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UNCLASSIFIED AD NUMBER AD480747 NEW LIMITATION CHANGE TO Approved for public release, distribution unlimited FROM Distribution authorized to U.S. Gov't. agencies and their contractors; Administrative/Operational Use; JAN 1966. Other requests shall be referred to Air Force Materials Laboratory, Attn: MAYT, Wright-Patterson AFB, OH 45433. AUTHORITY AFML ltr, 7 Dec 1972 THIS PAGE IS UNCLASSIFIED
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Page 1: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

UNCLASSIFIED

AD NUMBER

AD480747

NEW LIMITATION CHANGE

TOApproved for public release, distributionunlimited

FROMDistribution authorized to U.S. Gov't.agencies and their contractors;Administrative/Operational Use; JAN 1966.Other requests shall be referred to AirForce Materials Laboratory, Attn: MAYT,Wright-Patterson AFB, OH 45433.

AUTHORITY

AFML ltr, 7 Dec 1972

THIS PAGE IS UNCLASSIFIED

Page 2: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

Jr•

AFML-TR.66-28

Measurement of

OA Dielectric Parametersof High-Loss Materialsin Distributed Circuits

W. B. WestphalLaboratory for Insulation Research

LL" Massachusetts Institute of Technology

Cambridge, Massachusetts-- _

Technical Report AFMI-TR.66o28

Janaary, 19b6

This docmnent i Abject to special export controls and eachtransmittal to foreign governments "- fore;gr natimal's m~aybs made only- with prior approval of AF Materials Laboratory

(MAYT), WPAFB, Ohdo 45433

AIR FORCE MATERIALS L.ABORATOR Y I~~Y SRESEARCH AND'TEChNOLOGY DIVISION L'U.•z

'WRIGHT-PATTERSON AIR FORCE BASE, GHiO U.,A,0

't-

Page 3: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

VAL

NOTICES

When Government drawings, specificationf, or other data areu!ed for any purpose other than in connection with a definitelyrelated Government procurement operation, the United StatesGovernment thereby incurs no responsibility nor any obligationwhatsoever; and the fact that the Government may have formu-lated, furnished, or in any way supplise the said drawingB, umpwihc-tions, or other data, is not to be regarded by implication or otherwiseas in any manner licening the holder or any other person orcorporation, or conveying any rights or permission to manufacture,uee, or sle any patented invention that may in any way be relatedtherto.

Copies of this report should not be returned to the Rasearch andTechnology Division unlm return is required by security consider.ations. contractual obligations, or notice on a specifc document.

• : :.,•. •,

Page 4: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

SFo r m•Z

MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS

~MATERIALS IN DISTRIBUTED CIRCUITS

Q W.B. Westphal -

Laboratory for Insulation ResearchMassachusetts Institute of Technology

Cambridge, Massachusetts

Ja P066I

4) 3 5 p,

AF - 7 3 71

( 7,371701

This document is subject to special export controls and eachtransmittal to foreign governments or foreign nationals maybe made only with prior approval of AF Materials Laboratory

(MAYT). WPAFB, Ohio 45433

Page 5: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

FOREWORD

This report was prepared by the Massachusetts Institute of

Technology, Laboratory for Insulation Research, Cambridge,

Massachusetts, under USAF Contract AF 33(615)-2199. This

contract was initiated under Project No. 7371, "Exploratory

Development in Electrical, Electronic, and Magnetic Materials,"

Task No. 737101, "Dielectric Materials. " The work was

administered under the direction of the AF Materials Laboratory,

Research and Technology Division, with W., G. D. Frederick

acting as project engineer.

This technical report has been reviewed and approved.

State BranchMaterials Physics DivisionAF Materials Laboratory

SLj

Page 6: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

V

Illustrations

Page

Fig. 1. Inverse standing-wave ratio and xo/k for 3"infinite -length" nonmagnetic materials(TEM mode).

Fig. 2. Sample thickness d (in cm) for electrical .4thickness of 0.3 radians for various mag-nitudes of (E*/E 0)(*Io) vs. frequency.

Fig. 3. Method of clamping silvered sample in 5coaxial line.

Fig. 4. Soldered sample in a thin-walled (0.005 5to 0. 010") tubing.

Fig. 5. Magnetic ring sample in coaxial line. 6

Fig. 6. Sample clamped in a thin-walled (<0. 10") 7wave guide.

Fig. 7. Equipment for measurement of input 7impedance and transmission.

Fig. 8. Coaxial phase shifter for fixed frequency. 8

Fig. 9. Suggested cavity measurements for 9determining IA of conductors.

Fig. 10. Lumped-capacitor sample at end of co- 10axial line.

Fig. 11. A, nonmagnetic three-layer dielectric. 11

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rr

MEASUREMENT OF DIELECTRIC PARAMETERS OF HIGH-LOSS

MATERIALS IN DISTRIBUTED CIRCUITS

by

W.B. Westphal

Taboratory for Insulation ResearchMassachusetts Institute of Technology

Cambridge, Massachusetts

Abstract: Measurement techniques for determination of the complexdielectric constant and complex permeability are given a short

review with emphasis on the problems encountered in practical

high-loss materials. Typical calculations and descriptions of

special sample holders are included.

Introduction

For purposes of discussing measurement techniques, we can divide

electromagnetic energy-absorbing materials for perpendicular impedance

into several categories.

1. In uniform materials the macroscopic parameters t* and gP are

invariant along the axis of wave propagation, They may be (a) isotropic

or (b) anisotropic, depending on whether or not these parameters are the

same in other directions also. When reflected as well as traveling waves

are considered, the question of reciprocity arises, and additional classifi-

cations are: (c) for reciprocal materials, (d) for nonreciprocal.

2. Uniform-layered materials are composites of layers, each layer

being uniform, and the thickness of the junction is very small compared

to wavelength in adjacent layers.

3. Nonuniform materials have i* and/or 10, varying gradually along

the axis of propagation. The nonuniformity may arise from external

shaping (tapers) or gradual change in chemical composition or loading.

Combinations of uniform and nonuniform layers constitute a nonuniform

material.

*G-I--.-

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-2-

Obviously all layered materials may be symmetric or unsymmetric

in reference to their center plane.

Composite materials of mixed ingredients are uniform if particle

szcs arc s,,allA compared t&o wavelengthl ad iH the materials are homo-

geneous. Clumping of particles causes electrical inhomogeneities; the

measured values of i* and • will then be dependent on sample thickness

and how the measurement techniques are affected by scattering.

Measurement Techniques

The general methods for determining both Er and ;[ are (a) the in-

put impedance measurements with sample in two positions using resonant

cavities or standing-wave detectors; (b) perturbation measurements with a

small sample in two positions of resoaant cavity; (c) combination of input

impedance and transmission measurement.

In (a) the use of resonant cavities is limited by the need for at least

moderately high loaded Q's (50 or more) to obtain accurately measurable

amplitude resonance characteristics. When approximate sample properties

are not known before measurement, this is a severe restriction. The

standing-wave method limitations arise at much higher values of loss

(lower values of impedance) when the sample in both positions has the

same impedance, that of an infinite-length sample. Then only the

ratio */AA * will be measured with poor accuracy. because the separation

of node and sample face will be very small. Figure 1, for nonmagnetic

materials, illustrates the difficulties. The x0 values are generally small

fractions of a wavelength, and inverse standing-wave ratios are high

except for materials having very high K' values and/or very high tan 6

values. Also the fractional errors in dielectric constant and loss are

always nearly twice the error in experimental quantities because of the

suare-law dependence. For example, for K' and tan 6 = 10, Emin /Emax

M 75 and x0A =. 012 or approximately • (Ax/4.. If the node position is

located to within l/ZO of Ax, a reasonable error, and EminEmax is

accurate to 5%, the resultant error in K" is 14%.

In the two-position measurement system. good results dipend mainly

on having a thin enough sample to avoid "indinite-lenSth" conditions and

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3I

., - ±-0.1,

S" .*: :"1 "___ __ __ __. :

0.00 0.I I I0 100ton

Fig. I. Inverse standing-wave ratio and Xo/k for "infinite-length" nonrnagnetic materials (TEM mode).

making good contact with the metallic conductor(s). If the approximate

magnitude of the product .*/ o"p*/po is known, the physical thickness

of ssmplh for an electrical thickness of 0. 3 radian can be readilyS~determined (Fig. 2). This thickness assures good measurements in the

sense that the experimentally measured quantities vazy almost linearly

S~with sample parameters, and nearly separate measurements of electric! and magnetic paramneters are achieved. Alecu higher order modes can

hardly exist. Limitationw of the method arise when sample thickness

must be so small to achieve electrical thinness that the sample no longeris representative of bulk material; e. g., evaporated 1fires often have k

dif~ferent electrical parameter s.H-igh-constant and/or high-loss samples require good contact with

the conductor(s) in the measurement system. For example, in a l-incb

~!

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-4-

E T1

S;---4- -4-- - r- f- +-+ -4 -. 4- --

, - ._: • • __ .t -¢ f .....

' j@-f-

j 4 uý 4

Freqiecy an cycle per send

Fig. 2. Sample thickness d (in cm) for electrical thick-hess of 0. 3 radians for various magnitudes of(EVE 0/L 4/s0 versus frequency.

60-ohm coaxial line a clearance of 0. 0005 inch on the center conductor

causes a 13%• error in measuring a material with K' 1 00. Correction

equations and charts are given in the Appendixes IU and IXIC. Usuallythe clearance cannot be defined with suficic'ent accuracy for good measure-

ments and intimately bonded electrodes should be added. To avoid leakage

and insure contact the sample holder of Fig. 3 is used. A peripheral

coat of silver paint is allowed to overflow onto the faces which are clamped

" ~between silver conductors, one of which is thin-walled and collapses to

' ~accommodate variatilo. "_• sample thickness. The samples must bestrong enough to withstand the compressive strain: repeated use dulls

S~the tubing edge which can be reformed by lathe turning. The silver on

oIo

Frwerc in cyle seon

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5

ISilver inlay\

"____._____ ICopper Sample Thin wall silver tubing

Fig. 3. Method of clamping silvered sample in coaxial line.

the faces introduces additional fringing field and limits the accuracy of

measurements to about 5%. A better arrangement uses coated samples

soldered to thin-walled tubing as shown in Fig. 4.

'Thin wall silvertubing

Fig. 4. Soldered sample in a thin-walled (0. 005 to 0. 010") tubing.

In measuring the magnetic properties of materials, ring-shaped

samples are sometimes used in a coaxial line or cavity. 1) This procedureleads to a different and more subtle source of error. If the electricalthickness along either the axa' or radiai direction exceeds 0. 3 radian.

r'.

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-6-

. Ring E- FIELDSsomple

line

(c)(a) (b) H-FIELDS

Fig. 5. Magnetic ring sample in coaxial line: (a) physicalarrangement, (b) electric and magnetic fields inradially thin sample, (c) electric and magneticfields in longitudinally thin sample.

other i,,odes exist which are readily coupled by the magnetic field as

sh- -n in Figs. 5a and 5b. Good contact at coaxial conductors by a full-

sized sample reduces chance for this type of error. Highly conducting

samples car give false diamagnetic readings caused by eddy current

shielding of the sample interior.

SIn hollow waveguide the same ideas apply, but in addition one can

possibly deform the center of the broad faces of rectangular guide to

make contact with a sarr le coated on the longer edges only (Fig. 6).

The two-position, thin-sample technique gives best separation of

electric and magnetic parameters. When thick samples only can bc used,

the input-1mpedance measurement givres the ratio K'n/I' and the difference

in loss angles. Since .his is essentially a measurement of the ratio of

magnetic to electric field strengths, nam-nely, ratio of two different kinds of

uuits, this deterrrm.nation will be done with less precision than achieved

in measurement of the propagation function. rhe latter can be measured

Page 13: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

7

1- Fig. 6.

7 &c. Sample Sample clamped in a

thin-walled ( < 0. 10)wWa-eguide.

T''hin wall waveguide

It

Isolato wave Sample holder -indicator J

ii

Oscillator ,-audio null indicator

"Islao Phase L•VariableSquatre! shif ter Jattenuator

Squlatre

modulator

Fig. 7. Equipment for measurement of input impedanceand transmission.

with either electric or magnetic indicators. Figure 7 is a schematic

diagram of equipment for combination measurement of input impedance

t •and transmission. A suitable phase shifter for coaxial line is shown in

Fig. 8. The calculation procedure follows the two-position method

1 • I

Page 14: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

-8-

h.

z2I-s

* S

'N'S

.' *�1.a�1...o UEA

*YL.o4-o $4

'44C �0

4-4-

* '44

$40

0) '44

$4

-� 4.''44__ .44

*14-4

IU

00

I '.4

I if

Page 15: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

-9 -

cavity

KlystronI

Sow-tooth , ments for determining JA*generator Differential of conductors. Laser head

O e aplifier would be mounted on cavity.Sample surface is bottom

swI c of measuring cavity.

except that 702/Z01 and y 2 (e. g., 12 and 15, Appendix ID) are given di-rectly by the input impedance measurement and the change in amplitude

and phase per unit length of sample increase.

Metallic materials, even as thin foils, have attenuations greater

than can be readily measured in transmission. The sample can serve as

a conducting wall in a waveguide, a resonant cavity, or surface-guided

wave system. A proposed measurement system is shown in Fig. 9. A gas

laser interferometer is suggested to measure the position of the cavity

wall, so the small changes in resonant frequency due to the ji' term can

be detected. Measurements of the complex permeability of iron were

made some years ago by Dr. Rado at NRL. He superimposed a

saturating magnetic field to reduce g* to A to establish a nonmagnetic

reference condition in a coaxial cavity with the sample serving as center

conductor.

The small-sample technique is similar to common ferromagnetic reso-

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-10-

Signal

,, , 1 Zc generatorYI ZC1

L50modulator plunger

IZ{ }Tuned audio Measuringfrequency amplifier line

- with outputindicator ••

detector

Fig. 10. Lumped-capacitor sample at end of coaxial line: (a) sample inline, (b) equivalent circuit, (c) equipment arrangement.

nance experiments3) with external d-c field. A spherical sample placed in

two positions in a cavity, or in two different cavities, allows both E* and

A to be determined. Since the dipole field corrections4) used are

derived from magneto- and electrostatics, the diameter of the sphere

should be 0. 1 radian or less. At high frequencies very small spheres

(0.005-inch) are required, and surface finish becomes important. To

cover a wide range of frequencies, a series of spheres are required.

For nonmagnetic materials, rodlike samples can be used as lumped

capacitors at the end of a coaxial line (Fig. 10).

Measurements on uniform-layered materials with parallel electric

iitilds to determine t* and g.* have progressively less meaning when

the electrical thickness along layer rises above 0. 3 radian.

With uniform-layered materials, the two-position method for mag-

netic dielectrics or the single-position measurement of nonmagnetic

dielectrics have progressively less meaning as frequencies rise, so that

the total electrical thickness exceeds 0. 3 radian. In an extreme case

the measurements are meaningless as an example will show. Figure 11

shows a symmetrical-layered sample having nonmagnetic pararmters

Page 17: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

S- 11 -

i

K' = 3 K' 100 K' = 3

6 =0 tan6=0.1 6 =0

Thickness (in radians) 0. 512 0. 300 0. 512

Relative physical thickness 10 1 10

Fig. 11. A nonmagnetic thr%ýe-layer dielectric.

for simplicity. Measurements against the short circuit place the high-

constant portion in a region of high field strength and and give an effective

K' value of 9.22 and an equivalent length of 1. 88 radians. In the open-

circuit measurement, the high-K center receives lower field strength,

the effective constant is 7. 78 and the length is 1. 73 radians. The com-

bined two-position calculation gives K' = 7.4 and K 0. 44. The average

K value in a uniform field is 2d~lc + d2 Kj = 7. 68. If many of these three-

layer laminates are stacked, the phase change and attenuation rer unit

length will vary as each laminate is added, but if enough layers are used,

an average value can be defined (if only one mode exists). Because of

internal reflections between successive high-K layers, the K and tan 6values obtained will not be the same as the uniform-field value. With a

thicker high-K section, the difference would be appreciable. The same

reasoning regarding the necessity for overall thinness applies to nonuniform

layers.Thus absorbers are best defined by input impedance (or reflection

factor) as a function of angle of incidence, not by attempts to measure or

define t* and p

Page 18: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

- 12 -

APPENDIX I

Calculation Procedures for Standing-Wave Methods

A. General Notation:

x = distance from face of sample (Fig. AL. 1) to first minimum.0

AN = node shift toward short with introduction of sample (N a-N )

Lx = width of minimum with measured at twice minimum power

points (2/I current ratio with square-law, detector) corrected

for line lobs between mi.imum and sample face.

N = node reading, sample in.

Nq = node reading without sample, X/4 spacer in.

U = (X /c)ý- 0 for TEM modes.

w l+U.

X = wavelength in air-filled section of line.

X cutoff wavelength = 3.412586 times radius ol guide for TEll

mode, = twice broad dimension in rectangular waveguide

TE1 0 mode.

E mi/E = inverse standing-wave ratio = w- xmin max -- c15

B. General Relations for Nonmagnetic Sample X/4 From Short

x0 aN q- ,(r T

I- /h\]O~_____ _____Axa

Ax~nk AXAx ax s'lý

~Izz

E Emin Zxo0__d_________-_ns _ 01 1l- J - tan W

L B max1

0' cothy•td 1 ZBd : Zj• (Amt. 2)

Fig. A. -1.

=Yl 01

m l ml u to m imm ~ l lmm u ig A Lm -1. m u • m w mm lmn lm ~ mw mml u m~m m m i l I• )

Page 19: UNCLASSIFIED AD NUMBER - DTIC · MESUREMENT OF' DIELECTRIC PARAMETERS OF FUGHoLOSS ~MATERIALS IN DISTRIBUTED CIRCUITS ... In uniform materials the macroscopic parameters t* and gP

-13-

y 2 d is determined from charts or tables of cothx/x in literature or

Appendix ILIA if 3ample is less than Xs/4 in thickness:

2

u-- T y2 d) (Al.3)

C. Thin Sample Calculations

Restriction 1:

Y2 d < 0. IV for 0. 5A error,

< 0.15r for 1% error,

< 0. 3V for 5% error.

ZO I

- w"• + u(Al. 4)

Restriction 2:2-o x z01 -) Afx 1 rUf(Emi )az << Iland tan• > 1, then =- + j cot

andt

Ice : tan + u"A .5

goAX (lA. 6)

Restriction 3:

tan 2wA d_!R < 0. 1 for 3% error,

< 0. 15 for 1% error,

< 0. 3 for 3% error.

Ie + A 'N JAI. 7)

WT!

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- 14 -

If after calculating K* with Restrictions 2 or 3 satisfied, Restriction I

is not satisfied, the value of. w* already calculated can be corrected if

if y2 d < 0. 5r by noting that

Z 01 'Y2 2[.

T_- =•- tanhy 2 d2•- [Y 2 d - .(v/-d)3]. 1•..8)

Then

K r + AK' - jA*" (A. 1. 9)correctf~d ab~ort ialc. ' J"'ts. c.l

where

2

1 Awd 2 2]AK' -r k-7 (s. c. s ) (l.c. A 1 0

2K" -2 (2wd K" (K w - u) (A. I. 11)

" = •s/ "rc"

D. General Relations for Magnetic Samples, TE or TEM Waves

Z, 01 U 01

10

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- 15 -

1/2

tanh yd = r (A. L. 13)

From charts of tanh (a + jb) = r18

y 2 d = a + (A. L 14)

y 2 y 2dYZ -Y d A (A. 1. 15)

tan 6m = -tan (4-*) (A. L 16)

, AB (A. L 17)0 (1 + tan 6 )1/Z

A- = -(A.L 18)0

i. " A Uin1÷4}$ito +-=•- sin (0 - ,)(A. 1. 19)

0

For TEM mode only

A -o (+4 (A. 1. l8a)to 7 r

tan 6 d * tan 1+#) (A. L 19a)

Two sample calculations follow in Appendix m.

E. Thin •gnpetic Saple Calculations

With Restrictions I and 3 satisfied for sample in both positions:

AN, (A. LZ)

I 1

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-16-

(A. 1. 1)

AN +d.l0

4o ("" A. I.22 )

E' AN2 4-d u /oi

,~ ~~(o Po w•Z(•, A .2

Gt Ax2 + Ao (A. 1. 23)0 00) IA

For TEM modes:

- N -(A. 1. 22a)

0

A�- •(A. 1. 23a)

0

if Restriction 3 is satisfied only for sample at short,

+u ,, ,(A.1. Z4)

which reduces if Restriction 2 is satisfied to

\0ol ijo/

ta -WI 0 (A. 1.2Z5)

0~

I 1 lAX 2Z (A. 1. 26)

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r- 17 -

If after calculating i*/E and lfbo from Eq. 20 through Z6 Restriction I

is not satisfied, the values already calculated can be corrected if

Y2 d < 0. 5 r by making use of the series expansion as in Eq. A. I. 18. Then

=K = Kshort caxc - jAK" (A. I. 9)

0

•" • •mshort calc. ÷A

go + AA - :^K"ý (A. 1. 27)

where, for TEM mode,

AK, = ?- ( ) (K') - (K,)- 2 )- 2KPIWK',11 (A.1.28)

I (.Z aw(x 2 (sc 012) + 2IcMK',K"jI (A. 1. 29)

2&.a- (, [x'(c.a, -. 1,)2- Zic.,.A . (2wd)• [if (( C)Z- (Ki )z )-I. ,KwK;mK"I I (A. 1. 30)

".e)2).)' -n 20 (. 1. 31)

F. Input Impedance of Infinite Length Sample (TE or TEM waves)

For nounmagnetic dielectrics

•'-•"� u u+ (z--l (A.1. 32)0B

For conductors g" >> c'; V and tan are smanll and equal in

mapitude. Then

•" = '"-z-' (A. 1. 33)

tw' w( i T)

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-18-

- (A. I. 34)

a will be in zeciprocal ohm-cm when e is given in fd/cm and X in cm.

APPENDIX II

Corrections for Sample Fit in Coaxial Line

Letting D1 = diam. of center conductor,

D2 = diam. of hole in sample,

D = outside diam. of sample,3

D4 = inside diam. of outer conductor,

and defining

L 1 log D2 /DI + lot, D4 /Dy

L2 log D3 /D 2 ,

L 3 leg D4 /DI,

gives:

1I, (l+t2nI- -K ( +ta 26 )

m-;eas. meas.' =K' 3(A. 31. 1)

cor. meas. L 3 L 1 (1)-2• K' r1s+ +tan

m2 2 aas. 1 meas. meav.

tan6 cor =tan 6 eas (A.I. 2)

K 1 (1 + tan6 )Ineas. meas.

2When tan 610< «1, the above equations simplify to

IC' fiK' , (A. I1. 3)o3. me as. 1"3 ineas.

n ot. tan6 r-eau" [1+ e. L] - t(A. U. 4)

(A. 11.4 )

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- 19 -

In addition, when clearances are small, they may both be referred to

"the same diameter and added

2[(K)eas) - KneasI clearance

K' -KI diameter (A. 11. 6)cor. KMeas. .30lgoD 42. 30 loglo10

D1

1 1+ c clearance1tan 6 = tanr ;neas. diameter (A. II. ?)L 2.30 log1 0 D4

APPENDIX III

Charts and Sample Calculations

A. Charts of the complex function cothx/x. These have been refined

and extended since previously given and show values of the function

coth T .L

T h

8r .3 0Chart XVI. T, 0 to 0. ; l; 380 to 90 (abscissa is l/C)

XVII. T, 0.8 tol. Sr; 500 to 90°

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- 20 -

CHART XVI

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.6

170

WIT

X1. C ha XVI1 94 Oi: 1 -.14 to l t90 t

: I00

f717

MR SAM 0°2 0.N 0.4ý 0.5 0, 0. 0i N~if.8fýh ~

0 ~r 0VI. T, 00. 0.4 • 0',3 Ole 07 0.*I/C

Chart. . . . . .. . .. .. ....... . . ... . ......

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- 21 -

CHART XVU

ii

I •[

I7 ; fi l l

II4 -T

17 m l,,° iEA

101

;A ihfr XVII Ml 0.Ao15 r,5 0

13

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B. Charts of the complex function tanhx. These are shown in the form

tanh (a + jb) = r/e . Chart I is a survey chart7) with b in quadrants,

showing the symmetry properties. Chart II shows the first half-

quadrant of Chart I in enlarged form with b in radians. Chart III

shows an enlarged section of Chart II near the origin. Charts IV,

b and c, show parts of the first quadrant for low-loss samples only

(a 0 0. 1).

Acknowledgments

We are grateful to Barbara B. East and John J. Mara for preparation

of all charts shown in this section.

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-23-

c.

0

Ii)0u

'4 0

ra

00

k 14

4 54

INI VWVI7TT

!I~ klt

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- 24 -

CHART 11

tar*h (o Jb) r LO

1.40 9 8 .5.~ 8 .7 8.M'WI

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-25-

CHART M

tanh (a+jb) * r/.

aJ

.52 I

.44

.361

• ~.32 d

S~~.24!

.1,2

0 A4 .0 .12t .4i .-O -194 el e .40

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-26-

CHART IVb

.10

.09

.08

.07

.06

.05

.04

.01

.30 ,4 .38 .42 .46 .50 .54

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CHART l~c

.1

Ar.

.01

.0

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-28-

C. Charts for Sample Fit Corrections in Coaxial Line with DiameterRatio 8/3

Somple-fit Correctiom Chart, 2 O-"c'€- 4 .04.0

ot,

S.8

AC .6ANM." ANAftoo mio inJrt WC W*

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-29-

Sample-fit Correcton Chart, 3.6ure4 c7.6

-IM

RatoW..f ckeonce w, dkmwters k Drwhc1F w cLcurtf

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30

/Samplv-fit Correcdon Chart, t" 8 r be I 2D0 to 7.5

0.11

LII

I.0S

4-

1.03

off

.00 .01 .02 -04 orRatio of clearance on diameters to conductor diameter

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-31 -

D. 1. Sample Calculation for an Epoxy-Loaded with Al in Coaxial Line

l~e f *, =30.300 e/so = 7.90coaxial line

tM # Date w I/I 0 90825

Sample: Al~usini-loakded epoxy Tamp ten 8d - 0.01511

Ibicknsu* 1.8665 e tanOn. 0.076.4

I &A-le on triul plate II Saplt X/h fr terminal plate

/-N" /Yt804 -1-04 0/ "," i8"-Ia

zo Im-. "/-)" 7.50° -7-0

40k. + 0 + si 0T

S1.8665LiL 6961 17.7820 d 1.8W65

rn30 - 2.1573 i .06201620

Lo - .•o a • ' .•a .1324

.1321

• ~~r .W -To 1, .01-382 ••oQ )•m5 •.4. o.o0

,Wi

:36OZO 360z:--tan 25.8e-*.1111 4~ tan X..~- 0 teni 12.77 - .2268

1 23)4 1[2c~i 051[0 023 2+00

-960 + 5*51 9d-.060 F- 0 9W9 0 - 3o29.41

07 w- z@ =.03W-io2v07ta-l' x .03F.do30.8

tanz .02]1 1.003.22 0 + 2 Ot ]w

0A6 Z, M 0 0 J4 Qj 10.8' T

a W~7 f0.21 w.22 40

*Pr65. T.R. 182.

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- 32 -

i3

z 0

tan -. &Y,,c'2.4 12c .2148 ,45/9052

,.-r--•

from Char't IVe

Y n d n (?-) =01.57682 0• o.8

dA

oo'

'2%d/oo•5

0-01405 -, oos(.0 + 0. l9-o ,

0.07635 xi(J 1.06 *0.05

tan b - t,=(9, -,i o.oe i

@ "-:.=- • - o.825

-A wAB

For coaxial lime omit steps 17. 20p) 21., 24j 25 above

tan d;' tan"•(q +, 0 .0146

0.0.-43 x =1.0'6 0.0154 ,fsame fit

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- 33-

D. 2. Sample Calculation for a Ferrite in Hollow Wave Guide

S;2le=# 2 ,31 5.748 e#/t w 18,7

Date - 5/23/50 . 0.51

5m tm.=?wic C rew a 2?C tM 8 d - 0.58

!bS~cknea8m t an8 1.26

I SMAmpl on trMInal plate 11 SMple Xi/ 14 frm termndl plate

1.! @ -Nou *)

(7[x* ' N®' N...

a 0 U ,64GC + sicH.5a a a ao

at. 3611 B..x

3 P

,- 033 W tan - tan 14.030 2

(6Da + 6~~ @ ta 1 0 [- 206 'Q ~ Z

.30 Ie3.5 .. 3D82 106

Ppag 65, T.R. 3&2.

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-34-

Surn~ 2.33 @ V I+u U .3

Z2 1/2 Z __z__ = 1 .21o33, =/BLooi7,

[Z1.-z1 ] -2 4p B/ O -03316

1/2

tan y2d2 = = 1. oo 2 58°39,) 2920,

from Chart II

N =2 .675 + . 785' 1.033 /tan" 1•163 = 49°19'

'2d

2 *03 xL 2(7 "7.55) /•°•= =~ 6.28 x .1250

(~ e+)= 29054, (~ sin (rp +w= .4i98 @~ coo (jo+~r .867

(Cr-) -5 1o2 8 ' @~ si (rCe.f - -. 623 @~ coo (Scr - .782

F tan bm tan (rft 1.256

) I, AB . %86 x 7.55 0 510Pro 1 /2 1• .)/2

( (1+ 1.58)

20 - Sf- + -2 (~69.5.~ + 5.337'~ x 18.o6 + .668- 18.73

0 . -.1 +A 3 UldA @ +tan *d A uAq.~ .527

For coaxial line omit steps 17, 20, 21, 24., 25 above.

0

ta 5= . ton +•,

Sm f I I NIII1 =/IT@

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- 35 -

References

1. H..J. Lindenhovius and J. C. van der Breggen, Philips Res.

Repts. 3, 37 (1948); C. M. van der Burgt, M. Gevers,

J. P. J. Wijn, Tech. Rev. 14, 245 (1953); P.H. Haas,

R. D. Harrington, and R. C. Powell, J. Research Natl. Bur.

Standards 56, 129 (1956).

2. M. H. Johnson and G. T. Rado, Phys. Rev. 75, 841 (1949); see

also A. Wieberdink, Appl. Sci. Res. BI, 439 (1950); and

G. Eicholz and G. F. Hodsman, Nature 160, 302 (1947).

3. E.G. Spencer, R.C. LeCraw, and F. Reggia, Proc. IRE 44,

790 (1956).

4. E.G. Spencer, L.A. Ault, and R. C. LeCraw, ibid. 44, 1311(1956).

5. Tech. Rep. 182, Lab. Ins. Res., Mass. Inst. Tech., October,

1963.

6. W. B. Westphal, in "Dielectric Materials and Applications,",

A. von Hippel, Ed., M.I.T. Press and John Wiley and Sons,

New York, 1954, pp. 102 and 103.

7. H. E. Hartig, Physics 1, 386 (1931).

I

I

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,Unelasuiled" -Secait Casfcanti/oo .,

DOCUMENT CONTROL DATA. R&D

|. ORIGINATING ACTIVI .TY (Coape .... inul i. AEPOmT acUmeTy C"LAS.SIP1CATSO

Meaourelent of Dielectric Parmeteru of 118h-Ioua Materals In DilstributedCfrcu~tt

lechuical ReportS. AUTHORIS) •7.... i& mint. m, •uV

V. B. Westphal

Si. ¢€IIRACY ON gRANT .@. 58. @OMA?@U RPN NAT WUhSI•S)

& PROJECT NO.

No. 7Y7l

2•1s aoae~t is subject to sjpecial ezport camtroLs an each trnttal toforeiin go ieta or forel.• netlossla • be ud wil with prior appovalof" A? Materials labo •ra (M•lT), We• l,• Ohi .5

| !. SUU~I. I[MEMTAlm NOTlS Ii SP" W~n'Ne•N UilLRANY AC1'MTY

Reprt i Deletri Maeril ix A ftr eoe Material LbratoryRepot e DlleerleMatrias [Wrlgtt-Pattereom Air Force Base, Ohio

'¶*mwmt techniques tow detezulnation of the oemlez dLielectric owistantenoeqlex pez•blt awe gie '- a.---- .... r vith emauise wi the probiemeoo~mtere in :practical haleeslo mtaw-als. 1•pioal calculatimi andGeacriptiwi of secialJ~ sap3a bolAsr are 1noludl.

DD,'"..1473

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Secuity Cla.ssfication ,.1K W LINK A LINK [ LINK c

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Materials, lossy, laminated

Dielectric-measurement techniques

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