Engineering Commons^™

A Narrow-Wall Complementary-Split-Ring Slotted Waveguide Antenna For High-Power-Microwave Applications, Xuyuan Pan

Electrical and Computer Engineering ETDs

A narrow-band, rugged, complementary-split-ring (CSR) slotted waveguide antenna (SWA) with significant size reduction is presented. The antenna is to be vertically front mounted on a land vehicle, with a horizontally polarized fan-beam radiation pattern. The radiation characteristics of a CSR slot in the narrow-wall of a rectangular waveguide are studied for the first time in this work. Both simulation and experimental results show that the complementary-split-ring slot radiates a linearly polarized wave with a total efficiency and gain close to those of conventional longitudinal slots, while the proposed CSR slots have a maximal outer diameter of 0.23λ₀, much …

Pulse Sharpening Circuit For Explosive Emission Cathode Driver, Nicholas D. Kallas

Electrical and Computer Engineering ETDs

Explosive field emission cathodes (EEC), used for the generation of relativistic electron beams, require short rise-time high-voltage pulses in order to minimize the extraction of off-energy electrons. To this end, a rise-time sharpening circuit has been developed at the Los Alamos National Laboratory (LANL). The circuit consists of a 7 nF water-filled peaking capacitor with an integrated self-breakdown switch designed to operate up to -300 kV. This unit is intended to reduce the rise-time of a 4-stage Type-E PFN Marx Generator that will be used to study operational characteristics of velvet cathodes. Simulations of the peaking circuit show a reduction …

Novel Compact Narrow-Linewidth Mid-Infrared Lasers For Sensing Applications, Behsan Behzadi

Optical Science and Engineering ETDs

The mid-infrared (2-14 μm) spectral region contains the strong absorption lines of many important molecular species, which make this region crucial for several well-know applications such as spectroscopy, chemical and biochemical sensing, security, and industrial monitoring. To fully exploit this region through absorption spectroscopic techniques, compact and low-cost narrow-linewidth (NLW) mid-infrared (MIR) laser sources are of primary importance.

This thesis is focused on three novel compact NLW MIR lasers: demonstration and characterization of a new glass-based spherical microlaser, investigation of the performance of a novel fiber laser, and the design of a monolithic laser on a silicon chip. Starting with …

Split-Ring Resonator Waveguide Structure Characterization By Simulations, Measurements And Linear Time-Invariant Modeling, Mohamed Aziz Hmaidi

Electrical and Computer Engineering ETDs

Interest in Metamaterials has been rising drastically in the recent years as they have been used in several optical and RF applications, from antennas to perfect lenses and pulsed power devices. Nevertheless, the time-behavior of metamaterials remains opaque and poorly understood.

In this research work, characterization of a metamaterial structure in time and frequency-domain was made through simulations and experiments. The structure consists in a series of edge-side coupled Split Ring Resonators (SRRs) in a below cutoff waveguide. A linear time invariant model of distributed elements has been elaborated as well in an attempt to approach the structure’s behavior. The …

Experimental Testing Of A Metamaterial Slow Wave Structure For High-Power Microwave Generation, Kevin Aaron Shipman

Electrical and Computer Engineering ETDs

Experimental Testing of a Metamaterial Slow Wave Structure for High-Power Microwave Generation

by

Kevin Aaron Shipman

B.S., Exercise Science, University of New Mexico, 2008

A.S., Mathematics, San Juan College, 2014

M.S., Electrical Engineering, University of New Mexico, 2018

Abstract

A high-power L-band microwave source has been developed using a metamaterial (MTM) to produce a biperiodic double negative slow wave structure (SWS) for interaction with an electron beam. The beam is generated by a ~700 kV, ~6 kA short pulse (~ 10 ns) electron beam accelerator. The design of the metamaterial SWS (MSWS) consists of a cylindrical waveguide, loaded with alternating …

An Exploration Of The Optical Detection Of Ionizing Radiation Utilizing Modern Optics Technology, Sean D. Fournier, Adam Hecht, Cassiano De Oliveira, Jeffrey B. Martin, Richard K. Harrison, Charles Potter

Nuclear Engineering ETDs

Modern ultraviolet (UV) cameras, when combined with UV-transmitting lenses/filter arrangements, can be used to detect radiation dose in air. Ionizing radiation excites nitrogen molecules in ambient air, the resulting decay includes weak emission of ultraviolet photons. Previous work has proven this phenomenon is detectable using highly-sensitive electronically cooled cameras traditionally used in astronomy for low-background imaging. While the ability to detect the presence of radiation (i.e. qualitative measurement) has been demonstrated at Sandia National Laboratories, there are several challenges in correlating images to known dose-fields (quantitative measurement). These challenges include: a low signal to background ratio, interferences due to electronic …

Antennas For Wv Band Applications, Firas Ayoub

Electrical and Computer Engineering ETDs

This dissertation focuses on designing, fabricating and testing antennas that are suitable for operation within the V/W bands. In particular, this work focuses on the design of slotted rectangular waveguide antenna arrays and cross slotted waveguide fed horn antennas. These structures are known for their high efficiency and high circularly polarized gain that can be implemented in satellite and terrestrial communication links. In addition, such designs can be implemented in radar applications that operate infrequency bands around 72 GHz or 84 GHz bands. Such antenna structures are inexpensive to fabricate since they can simply be machined using high precision conventional …