Dielectric measurement probe for curved surfaces

Patent metadata

Field	Value
Publication number	US-10649016-B1
Application number	US-201816195897-A
Country	US
Kind code	B1
Filing date	Nov 20, 2018
Priority date	Nov 22, 2017
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

A probe is provided for measuring permittivity of a dielectric material. The probe includes side electrodes and a pivotable center electrode with a bulbous tip to contact the material. A mounting harness supports the side electrodes and a feed connector with the center electrode soldered to the connector. The tip includes a contoured surface for measurement and rotation on the material. The bulbous tip can rest perpendicularly or in a pivoted position on the material without a loss of measurement accuracy. A saddle ensures that a measurement of the reflection coefficient is near the bulbous tip. In use, a voltage wave generated by a vector network analyzer is guided between the electrodes toward the tip and into the material. The material reflects this voltage wave back to the analyzer. The ratio of the reflected and forward voltages forms a reflection coefficient as a baseline for measuring permittivity.

First claim

What is claimed is:

1. A probe for non-destructive measurement of complex relative dielectric permittivity of a dielectric material, said probe comprising:
a mounting harness having a first rectangular section with a thickness with said mounting harness having a first face and a second face along a longitudinal axis of said first rectangular section with a first aperture thru the thickness of said first rectangular section in proximity to a first longitudinal end of said first rectangular section and a second aperture thru the thickness in proximity to a second longitudinal end of said first rectangular section, a second rectangular section having a cutout with a recess for fastener attachment and with said second rectangular section extending from the second face of said first rectangular section on a side of the first aperture opposite to the first longitudinal end, a third rectangular section having a cutout with a recess for fastener attachment to face the cutout of said second rectangular section and with said third rectangular section extending from the second face of said first rectangular section on a side of the second aperture opposite to the second longitudinal end, and a feed point connector positioned at a center of said first rectangular section to have a recess connection on the second face of said first rectangular section and a cylindrical protrusion connection on the first face of said first rectangular section;
a first side electrode formed as a rectangular section with a longitudinal first face and a longitudinal second face separated by a thickness with said section having a cutout on the longitudinal first face with a recess for fastener attachment, said first side electrode having a first end and a second end formed as a bulbous tip having a surface area wherein said first end is fastened to said second rectangular section and the second face of said first rectangular section of said mounting harness;
a second side electrode, said second electrode being a same size and shape as said first side electrode and having a cutout with a recess for fastener attachment to face the cutout of said first side electrode, said second side electrode having a first end and a second end formed as a bulbous tip having a surface area wherein said first end is fastened to said second rectangular section and the second face of said first rectangular section of said mounting harness; and
a center electrode with a thickness with said center electrode having a first end and a second end positioned between and spaced apart from said first electrode and said second electrode with said center electrode soldered at the first end to said feed point connector within the recess connection, said center electrode formed as a rectangular section with a first cutout in alignment with the cutouts of said first side electrode and said second side electrode and having a recess for fastener attachment, a second cutout in alignment with the cutouts of said second rectangular section and said third rectangular section and having a recess for fastener attachment with said center electrode having an axis of rotation between the first end and the second end to allow said center electrode to pivot, the second end formed as a bulbous tip with a surface area with a same radius as the bulbous tip of said first side electrode and a same radius as the bulbous tip of said second side electrode;
wherein a portion of the surface area of said bulbous tip of said center electrode is contactable with the material thereby permitting measurement of the dielectric permittivity of the material such that said probe is capable of accommodating a voltage wave generated by a vector network analyzer that is guided between the electrodes and travels toward the bulbous tip and into the material, the material reflects the incoming voltage wave back to thru the bulbous tip of said center electrode and said feed point connector to the network analyzer with the ratio of the reflected and forward voltages being a reflection coefficient having dielectric properties of the material inferred from data of the reflection coefficient.

2. The probe in accordance with claim 1 , wherein said probe further comprises a first plate connected by fasteners to said first side electrode, said second side electrode and said center electrode at the cutouts of said first side electrode, said second side electrode and said center electrode.

3. The probe in accordance with claim 2 , wherein said probe further comprises a second plate connected by fasteners to said second rectangular section, said third rectangular section and said center electrode at the cutouts of said second rectangular section, said third rectangular section and said center electrode.

4. The probe in accordance with claim 3 , wherein said mounting harness said mounting harness is capable of attachment to a mechanical positioning arm thru the apertures of said rectangular section.

5. The probe in accordance with claim 3 , said probe further comprising a calibration saddle with a rectangular base plate having a longitudinal first end and a longitudinal second end with a first face and a second face along a longitudinal axis of said rectangular base plate, a first bracket fastened perpendicular to the longitudinal first end with a vertical portion inside of the longitudinal first end, a second bracket fastened perpendicular to the longitudinal second end with a vertical portion inside of the longitudinal second end, a first flat section extending between a first vertical side of the vertical portion of said first bracket and an opposing first vertical side of said second bracket with said first flat section indented in proximity to the first vertical side of said first bracket and said second bracket, a second flat section extending between a second vertical side of the vertical portion of said first bracket and an opposing second vertical side of said second bracket with said second flat section indented in proximity to the second vertical side of said first bracket and said second bracket, a first half-circular section extending between the indents of said first flat section and said second section with a straight portion of said first half circular section facing away from said base plate and a second half-circular section spaced apart from said first half-circular section and extending between the indents of said first flat section and said second flat section with a straight portion of said second half-circular section facing away from said base plate wherein said rectangular base plate, said first bracket, said second bracket, said first flat plate, said second flat plate, said first half-circular section and said second half-circular section form a saddle for insertion of the probe and to cradle said first side electrode, said second side electrode and said center electrode for calibration of the probe by shorting said first side electrode, said second side electrode and said center electrode.

6. The probe in accordance with claim 5 , wherein said mounting harness said mounting harness is capable of attachment to a mechanical positioning arm thru the apertures of said first rectangular section.

Assignees

• Us Navy

Inventors

• Rivera David F

Classifications

• G01R27/2623

  Measuring-systems or electronic circuits (G01R27/2635, G01R27/2682 take precedence) · CPC title

• G01R27/267

  Coils or antennae arrangements, e.g. coils surrounding the sample or transmitter/receiver antennae · CPC title

• G01R27/2676 Primary

  Probes · CPC title