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in subjects: "Antennas."

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Time reversal signal processing for communication.

Time-reversal is a wave focusing technique that makes use of the reciprocity of wireless propagation channels. It works particularly well in a cluttered environment with associated multipath reflection. This technique uses the multipath in the environment to increase focusing ability. Time-reversal can also be used to null signals, either to reduce unintentional interference or to prevent eavesdropping. It does not require controlled geometric placement of the transmit antennas. Unlike existing… more

Date: September 1, 2011

Creator: Young, Derek P.; Jacklin, Neil; Punnoose, Ratish J. & Counsil, David T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Airbourne WiFi Networks Through Directional Antenna: An Experimental Study

In situations where information infrastructure is destroyed or not available, on-demand information infrastructure is pivotal for the success of rescue missions. In this paper, a drone-carried on demand information infrastructure for long-distance WiFi transmission system is developed. It can be used in the areas including emergency response, public event, and battlefield. The WiFi network can be connected to the Internet to extend WiFi access to areas where WiFi and other Internet infrastructu… more

Date: May 2015

Creator: Gu, Yixin

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Combline antenna modeling for plasma heating

The combline antenna for plasma heating, as proposed by General Atomics, has unique potential for solving many plasma drive problems. The benefit of the combline design is the utilization of the coupling between elements that avoids a more cumbersome multidrive system. This design is being investigated using computational EM modeling codes in the 100-400 MHz band using resources at General Atomics and LLNL. Preliminary experimental results, using a combline mockup, agree well with 3D modeling e… more

Date: May 15, 1995

Creator: Nelson, S. D.; Kamin, G. & Van Maren, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A TEM-horn antenna with dielectric lens for fast impulse response

We designed and constructed a pair of TEM-horn antennas specifically for the very fast time-domain boresight response. Two physical topologies were made. A printed-board configuration has much slower transient response, which we think is due to pulse-smearing of the antenna currents in the dielectric substrate of the printed wiring boards. The solid state version has a 20 ps transition duration response in the main beam endfire (boresight) direction, which is the fastest we have seen to date. A… more

Date: December 31, 1995

Creator: Aurand, J. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Pair-Trawl Detection of PIT-Tagged Juvenile Salmonids Migrating in the Columbia River Estuary, 2008 Report of Research.

In 2008, we sampled migrating juvenile Pacific salmonids Oncorhynchus spp. tagged with passive integrated transponder (PIT) tags using a surface pair trawl in the upper Columbia River estuary (rkm 61-83). The cod-end of the trawl was replaced with a cylindrical PIT-tag detection antenna with an 86-cm-diameter fish-passage opening and two detection coils connected in series. The pair trawl was 105 m long with a 91.5-m opening between the wings and a sample depth of 4.9 m. Also during 2008, we fi… more

Date: June 3, 2009

Creator: Magie, Robert J.; Morris, Matthew S. & Ledgerwood, Richard D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Using the Antenna Effect as a Spectroscopic Tool; Photophysics and Solution Thermodynamics of the Model Luminescent Hydroxypyridonate Complex [EuIII(3,4,3-LI(1,2-HOPO))]-

While widely used in bioassays, the spectrofluorimetric method described here uses the antenna effect as a tool to probe the thermodynamic parameters of ligands that sensitize lanthanide luminescence. The Eu3+ coordination chemistry, solution thermodynamic stability and photophysical properties of the spermine-based hydroxypyridonate octadentate chelator 3,4,3-LI(1,2-HOPO) are reported. The complex [EuIII(3,4,3-LI(1,2-HOPO))]- luminesces with a long lifetime (805 mu s) and a quantum yield of 7.… more

Date: November 20, 2009

Creator: Abergel, Rebecca J.; D'Aleo, Anthony; Ng Pak Leung, Clara; Shuh, David & Raymond, Kenneth

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Accuracy and optimization of tracking systems

No Description Available.

Date: August 1, 1973

Creator: Sanford, R.L.

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

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Nonphotochemical Hole-Burning Studies of Energy Transfer Dynamics in Antenna Complexes of Photosynthetic Bacteria

This thesis contains the candidate's original work on excitonic structure and energy transfer dynamics of two bacterial antenna complexes as studied using spectral hole-burning spectroscopy. The general introduction is divided into two chapters (1 and 2). Chapter 1 provides background material on photosynthesis and bacterial antenna complexes with emphasis on the two bacterial antenna systems related to the thesis research. Chapter 2 reviews the underlying principles and mechanism of persistent… more

Date: August 1, 2002

Creator: Matsuzaki, Satoshi

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

open access

Arbitrary Order Hierarchical Bases for Computational Electromagnetics

We present a clear and general method for constructing hierarchical vector bases of arbitrary polynomial degree for use in the finite element solution of Maxwell's equations. Hierarchical bases enable p-refinement methods, where elements in a mesh can have different degrees of approximation, to be easily implemented. This can prove to be quite useful as sections of a computational domain can be selectively refined in order to achieve a greater error tolerance without the cost of refining the en… more

Date: December 20, 2002

Creator: Rieben, R N; White, D & Rodrigue, G

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Solution-processed dielectric films and Au RF antenna for temperature sensing

Article discusses how sensing temperature is important for a wide variety of applications such as control systems and instrumentation which are integral to various industrial sectors and in research settings. The authors emphasize the importance of high sensitivity and reliable methods using a frequency-based approach for detecting temperature changes. In their study, Au rectangular single-arm spiral antennas with varying sizes were fabricated and RF S-parameter measurements were conducted over… more

Date: October 3, 2022

Creator: Aryal, Sujan; Biswas, Dipon K.; Mehta, Ravindra K.; Mahbub, Ifana & Kaul, Anupama

Item Type: Article

Partner: UNT College of Engineering

open access

Interference Mitigation in Transmitted-Reference UWB Receivers

The transmitted-reference (TR) ultra-wideband transceivers [4] have recently become increasingly popular for their simplicity, capability to reduce the stringent UWB timing requirements, and robust performance in multipath channels. However, the performance of TR receivers is considerably limited by the severity of noise-on-noise component introduced by various types of channel noise such as additive white Gaussian noise (AWGN) or narrowband interference (NBI) on the transmitted signal [6]. It … more

Date: January 14, 2004

Creator: Spiridon, A.; Nekoogar, F. & Dowla, F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Quench antenna studies of mechanical and quench performance in Fermilab interaction region quadrupoles for LHC

As part of the US-LHC collaboration, Fermilab has built and tested seventeen high gradient quadrupole magnets, assembled into nine cryostats, for installation at the Large Hadron Collider Interaction Regions. Most of these magnets have only quarter coil voltage taps for quench characterization, but the magnetic measurement warm bore is instrumented with a quench antenna for localization and characterization. We report on studies using the quench antenna for pre-production prototype (with extens… more

Date: September 1, 2005

Creator: Tartaglia, M. A.; Feher, S.; Hocker, A.; Lamm, M.; Schlabach, P.; Sylvester, C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Electrical optimization of the ICH antenna array for ITER

The present design of the ITER ICH antenna array comprises two poloidal by four toroidal current elements in each of four ports.Each current element forms a resonant double loop (RDL) with power fed to a pretuned matchpoint on the strap; the matching is accomplished using slow-wave transmission lines as adjustable shorted-stub tuners on either end of the current strap. The power requirement is 12.5 MW per port over the frequency range of 40--70 MHz, with extended operation to 80 MHz desirable. … more

Date: August 1, 1997

Creator: Ryan, P. M.; Swain, D. W.; Carter, M. D.; Taylor, D. J. & Bosia, G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Engineering design of the ITER RF systems

Parallel conceptual design efforts for auxiliary heating systems on ITER are being carried out in both the electron cyclotron range of frequencies (ECRF) and ion cyclotron range of frequencies (ICRF). These systems are required to deliver a minimum of 50 MW of CW power to the plasma for the primary purpose of heating and the secondary purpose of current drive. Current designs of the two systems are presented and the primary design issues are discussed.

Date: December 31, 1994

Creator: Makowski, M.; Bosia, G.; Nagashima, T. & Remsen, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Folded Compact Range Development and Coherent Change Detection Measurement Project

A novel, folded compact range configuration has been developed at the Sandia National Laboratories compact range antenna and radar cross section measurement facility, operated by the Radar/Antenna Department 2343, as a means of performing indoor, environmentally-controlled, far-field simulations of synthetic aperture radar (SAR) coherent change detection (CCD) measurements. This report describes the development of the folded compact range configuration, as well as the initial set of coherent ch… more

Date: March 1, 1995

Creator: Sorensen, K.W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The technology of ICRF systems

The technology of ICRF systems has made substantial gains in the past few years. The total power levels have increased from the 5-MW level to greater than 20 MW; the pulse lengths have increased from the 100-msec level to 30 seconds. Recently, fast wave current drive (FWCD) has been demonstrated using phased arrays of ICRF antennas. In order to achieve such large gains, substantial changes and improvements were needed in the level of design analysis, fabrication techniques, and system controls.

Date: December 1995

Creator: Baity, F. W.; Barber, G. C. & Bigelow, T. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Development of fast wave systems tolerant of time-varying loading

A new approach to fast wave antenna array design based on the traveling wave antenna has been successfully demonstrated on the JFT-2M tokamak. A traveling wave antenna is powered though a single feed and the power flow from element to element is only via mutual reactive coupling. A combine is a particular type of traveling wave antenna, in which only the fed element and the element at the downstream end of the array are connected to vacuum feed troughs, while the intermediate elements are termi… more

Date: June 1, 1996

Creator: Pinsker, R. I.; Moeller, C. P.; Petty, C. C. & Phelps, D. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Using Vector Spherical Harmonics to Compute Antenna Mutual Impedance from Measured or Computed Fields

No Description Available.

Date: September 6, 2000

Creator: BROCK,BILLY C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Helicon Plasma Source Configuration Analysis by Means of Density Measurements

Initial results have been obtained from operation of a helicon plasma source built to conduct optimization studies for space propulsion applications. The source features an easily reconfigurable antenna to test different geometries. Operating with He as the source gas, peak densities >= 1.6X10{sup 19} m{sup -3} have been achieved. Radial and axial plasma profiles have been obtained using a microwave interferometer that can be scanned axially and a Langmuir probe. The source will be used to i… more

Date: November 13, 1999

Creator: Angrilli, F.; Barber, G. C.; Carter, M. D.; Goulding, R. H.; Maggiora, R.; Pavarin, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

First demonstration of a traveling wave antenna in a tokamak and relevance to the JFT-2M combline

First observations of a traveling wave antenna (TWA) in a tokamak are reported. For a fractional bandwidth ({delta}{omega}/{omega}) of about 20%, TWA experiments using a four-element antenna in DIII-D showed less than 1% reflected power and excellent stability of the phase velocity of the launched wave -- even during giant ELMs. The power radiated into the plasma varied from about 40% during ELM-free H-mode to almost 90% during L-mode and ELMing H-mode. Theoretical modeling validated by these l… more

Date: June 1, 1995

Creator: Phelps, D. A.; Moeller, C. P.; Ikezi, H. & Chiu, S. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ICRF heating on helical devices

Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Results… more

Date: September 1, 1995

Creator: Rasmussen, D.A.; Lyon, J.F. & Hoffman, D.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ICRF heating on helical devices

Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7-AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Result… more

Date: September 1, 1995

Creator: Rasmussen, D. A.; Lyon, J. F.; Hoffman, D. J.; Murakami, M.; England, A. C.; Wilgen, J. B. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design options for an ITER ion cyclotron system

Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-separatrix distance of 10--20 cm. Designs of a conventional strap launcher and a folded waveguide launcher than can meet the new requirements are presented.

Date: September 1, 1995

Creator: Swain, D. W.; Baity, F. W.; Bigelow, T. S.; Ryan, P. M.; Goulding, R. H.; Carter, M. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design of fast tuning elements for the ITER ICH system

The coupling between the ion cyclotron (IC) antenna and the ITER plasma (as expressed by the load resistance the antenna sees) will experience relatively fast variations due to plasma edge profile modifications. If uncompensated, these will cause an increase in the amount of power reflected back to the transmitter and ultimately a decrease in the amount of radio frequency (rf) power to the plasma caused by protective suppression of the amount of rf power generated by the transmitter. The goals … more

Date: May 1, 1996

Creator: Swain, D. W. & Goulding, R. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department