نتایج جستجو برای: antennas

تعداد نتایج: 14619  

2017
JOHAN MALMSTRÖM

This thesis presents research on methods for calculating the mutual coupling between antennas. The mutual coupling between antennas is a measure of the amount of energy transmitted from one antenna that is received by another, and is a key parameter when installing antennas on platforms, such as aircraft. To avoid interference between systems connected to the antennas, the mutual coupling shoul...

Journal: :Advanced materials 2010
Masahiro Kubo Xiaofeng Li Choongik Kim Michinao Hashimoto Benjamin J Wiley Donhee Ham George M Whitesides

www.MaterialsViews.com C O M Stretchable Microfl uidic Radiofrequency Antennas M U N I By Masahiro Kubo , Xiaofeng Li , Choongik Kim , Michinao Hashimoto , Benjamin J. Wiley , Donhee Ham , and George M. Whitesides * C A IO N This paper describes a new method for fabricating stretchable radiofrequency antennas. The antennas consist of liquid metal (eutectic gallium indium alloy, EGaIn [ 1 , 2 ] ...

2012
Yvan Duroc

1.1 Brief history of antennas and their evolution The antenna is an essential part of any wireless system as it is the component providing transition between a guided wave and a free-space wave. According to the IEEE standard definitions of terms for antennas (IEEE, 1993), an antenna is defined as a means for radiating or receiving radio waves. During the period 1885-1900, some pioneers invente...

2008
F. Tong P. R. Shepherd

The impact of distributed antennas using co-phasing transmission diversity on downlinkCDMAchannels is examined.An expression is derived that demonstrates that uniform downlink signal-to-interference ratio across users can be achieved by appropriately weighting the distribution of transmit powers across distributed antennas. The capacity of a downlink CDMA system employing distributed antennas w...

2012
Sandhya Sharma Abhishek Sharma

⎯ This paper is dedicated to simulate a rectangular patch antenna by using the software HFSS. Microstrip or patch antennas are becoming increasingly useful because they can be printed directly onto a circuit board. Microstrip antennas are becoming very widespread within the mobile phone market. Patch antennas are low cost, have a low profile and are easily fabricated.

2014
Harshal Nigam Mithilesh Kumar

In this paper, compact antenna has been designed that can be implemented in a 2X2 Multiple-Input MultipleOutput (MIMO) system. A microstrip patch antenna fed by a microstrip line is designed for a frequency of 2.4 GHz used for industrial, scientific and medical (ISM) band applications. Polarization diversity of the two antennas is used to construct independent and uncorrelated signals on each a...

2007
S. R. Ostadzadeh M. Soleimani M. Tayarani

In this paper, the previously introduced fuzzy modeling method is used to model the input impedance of two coupled dipole antennas in the echelon form. The initial data of two coupled dipole antennas in the parallel and collinear form, which are required for the model, are obtained using the MoM (Method of Moments). Then, the knowledge of two coupled dipole antennas in the echelon form is easil...

Journal: :IEEE Journal on Selected Areas in Communications 1998
Siavash M. Alamouti

This paper presents a simple two-branch transmit diversity scheme. Using two transmit antennas and one receive antenna the scheme provides the same diversity order as maximal-ratio receiver combining (MRRC) with one transmit antenna, and two receive antennas. It is also shown that the scheme may easily be generalized to two transmit antennas and M receive antennas to provide a diversity order o...

Journal: :IEEE Trans. Mob. Comput. 2002
Jeffrey E. Wieselthier Gam D. Nguyen Anthony Ephremides

We consider ad hoc wireless networks that use directional antennas and have limited energy resources. To explore quantitatively the advantage offered by the use of directional antennas over the case of omnidirectional antennas, we consider the case of connection-oriented multicast traffic. Building upon our prior work on multicasting algorithms, we introduce two protocols that exploit the use o...

2006
C. Gandy Chris Gandy

Much of the work of Spectrum Planning Group is based on well established principles of ‘antennas and propagation’. Propagation matters have received a lot of attention over the years and much has been written on the topic but the ‘antennas’ part, although arguably simpler, may lack a suitable written reference that gathers much of the relevant material into one place. The primary purpose of thi...

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