637 research outputs found
Configuration study for a 30 GHz monolithic receive array, volume 1
Gregorian, Cassegrain, and single reflector systems were analyzed in configuration studies for communications satellite receive antennas. Parametric design and performance curves were generated. A preliminary design of each reflector/feed system was derived including radiating elements, beam-former network, beamsteering system, and MMIC module architecture. Performance estimates and component requirements were developed for each design. A recommended design was selected for both the scanning beam and the fixed beam case. Detailed design and performance analysis results are presented for the selected Cassegrain configurations. The final design point is characterized in detail and performance measures evaluated in terms of gain, sidelobe level, noise figure, carrier-to-interference ratio, prime power, and beamsteering. The effects of mutual coupling and excitation errors (including phase and amplitude quantization errors) are evaluated. Mechanical assembly drawings are given for the final design point. Thermal design requirements are addressed in the mechanical design
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Delay-line stabilized microwave oscillator with frequency control
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The technique whereby the frequency of an oscillator is stabilized using an external feedback network incorporating a delay-line is extended in this thesis to provide digital control of the frequency of the oscillator. Novel circuit techniques have been developed and analysed to permit the
implementation of the proposed frequency control technique in a compact format,
suitable for implementation in either hybrid or monolithic microwave integrated circuits. Two new microstrip circuits have been introduced, namely the three-port ring discriminator and the single PIN diode phase shifter. Frequency control of an oscillator is achieved by digitally controlling the
time delay through phase shifters in the feedback path of the oscillator's stabilization circuit. A new microstrip phase shifting circuit has been developed
which has the advantage of requiring only one active switching element to achieve each digital bit of phase change. The circuit has been analysed in detail and results obtained at X-band to support the theoretical predictions. As part of the analysis of this new component, and in order to permit a
greater degree of precision in the design of the phase changes, some new microstrip
design techniques have been introduced. These have led to a more exact design for coupled line phase shifters and to an equivalent circuit to represent the excess phase in microstrip DC breaks. Delay-line stabilization of an oscillator requires the use of a phase sensitive network, or frequency discriminator. Whilst this could be realised on microstrip using conventional circuitry, by interconnecting two hybrid rings, a new circuit component, namely the three-port ring discriminator, was developed
to provide a simpler, more compact solution. A rigorous analysis of the new circuit is presented, and the behaviour verified through measurements over the frequency range 8-12GHz. The new single PIN diode phase shifter has been incorporated in the delay path of a three-port ring discriminator, and used to control the frequency of an oscillator. Results are presented for circuits at X-band which show the degree of frequency stabilization that has been obtained, together with the
reduction in oscillator phase noise. In addition, the original concept of delayline
switching to control the frequency of an oscillator has been extended to yield a further new circuit, based on a three-port ring with a switchedfeed mechanism; results are presented which verify the operation of this new circuit both theoretically and through practical measurement. New techniques for controlling the frequency of microstrip oscillators have thus been established, both theoretically and through practical measurement, which combine simple methods of frequency selection with inherent low-noise performance
Development of versatile high power bounce geometry lasers
This thesis details an investigation into the development of bounce geometry lasers to
achieve a more versatile range of laser characteristics. The bounce geometry has matured
in recent years into a useful solid-state pumping scheme, but its performance has to
date been limited by a number of factors, as well as largely restricted to neodymium
systems. For real-world application, a more versatile range of laser characteristics would
be desirable.
A new design for a bounce geometry amplifier is presented that achieves a symmetric
gain profile and thermal lens by control of the amplifier dimensions. The laser produces
a circular stigmatic TEM00 (M2 < 1:11) beam with 14 W power. When Q-switched, the
design permits versatile control over the repetition rate (single-shot to 480 kHz) with
pulse energies up to 0.45 mJ. The stigmatic design also allows the direct generation
of a Laguerre-Gaussian `vortex' beam, and proves favourable for modelocking with the
nonlinear mirror method.
Several designs are investigated to study power scaling in a master oscillator power
amplifier (MOPA) configuration, including a stigmatic MOPA based on the amplifier
described above, and a chain of multiple power amplifiers. A folded dual-pumped amplifier design is also demonstrated, which reduces the size and complexity of a multi-stage
amplifier and allows power scaling to the 100 W level. Pulse amplification is also investigated,
and a MOPA is optimised for energy extraction by a Q-switched oscillator.
Finally a 3-micron bounce laser is presented using an erbium-doped YSGG gain
medium. Different cavity designs are investigated, and a simple compact cavity is found
to be optimum. Thermal effects are investigated and found to be a limiting factor
on the laser's performance. Quasi-continuous wave pulse energies of up to 15 mJ are
demonstrated, with an average power of up to 430 mW
Methods of analysis of equity securities risk and return : issues and prospects
In terms of capacities and characteristic features of macroeconomic policy in Russia today, the issue of more efficient use of the equity capital market potential where the main tools are shares or equity securities is highly relevant. More efficient use of the capitals of joint stock companies, obtaining reliable information for defining the cost of the business reinforce the need of more detailed theoretical and practical analysis of the equity securities. This is one of the most important prerequisites for creating favorable informational environment and improving the quality of stock market monitoring both at the national and international levels. The author analysed opinions on this issue among Russian and foreign researches, applying the methods of theoretical knowledge and general logic. It systematizes various methodological approaches to the analysis of the equity securities and justifies the need of using the methods of fundamental and technical analysis of equity securities in the Russian context. We pay special attention to studying the rates of return and the risks of the equity securities and look at the opportunities to use this information for developing a scale of rating investment attractiveness of joint stock companies. The recommendations stated in the article may be used for operational management and development of strategic solutions to attract financial resources required for economic growth and modernization of production.peer-reviewe
A Novel Physical Unclonable Function (PUF) Featuring 0.113 FJ/B for IOT Devices
A physically unclonable function (PUF) is useful for authentication purposes and is a function created for its inherent uniqueness and inability of adversaries to duplicate it. In this thesis, a PUF is designed, which is a combination of both digital and analog circuits. This PUF could be designed partially based on a semi-automated approach using custom-built P-cells. The PUF is implemented using novel digital circuits, which have been designed using basic digital gates with a minimal number of transistors. The proposed PUF is developed by the introduction of a layer of multiplexers, which is triggered by a novel SR-latch based model for driving the selection lines. For a higher bit stability, the SR latch is combined with four-way asynchronous circuits, which are a class of coincident flip-flops. The resulted PUF consumes very little power and is suitable for sensors and low power applications. The proposed design was implemented in using the Cadence virtuoso IC 5.1.4 and based on the 180nm TSMC transistor models. The energy consumption and area of the proposed PUF is shown to be equal to 0.1132 fJ/bit and 8.03, which is considerably lower than the state of the arts. The uniqueness and reliability of the proposed PUF are estimated to be 48.66% and 99.33%
Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 2
This report summarizes and documents the results of the 12-month phase 1 work effort. The objective of phase 1 was to establish the conceptional definition of the laser atmospheric wind sounder (LAWS) sensor system, including accommodations analyses to ensure compatibility with the Space Station Freedom (SSF) and the Earth Observing System (EOS) Polar Orbiting Platform (POP). Various concepts were investigated with trade studies performed to select the configuration to be carried forward to the phase 2 Preliminary Design Definition. A summary of the LAWS system and subsystem trade studies that were performed leading to the baseline design configuration is presented in the appendix. The overall objective of the LAWS Project is to define, design, and implement an operational space based facility, LAWS, for accurate measurement of Earth wind profiles. Phase 1 addressed three major areas: (1) requirements definition; (2) instrument concepts and configurations; and (3) performance analysis. For the LAWS instrument concepts and configurations, the issues which press the technological state of the art are reliable detector lifetime and laser performance and lifetime. Lag angle compensation, pointing accuracy, satellite navigation, and telescope design are significant technical issues, but they are considered to be currently state of the art. The primary issues for performance analysis concern interaction with the atmosphere in terms of backscatter and attenuation, wind variance, and cloud blockage. The phase 1 tasks were formulated to address these significant technical issues and demonstrate the technical feasibility of the LAWS concept. Primary emphasis was placed on analysis/trade and identification of candidate concepts. Promising configurations were evaluated for performance, sensitivities, risks, and budgetary costs. Lockheed's baseline LAWS configuration is presented
The Los Alamos Trapped Ion Quantum Computer Experiment
The development and theory of an experiment to investigate quantum
computation with trapped calcium ions is described. The ion trap, laser and ion
requirements are determined, and the parameters required for quantum logic
operations as well as simple quantum factoring are described.Comment: 41 pages, 16 figures, submitted to Fortschritte der Physi
Optics and Quantum Electronics
Contains table of contents for Section 2 and reports on eighteen research projects.National Science Foundation (Grant EET 87-00474)Joint Services Electronics Program (Contract DAAL03-86-K-0002)Joint Services Electronics Program (Contract DAALO3-89-C-0001)Charles Stark Draper Laboratory (Grant DL-H-285408)Charles Stark Draper Laboratory (Grant DL-H-2854018)National Science Foundation (Grant EET 87-03404)National Science Foundation (Grant ECS 84-06290)U.S. Air Force - Office of Scientific Research (Contract F49620-88-C-0089)AT&T Bell FoundationNational Science Foundation (Grant ECS 85-52701)National Institutes of Health (Grant 5-RO1-GM35459)Massachusetts General Hospital (Office of Naval Research Contract N00014-86-K-0117)Lawrence Livermore National Laboratory (Subcontract B048704
Optics and Quantum Electronics
Contains table of contents for Section 2 and reports on twenty research projects.Charles S. Draper Laboratory Contract DL-H-404179Joint Services Electronics Program Contract DAALO3-89-C-0001National Sciences Foundation Grant EET 87-00474National Science Foundation Grant EET 88-15834U.S. Air Force - Office of Scientific Research Contract F49620-88-C-0089National Science Foundation Grant ECS 85-52701International Business Machines CorporationMassachusetts General Hospital Contract N00014-86K-0117National Institutes of Health Grant 2-RO1-GM35459U.S. Department of Energy Grant DE-FG02-89-ER14012Lawrence Livermore National Laboratory Subcontract B04870
Optics and Quantum Electronics
Contains table of contents for Section 3 and reports on twenty-one research projects.Joint Services Electronics Program Contract DAAL03-89-C-0001Joint Services Electronics Program Contract DAAL03-92-C-0001U.S. Air Force - Office of Scientific Research Contract F49620-91-C-0091Charles S. Draper Laboratories Contract DL-H-441629MIT Lincoln LaboratoryCharles S. Draper Laboratories, Inc. Contract DL-H-418478Fujitsu LaboratoriesNational Science Foundation Grant ECS 90-12787National Center for Integrated PhotonicsNational Science Foundation Grant EET 88-15834National Science Foundation Grant ECS 85-52701U.S. Air Force - Office of Scientific Research Contract F49620-88-C-0089U.S. Navy - Office of Naval Research Contract N00014-91-C-0084U.S. Navy - Office of Naval Research Grant N00014-91-J-1956Johnson and Johnson Research GrantNational Institutes of Health Contract 2-R01-GM35459U.S. Department of Energy Grant DE-FG02-89 ER14012-A00
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