnetic Compatibility (EMC) and Electromagnetic Interference (EMI) testing, particularly regarding radiated emissions. This study proposes an innovative embroidered disc-shaped textile array antenna to address the challenges in radiated emission testing. The proposed array antenna is designed to operate at the frequency of 3.48 GHz, making it highly suitable for wearable and portable applications while ensuring compatibility with modern communication systems. The measurement of radiated emission is carried out in two conditions, namely flat and 50-mm bent, with radiated emission measurement under two polarizations, namely vertical and horizontal. The measurement results are compared with those of the Ultralog antenna, revealing that the electric field intensities for both Ultralog antenna and 50 mm-bent array antenna are higher under vertical polarization than horizontal polarization. These results underscore the potential of proposed array antenna for wearable devices, highlighting its ability to maintain the performance under bending conditions while satisfying standards in complex EM environments.
In this paper, a magneto-dielectric-based microstrip antenna is presented, focusing on the effect of antenna configuration on its radiation characteristics. A square-shaped magnetic material, namely Yttrium Iron Garnet (YIG), is incorporated within the host Rogers RT/duroid RO5880 dielectric substrate. The proposed antenna is characterized and analyzed using a simulation-based approach under two different scenarios related to the magnetization states of material, i.e., demagnetized and magnetically saturated, to observe the anisotropy effect on antenna radiation performance. The analysis also includes the impact of YIG material position within the substrate. The results of characterization and analysis indicate that the magneto-dielectric-based microstrip antenna can enhance the polarization characteristics under magnetized conditions, while maintaining the gain of above 4.5 dBi and the radiation efficiency of above 90%, particularly for multi-layer configurations.
