Results 61 to 70 of about 210,822 (303)

Receiving antenna electrodynamic model in terms of waveguide representation of HF field

open access: yesSolar-Terrestrial Physics, 2018
The receiving antenna is an important part of a radio channel that requires electrodynamic approach in mathematical simulation of its characteristics. Since the invention of radio, and due to further theoretical studies of radio signal transmission, the ...
Khakhinov V.V.
doaj   +1 more source

Impact of Power Allocation and Antenna Directivity in the Capacity of a Multiuser Cognitive Ad Hoc Network [PDF]

open access: yes, 2012
This paper studies the benefits that power control and antenna directivity can bring to the capacity of a multiuser cognitive radio network. The main objective is to optimize the secondary network sum rate under the capacity constraint of the primary ...
Alfonso, V.   +3 more
core   +1 more source

Additive Gaussian Process Regression for Predictive Design of High‐Performance, Printable Silicones

open access: yesAdvanced Engineering Materials, EarlyView.
A chemistry‐aware design framework for tuning printable polydimethylsiloxane (PDMS) for vat photopolymerization (VPP) is developed using additive Gaussian process (GP) modeling. Polymer network mechanics informs variable groupings, feasible formulation constraints, and interaction variables.
Roxana Carbonell   +3 more
wiley   +1 more source

Minimized Low-Profile Wideband Antennas Using High Impedance Surface

open access: yesInternational Journal of Antennas and Propagation, 2017
This paper proposes minimized low-profile wideband antenna by employing high impedance surface (HIS), for wireless application scenarios at radio frequency, microwave, and even terahertz.
Yizhu Shen
doaj   +1 more source

Oxide‐Free Titanium Coatings by Wire Arc Spraying in a Silane‐Doped Inert Atmosphere

open access: yesAdvanced Engineering Materials, EarlyView.
A silane‐doped argon atmosphere enables the production of oxide‐free titanium coatings via twin‐wire arc spraying at ambient pressure. This innovative approach eliminates residual oxygen, creating process conditions that prevent oxidation and nitride formation.
Manuel Rodriguez Diaz   +4 more
wiley   +1 more source

Primary Beam and Dish Surface Characterization at the Allen Telescope Array by Radio Holography

open access: yes, 2011
The Allen Telescope Array (ATA) is a cm-wave interferometer in California, comprising 42 antenna elements with 6-m diameter dishes. We characterize the antenna optical accuracy using two-antenna interferometry and radio holography. The distortion of each
Ackermann, R. F.   +48 more
core   +1 more source

Air‐Pressure–Actuated Vibroacoustic Metamaterial With Tunable Bandgap: Design, Modeling, and Characterization

open access: yesAdvanced Engineering Materials, EarlyView.
This article presents the design, modeling, and characterization of air‐pressure–actuated programmable vibroacoustic metamaterials (PVAMM). The study focuses on leveraging air pressure to dynamically tune resonance frequencies for effective noise attenuation.
William Kaal   +2 more
wiley   +1 more source

Frequency-Tunable and Pattern Diversity Antennas for Cognitive Radio Applications

open access: yesInternational Journal of Antennas and Propagation, 2014
Frequency-tunable microstrip antennas, for cognitive radio applications, are proposed herein. The approach is based on tuning the operating frequency of a bandpass filter that is incorporated into a wideband antenna.
A. H. Ramadan   +4 more
doaj   +1 more source

Laser radio transmitter

open access: yes, 2019
Since the days of Hertz, radio transmitters have evolved from rudimentary circuits emitting around 50 MHz to modern ubiquitous Wi-Fi devices operating at gigahertz radio bands.
Belyanin, Alexey   +10 more
core   +2 more sources

Al–Cu Composite Casting of Laser‐Deoxidized Copper: Bonding, Interfacial Chemistry, and Thermal Conductivity

open access: yesAdvanced Engineering Materials, EarlyView.
This study investigates laser‐based oxide removal of Cu inserts in oxygen‐free conditions and examines long‐term oxidation kinetics and surface chemistry under different atmospheres via X‐ray photoelectron spectroscopy. Al–Cu compound casting with differently oxidized surfaces is performed, and intermetallic phase formation, morphology, and thermal ...
Timon Steinhoff   +9 more
wiley   +1 more source

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