Now showing items 1-10 of 10
A Generalized Analysis of Multiple-Clad Fibers with Arbitrary Step-Indx Profiles and Applications
(Virginia Tech, 1997-04-22)
A generalized analysis of multiple-clad cylindrical dielectric structures with step-index profiles is presented. This analysis yields unified expressions for fields, dispersion equation and cutoff conditions for weakly ...
Helical Antenna Optimization Using Genetic Algorithms
(Virginia Tech, 1999-10-01)
The genetic algorithm (GA) is used to design helical antennas that provide a significantly larger bandwidth than conventional helices with the same size. Over the bandwidth of operation, the GA-optimized helix offers ...
The Spiro-Helical Antenna
(Virginia Tech, 1999-08-10)
<P ALIGN="JUSTIFY">A novel antenna made of a spiral wire wrapped into a larger helical shape is introduced. The geometry of this antenna, which is a doubly helical structure, is fully described by five independent parameters, ...
Study of fade and inter-fade durations in Ku- and Ka- band frequencies using OLYMPUS satellite beacons
(Virginia Tech, 1993-09-03)
<p>Fade and inter-fade duration data obtained from the three beacons at 12, 20, and 30 GHz aboard the OLYMPUS satellite were analyzed.</p> <p>The different types of signal impairments and their causes were highlighted and ...
Dual channel bidirectional wavelength division multiplexing datalink
(Virginia Tech, 1988-06-05)
Wavelength division multiplexing two channels on one fiber is one approach that enables us to make use of the extremely large bandwidth of optical fibers. We start with an analysis of optical fibers, sources, detectors, ...
All-fiber Spectral Filters based on LP01 - LP11 Mode Coupling and Applications in Wavelength Division Multiplexing and Dispersion Compensation
(Virginia Tech, 1996-06-27)
All-fiber spectral filters have the advantages of providing low coupling loss and being readily integrated into fiber-optic networks. Spectral filters made of single-mode identical or dissimilar core parallel fibers provide ...
Log-Periodic Loop Antennas
(Virginia Tech, 1999-07-27)
The Log-Periodic Loop Antenna with Ground Reflector (LPLA-GR) is investigated as a new type of antenna, which provides wide bandwidth, broad beamwidth, and high gain. This antenna has smaller transverse dimensions (by a ...
Coupled-waveguide Fabry-Perot resonator
(Virginia Tech, 1992-12-04)
Gratings With Multiple, Independently Apodized Layers
(Virginia Tech, 1999-03-26)
An index grating is a periodic perturbation of the refractive index in a waveguide's axial direction. Gratings have important roles in optical communication as spectral filters and dispersion compensators. The spectral ...
The spherical helical antenna
(Virginia Tech, 1992-09-16)
The spherical helical antenna is investigated as a new variation of the conventional helical antenna. The spherical helix is a wire antenna in a helix shape that is wound over a spherical surface instead of the standard ...