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in subjects: "Acoustic Impedance."  
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An improved statistical model for linear antenna input impedance in an electrically large cavity.

Description: This report presents a modification of a previous model for the statistical distribution of linear antenna impedance. With this modification a simple formula is determined which yields accurate results for all ratios of modal spectral width to spacing. It is shown that the reactance formula approaches the known unit Lorentzian in the lossless limit.
Date: March 1, 2005
Creator: Johnson, William Arthur; Warne, Larry Kevin; Jorgenson, Roy Eberhardt & Lee, Kelvin S. H. (ITT Industries/AES, Los Angeles, CA)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Thermally Tunable Acoustic Beam Splitter Based on Poly(vinyl alcohol) Poly(N-isopropylacrylamide) Hydrogel

Description: Article demonstrating a thermally tunable acoustic beam splitter using a poly(vinyl alcohol) poly(N-isopropylacrylamide) hydrogel (PVA-pNIPAM). The nature of PVA-pNIPAM hydrogel offers exceptional temperature-dependent physical properties due to its phase transition around its lower critical solution temperature. The acoustic impedance of the hydrogel can be tuned below, above, or matched to that of water by changing the environmental temperature. An acoustic wave propagating in water can be sp… more
Date: September 13, 2021
Creator: Jin, Yuqi; Zhou, Mi; Choi, Tae-Youl & Neogi, Arup
Item Type: Refine your search to only Article
Partner: University of North Texas
open access

Reduced-volume antennas with integrated high-impedance electromagnetic surfaces.

Description: Several antennas with integrated high-impedance surfaces are presented. The high-impedance surface is implemented as a composite right/left-handed (CRLH) metamaterial fabricated from a periodic structure characterized by a substrate, filled with an array of vertical vias and capped by capacitive patches. Omnidirectional antennas placed in close proximity to the high-impedance surface radiate hemispherically with an increase in boresight far-field pattern gain of up to 10 dB and a front-to-back … more
Date: November 1, 2006
Creator: Forman, Michael A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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