Materials Measurement Phil Bartley Shelley Begley

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Dielectric MechanismsIonic PolarizationTCl-Na+Cl-Na+Na+ Cl-Cl-Na+F−E+FNa+Cl- Na+ Cl- Na+ Cl- Na+ Cl-EOrientationPolarization(Dipole Rotation)Electronic or AtomicPolarization-+ + E -A static electric field will exercise torque on the electricdipole which will tend to align this dipole in the directionof the field. If the field changes the direction, so will thetorque. The friction accompanying the orientation of thedipole will contribute to the dielectric losses.12
Mechanisms vs. Frequency'ε rIonic Ionic Conductivity and and Electric Electric PolarizationDipolar(Rotational)+++-Ionic''ε r-Atomic-Electronic10 3 10 6 10 9 10 12 10 15 f, HzMWIR V UVThis plot illustrates how the dielectric properties of the salt/water mixture varies with thefrequency of the applied electric field. The dielectric properties of a material isrepresented by a complex quantity known as permittivity. A material’s permittivity isusually normalized to the permittivity of a vacuum. The real part of permittivity, e r ’, is ameasure of the energy stored and is called the dielectric constant. The imaginary partof permittivity, e r ’’, is a measure of the energy loss and called the loss factor.At low frequencies, the water molecules can follow the applied electric field resulting inmaximum values of e r ’. This polarization is a form of energy storage. At these samefrequencies, the positive and negative ions move in accordance to the electric field.This electric current corresponds to an energy loss.As the frequency increases the water molecules can no longer keep up with thechanging electric field. This results in less energy storage and higher rotational losses.At these frequencies the mass of the ions prevents them from responding the thechanging electric field.At even higher frequencies the water molecules no longer respond to the electric field .Permittivity usually is measured at frequencies below 10 11 Hz. At frequencies abovethis the water molecules are stretched. At even higher frequencies the water moleculesare pulled apart.13
Page 3: Extremely Diverse Applications“Ma
Page 6 and 7: Maxwell’s Equations∇× E=−∂
Page 8 and 9: Permittivity and Permeability Defin
Page 10 and 11: Definition of Dielectric Constant o
Page 14 and 15: Consider Dipole RotationRandom Orie
Page 16 and 17: Electric Field Changed DirectionEDi
Page 18 and 19: Small and Large MoleculesMany mater
Page 20 and 21: ε rε' '',r6040Debye Relaxation fo
Page 22 and 23: Cole-Cole Plot Explanation"ε r3020
Page 24 and 25: Other Empirical ModelsταβOnly fe
Page 26 and 27: Dielectric Properties (at 3 GHz)100
Page 28 and 29: Which Technique is Best? Frequency
Page 30 and 31: Impedance Analyzers and FixturesHer
Page 32 and 33: Measurement Techniques that use a V
Page 34 and 35: Transmission LineMaterial assumptio
Page 36 and 37: Transmission Algorithms in 85071EOp
Page 38 and 39: Problems with N-R Model• This set
Page 40 and 41: NIST Model• Technique uses all fo
Page 42 and 43: Transmission (Fast) Model• This t
Page 44 and 45: Weakness of both the NIST and Trans
Page 46 and 47: Transmission Line Measurement Error
Page 48 and 49: Typical Errors Caused By Air GapsPe
Page 50 and 51: Transmission Line Technique Summary
Page 52 and 53: Non-Contacting method for High or L
Page 54 and 55: 40 - 60GHz Free Space System54
Page 56 and 57: Free Space W-band SystemHere is a p
Page 58 and 59: Free Space Quasi-Optical SystemHere
Page 60 and 61: Before a Measurement Can be Made…
Page 62 and 63:
TRL CalibrationThruReflectMove the
Page 64 and 65:
Gated Reflect Line (GRL) Calibratio
Page 66 and 67:
MUT and GRL Error AdaptersAfter 2-P
Page 68 and 69:
MUT and GRL Error AdaptersAfter O11
Page 70 and 71:
GRL Thru Standard (Air)A 11 =A 22 =
Page 72 and 73:
QO System SchematicAdditional infor
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Measurement Results0.03Imaginary pa
Page 76 and 77:
Measurement with NRL Arch andoption
Page 78:
Free Space LabWith u-band calibrati
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Materials Measurement Phil Bartley Shelley Begley

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