NBSIR 86-3060

AlllOS Sbl751

REFERENCE

NBS

PUBLICATIONS

RVEY OF TRIAXIAL AND MODETECHNIQUES FOR

MEASURING THE SHIELDING

EFFECTIVENESS OF CONNECTORS

AND CABLES

Ramon L. Jesch

National Bureau of Standards

U.S. Department of Commerce

Boulder, Colorado 80303

October 1986

-QC

100

.U56

86-3060

1986

V

NBSIR 86-3060

NBS

RESEARCH

INFORMATION CENTER A SURVEY OF TRIAXIAL AND MODESTIRRED TECHNIQUES FOR

MEASURING THE SHIELDING

EFFECTIVENESS OF CONNECTORS

AND CABLES

Ramon L. Jesch

Electromagnetic Fields Division

Center for Electronics and Electrical Engineering

National Engineering Laboratory

National Bureau of Standards

Boulder, Colorado 80303

October 1986

Sponsored in part by

U.S. Army Aviation Systems Command

St. Louis, Missouri 63120

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

CONTENTS

Page

1. INTRODUCTION 1

2. BACKGROUND 2

2.1 Shielding Effectiveness 2

2.2 Sample Configuration 3

3. MEASUREMENT TECHNIQUES

3.1 Triaxial Technique

3.2 Mode-Stirred Technique

3.3 Comparison of Techniques 1

4. CONCLUSIONS 16

5. ACKNOWLEDGMENTS 17

6. REFERENCES 17

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A SURVEY OF TRIAXIAL AND MODE-STIRRED TECHNIQUES FOR MEASURING

THE SHIELDING EFFECTIVENESS OF CONNECTORS AND CABLES

Ramon L. Jesch

Electromagnetic Fields Division

National Bureau of Standards

Boulder, Colorado 80303

This report is the result of an extensive literature search

conducted in the field of connectors and cables, and of the

problem dealing with radio frequency leakage characteristics and

the ability to measure the shielding effectiveness of these

connectors and cables. It reviews two measurement techniques

for determining the shielding effectiveness: the triaxial test

technique that has been used for over 20 years and the modestirred test technique that recently has started to gain in

popularity. From this survey, certain inferences are drawn about

these techniques in terms of device configuration, frequency

range, and ease of measurement and are presented in chart form

for comparative purposes.

Key Words: cables; connectors; mode-stirred; relative leakage

power; shielding effectiveness; triaxial.

1 . INTRODUCTION

In recent years, one major concern with the design and use of coaxial

and multicontact connectors and accompanying cable assemblies has been the

amount of electromagnetic (EM) energy or radio frequency (rf) leakage that

can be tolerated in today’s advanced electronic systems. Toward this end,

these systems have been designed to withstand the effects of electromagnetic

interference (EMI) at operating frequencies from a few megahertz to many

gigahertz. To facilitate system design, shielding effectiveness data are required for connectors and cables that interconnect various components,

subassemblies, equipment, and subsystems. The evaluation of shielding

effectiveness measurements of connectors and cables has been the subject of

a great deal of analysis and research for some time.

Methods of measuring the rf leakage of connectors and cables have

received considerable attention over the years. Prominent among these are

1
the use of the triaxial technique [1] which configures the test sample

( connector/ cable under test) as a segment of transmission line. Recently

the mode-stirred technique [2] that utilizes a test chamber to expose the

test sample to random incident fields has started to gain in popularity.

This paper briefly reviews the background and analytical principles

involved with measuring the shielding effectiveness of test samples with the

triaxial and mode-stirred techniques from which their advantages and limitations are given.

2. BACKGROUND

2.1 Shielding Effectiveness

In general, the shielding effectiveness (SE) of a coaxial transmission

line is the ability of the outer conductor to protect the transmission line

from being disturbed by EM fields leaking into or out of the transmission

line. Many groups and organizations have spent considerable time and effort

in studying measurement methods dealing with SE [3 ~ 5]. For connectors and

cables, a measure for determining the SE is defined or specified in terms of

transfer impedance or relative leakage power.

The transfer impedance is the ratio of the transferred voltage inside

the coaxial line (into which the connectors are inserted) to the longitudinal current flowing on the outside of the coaxial line. The general

theory of coaxial shields was first presented in 193^ by Schelkunoff [6], in

his classic paper, that conceived the term "transfer impedance" to relate

the open-circuit voltage induced in the conductors inside a cylindrical

shield to the external current flowing on the shield. The evaluation of

transfer impedance and thus SE is a relatively complex procedure that is

especially difficult to implement for frequencies over 10 MHz [?] and will

not be used here.

The relative leakage power, on the other hand, is a more convenient

method to implement and use to determine the SE for both the triaxial and

2
mode-stirred techniques. The relative leakage power for determining SE is

the rf power which leaks into, or out of, a connector or other device, at a given frequency and is defined by the relationship,

SE = 10 J,ogio(Pi/P2) dB, (1)

where

Pj = total applied power, and

P 2 = total leaked power.

2.2 Sample Configuration

In the measurement of SE, the device (connector or cable) from which

leakage is to be measured is incorporated in a coaxial transmission line

which in turn is terminated in a matched load. The matched load simplifies

both the measurement procedure and data reduction by minimizing the formation of standing waves which are a major source of error in SE measurements

[8]. In measuring the SE of multicontact connectors in a triaxial test

fixture, the interior of the connector must be configured as a segment of

coaxial transmission line of known impedance. This is accomplished by

removing the inserts and the multi-pin contacts from the connector and then

substituting a coaxially located center conductor.

The assumption is made that the SE is identical whether the rf power is

leaking into or out of the device. In the case of mode-stirring, the power

leaking into the device is measured while with the triaxial technique, the

power leaking out of the connector is determined.

3. MEASUREMENT TECHNIQUES

3.1 Triaxial Technique

The triaxial technique was developed by Zorgy and Muehlberger [1] for

measuring the SE of connectors and cables and enhanced by others [9]. The

triaxial technique is used by many organizations and prescribed in MIL-C3
3901 2B [10] for testing certain rf connectors and in MIL-C-38999H [11] for

testing multicontact cylindrical connectors.

Figure 1 is a diagram of a test fixture that is used as the triaxial

technique. The test fixture is a segment of coaxial transmission line

surrounded by an outer tubular conductor which forms, externally, a second

coaxial system that is normally configured for a characteristic impedance of

50 ohms. This implies for each connector and cable size measured that a new test fixture has to be designed and configured to maintain a constant 50-ohm

characteristic impedance throughout the test fixture and reduce internal

reflections which are a source of errors in the measured SE. The excitation

of the outer coaxial line is believed to be principally TEM although it is

possible for higher order modes to exist, depending on frequency. The

wavelength at the operating frequency must be greater than the mean circumference of the coaxial system to prevent propagation of higher order modes.

The second external coaxial system in figure 1 is terminated at one end

in a sliding short circuit and at the other tapered transition in a matched

RF CONNECTOR 50 OHM

FROM TERMINATION

GENERATOR FOR INNER

RODS UNDER TEST DETECTOR

Figure 1. Triaxial test fixture.

4
detector. The sliding short circuit is positioned to produce a maximum

indication at the detector for each test frequency measured. Positioning

of the sliding short-circuit must exceed a half-wavelength between the

short-circuit and the connector pair under test. On a connector assembly

that is properly mounted on semi-rigid cables or air lines, there are three

possible leakage areas: the region around the mating face and locking

mechanism of the connector plus the two regions where the connector is

attached to the cable or air line. For complete leakage measurements, the

detector should couple to all three areas.

The SE of the connector pair under test is determined by establishing

as a reference and measuring the total applied power P.^ that is fed through

the inner coaxial line. Next the power ?2 leaking through the connector

pair into the outer coaxial structure is maximized at the detector by the

sliding short-circuit and measured. The SE of the connector pair in

decibels is determined using equation (1).

Figure 2 is a block diagram of a substitution technique that is also

used to determine the SE of the connector pair under test which requires

producing a maximum indication at the detector. This is achieved by sliding

the short-circuit until the power P 2 leaking through the connector pair into

the outer coaxial structure is maximized at the detector. The detector is

then connected directly to the power source and the amount of attenuation

that is required to bring the detector back to the same detector level as before is measured. The measured amount in decibels is the SE. For low

Figure 2. Block diagram of substitution technique.

5
level SE measurements below about 100 dB, the power source is enclosed in a well shielded enclosure to reduce spurious leakage pickup. If cables are

used, additional shielding over the cables is required.

Figures 3 and M show SE data obtained using the substitution technique

by the National Bureau of Standards (NBS) and others for the IEEE I & M

Technical Subcommittee on Precision Coaxial Connectors. The data are of 1 M- mm coaxial connector pairs measured for SE up to 3 GHz and of 7-mm coaxial

connector pairs measured for SE up to 6 GHz using the triaxial technique,

respectively. Moreover, these leakage data are representative of several

1 4-mm and 7-mm coaxial connectors pairs that were measured. About the only

thing that can be stated about these measurement results is that the resulting leakage is at least that amount and may not be indicative of the total

leakage. The specification limits in figures 3 and H are specified in the

IEEE Standard on Precision Coaxial Connectors [12].

c

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0.5 1 2 3

Frequency (GHz)

Figure 3» Representative SE of 1 1l-mm coaxial connector pairs

up to 3 GHz using the triaxial technique.

6
SE

(dB)

down

100

1 10

120

130

140

< ^>ecificatio 1 Limit —

1 2 3 4 5 6

Frequency (GHz)

Figure 4. Representative SE of 7~niin coaxial connector pairs

up to 6 GHz using the triaxial technique.

TEii mode propagation in the external line of the triaxial test fixture

is a possible source of error at frequencies about the cutoff frequency for

propagation of this mode. Therefore, for reliable measurement results of SE

in typical test fixtures, a high-frequency limit for a 1 4-mm coaxial connec- tor is 3 GHz while that for a 7“mm coaxial connector is 6 GHz. The regular

operating frequencies of these same connectors outside the test fixtures are 8.5 and 18 GHz respectively which precludes the use of the triaxial technique for determining SE on these same connectors over their high-frequency

limits because of higher order modes.

A low-frequency limit of 500 MHz is suggested because of the excessive

length (30 cm) required for the position of the sliding short-circuit of a

7
half-wavelength below this frequency. Under certain conditions e.g., test

fixture size and detector sensitivity, 100 MHz can be achieved by moving the

the sliding short-circuit as close as possible to the connectors under test.

To ensure that maximum leakage is obtained, the measurement is repeated

for several different orientations of the connector pair. Much effort is

required to assure that extraneous signals are not present at the detector.

The connector coupling and attachment system are set to the torque limits

specified by the manufacturer.

While the triaxial technique has been used for over 20 years for

determining the SE of connectors and cables, there are a number of limitations associated with the use of this technique that make this technique

experimentally difficult to implement. Typical limitations include one or more of the following:

1 . Elaborate test fixture;

2. Problem with higher order modes;

3. Lack of sensitivity at the detector;

4. Requirement of matched terminations to reduce test fixture and

generator reflections;

5. Unsuitable for multi contact connectors and te^t objects not

having a cylindrical geometry;

6. Limited in frequency to about 35/S of the upper frequency limit of

the connector/cable under test;

7. Long setup times.

The main advantage of the triaxial technique is the wide dynamic range

(leakage measurements to -150 dB) that can be achieved in the triaxial test

fixture.

Finally, special care must be taken to assure that the test cable or connector system that makes up the inner coaxial system must be mounted

concentrically with respect to the outer tubular conductor, to minimize TEij

mode generation.

8
Some SE measurements of connectors and cables using quadraxial and

quintaxial test methods have been tried [ 3 ]. The quadraxial method is

somewhat complex to implement but it does allow both the signal generator

and detector path to be matched at all frequencies from DC up to that frequency for which TEM modes predominate thus eliminating the need for a sliding short-circuit. The quintaxial test fixture is designed for greater

ease of access to the device under test which requires less modification to

measure different diameter size connectors and cables.

3.2 Mode-Stirred Technique

The mode-stirred technique is a relatively new method for radiated

susceptibility/vulnerability testing using a reverberation chamber. The

idea of stirring or tuning the modes inside a large shielded enclosure

(reverberation chamber) for electromagnetic compatibility (EMC) measurements

was first proposed in 1968 [ 13 ]. The objective is to obtain a statistical,

time averaged distribution of field strength or power density within a test

volume inside the enclosure such that the location of the equipment or device under test (EUT) or (DUT) inside the chamber is not important.

The mode-stirred technique uses two operational approaches depending

upon frequency for performing EMC measurements inside the chamber. The

first approach, mode tuned (used when the input VSWR is relatively large in

the order of 1.5 or more), steps the tuner at selected uniform increments

(typically 200 steps or more), permitting measurements of the net input

power, reference antenna received power, and the monitored EUT response at

each tuner position. This allows corrections to be made for the variations

in the chamber's test field resulting from changes in the VSWR of the transmitting antenna as a function of the tuner position. The second approach,

mode stirred (used when the input VSWR is below 1.5), rotates the tuner

continuously while sampling the reference antenna received power and EUT

response at rates much faster than the tuner revolution rate. Large data

samples up to 9,999 can be obtained for a single tuner revolution.

The mode-stirred technique for measuring the SE of connectors and

cables was adapted by Bean and Hall [2] and is based upon a technique

9
developed by Jarva [14] and work performed by others [15]. The military

reported the use of the mode-stirred technique for measuring the SE of

connectors and cables in 1978 in proposed MIL-STD-1 377A [16]. MIL-STD-1

[17] was later issued as a design guide of a mode-stirred test chamber and

Method 3008 of the same standard for measuring the SE of multicontact

connectors. One major manufacturer of electrical connectors developed their own mode-stirred test facility [18] in 1981 in accordance with Method 3008

of MIL-STD-1 3^^A [17] for measuring the SE of multicontact connectors in the

1 to 1 0 GHz frequency range.

Figure 5 is a diagram of a mode-stirred test system as specified in

accordance with Method 3008 of MIL-STD- 1 3^^A [17]. The test chamber is

essentially a low loss shielded enclosure that includes an input antenna, a reference antenna and a mode stirrer. Testing is conducted inside the test

chamber whose smallest dimension is at least three wavelengths at the lowest

test frequency to assure an ample mode density which is a necessary

Figure 5. Diagram of mode-stirred test system from MIL-STD-1 3^^A.

10
condition for the validity of the mode-stirred technique [19]. In addition,

the minimum distance between the DUT and the chamber walls is at least one wavelength at the lowest test frequency to maintain a uniform electric field

throughout the chamber. The chamber is excited by an \nput antenna provided

by a long wire mounted parallel to the chamber walls. To reduce reflections, impedance matching tapers are used at both ends of the antenna. One

end of the antenna is terminated in 50 ohms while the other end is connected

to the signal source. A reference antenna of the same length as the input

antenna is mounted on the opposite wall with one end connected to a receiver

and the other terminated into 50 ohms through impedance matching tapers.

The mode stirrer or paddle wheel tuner serves to randomize the multi-mode EM

fields existing inside the test chamber when rotated by significantly altering the complex standing wave patterns. Rotation of the mode stirrer

changes the relative amplitude of the modes and is intended to ensure that

the net field at any point is uniform on a time averaged basis.

To measure the SE of the connector pair under test (DUT), the power Pj

is fed through the input antenna and received by the reference antenna to

establish a reference level. Next the power leaking into the DUT is

measured. The SE of the DUT is determined using equation (1) by taking the

ratio of the averages (Pj and P 2

) over one rotation of the mode stirrer.

Figure 6 is a block diagram of the mode-stirred reverberation chamber

and measurement system at NBS-Boulder. This chamber was developed and

evaluated [20] by NBS over a three year period starting in 1982 for performing radiated susceptibility/ vulnerability measurements. The dimensions of

the chamber are 2 . 7 ^ m x 3.05 m x 4.57 m, which allows a typical frequency

range of application from about 200 MHz to 18 GHz or higher. The test field

is established by means of rf source(s) connected to the transmitting

antenna(s) placed inside the chamber. Four antennas are required to cover

the 200 MHz to I 8 GHz frequency range which include:

1) Long wire (200 MHz - 1000 MHz), receiving mode,

2) Log periodic (200 MHz - 1000 MHz), transmitting mode.
3) Ridged horn (1 GHz - 10 GHz), transmitting and receiving modes,

4) Double ridged circular horn (2 GHz - 18 GHz), transmitting and

receiving modes.

TUNER CONTROL

Figure 6. Block diagram of mode-stirred reverberation chamber

and measurement system at NBS-Boulder.

Within the recommended frequency bands of operation, the long wire and

log periodic antennas can accommodate (below about 500 MHz) up to 1000 W

input power while the ridged horns and double ridged circular horns can accomodate up to 200-W input power. Some of these power requirements are necessary for various reference conditions.

Figure 7 shows the placement of a DUT inside the NBS mode-stirred

reverberation chamber. The DUT consists of a pair of SMA coaxial connectors

mounted on 1.5 m (5 ft) lengths of 0.351 cm (0.141 in) semi-rigid coaxial

cable terminated at one end into a 50-ohm load. To measure the SE of the

DUT, the power is fed through the transmit antenna and detected by the

receive antenna to establish a reference level. Next the power Pg leaking

into the DUT is sampled continuously (mode-stir) and averaged over one tuner

revolution. The SE of the DUT in decibels is determined using equation (1).

12
Figure 7. Placement of the DUT (SMA connector pair inside)

the NBS mode-stirred reverberation chamber.

Figure 8 shows the SE data that were obtained on the pair of SMA

coaxial connectors from figure 7 which were measured for SE at discrete

frequencies of 8, 10, and 18 GHz using the mode-stirred technique. MILC-39012B [10] lists a specification limit of -90 dB between 2 and 3 GHz for

the SE requirements of SMA connectors mounted on semi-rigid cable.

While the mode-stirred technique is a relatively new method for

radiated susceptibility/vulnerability testing using a reverberation chamber,

there are a number of advantages associated with this technique that make it

worth considering for SE measurements on connectors and cables. Typical

advantages include one or more of the following:

1 . An easily automated test system;

2. Rapid processing of large quantities of test data;

3. Short setup times and test time requirements;

4. The ability to generate high level fields efficiently around the

DUT;

5. Easy access to the DUT;

13
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D

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Frequency (GHz)

Figure 8. SE of SMA coaxial connector pair at discrete frequencies

of 8, 10, 14 and 18 GHz using the mode-stirred technique.

6. Broad frequency coverage up to a least 18 GHz;

7. No requirement to physically rotate the DUT;

8. Easy to configure for multicontact connectors;

9. Convenient for measuring cables;

10.

Suitable for measuring connectors and cables having

different diameter sizes in the same chamber.

One limitation of the mode-stirred technique is that stray leakage from

other leakage paths cannot be directly identified with mode-stirred

measurements without retesting. Also, sealing to prevent stray leakage from

other sources except the DUT can be a problem, especially with the low SE

levels that can be achieved with the mode-stirred system. Another possible

limitation with the mode-stirred system is the ability to achieve a dynamic

range of -120 dB. This value is dependent to a certain degree upon input

power and detector sensitivity limitations, in addition to isolation

aspects

.

14
3.3 Comparison of Techniques

Table 1 contains a comparison chart for the triaxial and mode-stirred

techniques used for measuring the SE of connectors and cables. The information is taken from the summary of techniques contained in sections 3.1 and

3.2.

TABLE 1

COMPARISON OF THE TRIAXIAL AND MODE-STIRRED TECHNIQUES

TECHNIQUE Frequency Range Dynamic

Range

Setup

Time

Test

Time

Elaborate

Test Fixture

Triaxial 100 MHz to 6 GHz* -150 dB Long Long Yes

Mode- -500 MHz** to 18 GHz -120 dB*** Short Short No

Stirred

* - the frequency range can be extended somewhat by

adding a mode filter to the triaxial test fixture.

** - lower frequency limited by size of chamber.

*** - dynamic range of the chamber could be extended by placing

the measurement system (power sources, detector, computer

and etc.) inside a separate shielded enclosure and then

use low-noise preamplifiers to extend the usable dynamic

range of the detector (spectrum analyzer).

15
TABLE 1 (continued)

COMPARISON OF THE TRIAXIAL AND MODE-STIRRED TECHNIQUES

TECHNIQUE Detector

Sensitivity

Problem With

Stray Leakage

Accessability

to DUT

Need to

Rotate DUT

Triaxial Poor* Average Hard Yes

ModeStirred

Good Yes Easy** No

* - sliding short-circuit required in triaxial test fixture.

** - Also, much

connectors

easier to configure and measure multicontact

and cables inside the chamber.

Some good agreement (-2 dB) between the triaxial and mode-stirred

techniques has been reported [18] on SE measurements taken on a simulated

connector using both techniques at overlapping frequencies between 1 and 2

GHz.

4. CONCLUSIONS

The triaxial and mode-stirred measurement techniques for determining

the SE of connectors and cables were reviewed and the information compared

in chart form. From the information presented, there are a number of advantages associated with the mode-stirred technique that makes this

technique worth considering for conveniently measuring the SE on connectors

16
and cables over a wide frequency range above a few hundred megahertz.

Toward this end, the NBS plans to build another mode-stirred chamber to

specifically accommodate SE measurements of connectors and cables plus

additional requirements for SE measurement of composite materials and cable

shield terminations for the U.S. Army Aviation Systems Command (AVSCOM).

To date, there have been comparisons of test results [20, 21] of approximately 5 dB between different-sized reverberation chambers at different

test facilities of EM susceptibility response measured on the same EUTs.

Other interlaboratory comparisons on an artifact need to be performed and

the results compared.

5 . ACKNOWLEDGMENTS

The work in this report was supported in part by AVSCOM, St. Louis,

Missouri. The author wishes to thank John Bean of the Naval Surface Weapons

Center, Stanley Hale and Paul Pressel (retired) of A1 1 i ed/Bendix

Corporation, and Galen Koepke and John Wakefield of the NBS for helpful

comments and suggestions.

6. REFERENCES

[1] Zorzy, J.; Muehlberger, R.F. RF leakage characteristics of popular

coaxial cables and connectors, 500 Me to 7.5 Gc. Microwave J., Vol

.

4; 1961 November. 80-86.

[2] Bean, J.L.; Hall, R.A. Electromagnetic susceptibility measurements

using a mode-stirred chamber. Proc. IEEE International EMC Symposium;

1978 June 20-22; Atlanta, GA. IA 3 - 15 O.

[ 3 ] Madle, P.J. Cable and connector shielding attenuation and transfer

impedance measurements using quadraxial and quintaxial test methods.

IEEE EMC Symposium Record; 1975 October; San Antonio, TX. 7-9.

17
[4] Luca, V.; Pressel, P. The radiation efficiency technique for

measuring the shielding effectiveness of cylindrical connectors at

microwave frequencies. Thirteenth Connectors & Interconnectors

Symposium; 1980 October; Philadelphia, PA.

[5] Hoeft, L.O. Measurement of surface transfer impedance of cables and

connectors. EMC EXPO Conference Record; 1986 June 16-19; Washington,

D.C. T17.1-T17.15.

[6] Schelkunoff, S.A. The electromagnetic theory of coaxial transmission

lines and cylindrical shields. Bell Syst. Tech. J.; vol. 1 3: 532-

579; 1934 October.

[7] Martin, A.R.; Mendenhall, M. A fast, accurate, and sensitive method

for measuring surface transfer impedance. IEEE Trans, on EMC; EMC-26

(2): 66-70; 1984 May.

[8] Pressel, P.I. Mismatch: a major source of error in shielding effectiveness measurements. Proc. Seventeenth Annual Connector and

Interconnector Technology Symp; 1984 September; Anaheim, CA.

[9] Staeger, C.; Bolinger, W. Screening effectiveness of coaxialconnectors and measuring methods at high frequency and microwave.

Tech. Mitteilungen PTT, No. 9; 1981; published by the Swiss PTT,

Berne, Switzerland.

[10] MIL-C-3901 2B. Military Specification, Connectors, Coaxial, Radio

Frequency, General Specifications For. 1972 October.

[11] MIL-C-38999H . Military Specification, Connectors, Electrical,

Circular, Miniature, High Density, Quick Disconnect, Environment

Resistant, Removable Crimp Contacts, and Hermetic Contacts. 1981

February.

[12] G-IM Subcommittee: Precision coaxial connectors. IEEE Trans. Instrum.

Meas.; IM-17(4): 204-224; 1968 September.

18
[13] Menes , H.A. A new approach to electromagnetic field-strength measurements in shielded enclosures, in Wescon Tech. Papers; Los Angeles, CA.

1968 August.

[14] Jarva, W. Shielding tests for cables and small enclosures in the 1-

to 10-GHz range. IEEE Trans, on EMC; EMC-12(1): 12-24; 1970 February.

[15] Final Report, MDCE1516. Characterization of Shielding Effectiveness

Measurement Technique. McDonnell Douglas Astronautics Co, St. Louis,

Missouri; 1976 July.

[16] Proposed MIL-STD-1 377A (Navy). Shielding Effectiveness of Cables,

Connectors, and Enclosures, Measurement of. 1978 October.

[17] MIL-STD-1 344a Appendix A. Design of Mode-Stirred Test Chamber. Method

3008. Shielding Effectiveness of Multicontact Connectors. 1980

September

.

[18] Hale, S.C.; Pressel, P.I. Mode stirring shielding effectiveness

measurement an automated system. Fifteenth Connectors &

Interconnectors Symposium; 1982 November; Philadelphia, PA.

[19] Ma, M.T.; Kanda, M.; Crawford, M.L.; Larsen, E.B. A review of

electromagnetic compatibility/interference measurement methodologies.

Proc. of the IEEE; 73(3): 388-411; 1985 March.

[20] Crawford, M.L.; Koepke, C.H. Design, Evaluation, and Use of a Reverberation Chamber for Performing Electromagnetic Susceptibility/

Vulnerability Measurements. Nat. Bur. Stand. (U.S.) NBS Tech. Note

1092; 1986 April.

[21] Crawford, N.L.; Koepke, C.H. Electromagnetic radiation test

facilities evaluation of reverberation chambers located at NSWC

,

Dahlgren, Virginia. Nat. Bur. Stand. (U.S.) NBSIR 86-3051; 1986 June.

19
NBS-114A (REV. 2-B U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO. NBSIR 86-3060

2. Performing Organ. Report No 3. Publication Date

October 1986

4. TITLE AND SUBTITLE

A Survey of Triaxial and Mode-Stirred Techniques for Measuring the

Shielding Effectiveness of Connectors and Cables

5. AUTHOR(S)

Ramon L. Jesch

6. PERFORMING ORGANIZATION (If joint or other than N BS, see instructions)

national bureau of standards

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City, State. ZIP)

Sponsored in part by AVSCOM, St. Louis, Missouri

10. SUPPLEMENTARY NOTES

Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document Includes a significant

bi bliography or literature survey, mention It here)

This report is the result of an extensive literature search conducted in

the field of connectors and cables, and of the problem dealing with radio

frequency leakage characteristics and the ability to measure the shielding

effectiveness of these connectors and cables. It reviews two measurement

techniques for determining the shielding effectiveness: the triaxial test

technique that has been used for over 20 years and the mode-stirred test

technique that recently has started to gain in popularity. From this survey,

certain inferences are drawn about these techniques in terms of device

configuration, frequency range, and ease of measurement and are presented in

chart form for comparative purposes.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) cables; connectors, mode-stirred; relative leakage power; shielding effectiveness;

triaxial

13. AVAILABILITY

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