Now showing items 1-10 of 84
Fundamental-limit perspectives on ultrawideband antennas
(American Geophysical Union, 2009-02-25)
The fundamental-limit theory of antennas provides a theoretical limit to assist in the evaluation of antenna performance in terms of antenna size, fractional impedance bandwidth, and gain. The limit is very useful in ...
Low Frequency Oscillations in A Plasma with Spatially Variable Field-Aligned Flow
(AIP Publishing, 2002-05-01)
The effects of a transverse gradient in the plasma flow velocity parallel to the ambient magnetic field are analyzed. A transverse velocity gradient in the parallel ion flow, even in small magnitude, can increase the ...
Optimal Dispersion Precompensation By Pulse Chirping
(Optical Society of America, 2002-03-01)
For the procedure of dispersion precompensation in fibers by prechirping, we found that there is a maximum distance over which a pulse initially compressed by prechirping can return to its original width. The distance ...
Optical Sectioning For Optical Scanning Holography Using Phase-Space Filtering with Wigner Distribution Functions
(Optical Society of America, 2008-10-01)
We propose a novel optical sectioning method for optical scanning holography, which is performed in phase space by using Wigner distribution functions together with the fractional Fourier transform. The principle of ...
Experiments with compact antenna arrays for MIMO radio communications
(Ieee-Inst Electrical Electronics Engineers Inc, 2006-11-01)
The problem addressed in this study is how to design and test compact antenna arrays for portable Multiple-Input Multiple-Output (MIMO) transceivers.
High Precision Refraction Measurements By Solar Imaging During Occultation: Results From Sofie
(Optical Society of America, 2009-09-01)
A new method for measuring atmospheric refraction angles is presented, with in-orbit measurements demonstrating a precision of +/-0.02 arcsec (+/-0.1 mu rad). Key advantages of the method are the following: (1) Simultaneous ...
Analysis of one-dimensional photonic band gap structures with a liquid crystal defect towards development of fiber-optic tunable wavelength filters
(Optical Society of America, 2003-03-01)
A theoretical analysis of a fiber optical photonic band gap based tunable wavelength filter is presented. The design presented here is based on the quarter wave reflector with a liquid crystal defect layer in the middle ...
On initial enhancement of mesospheric dust associated plasma irregularities subsequent to radiowave heating
(Copernicus Publications, 2008)
Important observational manifestations of subvisible mesospheric dust are Polar Mesospheric Summer Echoes PMSE which are produced by scattering from electron irregularities produced by dust charging. It has been observed ...
On the Theory of Optical Hilbert transform for incoherent objects
(Optical Society of America, 2007-03-01)
The Hilbert transform as been investigated abundantly in coherent imaging. To the best of our knowledge, it is for the first time investigated in the context of incoherent imaging. We present a two-pupil optical heterodyne ...
Autofocusing in optical scanning holography
(Optical Society of America, 2009-12-01)
We present autofocusing in optical scanning holography (OSH) with experimental results. We first record the complex hologram of an object using OSH and then create the Fresnel zone plate (FZP) that codes the object constant ...