US 2019/0377054 A1 · PLANAR TRANSMISSION-LINE PERMITTIVITY SENSOR AND CALIBRATION METHOD FOR THE CHARACTERIZATION OF LIQUIDS, POWDERS AND SEMISOLID MATERIALS

Abstract

A low cost planar transmission line sensor and simple calibration method for measuring the complex permittivity of materials with minimal sample preparation over a wide band of radio- and microwave frequencies. The sensor is also used for measuring anisotropic dielectric properties of materials with a defined grain.

Claims3

Dependent claims

(canceled)

A method for measuring the anisotropic dielectric properties of materials with planar transmission lines comprising:

(a) obtaining any liquid, powder, or semisolid material of different geometry, dimensions, and compositions, wherein said materials have known or unknown complex relative permittivities that can be represented by a uniaxial permittivity tensor with the expression
[
ɛ
*
]
=
[
ɛ
′
-
j


ɛ
″
]
=
[
ɛ
⊥
*

cos
2


θ
+
ɛ
∥
*

sin
2

θ
0
(
ɛ
⊥
*
-
ɛ
∥
*
)

sin


θ


cos


θ
0
ɛ
⊥
*
0
(
ɛ
⊥
*
-
ɛ
∥
*
)

sin


θ


cos


θ
0
ɛ
⊥
*

sin
2

θɛ
∥
*

cos
2

θ
]
where ε⊥*=ε⊥′−jε⊥″ and ε∥*=ε∥′−jε∥″ are the perpendicular and parallel components of the permittivity tensor;
(b) obtaining calibration constants by measuring the propagation constant γ, via any technique, of material-loaded planar transmission lines for at least one radio-frequency and for at least two materials with known permittivities by using the expressions
d
*
=
γ
1
2
-
γ
2
2
β
0
2

(
ɛ
1
*
-
ɛ
2
*
)
c
*
=
(
γ
1
β
0
)
2
-
d
*

ɛ
1
*
;
(c) determining the relative complex permittivity for each said material by using the expression
ɛ
meas
*

(
θ
)
=
ɛ
meas
′

(
θ
)
-
j


ɛ
meas
″

(
θ
)
=
-
1
d
*

[
(
γ

(
θ
)
β
0
)
2
+
c
*
]
by using the calibration constants, d* and c*, and the propagation constant γ measured via any technique for at least one radio-frequency;
(d) determining the permittivity of the sample material for a range of known θ with the expression in 1(c) above;
(e) fitting the inverse square roots of εmeas′(θ) and εmeas″(θ) with ellipses by a direct least squares fitting algorithm or other numerical technique;
(f) determining √{square root over (εu′)} and √{square root over (εu″)}, and √{square root over (εw′)} and √{square root over (εw′)} as the semimajor and semiminor axes respectively as the coefficients of the fitted ellipse;
(g) obtaining the perpendicular and parallel components of the permittivity tensor ε⊥* and ε∥* from √{square root over (εu′)} and √{square root over (εu″)}, and √{square root over (εw′)} and √{square root over (εu″)} with the expression
εw*=√{square root over (ε⊥*ε∥*)}+(ε∥*−ε⊥)(d*d0−1)
where d0 is the calibration constant for t=0
(h) using the perpendicular and parallel components to determine a physical property of an anisotropic material.

195 more elements

Dependencies are inferred from the claim text.

Facts

Application

16/169,103Filed 24 Oct 2018

Priority

29 Aug 2014

Published

12 Dec 2019

Term ends

Not estimatedThe source records don’t support an estimate.

Classification4 codes

G01R 35/005
Testing or calibrating of apparatus covered by the other groups of this subclass: calibrating; Standards or reference devices, e.g. voltage or…
G01N 22/00
Investigating or analysing materials by the use of microwaves or radio waves
G01R
Measuring electric variables
G01N
Investigating or analysing materials by determining their chemical or physical properties

Family

Application62/043,659Us provisional application · filed 29 Aug 2014

Application14/839,083Division · filed 28 Aug 2015

Application16/169,103Division

US 10,139,468 B2Related patent

US 10,955,514 B2Related patent

US 2016/0187402 A1Published application

US 2019/0377054 A1This patent

From the US filing history. Foreign family members aren’t listed.

Abstract

Claims3

Dependent claims

(canceled)

A method for measuring the anisotropic dielectric properties of materials with planar transmission lines comprising:

(a) obtaining any liquid, powder, or semisolid material of different geometry, dimensions, and compositions, wherein said materials have known or unknown complex relative permittivities that can be represented by a uniaxial permittivity tensor with the expression
[
ɛ
*
]
=
[
ɛ
′
-
j


ɛ
″
]
=
[
ɛ
⊥
*

cos
2


θ
+
ɛ
∥
*

sin
2

θ
0
(
ɛ
⊥
*
-
ɛ
∥
*
)

sin


θ


cos


θ
0
ɛ
⊥
*
0
(
ɛ
⊥
*
-
ɛ
∥
*
)

sin


θ


cos


θ
0
ɛ
⊥
*

sin
2

θɛ
∥
*

cos
2

θ
]
where ε⊥*=ε⊥′−jε⊥″ and ε∥*=ε∥′−jε∥″ are the perpendicular and parallel components of the permittivity tensor;
(b) obtaining calibration constants by measuring the propagation constant γ, via any technique, of material-loaded planar transmission lines for at least one radio-frequency and for at least two materials with known permittivities by using the expressions
d
*
=
γ
1
2
-
γ
2
2
β
0
2

(
ɛ
1
*
-
ɛ
2
*
)
c
*
=
(
γ
1
β
0
)
2
-
d
*

ɛ
1
*
;
(c) determining the relative complex permittivity for each said material by using the expression
ɛ
meas
*

(
θ
)
=
ɛ
meas
′

(
θ
)
-
j


ɛ
meas
″

(
θ
)
=
-
1
d
*

[
(
γ

(
θ
)
β
0
)
2
+
c
*
]
by using the calibration constants, d* and c*, and the propagation constant γ measured via any technique for at least one radio-frequency;
(d) determining the permittivity of the sample material for a range of known θ with the expression in 1(c) above;
(e) fitting the inverse square roots of εmeas′(θ) and εmeas″(θ) with ellipses by a direct least squares fitting algorithm or other numerical technique;
(f) determining √{square root over (εu′)} and √{square root over (εu″)}, and √{square root over (εw′)} and √{square root over (εw′)} as the semimajor and semiminor axes respectively as the coefficients of the fitted ellipse;
(g) obtaining the perpendicular and parallel components of the permittivity tensor ε⊥* and ε∥* from √{square root over (εu′)} and √{square root over (εu″)}, and √{square root over (εw′)} and √{square root over (εu″)} with the expression
εw*=√{square root over (ε⊥*ε∥*)}+(ε∥*−ε⊥)(d*d0−1)
where d0 is the calibration constant for t=0
(h) using the perpendicular and parallel components to determine a physical property of an anisotropic material.

195 more elements

Dependencies are inferred from the claim text.

Planar transmission-line permittivity sensor and calibration method for the characterization of liquids, powders and semisolid materials

Life of this patent

Abstract

Claims3

Planar transmission-line permittivity sensor and calibration method for the characterization of liquids, powders and semisolid materials

Life of this patent

Abstract

Claims3