scholarly journals Conformal Patch Antenna Arrays Design for Onboard Ship Deployment Using Genetic Algorithms

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Stelios A. Mitilineos ◽  
Symeon K. Symeonidis ◽  
Ioannis B. Mpatsis ◽  
Dimitrios Iliopoulos ◽  
Georgios S. Kliros ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Antenna Arrays ◽  
Patch Antenna ◽  
High Performance ◽  
Aerodynamic Drag ◽  
A Priori ◽  
Conformal Antennas ◽  
Antenna Performance ◽  
And Performance ◽  
Aerodynamic Drag Reduction

Conformal antennas and antenna arrays (arrays) have become necessary for vehicular communications where a high degree of aerodynamic drag reduction is needed, like in avionics and ships. However, the necessity to conform to a predefined shape (e.g., of an aircraft’s nose) directly affects antenna performance since it imposes strict constraints to the antenna array’s shape, element spacing, relative signal phase, and so forth. Thereupon, it is necessary to investigate counterintuitive and arbitrary antenna shapes in order to compensate for these constraints. Since there does not exist any available theoretical frame for designing and developing arbitrary-shape antennas in a straightforward manner, we have developed a platform combining a genetic algorithm-based design, optimization suite, and an electromagnetic simulator for designing patch antennas with a shape that is not a priori known (the genetic algorithm optimizes the shape of the patch antenna). The proposed platform is further enhanced by the ability to design and optimize antenna arrays and is intended to be used for the design of a series of antennas including conformal antennas for shipping applications. The flexibility and performance of the proposed platform are demonstrated herein via the design of a high-performance GPS patch antenna.

A Review of Commercial Vehicle Aerodynamic Drag Reduction Techniques

1985 ◽  
Vol 199 (3) ◽  
pp. 215-220 ◽  
Author(s):  
K P Garry
Keyword(s):  
Aerodynamic Drag ◽  
Fuel Efficiency ◽  
Relative Effectiveness ◽  
Aerodynamic Characteristics ◽  
Performance Assessments ◽  
Commercial Vehicles ◽  
Reduction Techniques ◽  
Legal Constraints ◽  
And Performance ◽  
Aerodynamic Drag Reduction

The aerodynamic characteristics of commercial vehicles have been of interest to researchers for many years, primarily with a view to reducing drag and consequently improving fuel efficiency. Despite developments in the design of low drag vehicles proprietary devices in various forms remain the most effective method of reducing drag on the majority of vehicles in current use. The relative effectiveness of these devices is discussed in relation to the variety of vehicle geometries to which they are fitted and performance assessments are made, particularly with reference to the need for crosswind efficiency. A general summary of potential aerodynamic developments is given, emphasizing the concept of matching the flowfield of cab and container to obtain optimum interference. The effectiveness of cab–container gap seals and trailer side skirts, both intended to reduce drag under crosswind conditions, is also discussed. All such developments are taken in the context of existing commercial and legal constraints likely to influence their impact on the next generation of commercial vehicles.

Mutual Coupling Reduction for High-Performance Densely Packed Patch Antenna Arrays on Finite Substrate

2016 ◽  
Vol 64 (5) ◽  
pp. 1653-1660 ◽  
Author(s):  
Zeeshan Qamar ◽  
Umair Naeem ◽  
Shahid A. Khan ◽  
Mitchai Chongcheawchamnan ◽  
M. Farhan Shafique
Keyword(s):  
Antenna Arrays ◽  
Patch Antenna ◽  
High Performance ◽  
Mutual Coupling ◽  
Mutual Coupling Reduction

Reduction of the mutual coupling in patch antenna arrays based on EBG by using a planar frequency-selective surface structure

2015 ◽  
Vol 9 (2) ◽  
pp. 349-355 ◽  
Author(s):  
Ehsan Beiranvand ◽  
Majid Afsahy ◽  
Vahid Sharbati
Keyword(s):  
Antenna Arrays ◽  
Patch Antenna ◽  
Mutual Coupling ◽  
Periodic Structures ◽  
Frequency Selective Surface ◽  
Microstrip Technology ◽  
Antenna Performance ◽  
Antenna Directivity ◽  
Before And After ◽  
Frequency Selective

This paper describes a new configuration of frequency-selective structure (FSS) structures to reduce mutual coupling between the radiating elements. Also, the antenna performance before and after the implementation of FSS have been investigated. The proposed configuration provides an improvement in mutual coupling by 14 dB (measured value) with a reduced edge-to-edge spacing of 23 mm. The reduction of mutual coupling between antenna elements is interesting in the electromagnetic and antenna community. The use of electromagnetic band-gap structures constructed by microstrip technology is a way to appease the mutual coupling problem. Periodic structures such as FSS can help in the reduction of mutual coupling using their ability of suppressing surface waves propagation in a given frequency range. The goal of this present study is to use it in patch antenna arrays, keeping both the element separation smaller than λ0for grating lobes evasion and the patch antenna size large enough to have good antenna directivity. The results showed that the proposed configuration eliminates disadvantages of similar structures presented in the previous works.

scholarly journals Design and optimization of 2x2 corporate-series fed microstrip antenna array

2018 ◽  
Vol 7 (1.9) ◽  
pp. 84
Author(s):  
Jobins George ◽  
B Lethakumari
Keyword(s):  
Antenna Array ◽  
Patch Antenna ◽  
Microstrip Patch Antenna ◽  
Design And Optimization ◽  
High Frequency Structure Simulator ◽  
Microstrip Patch ◽  
Antenna Performance ◽  
Before And After ◽  
And Performance ◽  
Performance Analyze

The limitation of microstrip patch antenna is relatively low gain and narrow bandwidth. By using the microstrip patch antenna array antenna performance can be improved. In this paper design and stimulation of a 4 element rectangular microstrip patch array is described and the performance of antenna array is optimized by varying patch element dimensions. Antenna array is designed to operated at the frequency of 10 GHz. The corporate-series feed network is implemented for feeding patch elements. The 2x2 antenna array is implemented on FR4 substrate with 1.588mm thickness and dielectric constant of 4.4.The stimulation and performance analyze of antenna is done using Ansoft High frequency structure simulator software. Finally, comparison of antenna arraycharacteristics before and after optimization is presented.

Trace nanoanalysis

1994 ◽  
Vol 52 ◽  
pp. 940-941
Author(s):  
D. E. Newbury ◽  
R. D. Leapman
Keyword(s):  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Detection Efficiency ◽  
Volume Element ◽  
And Performance ◽  
Trace Constituents ◽  
Secondary Ion ◽  
Concentration Levels ◽  
Structure Properties

Trace constituents, which can be very loosely defined as those present at concentration levels below 1 percent, often exert influence on structure, properties, and performance far greater than what might be estimated from their proportion alone. Defining the role of trace constituents in the microstructure, or indeed even determining their location, makes great demands on the available array of microanalytical tools. These demands become increasingly more challenging as the dimensions of the volume element to be probed become smaller. For example, a cubic volume element of silicon with an edge dimension of 1 micrometer contains approximately 5×1010 atoms. High performance secondary ion mass spectrometry (SIMS) can be used to measure trace constituents to levels of hundreds of parts per billion from such a volume element (e. g., detection of at least 100 atoms to give 10% reproducibility with an overall detection efficiency of 1%, considering ionization, transmission, and counting).

Replication of the Superstition and Performance Study by

2014 ◽  
Vol 45 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Robert J. Calin-Jageman ◽  
Tracy L. Caldwell
Keyword(s):  
Task Difficulty ◽  
Statistical Power ◽  
Meta Analysis ◽  
A Priori ◽  
Significant Heterogeneity ◽  
Performance Study ◽  
Improve Performance ◽  
Research Designs ◽  
Series Of Experiments ◽  
And Performance

A recent series of experiments suggests that fostering superstitions can substantially improve performance on a variety of motor and cognitive tasks ( Damisch, Stoberock, & Mussweiler, 2010 ). We conducted two high-powered and precise replications of one of these experiments, examining if telling participants they had a lucky golf ball could improve their performance on a 10-shot golf task relative to controls. We found that the effect of superstition on performance is elusive: Participants told they had a lucky ball performed almost identically to controls. Our failure to replicate the target study was not due to lack of impact, lack of statistical power, differences in task difficulty, nor differences in participant belief in luck. A meta-analysis indicates significant heterogeneity in the effect of superstition on performance. This could be due to an unknown moderator, but no effect was observed among the studies with the strongest research designs (e.g., high power, a priori sampling plan).

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