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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Pattern synthesis of linear and circular arrays.

Wu, Chuang-Jy. January 1962 (has links)
No description available.

Nanocoax Arrays for Sensing Devices

Rizal, Binod January 2014 (has links)
Thesis advisor: Michael J. Naughton / We have adapted a nanocoax array architecture for high sensitivity, all-electronic, chemical and biological sensing. Arrays of nanocoaxes with various dielectric annuli were developed using polymer replicas of Si nanopillars made via soft lithography. These arrays were implemented in the development of two different kinds of chemical detectors. First, arrays of nanocoaxes constructed with different porosity dielectric annuli were employed to make capacitive detectors for gaseous molecules and to investigate the role of dielectric porosity in the sensitivity of the device. Second, arrays of nanocoaxes with partially hollowed annuli were used to fabricate three-dimensional electrochemical biosensors within which we studied the role of nanoscale gap between electrodes on device sensitivity. In addition, we have employed a molecular imprint technique to develop a non-conducting molecularly imprinted polymer thin film of thickness comparable to size of biomolecules as an "artificial antibody" architecture for the detection of biomolecules. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.

Antenna array processing in wireless communications and radar systems /

Lin, Xiaotong, January 2000 (has links)
Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 146-147).

Robust minimum variance beamforming with multiple response constraints

Robinson, Michael, 1982- January 2007 (has links)
Conventional beamformers can be sensitive to mismatches between presumed and actual steering vectors of the signal-of-interest. A recently proposed class of robust beamformers aim to counteract this problem by using a non-attenuation constraint inside a single hypersphere centered at the presumed steering vector of the signal-of-interest. In an effort to strike a balance between robustness to steering vector error and interference-plus-noise suppression, we propose in this manuscript to use multiple concentric hyperspheres instead of one with different degrees of protection in each. We derive several useful properties of this multiply constrained beamformer and use numerical simulations to show that using two constraints yields improved signal-to-interference-plus-noise-ratio compared to one constraint in certain scenarios, particularly at a large input signal-to-noise-ratio. / The manuscript also includes an overview of conventional beamforming, the mismatch problem and previously proposed robust beamformers.

Array pattern synthesis and hardware realisation for active communication arrays.

Lange, Volker Wolfgang. January 1969 (has links) (PDF)
Thesis (M.E. 1971) from the Faculty of Engineering, University of Adelaide.

Analysis of phased array antenna radiation patterns including mutual coupling /

Kelley, David Frederick, January 1990 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 135-137). Also available via the Internet.

The design of a log periodic microstrip antenna array

Mulyanto, Agus. January 1978 (has links)
Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 161-164).

Toepassing van komplekse ruimtelike interpolasie in rignetantennes

Van Wyk, Michael Antonie 02 June 2014 (has links)
M.Ing. (Electrical & Electronic Engineering) / A new method is presented for significantly reducing the large number of complex computations associated with beamforming, -steering and adaption in large antenna arrays. The structure is based on linear interpolation over (L +1) array elements implying that the (L -1) antenna or sensor signals in-between are added with simple weights to the neighbouring antenna signals for beamforming and/or steering. If L is chosen to be a power of two, these simple weights become h t, i, etc. or multiples thereof. It is easily implemented on a microcomputer with shift operations and can be performed in reduced time compared to byte and word multiplications. The maximum value of L that can be used increases with decreasing mainlobe width. A problem that arises when performing beam steering on such an array is that the level of the sidelobes-more specifically the suppressed mainlobe images which are the result of the interpolation process-increase with increasing steering angle. The maximum.steering angle is determined by the constraints placed on the sidelobe level. To be able to steer wider than the maximum steering angle, it becomes necessary to apply complex interpolation to the array. Complex interpolation refers to the steering of the interpolator beam. The interpolation process reduces the number of weights. This results in a significant reduction of the number of computations associated with adaptive beamforming algorithms.

Investigation of planar arrays of superheated superconducting spheres

Meagher, Gail Aileen January 1991 (has links)
The Planar Array of Superheated Spheres (PASS) has been put forward as a possible neutrino and dark matter detector. This work has concentrated on the characteristics of a 100x100 array of spheres, of indium or tin. The superheated-supercooled hysteresis curves, for magnetic fields ranging from the earth's to 16 mT, have been measured in a pumped ⁴He cryostat using an RF-SQUID readout system. Individual superconducting to normal grain flips were recorded with the indium sample due to exposure to 60 keV gammas. The effect of gravity on the shape and structure of the spheres was tested by remelting arrays in a microgravity environment. The hysteresis curves obtained for these arrays showed a decreased transition width, i.e. the temperature difference from where all the spheres are superconducting to where they are all normal. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Robust minimum variance beamforming with multiple response constraints

Robinson, Michael, 1982- January 2007 (has links)
No description available.

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