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Proceedings Paper

New method of measurement of complex permittivity and permeability with a W-band unbalanced quasi-optical waveguide bridge spectrometer
Author(s): Mohammed N. Afsar; Igor I. Tkachov; Karen N. Kocharyan
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Paper Abstract

A new method of precision measurements of dielectric permittivity and loss tangent of medium and highly absorbing materials over an extended W-band frequency range is developed. A quasi-optical-waveguide spectrometer is designed and constructed. An electronically sweeping backward wave oscillator (BWO) is used as the source of tunable coherent radiation in the frequency range 70 to 118 GHz for the spectrometer. The high output power of BWO, precision waveguide and quasi-optical components and an extra high sensitivity specially constructed liquid helium cooled InSb detector enable adequate energy throughput in transmission for the first time for highly absorbing materials. A simple quasi- optical-waveguide transmission measurement set up of the spectrometer provides the transmittance measurement from which the loss tangent and imaginary part of dielectric permittivity spectra of materials are evaluated very accurately. A quasi- optical-waveguide bridge configuration of the spectrometer provides the measurement of the phase retardation through a specimen from which the real part of dielectric permittivity spectrum are determined with high accuracy. Data for acrylic (medium absorbing), CVD grown low resistivity germanium, General Diode Corp. low resistivity silicon (very absorbing) and thick layer of water are presented and compared.

Paper Details

Date Published: 13 November 1998
PDF: 12 pages
Proc. SPIE 3465, Millimeter and Submillimeter Waves IV, (13 November 1998); doi: 10.1117/12.331179
Show Author Affiliations
Mohammed N. Afsar, Tufts Univ. (United States)
Igor I. Tkachov, Tufts Univ. (United States)
Karen N. Kocharyan, Tufts Univ. (United States)

Published in SPIE Proceedings Vol. 3465:
Millimeter and Submillimeter Waves IV
Mohammed N. Afsar, Editor(s)

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