نتایج جستجو برای: antenna arrays

تعداد نتایج: 94493  

Nonuniform Phased Sampling method is proposed to phase-only synthesize the power pattern of both linear and planar antenna arrays. This method modifies the conventional sampling method which is used for amplitude-phase synthesis. This method is based on assigning suitable phases to the sampling points of radiation pattern in order to reach desired amplitude of currents. Some examples are given ...

Journal: :IEEE Transactions on Antennas and Propagation 2015

2011
Abinash Gaya

Different antenna arrays are used at transmitter and receiver in MIMO communication system. The different multipath causes the interference at the receiver which impacts on the efficiency and also increases the channel estimation error of the MIMO system. Here I have studied over different antenna arrays and their radiation patterns with individual gains and efficiency and also a Proposal for b...

2005
Gonca ÇAKIR Levent SEVGİ

Typical low-cost, low-weight microstrip base station antenna arrays with beam-scanning capabilities are taken into account. In downtowns of large cities like New York, Chicago, and in historical cities like Istanbul, where high buildings are separated by narrow but densely occupied streets, antenna arrays with approximately 20◦− 35◦ beam-widths are required to complete the cellular communicatio...

The nominal directivity for uniformly spaced broadside parallel half-wave dipoles associated with a uniform excitation is evaluated. The amplitude distribution for an optimized directivity is then obtained for different numbers of elements with the separations between the dipoles as a variable. The optimum and nominal directivities are compared for different spacings of the elements. While thes...

In this work, the method of iterative Fourier transform phase reconstruction, conventionally used in holography and optical image reconstruction, is applied to phase only synthesis of antenna patterns. The method is applied to two types of pattern synthesis problems: "main lobe beam shaping" and "side-lobe-level reduction". The proposed method is most useful in the efficient employment of attai...

Journal: :International Journal of Antennas and Propagation 2012

2006
Z. ZAHARIS

An optimal design of a linear antenna array is presented. The antenna array is optimized using a particle swarm optimization based method in order to produce a radiation pattern that has the minimum possible side lobe level and the maximum possible gain at the desired direction. The method has been applied to collinear wire-dipole arrays and seems to be suitable for improving the radiation patt...

2014
Yvan Duroc

This paper proposes some approaches to model Ultra Wideband (UWB) antenna arrays. Based on the array factor, often stipulated as not adapted for the description of the properties of UWB arrays in the literature, an analytical expression of the beampattern is developed. The achieved results are coherent with other formulations and empiric studies proposed in the literature. Furthermore, a time-f...

Journal: :رادار 0
امیر اکبری ایاز قربانی

detection of stealth targets calls for employment of high-power radars which itself relies on usage of high-gain antennas like large parabolic reflectors. in the past few years, using of an array with many small reflectors instead of a large reflector antenna has been considered. this method provides enhanced eirp by a factor of n2 where n is the number of array antennas. regarding improvement ...

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