Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Distributive type parameters
Patent
1988-12-02
1990-11-06
Eisenzopf, Reinhard J.
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Distributive type parameters
324636, 324653, 324708, G01R 2732, G01N 2200
Patent
active
049689452
ABSTRACT:
An apparatus and method for measurement of ohmic loss and surface resistivity is provided with a straight lumen waveguide with at least one opening at one end. Diffraction of radiation introduced to the lumen at one end of the tube provides feedback to establish resonances within the tube. Using the "whispering gallery" resonant modes maximizes the total ohmic loss and thereby enhances sensitivity of resistivity measurements. The angle at which resonant radiation exits the lumen is a function of the mode and size of the operative. Thus, preferred spatial detection allows enhancement of the device signal while discriminating against undesired modes. Selection of modes allows high frequency measurements, into the tetraherz range, to be made without disabling restrictions in the device dimensions, spatial input/output coupling or ohmic loss depending on alignment for analysis of, for example, high temperature superconductors. Furthermore, more than one longitudinal mode for a given transverse mode can be detected allowing for an unambiguous determination of ohmic losses from a measurement of the total Q.
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Cohn Daniel R.
Woskov Paul P.
Eisenzopf Reinhard J.
Massachusetts Institute of Technology
Mueller Robert W.
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