Flexible Beamforming for Direct Radiating Arrays in Satellite Communications

Vásquez-Peralvo, Juan Andrés; Querol, Jorge; Ortíz, Flor; Rios, Jorge Luis González; Lagunas, Eva; Baeza, Victor Monzon; Fontanesi, Gianluca; Garcés-Socorrás, Luis Manuel; Duncan, Juan Carlos Merlano; Chatzinotas, Symeon

doi:10.1109/access.2023.3300039

Cited by 10 publications

(4 citation statements)

References 37 publications

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“…Thereafter, Baeza et al investigated the placement of the gateway stations based on multiple criteria of the system with NGSO satellites [14]. In [15], an approach was described for beam pattern synthesis applied to geostationary satellite communication systems, considering latitude and longitude, required EIRP, minimum and maximum side love levels for the two principal cuts, and nulling direction. However, the traditional channel model must account for the stochastic geometry distribution of terminals, especially for the NOMA-based SAGIN system with increased moving terminals [16,17].…”

Section: Methodsmentioning

confidence: 99%

Secrecy Performance of a Non-Orthogonal Multiple Access-Based Space–Air–Ground Integrated Network System with Stochastic Geometry Distribution of Terrestrial Terminals and Fog Absorption in Optical Link

Wang,

He,

et al. 2024

Aerospace

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Recently, non-orthogonal multiple access (NOMA)-based space–air–ground integrated networks (SAGINs) have gained increasing attention due to their robust communication, broader coverage, and resource-saving advantages. However, it is imperative to consider physical layer security as a crucial performance metric in NOMA-based SAGINs. This study addresses this concern by constructing a NOMA-based free space optical (FSO)/radio frequency (RF) dual-hop SAGIN system with eavesdroppers on both links. The two new fading channel models were proposed, considering the FSO link’s fog absorption and the RF link’s stochastic distribution based on Málaga and shadowed Rician distributions. The closed-form expressions for the secrecy outage probability are derived for the SAGIN system. Monte Carlo simulations were conducted to validate the theoretical findings. The results revealed the influence of fog absorption and the stochastic geometry distribution on the SAGIN system.

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Section: Methodsmentioning

confidence: 99%

Secrecy Performance of a Non-Orthogonal Multiple Access-Based Space–Air–Ground Integrated Network System with Stochastic Geometry Distribution of Terrestrial Terminals and Fog Absorption in Optical Link

Wang,

He,

et al. 2024

Aerospace

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“…This approach often employs analytical methods using established taper distributions like Chebyshev, Taylor, Hamming, or Hann for amplitude values [15]. Non-deterministic techniques, such as Genetic Algorithms (GA) [16], [17] and Particle Swarm Optimization (PSO) [18], are also utilized when analytical methods are not available. The second category, phase-only synthesis, focuses on shaping the beam or reducing interference by exclusively modifying the phase of the array elements.…”

Section: Introductionmentioning

confidence: 99%

“…To achieve the desired tapering in each antenna element without incurring high manufacturing costs or increasing the risk of failure due to step amplitude variation, array thinning emerges as a superior method. This approach not only maintains cost-effectiveness but also preserves the capability for beam steering in the antenna array [17]. Array thinning is a concept used in the field of antennas, more specifically in phase arrays, where the main aim is to deactivate certain elements to obtain a desired radiation pattern.…”

Section: Introductionmentioning

confidence: 99%

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Multibeam Beamforming for Direct Radiating Arrays in Satellite Communications Using Genetic Algorithm

Andrés Vásquez-Peralvo,

Querol,

Ortíz

et al. 2024

IEEE Open J. Commun. Soc.

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Recent advancements in onboard satellite communication have enhanced the capability of dynamically modifying the radiation pattern of a Direct Radiating Array (DRA). This is crucial not only for conventional communication satellites like Geostationary Orbit (GEO) but also for those in lower orbits such as Low Earth Orbit (LEO). Key design factors include the number of beams, beamwidth, Effective Isotropic Radiated Power (EIRP), and Side Lobe Level (SLL) for each beam. However, a challenge arises in multibeam scenarios when trying to simultaneously meet requirements for the aforementioned design factors which are reflected as uneven power distribution. This leads to over-saturation, especially in centrally located antenna elements due to the activation times per beam, commonly referred to as activation instances. In response to this challenge, this paper presents a method to balance the activation instances across antenna elements for each required beam. Our focus is on beams operating at 19 GHz on a CubeSat positioned 500 km above the Earth's surface. We introduce a Genetic Algorithm (GA)-based algorithm to optimize the beamforming coefficients by modulating the amplitude component of the weight matrix for each antenna element. A key constraint of this algorithm is a limit on activation instances per element, which avoids over-saturation in the Radio Frequency (RF) chain. Additionally, the algorithm accommodates beam requirements such as beamwidth, SLL, pointing direction, and total available power. With the previous key design factors, the algorithm will optimize the required genes to address the desired beam characteristics and constraints. We tested the algorithm's effectiveness in three scenarios using an 8×8 DRA patch antenna with circular polarization, arranged in a triangular lattice. The results demonstrate that our algorithm not only meets the required beam pattern specifications but also ensures a uniform activation distribution across the antenna array.INDEX TERMS Antennas, beamforming, direct radiating array, satellite communications.

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Flexible Dielectric Materials: Potential and Applications in Antennas and RF Sensors

Hussain,

Zahra,

Abbas

et al. 2024

Adv Elect Materials

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Dielectrics are non‐conducting substances that are primarily utilized to hold electric charges. These materials are widely employed in the field of chemical mechanical, civil and structural engineering, because of their inherent insulating properties. Besides these domains, dielectric materials are also used in electrical and electronic applications. Dielectric materials have shown an ever‐increasing potential in recent years in the fabrication of antennas, sensors, and optical devices that are extensively utilized for on‐body, environmental, robotics, and biomedical applications. With inherent electrostatic shielding, insulation, and dielectric relaxations, these materials are used in intelligent electronic devices used for biomedical applications, smart devices, vehicles, and future IoT applications. Numerous applications necessitate multiple kinds of dielectric, classified based on their polarization, flexibility, thickness, dielectric constant, and specific application. In this extensive research review, the characteristics and various aspects of dielectric materials are discussed, followed by a thorough and detailed review of flexible dielectrics and their usage in flexible electronics. Additionally, the practicality and applications of these materials which come from a variety of publications in the literature are also discussed. Moreover, in‐depth study of dieletrics in sensors and RF applications are performed.

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Flexible Beamforming for Direct Radiating Arrays in Satellite Communications

Cited by 10 publications

References 37 publications

Secrecy Performance of a Non-Orthogonal Multiple Access-Based Space–Air–Ground Integrated Network System with Stochastic Geometry Distribution of Terrestrial Terminals and Fog Absorption in Optical Link

Secrecy Performance of a Non-Orthogonal Multiple Access-Based Space–Air–Ground Integrated Network System with Stochastic Geometry Distribution of Terrestrial Terminals and Fog Absorption in Optical Link

Multibeam Beamforming for Direct Radiating Arrays in Satellite Communications Using Genetic Algorithm

Flexible Dielectric Materials: Potential and Applications in Antennas and RF Sensors

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