SVD-beam-shaping synthesis method of reflector antennas

2008 ◽  
Author(s):  
B. Gonzalez-Valdes ◽  
J.A. Martinez-Lorenzo ◽  
A. Garcia-Pino ◽  
C. Rappaport
Keyword(s):  
Synthesis Method ◽  
Beam Shaping ◽  
Reflector Antennas

Cosecant‐squared pattern synthesis method for broadband‐shaped reflector antennas

2014 ◽  
Vol 8 (5) ◽  
pp. 328-336 ◽  
Author(s):  
Ali Akbar Dastranj ◽  
Habibollah Abiri ◽  
Ali Reza Mallahzadeh
Keyword(s):  
Synthesis Method ◽  
Reflector Antennas ◽  
Pattern Synthesis

scholarly journals A Dual-Band Circularly Polarized Patch Array Antenna for Phase-Only Beam Shaping with Element Rotation

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 643
Author(s):  
Edoardo Pelliccia ◽  
Roberto Vincenti Gatti ◽  
Piero Angeletti ◽  
Giovanni Toso
Keyword(s):  
Phase Distribution ◽  
Synthesis Method ◽  
Satellite System ◽  
Beam Shaping ◽  
Dual Band ◽  
Circularly Polarized ◽  
Frequency Bands ◽  
Radiating Element ◽  
Effective Phase ◽  
Global Navigation Satellite

In this paper, an innovative patch antenna optimally designed for phase-only beam shaping is presented. The radiating element generates a circularly polarized field and exhibits two separate operative frequency bands. The element is center-fed by a pin connected to the beam forming network (BFN) layer. This unique feature allows us to generate any given phase distribution by simply proportionally rotating the radiating elements with respect to their feeding points. An effective phase-only synthesis method is also illustrated, which takes into account the radiating element rotations. To demonstrate the effectiveness of the proposed solution, two linear arrays for global coverage have been designed, specifically operating in the E1 and E6 frequency bands of the European Global Navigation Satellite System (GNSS) Galileo. The two presented antennas performance have been verified with full-wave simulations, showing excellent agreement with theoretical results and, therefore, confirming the effectiveness of the presented design approach.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

Calculation of the Side and Back Far-Field Zone Radiation for Reflector Antennas with Radio Absorbing Coating on Edges

2004 ◽  
Vol 61 (1) ◽  
pp. 67-74
Author(s):  
O. I. Sukharevsky ◽  
V. A. Vasilets ◽  
S. V. Nechitaylo ◽  
S. V. Orekhov
Keyword(s):  
Far Field ◽  
Field Zone ◽  
Reflector Antennas

Discovery of a Difluoroglycine Synthesis Method through Quantum Chemical Calculations

2020 ◽  
Author(s):  
Tsuyoshi Mita ◽  
Yu Harabuchi ◽  
Satoshi Maeda
Keyword(s):  
Quantum Chemical Calculations ◽  
Experimental Verification ◽  
Quantum Chemical ◽  
Synthesis Method ◽  
Target Product ◽  
Systematic Exploration ◽  
Hands On ◽  
Retrosynthetic Analysis ◽  
Synthetic Routes ◽  
Verification Process

The systematic exploration of synthetic pathways to afford a desired product through quantum chemical calculations remains a considerable challenge. In 2013, Maeda et al. introduced ‘quantum chemistry aided retrosynthetic analysis’ (QCaRA), which uses quantum chemical calculations to search systematically for decomposition paths of the target product and propose a synthesis method. However, until now, no new reactions suggested by QCaRA have been reported to lead to experimental discoveries. Using a difluoroglycine derivative as a target, this study investigated the ability of QCaRA to suggest various synthetic paths to the target without relying on previous data or the knowledge and experience of chemists. Furthermore, experimental verification of the seemingly most promising path led to the discovery of a synthesis method for the difluoroglycine derivative. The extent of the hands-on expertise of chemists required during the verification process was also evaluated. These insights are expected to advance the applicability of QCaRA to the discovery of viable experimental synthetic routes.

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