Current Issue : April-June Volume : 2025 Issue Number : 2 Articles : 5 Articles
This article presents a circular polarized enclosed dielectric resonator antenna (DRA), operating at 5.8 GHz. The design consists of a twist DRA, which is enclosed in a box to give stability to the structure. The circular polarization of the antenna depends on the sense of twisting the top with respect to its base to achieve Left Hand Circular Polarization (LHCP) or Right Hand Circular Polarization (RHCP). The antenna was manufactured using 3D printing and low-loss dielectric filament. The measurement results show the two resonance frequencies and an axial ratio below 3 dB at the operational frequency, while exhibiting a bandwidth and gain compatible for unmanned aerial vehicle (UAV) applications....
Radar polarimetry is a technique that can be used to enhance target detection, identification and classification; however, the quality of these measurements can be significantly influenced by the characteristics of the radar antenna. For an accurate and reliable system, the calibration of the antenna is vitally important to mitigate these effects. This study presents a methodology to calibrate Ultra-Wideband (UWB) dual-polarised antennas in the near-field using a thin elongated metallic cylinder as the calibration object. The calibration process involves measuring the scattering matrix of the metallic cylinder as it is rotated, in this case producing 100 distinct scattering matrices from which the calibration parameters are derived, facilitating a robust and stable solution. The calibration procedure was tested and validated using a Vector Network Analyser (VNA) and two quad-ridged antennas, which presented different performance levels. The calibration methodology demonstrated notable improvements, aligning the performance of both functioning and under-performing antennas to equivalent specifications. Mid-band validation measurements indicated minimal co-polar channel imbalance (<0.3 dB), low phase error (<0.8◦) and improved cross-polar isolation (≈48 dB)....
In this paper, a novel single-layer dual-band orbital angular momentum (OAM) multiplexed reflective metasurface array antenna is proposed, which can independently generate OAM beams with different modes in the C-band and Ku-band, and complete flexible beam control in each operating band, achieving the generation of an OAM beam with mode l = −1 under oblique incidence at 7G with 94.4% mode purity, and having a wider usable operating bandwidth at 12G with a wide operating bandwidth, and an OAM beam with mode l = +2 is generated under oblique incidence, achieving 82.5% mode purity, which verifies the performance of the unit, makes preparations for the next research, and provides new possibilities for communication in more transmission bands and larger channel capacity....
In this paper, a design of a miniature antenna for biomedical implant applications is presented. The proposed structure consists of a printed antenna designed to cover all frequency bands below 1 GHz and is dedicated to biomedical applications with good matching, omnidirectional radiation, and a maximum realized gain of −26.7 dBi. It offers two bandwidths of 270 MHz and 762 MHz respectively. A Phantom model of the elliptical cylinder of 180 × 100 × 50 mm3 was used to simulate the electromagnetic radiation inside the human body. The tissue considered is equivalent to a muscle with a relative permittivity of 57 and a conductivity equal to 0.79 S/m. We also studied the antenna behavior when close to the internal electronic components. The simulation showed that the antenna remains robust in such an environment. Finally, the Specific Absorption Rate of the muscle was evaluated when the antenna was fed with 1 V. The evaluation proved that the calculated value of 0.48 W/Kg is well below the limit value imposed by the International Commission on Non- Ionizing Radiation Protection....
The development of space telecommunications in recent years has necessitated the design and the realization of compact, high-performance equipment operating at increasingly high frequencies. The use of high-precision radars for surveillance, detection and mobile communication systems orients research toward the antennas to electronic sweep. In this article, we present a microstrip leaky-wave antenna with periodic patches. Its design is based on an integral formulation solved by software using HFSS finite elements. A parametric study of this antenna is validated by simulations and compared with other results found in the literature. Analysis of the antenna’s radiation parameters shows that the main beam direction and levels of minor’s lobes can be controlled from these geometrical parameters. The interest of this study is to meet the requirements of antennas dedicated telecommunications systems....
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