* UNITED STATES DEPARTMENT OF COMMERCE

PUBLICATION NBS TECHNICAL NOTE 642

Summary of WR15 Flange Evaluation

at 60 GHz

QC

100

U5753

c.2. U.S. [PARTMENT

OF

COMMERCE

National

Bureau

of

Standards
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards ' was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology,

the Institute for Computer Sciences and Technology, and the Office for Information Programs. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United

States of a complete and consistent system of physical measurement; coordinates that system

with measurement systems of other nations; and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of a Center for Radiation Research, an Office of Measurement Services and the following divisions: Applied Mathematics — Electricity — Mechanics — Heat — Optical Physics — Nuclear

Sciences 2 — Applied Radiation = — Quantum Electronics " — Electromagnetics 3 — Time

and Frequency 3 — Laboratory Astrophysics 3 — Cryogenics n

. THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to improved methods of measurement, standards, and data on the properties of well-characterized

materials needed by industry, commerce, educational institutions, and Government; provides

advisory and research services to other Government agencies; and develops, produces, and

distributes standard reference materials. The Institute consists of the Office of Standard Reference Materials and the following divisions: Analytical Chemistry — Polymers — Metallurgy — Inorganic Materials — Reactor

Radiation — Physical Chemistry.

THE INSTITUTE FOR APPLIED TECHNOLOGY provides technical services to promote

the use of available technology and to facilitate technological innovation in industry and Government; cooperates with public and private organizations leading to the development of

technological standards (including mandatory safety standards), codes and methods of test; and provides technical advice and services to Government agencies upon request. The Institute consists of a Center for Building Technology and the following divisions and offices: Engineering and Product Standards — Weights and Measures — Invention and Innovation — Product Evaluation Technology — Electronic Technology — Technical Analysis — Measurement Engineering — Structures, Materials, and Life Safety' — Building Environment * — Technical Evaluation and Application * — Fire Technology.

THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts research and provides technical services designed to aid Government agencies in improving cost effec- tiveness in the conduct of their programs through the selection, acquisition, and effective utilization of automatic data processing equipment; and serves as the principal focus within

the executive branch for the development of Federal standards for automatic data processing equipment, techniques, and computer languages. The Center consists of the following offices and divisions: Information Processing Standards — Computer Information — Computer Services —

Systems Development — Information Processing Technology.

THE OFFICE FOR INFORMATION PROGRAMS promotes optimum dissemination and

accessibility of scientific information generated within NBS and other agencies of the Federal Government; promotes the development of the National Standard Reference Data System and

a system of information analysis centers dealing with the broader aspects of the National Measurement System; provides appropriate services to ensure that the NBS staff has optimum

accessibility to the scientific information of the world. The Office consists of the following

organizational units: Office of Standard Reference Data — Office of Technical Information and Publications —

Library — Office of International Relations.

1 Headquarters and Laboratories at Gaithersburg. Maryland, unless otherwise noted; mailing address Washington, D.C. 20234.

a Part of the Center for Radiation Research.

3 Located at Boulder, Colorado 80302.

* Part of the Center for Building Technology.
lationa! Bureaa pi Standard

APR 2 3 1374

1173

Summary of WR15 Flange Evaluation at 60 GHz

B. C. Yates and G. J. Counas

Electromagnetics Division

Institute for Basic Standards

National Bureau of Standards

Boulder. Colorado 80302

»*»T

US DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATIONAL BUREAU OF STANDARDS. Richard W Roberts Director

Issued October 1973
JNational Bureau of Standards Technical Note 642

Nat. Bur. Stand. (U. S.). Tech. Note 642. 32 |iages (October 1973) CODEN: IVBTNAE

For sale by the Superintendent of Documents, VS. Government Printing Office, Washington, D.C. 20402

(Order by SD Catalog No. C13.46*42)40«f
CONTENTS

Page

1. Introduction 1

2. Background 2

3. Measurement System and Techniques 4

4. Type of Flanges Measured 6

5. Type of Flange Loss Measurements 7

6. Measurement Results 8

6.1 Flange Loss Measurements 8

6.2 Reflection Coefficient Magnitude Measurements 13

7. Conclusion 16

Appendix 17

References 19

in
ILLUSTRATIONS

Page

1. Block diagram of the flange loss and reflection

coefficient magnitude measurement system. 21

2. Illustration of the detected ref lectometer response

versus position of the sliding short circuit. 22

3. Illustration of the detected reflectometer response

versus position of the sliding termination. 23

4(a) UG-385/U flange. 24

4(b) UG-385/U flange with enlarged bossed surface. 24

5(a) Flat flange. 25

5(b) Rectangular bossed flange. 25

IV
SUMMARY OF WR15 FLANGE EVALUATION AT 6 GHz

B.C. Yates and G.J. Counas

ABSTRACT

The measurement results of flange loss and

reflection coefficient magnitude at 60 GHZ (WR15

waveguide) of various flange configurations are presented. Included are the effects of alignment

pins, surface finish, metallic contact surface,

contact area, and flange bolt torque.

Key words: Attenuation, Flange measurements, Reflection coefficient, VSWR.

1 . Introduction

The purpose of the evaluation summarized herein was to

examine the effect of variations such as contact surface

material (gold, rhodium, etc.), contact surface area and

pressure (flange bolt torque), and flange alignment on the

flange dissipative loss and reflection coefficient magnitude

in the WR15 waveguide size. A knowledge of these effects is

necessary in order to specify flange dimensional tolerances,

protective plating material for standards applications,

and proper flange bolt tightening procedures to obtain

repeatable measurements. Also, possibilities for an improved

flange design might be suggested from the results of the

measurement data.

In addition, the NBS is proceeding to establish measurement services in the frequency range of 55 to 65 GHz (WR15

waveguide). Thus, in order to establish error analyses for
these services a knowledge of the dissipative and reflected

power losses and repeatability of these quantities is essential

The measurement frequency chosen for this evaluation was

60 GHz. Although further investigation at other frequencies

in the WR15 waveguide band would give a more complete bound

on the measured quantities, the results given are considered

typical for the 55-65 GHz range.

2 . Background

The major parameters of interest are the dissipative

loss (the component of attenuation associated with dissipation) of a flange pair and the reflection coefficient magnitude . The dissipative loss (L) is mathematically related to

the two-port efficiency (n) of the flange pair, by the equation [1, p. 63 and 91] l

L = 10 log

1Q

i, (1)

where [1, p. 49]

z 02 l s

i 2

l 2 Ci - lr Tl 2

) n

= • -. (2)

z oi I x

" s n r T I "

I Cs12 s 21

-s 11

s 22 ) r T+s 22 | 2

r T

is the reflection coefficient of the element or device

terminating the two-port, the S.. are the scattering para-

^igures in brackets indicate the literature references at

the end of this note.
meters of the junction, and Z n ,/Z n7 is the ratio of the

characteristic impedances of the input and output ports.

Techniques for the measurement of efficiency or dissapative loss are well known [2,3,4]. The more general approach

[4] gives the efficiency for a particular terminating element

T,y. This method is appropriate for obtaining the efficiency

for specific terminations but may be tedious if the loss for

all Tj is required. A more expeditious technique is to use

the tuned reflectometer method [5] , a special case of the

above, which gives the efficiency for a non -reflect ing

termination, r T

= . In this case eq. (2) reduces to

|s

12 | 2 n = - , (r T

= 0). (3)

i - |s 22

|* T

Equation (3) assumes equal input and output characteristic

impedances for the flange pair. Then, if the reflection

coefficients of the pair are small [|S,,| and |S-

?

| << 1),

which is the case, eq. (2) reduces to

i - |r T

| 2 n - n n

- (4)

° 1 " %|rT l 2

which can be used to adequately approximate the efficiency

for various terminating elements. This latter approach was used for the loss measurements. A more exact method than

described above is given by Beatty [6]

.
In addition, the timed reflectometer technique was chosen

since it allows the measurement of the reflection coefficient

magnitude of the flange pair immediately proceeding or following the loss measurement.

A measurement system, method, and results for the measure- ment of the reflection coefficient magnitude of WR12 (60-90

GHz) flanges is given in reference [7].

3. Measurement System and Techniques

The basic measurement system consists of a tuned reflectometer (fig, 1) and uses a sliding short circuit for measuring

the flange loss and a sliding termination (|r„| - 0.01) for

obtaining the reflection coefficient magnitude. Details for

implementing a millimeter reflectometer and the associated

components are given in reference [8].

The loss measurements are performed by sliding a short

circuit from section A (fig. 1), through the flange pair,

and into section B. A typical detected output response from

the reflectometer is shown in figure 2. When the ordinate

axis (fig. 2) is calibrated in decibels, the difference between the ordinate intercepts of the straight-line responses

(average of the periodic variations in section B) at the

plane of the flange pair is the dissipative loss of the

flange pair when terminated by a non-reflecting element.

(Section A is incorporated in the reflectometer, thus

the detected response shows little or no variation due

4
to initial reflectometer tuning operations.) The loss for

any terminating element |r T

| > can be obtained by applying

eqs . (1) and (4) . The reflection coefficient magnitude is measured with the

same configuration (fig. 1) except a sliding termination

(|rT

| <_ 0.01) replaces the sliding short circuit. Figure 3

is a typical detected response when the termination is moved

from section A to section B.

The reflection coefficient magnitude of the flange pair,

[ r

-p | , is given by (see Appendix A)

ri-Ri

or

tl+Rj

1 + R

ii-Rj

r T

| (l+e), |r

F

| < |r T |

r T

| (l+e), |r

F

| > |r T

|

(5)

(6)

where |r T

| is the reflection coefficient of the sliding termination (|r T

| is assumed known) and R is given in terms of

the decibel variation (L

R

) in the detected response (fig. 3)

by the equation

LR

(dB) = 20 log

1Q |. (7)

Tables [9] are available to facilitate the calculation of R. The term e is of third order and can usually be ne- glected. For completeness it is given by

r T l 2 r F l 2

i - |r T | 2 (8)
4 . Type of Flanges Measured

The type of flange used for the major portion of the

measurements was an altered UG-385/U (this is a JAN designation) flange with an enlarged bossed surface. To explain

the term altered, first consider the standard UG-385/U flange

(fig. 4(a)) which consists of a raised or bossed connecting

surface encircled by a groove of approximately 0.070 inch

width. The alteration to the UG-385/U flange is to omit the

groove and enlarge the bossed surface (fig. 4(b)) by approximately the groove width. The reason for choosing the enlarged

bossed flange for this study was because experience has shown

that the WR 42, WR 28, and WR 15 circular grooved flanges are susceptible to a bending distortion (at the groove) due to

flange bolt tightening, and thus, effects the long-term

repeatability of millimeter standards. It was found after

250 connect-disconnect operations that this type of distortion

was negligible with the enlarged bossed flange.

Two other altered flange types were tested for contact

surface effects . One was a flat (bossed surface removed)

circular flange of 0.75 inch diameter and a thickness of 0.20

inch (fig. 5(a)). The other was a circular flange with a rec- tangular bossed surface of 0.050 inch wall thickness (fig.

5(b)) and height of 0.010 - 0.020 inch.
Loss and reflection coefficient magnitude measurements

of standard UG-385/U flanges (fig. 4(a)) are included for

comparison.

5 . Types of Flange Loss Measurements

Measurements of flange loss. were made to determine

individually the effect of variations in: 1) alignment pins

and holes, 2) contact surface finish, 3) contact surface

material, 4) contact surface area, and 5) flange bolt torque.

Type 1 measurements (alignment pins and holes) consisted

of comparisons of: a) standard pin (0.0625 inch diameter)

and hole (0.064 inch diameter) dimensions, b) standard pins

in holes oversized (0.0655-0.066 inch), c) larger pins (0.125

inch diameter) and holes (0.127 inch diameter), d) larger

pins in oversized holes (0.130-0.1305 inch), and e) no pins.

The loss measurement results are tabulated in Table I. As

an example on how to read data from the table, the no pin

measurement results (type le above) are found in the row with the left column label: Type 1, row e, "No Pins."

Type 2 measurements (contact surface finish) consisted

of comparisons of: a) machined surface finish on enlarged

bossed flanges (fig. 4(b)), b) machined surface finish on flat

flanges (fig. 5(a)), c) lapped surface finish on enlarged

bossed flanges, and d) lapped surface finish on flat flanges.
Type 3 measurements (surface material) consisted of

comparisons between pairs of metallic contact surfaces of

a) brass, b) silver plate (approximately 50 microinch, equivalent to at least one skin depth) , c) tarnished silver (20 -

50 microinch thickness), d) rhodium plate (50 microinch thickness) , e) rhodium flash (20 microinch thickness) , and f ) gold

plate (50 microinch thickness).

Type 4 measurements (contact surface area) consisted of

comparison of the four flange connecting surfaces discussed

previously. They are the: a) standard UG-385/U flange (fig.

4(a)), b) enlarged bossed flange, (fig. 4(b)), c) flat flange

(fig. 5(a)), and d) rectangular bossed flange (fig. 5(b)).

Type 5 measurements (flange bolt torque) consisted of

applying various torques to a variety of flange pairs. The

torques were: a) 2, b) 3, c) 4, and d) 5 pound-inch.

The enlarged bossed flange was used exclusively for Type 1

and 3 measurements.

6. Measurement Results

6.1. Flange Loss Measurements

Table I is a summary of the measured average loss for a measurement set, estimated standard deviation of the mean of
m

U •n o

c

11) Tl o ^

c X o

'J m ^

>

lO V

rr* M

d

^H

CD rsj o~t r-- o r-- o m- O H W CMN H NO"* to ai O MOINO \o lo cr* to 010hOO<t vo en to lo OvOtON

N h r-- OO L^ h-WvOrl xO OO N N O^ N MOH^t OO Csl rH tO

r-H i-H r-1 t—1 i—1 to i—

1

rH CV1 j—1 r—1 I—

1

\0 i— 00 o t^ vOtOoOvO OO M vO Ol (vj to HcOlON O O O

^t ai to o to *n- co en oo CTi O rH LO ^f CD en en oo o O N vD (N

"3- f- "* LO O «g- t-- lo i^ LO o CTi r^ CS] \0 ^J LO t^ to O H <M H

a)nn

td

L|

rrt —

i

a

rsi ^f •* ^3- •* csi \o *0 vo vD •* "* OO «* OO 00 vO vD 00 *-i- m- >* >*

W

J

CQ<

CQ

T) V* i"> XJ

tu

£

CO w

T3

n]c

cd

*->

a

1O

r-- «nrd ">

c!cd 2

H tOlO Ol "t N LOLDrt/N

<u X

rH CON M/lHiD OO LO LO LO i-H CD

rH to tO O LO OSl N OO N H

LO rH ^D tO en ^o o«* t~- to ai

** r—i r—t r—l

caT) T3 O

cd rj o OvOHN N

if rd > CD < 2

Xa

01 rH

<* O "* 00 t— t~~

t~- -*

cxi *s- \o oo lOOOlKlt~- H Ol tN IONCN

13 O cd U

<D X rH CNl CD M V—

/

>—' bO H 13 a

to CD CO cd cd

CD r< M to oo ^

rH CD -H o to a 4h O > CO X to cd £ O (1) h O rH 13

i—1 CD 13 XI m cd At) o > CD r< ^^ to C C X o 60 13 CD CD 13 13 to

cd od (h CD > 00 CD CM O

rH 13 13 c a a a

cni cd <-> r-l Cd 00

!h to rH CD X

CD -H +J tO

«d- a <o *—'x

cd to LO X X XI X

CD •H .H Od cd CD a rH cd *-> CD 4-) to cd cd CD rH O CD ri CD u o u u

P< ft & ft CD <4H r-i Cd ft ,—

,

Cd rH rH CD ft MH X 00 Cd ft a a a a

>. a a X I 1 a r-t X UHT) ft^H 4-> X a i-i X •H .H -H "H H 13 13 -h -H H 13 13 CD WH H CNI ft CD rd H 3 i3 cd a E-i i i i i Sh Sh ft ft in CD CD 1 1 *

I xi e 6 I—

1

\ CD rH 00 13 13 13 13

cd cd c C COT) rlfl33 ft LO O0MH a a a a a

13 13 CD CD r-t • H -H CD CD I/) CD -H -H -H 0O Sh cd 3 3 3 3

a a oo oo ft x x ft ft 00 > a 13 13 13 to Cd +J 4-> o o o o

cd cd (h U u u ft ft cd iH fn O O rH i i-h cd u ft ft ft ft

•p 4-> cd cd o cd cd cd cd Sh H cd X X O U CH tl) WMJJ2 22JJ m u~i h cd a; u 3 m Ph ctj csi to ^a- lo

cd x (J 13 CD cd x O 13 cd X O 13 CD H-i cd X U 13 cd X O 13
the set, number of flange pairs in the set, and the 95 percent

confidence interval for the flange pair measurements. The

data for some of the flange pairs have been duplicated in

Table I for comparison purposes. These pairs are shown in

parentheses and are referenced to the first entry of the data

(e.g. , see type 2a)

All of the measurement data given in Table I were obtained

using flanges carefully finished at NBS (pin and hole alignment

and surface finish)

Also measured for loss were a sample of twelve various

commercially manufactured flanges. The average loss for these

flanges was 0.016 dB with a range of 0.007 to 0.045 dB. This

relatively high loss is probably attributed to two factors;

first, that some flanges were rhodium plated (see Type 3

results) , and second, the flange alignment holes and pins

were not compatible between flange pairs resulting in a

forced misalignment or an incomplete closing between the

connecting surfaces. In comparison, the measurement data

(le) for the loss measurements with no pins (brass flanges)

is approximately 0.013 dB with a range of ± 0.002 dB.

The following statements summarize the conclusions

drawn from the data of the loss measurement comparisons.

Type 1. Alignment Pins and Holes

1. Oversized holes (0.067 inch) when used with 0.0625

inch pins increased the loss by 0.003 to 0.004 dB.

10
2. The large pins (0.125 inch) in the 0.127 inch hole

did not affect the loss.

3. If oversized holes (0.130 inch) are used with large

pins (0.125 inch), the loss appeared to increase by

0.001 dB (this amount of loss difference is con- sidered negligible).

4. The flanges with no pins resulted in an approximate

doubling of the loss.

Type 2. Contact Surface Finish

1. Lapping of the enlarged bossed flange did not decrease the loss (if the machined surface is relatively flat), but the standard deviation between pairs

(not to be confused with the standard deviation of

the mean) of the lapped flanges was near zero (i.e.,

all randomly selected flange pairs appear to have

the same loss) .

2. Lapping of the flat flange gave a moderate reduction

in loss and a significant reduction in the estimated

standard deviation of the mean. (Here, lapping has

improved the surface flatness. Refer to Type 4 measurements for a discussion of flatness versus

loss) . Type 3. Contact Surface Material

1. Silver plated, gold plated, and brass contact sur- faces have similar loss characteristics.

11
2. Tarnished silver flanges had approximately twice

the loss as the untarnished flanges.

3. Rhodium flashing almost doubled the loss.

4. Rhodium plating quadrupled the loss.

Type 4. Contact Surface Area

The larger the contact surface the greater was the

loss (all flanges used in this test were lapped).

Comparison of the contact surfaces of the four types

of flanges showed a direct relation between flat- ness and loss (e.g., the flat-faced flange was flat

to approximately 200 microinch, the enlarged bossed

and UG-385/U flanges to 100 microinch, and the rectangular bossed flange to less than 50 microinch). The

average loss for these flanges was 0.0096, 0.0064,

0.0063, and 0.0038 dB, respectively.

Type 5. Flange Bolt Torque

The flanges in this group consisted of a random

sample of the various flanges (i.e., flat flange,

silver plated flange, etc.) used previously so the

results of the loss and standard deviation measurements given in Table I is only an indication of the

torque effects and not an exact measure of a particular type of flange. It was found that a 2 lb.-

in. torque, which is equivalent to finger- tight , did

not apply a sufficient amount of contact pressure;

12
however, a tightening of 3 to 4 lb. -in. appeared

to give adequate contact pressure. A torque of

5 lb. -in. was considered to exert too much strain

on the threads of the flange connecting holes (5

lb. -in. is approaching torsional failure). A

recommended tightening procedure is to use a hexagonally-tipped screw driver (most commercially

available flange bolts are of the Allenhead type).

Then, it is almost impossible to obtain manually a torque of 5 lb. -in. The 3-4 lb. -in. torque can be

obtained by applying a firm rotational pressure.

6 . 2 Reflection Coefficient Magnitude Measurements

The following is a summary of the reflection coefficient

magnitude measurements made on the various types of flanges.

A sample of 66 flange pairs were measured, all of which

were machined (alignment pins and holes and surface finish)

at the NBS . The waveguide to which the flanges were attached

was obtained commercially and was not of exact WR 15 dimensions (approximately 0.0002 inch undersized and an 0.008 inch

corner radius), although it was uniform to at least 0.0001

inch. Since the reflection coefficient magnitude is referenced to the waveguide dimensions, the inexactness of the

13
dimensions will be reflected as an inaccuracy (± 0.003 with

respect to WR15 waveguide of exact dimensions) in the measurement values obtained. The reflection coefficient measurements were performed with respect to such commercial waveguide sections because precision waveguide sections of exact

WR15 dimensions with the different flange configurations

would be difficult and expensive to obtain.

The average reflection coefficient magnitude of 66

flange pairs was 0.0023 as referenced to the commercial waveguide sections. From this sample 50 percent of the pairs

ranged between 0.002 and 0.003, 25 percent between 0.0015 and

0.002, and 15 percent between 0.003 and 0.0035. Except for

one pair (magnitude of 0.0037) the remaining 10 percent of

the reflection coefficient magnitudes of the pairs were less

than 0.0015. (The above percentages are approximate.)

The sample of 66 flange pairs consisted of all types of

flanges used for the loss measurements, and were pooled together to obtain an average since the average reflection

coefficient of the various types did not differ significantly

from the grand average except as discussed below.

In the sample two types of flanges exhibited a noticeably higher reflection coefficient that the average. These

were the flanges with no pins (- 0.003 average) and the

14
rhodium plated flanges (_- 0.0033 average). It was expected

that the flanges without pins would have a higher reflection

coefficient, but this result was not expected for the

rhodium plated flanges. The cause for this is not obvious

and cannot be explained at this time.

When a sample of six average valued (reflection coefficient) flanges were measured with respect to the NBS WR1

5

precision waveguide (dimensions are fabricated to 50 microinch tolerance), the average reflection coefficient magnitude

was 0.0036 with a range of 0.0015 to 0.0075. This is in agree

ment with theory [8, pp. 52-53, 10] for the tolerances of

the commercial waveguide used.

A sample of commercially manufactured waveguide section

and flanges was also tested; the measurements were performed

with respect to the commercial waveguide. The average

reflection coefficient was 0.006 with a range of 0.0033 to

0.009. This large value of reflection coefficient is largely

attributed to the fact that the alignment holes and pins were

not sufficiently perpendicular to the flange face, thus,

proper alignment was not obtained. Also, several of the

flanges varied widely in the placement of the alignment pins

and holes resulting in improper mating and alignment. When

these results are compared with those where no alignment pins were used, it appears that a forced misalignment resulted in

15
a higher reflection coefficient than the random alignment

obtained without pins. Since the two samples were small (8

pairs), a definite conclusion (in reference to the last statement) cannot be reached, but a more detailed testing would

probably resolve this question.

A set of twelve NBS machined enlarged bossed flange pairs were tested (eight measurements per pair) for repeatability.

The pin and hole tolerances of this set were approximately

0.0005 inch. The average reflection coefficient was 0.0018

with an estimated standard deviation of the mean of 0.00015.

The estimated standard deviation between pairs (11 degrees of

freedom) was 0.0005.

7 . Conclus ion

The flange measurements of loss and reflection coefficient

magnitude which have been presented are exemplary of the re- sults obtainable under a rigorous control of pin and hole

alignment tolerances (within 0.0005 inch when applicable).

Thus, it is necessary that care be exercised in the handling

of the contact surfaces and pins since any damage will effect

the loss and reflection characteristics. Further, contact

surfaces and alignment pins and holes must be made to

appropriate dimensions and tolerances by all manufacturers

and suppliers in order to achieve precision (repeatable) meas- urements .

16
Appendix A

A derivation of eqs. (5) and (6) follow.

Denote the magnitude of the maximum and minimum detected

ref lectometer responses by |b max

c Irl I I • rill, respectively. Then, mln L j 5 f J >

min min

c r and b •

1 'max * 'mm

= R. (9) max max

Also, it can be shown for the lossless 2 case [12, 13] that

max

r1 + r F

I

' i T l

1 +

| T V 1 T T \ b 1 and

1 mm

|r.

l - |r

F

r T

|

(10)

Cii)

or

= —— ~, |r T

| < |r

F

|. (12)

l - |r Fr T

| Now, substitution of eq. (10) and (11) into eq. (9) gives

R =

C I r T i r F |)(i + |r F

r T

|)

(13)

C|r T

| + r p |)(i - |r F

r T

|)

Next, performing the indicated algebra one obtains,

1-R

1 + R

Tpl i - |r T

| 2

i - |r

F | 2 (14)

2 Since the efficiency of the flanges was greater than 0.999,

losslessness has been assumed.

17
or

|Tpl

1+R

|r T |

r i- 1 r 1 2

' 1 F'

Li- |r T l 2

fl-Rl

L l+R

|r T | ;i + E)

(15)

(16)

where

e =

r T T - lr F

| 2

i - |r T

| 2 (17)

Likewise, substitution of eq. (10) and (12) into eq. (9)

gives

r l+R"

|r T

|

f 1 " l r F

l 2

| ii - |r T

| 2

J fl+Rl

1-R

|r T | ;i + £ )

(18)

(19)

where e is given by eq. (17)
References

[1] D.M. Kerns and R.W. Beatty, Basic Theory of Waveguide

Junctions and Introductory Microwave Network Analysis

(Pergamon Press, New York, N.Y. 1967).

[2] A.L. Cullen, Measurement of microwave transmission efficiency, Wireless Engineer 26, pp. 255-258 (Aug. 1949).

[3] R.W. Beatty, Determination of attenuation from impedance

measurements, Proc. IRE, 38, pp. 895-897 (Aug. 1950).

[4] G.F. Engen, An extension to the sliding short method of

connector and adaptor evaluation, J. Res. NBS (U.S.), 75C

(Eng. and Instr.), Nos. 3 and 4, pp. 177-183 (July-Dec.

1971) .

[5] R.W. Beatty, G.F. Engen, and W.J. Anson, Measurement

of reflections and losses of waveguide joints and connectors

using microwave reflectometer techniques, IRE Trans, on Instr., Vol. 1-9, No. 2, pp. 219-226 (Sept. 1960).

[6] R.W. Beatty, Efficiencies of microwave 2-ports from re- flection coefficient measurements, IEEE Trans, on Microwave Theory and Techniques, Vol. MTT-20, No. 5, pp. 343-

344 (May 1972) .

[7] O.L. Patty, W.E. Little, M.H. Zanboorie, Waveguide con- nector measurements with a millimeter-wave reflectometer,

IEEE Trans, on Microwave Theory and Techniques, Vol. MTT16, pp. 121-123, (Feb. 1968).

[8] B.C. Yates and W. Larson, Millimeter attenuation and re- flection coefficient measurement system, NBS (U.S.) Tech.

Note 619, 175 pages (July 1972).

19
[9] R.W. Beatty and W.J. Anson, Table of magnitude of reflection coefficient versus return loss (L D

= 20 log, n ), R 10

| r | NBS (U.S.), Tech. Note 72, 25 pages (Sept. 1960).

[10] D.M. Kerns and W.T. Grandy, Jr., Perturbation theorems for

waveguide junctions, with applications, IEEE Trans, on Microwave Theory and Techniques, Vol. MTT-14, pp. 85-

92, (Feb. 1966)

[11] W.S. Anson, A guide to the use of the modified reflectometer technique of VSWR measurement, J. Res. NBS (U.S.),

65C, (Eng. and Instr.), No. 4, 217 (Oct. -Dec. 1961).

[12] J.L. Altman, Microwave Circuits, pp. 393-395 (D. Van

Nostrand Co., New York, N.Y., 1964).

[13] R.W. Beatty, A guide to the measurement of reflection

coefficient and impedance in waveguides and transmission

lines, to be published by NBS.

20
o

CCLU o —

LUCE ZUJ

zooz

CTUJ I h- XO

CEUJX

ccp -it;

_io

COo

CD >^

CO s

<D +J

to

to

+-> aau

to

nJ

X!

+->

r-l d

boa

c!

0>uao

•r-l !-> U

<D

r-H MH

(1) hH T)d

Ri

to

too

.—(

0)

bfl d

0) rd

>-< b0

nioo

-—I

0)d

21
u

u

•l-l u

+Jho

J3

enM

fl

•r-i T)

•f-< ^^

CO

<u J3

+-> m

C

o

• r* +>

•i-" toa

to ^_ 3

to 3 h o V

k- > O COd o to SI (U co h

Fh o> CD _c

-4-> <D TD a *^CO o

1) M— —1 O <Uu c Tl o CD u

-^— O

CU en +> O

Q_

CU

CU ^3

+j

<+Ho

a

•»-i +j

rcj M

+j

CO3 (QP) 3SU0dS9^ p3p3i9Q III UOI|DUDA

CM

IDU

22
cc

o

o

CM

ii

CT _J U1- <4uj

orr — 7

2><

(T_J

UJQ_ o 1- . o \

o

UJ

CO

(gp) esuodsay papaya ui uoijduda

g

"toO

Q_

C

•l-t

enoa

CO3

c

o CD H

> o a) c en E

do

CD en H

1)

cnc -w

0) TJ

£ CO o

4->

0) i—

i

MH

CO

XI

CD

+->u

<D

+->CD TJ

cu

23
Figure 4(a). UG-385/u flange.

Figure 4(b). UG-385/u flange with enlarged bossed surface.

24
Figure 5(a). Flat flange.

Figure 5^b). Rectangular bossed flange.

25
FORM NBS-114A (1-71)

1. PUBLICATION OR REPORT NO. NBS TN-642

2. Gov't Accession No.

U."3. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

SUMMARY OF WR15 FLANGE EVALUATION AT 60 GHz

S. Publication Date October 1973

4. Performing Organization Code

7. AUTHOR(S)

B. C. Yates and G. J. Counas

t. Performing Organization

10. Project/Task/ Work Unit No. 2723141

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS, Boulder Labs

DEPARTMENT OF COMMERCE

Boulder, Colorado 80302

11. Contract/Grant No.

12. Sponsoring Organization Name and Address 13. Type of Report & Period Covered

14. Sponsoring Agency Code

IS. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant bibliography or literature survey, mention it here.) The measurement results of flange loss and reflection coefficient magnitude

at 60 GHz (WR15 waveguide) of various flange configurations are presented.

Included are the effects of alignment pins, surface finish, metallic contact surface,

contact area, and flange bolt torque.

17. KEY WORDS (Alphabetical order, separated by semicolons)

Attenuation; flange measurements; reflection coefficients; VSWR

18. AVAILABILITY STATEMENT

|3T| UNLIMITED.

I I FOR OFFICIAL DISTRIBUTION. DO NOT RELEASE

TO NTIS.

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF PAGES

32

22. Price 40£
NBS TECHNICAL PUBLICATIONS

PERIODICALS JOURNAL OF RESEARCH reports National Bureau of Standards research and development in

physics, mathematics, and chemistry. Comprehensive

scientific papers give complete details of the work,

including laboratory data, experimental procedures,

and theoretical and mathematical analyses. Illustrated with photographs, drawings, and charts. Includes

listings of other NBS papers as issued.

Published in two sections, available separately:

• Physics and Chemistry (Section A)

Papers of interest primarily to scientists working in these fields. This section covers a broad range of physical and chemical research, with major emphasis on standards of physical measurement, fundamental

constants, and properties of matter. Issued six times a year. Annual subscription: Domestic, $17.00; Foreign, $21.25.

• Mathematical Sciences (Section B)

Studies and compilations designed mainly for the mathematician and theoretical physicist. Topics in mathematical statistics, theory of experiment design, numerical analysis, theoretical physics and chemistry,

logical design and programming of computers and

computer systems. Short numerical tables. Issued quarterly. Annual subscription: Domestic, $9.00; Foreign,

$11.25.

DIMENSIONS, NBS

The best single source of information concerning the Bureau's measurement, research, developmental, co- operative, and publication activities, this monthly

publication is designed for the layman and also for the industry-oriented individual whose daily work

involves intimate contact with science and technology —for engineers, chemists, physicists, research managers, product-development managers, and company

executives. Annual subscription: Domestic, $6.50; Foreign, $8.25.

NONPERIODICALS Applied Mathematics Series. Mathematical tables, manuals, and studies. Building Science Series. Research results, test methods, and performance criteria of building materials, components, systems, and structures. Handbooks. Recommended codes of engineering

and industrial practice (including safety codes) de- veloped in cooperation with interested industries, professional organizations, and regulatory bodies. Special Publications. Proceedings of NBS conferences, bibliographies, annual reports, wall charts, pamphlets, etc. Monographs. Major contributions to the technical

literature on various subjects related to the Bureau's

scientific and technical activities. National Standard Reference Data Series. NSRDS provides quantitative data on the physical

and chemical properties of materials, compiled from

the world's literature and critically evaluated. Product Standards. Provide requirements for sizes, types, quality, and methods for testing various industrial products. , These standards are developed co- operatively with interested Government and industry groups and provide the basis for common understanding of product characteristics for both buyers and

sellers. Their use is voluntary.

Technical Notes. This series consists of communications and reports (covering both other-agency and

NBS-sponsored work) of limited or transitory interest. Federal Information Processing Standards

Publications. This series is the official publication within the Federal Government for information on

standards adopted and promulgated under the Public Law 89-306, and Bureau of the Budget Circular A-86

entitled, Standardization of Data Elements and Codes

in Data Systems. Consumer Information Series. Practical information, based on NBS research and experience, covering areas of interest to the consumer. Easily understandable language and illustrations provide useful background knowledge for shopping in today's tech- nological marketplace.

BIBLIOGRAPHIC SUBSCRIPTION SERVICES

The following current-awareness and literature-survey bibliographies are issued periodically by the Bureau : Cryogenic Data Center Current Awareness Service (Publications and Reports of Interest in Cryogenics). A literature survey issued weekly. Annual subscription: Domestic, $20.00; foreign, $25.00.

Liquefied Natural Gas. A literature survey issued quarterly. Annual subscription: $20.00.

Superconducting Devices and Materials. A literature survey issued quarterly. Annual subscription: $20.00. Send subscription orders and remittances for the preceding bibliographic services to the U.S. Department

of Commerce, National Technical Information Service, Springfield, Va. 22151.

Electromagnetic Metrology Current Awareness Service (Abstracts of Selected Articles on Measurement

Techniques and Standards of Electromagnetic Quantities from D-G to Millimeter-Wave Frequencies). Issued monthly. Annual subscription: $100.00 (Special rates for multi-subscriptions). Send subscription order and

remittance to the Electromagnetic Metrology Information Center, Electromagnetics Division, National Bureau

of Standards, Boulder, Colo. 80302. Order NBS publications (except Bibliographic Subscription Services) from : Superintendent of Documents, Government Printing Office, Washington, D.C. 20402.
U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington. D.C. 20334

OFFICIAL BUSINESS

Penalty for Private Use. $300

POSTAGE AND FEES PAID

U.S. DEPARTMENT OF COMMERCE COM—215

ilrGPO 1973—784-570 REGION NO. 8

^a^^^^^^m^^^^a^m