1 The Equations of Gas Dynamics 2 Magnetoplasma Dynamics 3 Waves in Magnetoplasmas 4 Magnetoplasma Stability 5 Transport in Magnetoplasmas 6 Extensions of Theory Bibliography Index

Physics of plasmas

https://romisatriawahono.net/lecture/rm/survey/computer%20vision/Mukhopadhyay%20-%20Hough%20Transform%20-%202014.pdf

A survey of Hough Transform

The advancement in wireless communications requires the integration of multiple radios into a single platform to maximize connectivity. In this paper, the design process of reconfigurable antennas is discussed. Reconfigurable antennas are proposed to cover different wireless services that operate over a wide frequency range. They show significant promise in addressing new system requirements. They exhibit the ability to modify their geometries and behavior to adapt to changes in surrounding conditions. Reconfigurable antennas can deliver the same throughput as a multiantenna system. They use dynamically variable and adaptable single-antenna geometry without increasing the real estate required to accommodate multiple antennas. The optimization of reconfigurable antenna design and operation by removing unnecessary redundant switches to alleviate biasing issues and improve the system's performance is discussed. Controlling the antenna reconfiguration by software, using Field Programmable Gate Arrays (FPGAs) or microcontrollers is introduced herein. The use of Neural Networks and its integration with graph models on programmable platforms and its effect on the operation of reconfigurable antennas is presented. Finally, the applications of reconfigurable antennas for cognitive radio, Multiple Input Multiple Output (MIMO) channels, and space applications are highlighted.

Reconfigurable Antennas: Design and Applications

A simple analytical model of the wireless infrared communication channel in indoor environments is presented. The infrared signal is modeled as the combination of a diffuse component and a line-of-sight (LOS) or direct component. For the diffuse component alone, the properties of the channel are found using Ulbricht's integrating sphere. When a LOS component is also present, the transfer function depends upon the Rician factor K given by the ratio of the electrical power in the LOS and diffuse signals after the detector. For small K, the transfer function shows notches down to low frequencies, but due to the nature of light never for zero frequency. We confirm that a K-factor /spl ges/13 dB is required also in infrared wireless links in order to support distortionless data transmission beyond 100 Mbit/s. Increasing the directivity at the receiver and/or at the transmitter improves the effective value of K. Here, we show that a moderate directivity will be sufficient for high-speed infrared communication in typical indoor scenarios.

/pdf/a-physical-model-of-the-wireless-infrared-communication-565jx734u0.pdf

A physical model of the wireless infrared communication channel

https://espace.library.uq.edu.au/view/UQ:7736/SIGPRO-3123.pdf

IF estimation for multicomponent signals using image processing techniques in the time-frequency domain

In this letter, novel designs for optically switching the resonant frequency of a microstrip patch antenna via photoconductive switches are proposed, and design considerations for maximizing frequency switching ratio with finite photo-conductance are investigated. Furthermore, a configuration to switch the resonant frequency with low switch conductance is proposed for cheap and easy fabrication of a frequency-reconfigurable antenna that can be operated with low optical power. Experimental verification of the low-power configuration is presented.

Optically Controlled Frequency-Reconfigurable Microstrip Antenna With Low Photoconductivity

This paper presents the numerical analysis of an EDFA operating in the saturation regime. Erbium-doped silica fibers with higher numerical aperture and erbium ion concentration can yield high output signal powers. The study of multichannel signal amplification in a high-power EDFA shows that the gain excursion in a particular channel lies within 0.5 dB as long as the number of channels dropped does not exceed a certain limit. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 64–70, 2002.

Analysis of high-power EDFA operating in saturated regime at λ=1530 nm and its performance evaluation in DWDM systems

Although corona is a phenomenon known, measured and analyzed for many decades, there are still some aspects which could be further explored; one of them being, analysis of the effect of magnetic field on the corona process and its measurement. This paper addresses the phenomenon from a physical level, and the effect of magnetic field and its influence on the ultra-high frequency (UHF) measurement is analyzed from a plasma perspective. Calculations are made using various formulae, pertaining to plasma, to identify the influence of magnetic field on corona. The theory developed is backed by experimental work involving UHF based measurements. The effect of the magnetic field in the form of gyro-frequency influences the UHF measurement. Magnetic field is seen to reduce the power spectral density of corona in the 650-800 MHz band.

Study of the effects of alternating magnetic field on point-plane corona

We analyze the dispersion characteristics of an optical fiber having linear chirp type refractive index profile. The chirp type profile is general in nature and by controlling the profile parameters, one can obtain a wide range of profiles from simple step index to complex multiple cladded type. The problem is treated as an optimization problem in the profile parameter space. It is shown that a variety of dispersion characteristics can be realized with proper optimization of the profile parameters. Linear finite element method (LFEM) is employed for computing the modal fields and propagation constants. Tolerance analysis of the fiber dispersion characteristics and bending loss calculation are also carried out.

R. K. Shevgaonkar

Papers

Optically Controlled Frequency-Reconfigurable Microstrip Antenna With Low Photoconductivity

Analysis of high-power EDFA operating in saturated regime at λ=1530 nm and its performance evaluation in DWDM systems

Study of the effects of alternating magnetic field on point-plane corona

Dispersion characteristics of an optical fiber having linear chirp refractive index profile

A fresh look at the Hough transform