The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 23, 1999
Filed:
Dec. 20, 1996
Stephen A Gabelich, Long Beach, CA (US);
Raytheon Company, Lexington, MA (US);
Abstract
An apparatus and method for measuring the dielectric constant or permittivity at a plurality of positions on a test specimen are provided. Accordingly, the present invention enables the spatial variance of the dielectric constant, i.e., the dielectric homogeneity, of the test specimen to be measured. In particular, high resolution dielectric homogeneity measurements are performed at low frequency (100 kHz to 10 MHz) using a specially designed guarded electrode assembly and a specially selected high permittivity matching liquid. The guarded electrode assembly comprises a guarded electrode surrounded by a guard electrode which is supported over a test specimen resting on a planar electrode. The test specimen and the planar electrode are immersed in a dielectric fluid. The guarded electrode as well as the guard electrode, which extends into the dielectric fluid, are translated across the test specimen while the capacitance between the guarded electrode and the planar electrode is measured. The present invention is designed so that the number of required measurements are reduced compared to other techniques for measuring permittivity. The present invention also overcomes problems associated with prior art methods such as long processing times, low accuracy, and low resolution. Accordingly, the present invention permits rapid accurate high resolution measurements of dielectric homogeneity at a significant cost reduction in contrast to prior art methods.