7/19/2002 kenneth john webb page 1 comparing emission measurements in a reverberation chamber and a...

7/19/2002Kenneth John Webb

COMPARING EMISSION MEASUREMENTS IN A

REVERBERATION CHAMBER AND A SEMI-ANECHOIC CHAMBER

By

Kenneth John Webb

Principal EMC Engineer


Agenda

• Purpose of Project

• Overview of Project

• Dipole Data

• Laptop Data

• Summary and Conclusions


Purpose of Project

• Validate Reverb Chamber (RC) Calibration• To define a possible test method for

performing emissions in a RC• Comparing results in a RC to conventional

test results in an Anechoic Chamber (AC)• Determine if equation is valid

– Power density to V/m equation– Use of CCF, ACF, IL, CLF defined later


Overview of Project• Perform Calibration in RC• Test a known source

• Test in RC and AC• Calculate E-field using different techniques• Validates method

• Test and unknown source• Test in RC and AC• Use methods derived on known source


Why Measure Emissions in a Reverb Chamber?

• New Robust Test Method– Test all sides of the unit

• Cost of reverb chamber is less than conventional anechoic rooms

• Measure total fields emanating from unit• Test systems without multiple antenna positions or

unit orientations• Less setup time from susceptibility testing to

emissions testing


Emissions in Reverb Chamber

Receiver

UUT IOConnectionBulkhead

UUT TestArea

Door

Mode StirrerPosition

Motor

ReceiveAntenna


Reverb Chamber Physical Characteristics

Chamber

20

'

30'

Tuner

Chamber12

'

Tuner

Door

AntennaTower

3106Antenna


Typical Tuner


Calibration Summary• Meets the calibration requirements of DO-160D

Change 1 from 400MHz to 18GHz. • Uniformity is marginal from 100-200 MHz, the

allowed standard deviation is acceptable. Above 1 GHz, chamber uniformity is acceptable.

• Antenna vs probe exceeds the allowed +/-3 dB tolerances using the log periodic antenna. – Using the EMCO 3106 antenna from 400MHz to 2GHz

allowed acceptable results

• Obtained calibration factors needed for emissions testing


Emission Comparison Methodology


Emission Comparison

• Use data collected in calibration for CCF, ACF, CLF ,and IL

• Use equation given in IEC 61000-4-21 for power density to E-field conversion

• Measure a known source (dipole antenna) and an unknown source (Laptop computer)

• Use basic test methods in AC• Develop a new method for RC


Dipole Testing


Dipole Antenna• Estimated 127dBuV/m with +20dBm

– Signal generator not linear, but used same one for both AC and RC tests

• AC will use conventional method– Use AF– Place RCV antenna in H and V polarities– Dipole in H only

• RC new method– No direct illumination

2

**30)/(

R

GPmVE tt

Radaited


Dipole Antenna in AC


Dipole Antenna AC Data(1)

Freq (MHz)

(2) HORIZ

dBm

(3) VERT dBm

(4) CL dB

(5) HORIZ dBuV

(6) VERT dBuV

(7) AF dB

(8) HORIZ dBuV/m

(9) VERT dBuV/

m

(10) H/V AVG dBuV/m

(11) RSS OF

H/V dBuV/m

400 1 -24.5 -4.6 112.6 87.1 13.7 126.3 100.8 120.728697 126.3122229

450 -0.1 -27.1 -4.9 111.8 84.8 15 126.8 99.8 121.1589689 126.8086567

500 -1.2 -29.6 -5.2 111 82.6 16.4 127.4 99 121.7035056 127.4062729

550 -1.7 -24.5 -5.5 110.8 88 16.6 127.4 104.6 121.9868893 127.4227325

600 -3.6 -24.1 -5.8 109.2 88.7 17.1 126.3 105.8 121.0629701 126.3385351

650 -4.5 -31.4 -6.1 108.6 81.7 17.5 126.1 99.2 120.4632684 126.1088581

700 -5.5 -33.1 -6.2 107.7 80.1 17.8 125.5 97.9 119.8341445 125.5075406

750 -6.9 -31 -6.3 106.4 82.3 18.5 124.9 100.8 119.4049445 124.9168632

800 -8.6 -33 -6.3 104.7 80.3 19 123.7 99.3 118.1876145 123.7157397

850 -9 -34 -6.5 104.5 79.5 20 124.5 99.5 118.954604 124.5137119

900 -10.1 -32.8 -6.6 103.5 80.8 20.2 123.7 101 118.2936807 123.7232606

950 -11.9 -37.2 -6.7 101.8 76.5 21 122.8 97.5 117.2388905 122.8127981

1000 -13.2 -38.5 -7 100.8 75.5 23 123.8 98.5 118.2388905 123.8127981


Dipole Antenna in RC


Summary of Equations

ACF

CCFCLF

00 10@310@9

Re

forfInput

cMax

P

PIL

CCF

PP TxAvgRcv

AVGRadiated

*)( ILCLF

PP TxMaxRcv

MAXRadiated *

*)(

2**4

377**)/(

R

PDmVE Radiated

Radiated

00 10@310@9

Re

forfInput

cAve

P

PACF

00 10@310@9

Re

forfInput

cAve

P

PCCF


Dipole Antenna RC Data• ERadiated (V/m) is the estimated field strength produced by the

dipole antenna• R was assumed to be 1m since the final measurement is in volts

per meter. • D is the equivalent directivity of the dipole.

– Determining the correct value would be an interesting experiment. For the purposes of this paper, 1.7 was used.

• Power into antenna was not linear– Same signal generator was used for both anechoic and reverb chamber

data

Tx, Rx = the antenna efficiency factors for the transmit and receive antenna respectively

– Used 0.75 for a log periodic antenna and 0.9 for a horn antenna


Antenna Calibration Factor

• Equation 5.4-1

• Needed for emissions calculations for max power radiated

• Takes into account the antenna losses, gain, and efficiency

00 10@310@9

Re

forfInput

cAve

P

PACF


CCF• CCF or Chamber Calibration Factor from eqn

5.7-1

• CCF is the normalized average received power• PAveRec is the average received power over one tuner

rotation• PInput is the forward power averaged over one tuner

rotation.• Used emission field level calculations for average

recevied power

00 10@310@9

Re

forfInput

cAve

P

PCCF


ACF and CLF• The chamber loading factor (CLF) is calculated

using equation 5.7-2.

• CCF is from equation 5.7-1• ACF is from equation 5.4-1• Also used for emissions level calculations

– Used with Insertion Loss equation 8.4-1 for max received power

ACF

CCFCLF


IL• IL is from equation 5.4-1• Also used for emissions level calculations

– Use with max radiated power

• IL is the normalized maximum received power– Calculated during calibration


Dipole Antenna RC Data, No CCF applied

(1) Freq (MHz)

(2) PAveRec mW

(3) PMax

mW

(4) PAveFwd

W

(5) PAveRec dBm

(6) PMax dBm

(7) Average dBuV/m

(8) Maximum dBuV/m

400 4.54 14.79 0.1 6.570558529 11.69968174 113.1887877 118.3179109

450 5.74 18.62 0.1 7.589118924 12.69979677 114.2073481 119.3180259

500 4.07 19.05 0.1 6.095944092 12.7989498 112.7141733 119.417179

550 3.66 18.41 0.1 5.634810854 12.65053789 112.25304 119.2687671

600 1.67 7.94 0.1 2.227164711 8.998205024 108.8453939 115.6164342

650 1.87 11.09 0.1 2.718416065 10.44931546 109.3366452 117.0675446

700 1.58 7.24 0.1 1.98657087 8.597385662 108.6048 115.2156148

750 1.29 5.07 0.1 1.105897103 7.050079593 107.7241263 113.6683088

800 1.4 6.61 0.1 1.461280357 8.202014595 108.0795095 114.8202438

850 1.09 4.12 0.1 0.374264979 6.14897216 106.9924941 112.7672013

900 0.99 5.89 0.1 -0.043648054 7.701152948 106.5745811 114.3193821

950 1.11 3.55 0.1 0.453229788 5.502283531 107.071459 112.1205127

1000 0.91 3.55 0.1 -0.409586077 5.502283531 106.2086431 112.1205127


Dipole RC and AC DataNo CCF

dB Delta

-5

-4

-3

-2

-1

0

1

2

3

4

5

400 500 600 700 800 900 1000

Frequency (MHz)

dB

RC MAX to ANECHOIC HORIZ RC MAX TO ANECHOIC AVG


Dipole RC Data Retest

• The retest data collected was for information only

• Performed manually using mode stirred approach

• Verify data collection techinique


Dipole RC Data Retest, No CCF applied, Mode Stirred

(1) Freq (MHz)

(2) Max dBuV

(3) Cable Loss

(4) Max dBm

(5) PMax Watts

(6) Max V/m

(7) Max dBuV/m

400 116.13 -3.5 5.63 0.003655948 1.28694898 122.1912266

450 115.21 -3.7 4.51 0.00282488 1.13125713 121.0712266

500 115.32 -3.8 4.52 0.002831392 1.13256029 121.0812266

550 117.17 -3.9 6.27 0.00423643 1.38535581 122.8312266

600 114.48 -4 3.48 0.002228435 1.00475767 120.0412266

650 111.83 -4.2 0.63 0.001156112 0.7237046 117.1912266

700 111.29 -4.2 0.09 0.001020939 0.68008208 116.6512266

750 111.18 -4.2 -0.02 0.000995405 0.67152368 116.5412266

800 110.46 -4.3 -0.84 0.000824138 0.61102831 115.7212266

850 112.03 -4.5 0.53 0.001129796 0.71542042 117.0912266

900 112.05 -4.6 0.45 0.001109175 0.7088614 117.0112266

950 109.06 -4.7 -2.64 0.000544503 0.49666246 113.9212266

1000 108.83 -4.7 -2.87 0.000516416 0.48368357 113.6912266


RC Dipole Data with CCF or CLF/IL

(1) Freq (MHz)

(2) PAveRec mW

(3) PMax

mW

(4) PAve Fwd

W

(5) CCF

(6) CLF

(7) IL

(8) PRadiated (AVG)

Watts

(9) PRadia ted(Max)

Watts

(10) Average dBuV/m

(11) Maximum dBuV/m

400 4.54 14.79 0.1 0.074 0.997 0.325 0.055 0.041 124.5085621 123.2111689

450 5.74 18.62 0.1 0.068 0.973 0.310 0.076 0.056 125.8741523 124.5221936

500 4.07 19.05 0.1 0.056 1.020 0.235 0.065 0.072 125.2265247 125.6224787

550 3.66 18.41 0.1 0.048 1.007 0.193 0.068 0.085 125.4106841 126.3832504

600 1.67 7.94 0.1 0.039 1.002 0.147 0.048 0.075 123.9195687 125.7984468

650 1.87 11.09 0.1 0.031 0.984 0.150 0.053 0.068 124.3569845 125.3784711

700 1.58 7.24 0.1 0.027 0.995 0.097 0.053 0.068 124.3150163 125.3717514

750 1.29 5.07 0.1 0.028 0.985 0.126 0.042 0.037 123.3191517 122.731209

800 1.4 6.61 0.1 0.026 1.017 0.104 0.048 0.056 123.8579266 124.5780609

850 1.09 4.12 0.1 0.020 1.012 0.086 0.048 0.043 123.931784 123.3718066

900 0.99 5.89 0.1 0.019 1.033 0.075 0.048 0.068 123.8820439 125.4289573

950 1.11 3.55 0.1 0.017 0.979 0.073 0.060 0.045 124.8608225 123.5811368

1000 0.91 3.55 0.1 0.017 1.028 0.083 0.047 0.037 123.7828009 122.8083788


RC Dipole Data with CCF, AVG to MAX

RC MAX vs RC AVG with CCF

120

121

122

123

124

125

126

127

128

129

130

400 500 600 700 800 900 1000

Frequency (MHz)

RC AVG RCV PWR Max Rcv Pwr in RC


RC Dipole Data with CCFAC and RC Data

Comparison of Dipole with CCF

110

112

114

116

118

120

122

124

126

128

130

400 500 600 700 800 900 1000

Frequency (MHz)

dB

uV

/m

dBuV/m in Anechoic Horiz Max Rcv Pw r in RC dBuV/m H/V AVG RSS OF H/V RC AVG RCV PWR


RC Dipole Data with CCFdB Delta

dB Delta with CCF

-4

-2

0

2

4

6

8

400 500 600 700 800 900 1000

Frequency (MHz)

dB

RC MAX to ANECHOIC HORIZ RC MAX TO ANECHOIC AVG RC AVG PWR to ANECHOIC RSS RC MAX PWR TO RSS ANECHOIC


RC Dipole Data with CCFdB Delta

dB Delta with CCF

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

400 500 600 700 800 900 1000

Frequency (MHz)

dB

RC MAX to ANECHOIC HORIZ RC AVG PWR to ANECHOIC RSS RC MAX PWR TO RSS ANECHOIC


Dipole Summary• Excellent correlation.

– 2dB delta between rooms for the dipole measurements can be considered validation of the test method.

• Use the RSS or MAX of the horizontal and vertical polarities– Must use CCF for AVG Power– Use CLF and IL for MAX power

• Retest RC data with mode stirring also has good correlation to AC– Verifies mode stirring technique using equation for average

power


Dipole Summary: Tuned or Stirred?

Mode Stirred Dipole Retest Data vs Mode Tuned Dipole Data

112

114

116

118

120

122

124

126

128

400 500 600 700 800 900 1000

Frequency (MHz)

dB

uV

/m

RC AVG RCV PWR RC dBuV/m retest w ith Pavg

Max Rcv Pw r in RC RC dBuV/m retest w ith Pmax


Laptop Testing


Laptop Setup in AC

Groundplane

Bulkhead

Laptop

Shieldroom Wall

10 cm

To EMI Receiver Placement only valid in anechoic room

1 m

Non-conductive Standoff


Laptop Setup in AC

Frequency Range Dwell Time per frequency step

Resolution Bandwidth (6dB)

Step Size Antenna Used

Dwell time for final measurement

20-100MHz 50ms 100kHz 50kHz 3104C 1sec 100-200MHz 50ms 100kHz 50kHz 3104C 1sec 200-400MHz 50ms 100kHz 50kHz 3106 1sec 400-800MHz 50ms 100kHz 50kHz 3106 1sec 800-1600MHz 50ms 100kHz 50kHz 3106 1sec 1600-2000MHz 50ms 1MHz 500kHz 3106 1sec 2000-4000MHz 50ms 1MHz 500kHz 3115 1sec 4000-6000MHz 50ms 1MHz 500kHz 3115 1sec


Laptop Setup in AC


Laptop Setup in RC

Frequency Range Dwell Time Resolution Bandwidth (6dB)

Step Size Antenna Used

Dwell time for final measurement

100-200MHz 50ms 100kHz 50kHz AT1080 60secs 200-400MHz 50ms 100kHz 50kHz 3106 60secs 400-800MHz 50ms 100kHz 50kHz 3106 60secs 800-1600MHz 50ms 100kHz 50kHz 3106 60secs 1600-2000MHz 50ms 1MHz 500kHz 3106 60secs 2000-4000MHz 50ms 1MHz 500kHz 3115 60secs 4000-6000MHz 50ms 1MHz 500kHz 3115 60secs


Laptop Setup in RC


Sample Laptop Data RCFrequency

(MHz) dBµV dBm Watts CCF

IL ACF CLF V/m with CCF

dBuV/m with CCF

V/m with CLF and

IL

dBuV/m with CLF

and IL

100 30 -77 1.9953E-11 0.170 0.530 0.170 1.000 6.7051E-05 36.528161 3.7949E-05 31.5841207 100.05 17.67 -89.33 1.1668E-12 0.169 0.530 0.169 1.000 1.6242E-05 24.2130341 9.1803E-06 19.257181 100.1 17.8 -89.2 1.2023E-12 0.169 0.529 0.169 1.000 1.6516E-05 24.3579509 9.3221E-06 19.3902419

100.15 18.6 -88.4 1.4454E-12 0.168 0.529 0.168 1.000 1.814E-05 25.1729115 1.0225E-05 20.1933035 100.2 18.2 -88.8 1.3183E-12 0.167 0.528 0.167 1.000 1.7354E-05 24.7879164 9.7683E-06 19.7963657

100.25 19.16 -87.84 1.6444E-12 0.167 0.528 0.167 1.000 1.9415E-05 25.7629657 1.0914E-05 20.7594285 100.3 18.33 -88.67 1.3583E-12 0.166 0.528 0.166 1.000 1.7677E-05 24.9480599 9.9226E-06 19.932492

100.35 18.6 -88.4 1.4454E-12 0.166 0.527 0.166 1.000 1.8267E-05 25.2331991 1.0239E-05 20.2055561 100.4 20.74 -86.26 2.3659E-12 0.165 0.527 0.165 1.000 2.3411E-05 27.3883837 1.3105E-05 22.3486208

100.45 19.99 -87.01 1.9907E-12 0.165 0.527 0.165 1.000 2.1512E-05 26.653614 1.2025E-05 21.6016862 100.5 20.49 -86.51 2.2336E-12 0.164 0.526 0.164 1.000 2.2827E-05 27.1688903 1.2742E-05 22.1047522

100.55 18.46 -88.54 1.3996E-12 0.163 0.526 0.163 1.000 1.8101E-05 25.1542128 1.009E-05 20.0778189 100.6 21.77 -85.23 2.9992E-12 0.163 0.525 0.163 1.000 2.6545E-05 28.479582 1.4776E-05 23.3908862

100.65 20.62 -86.38 2.3014E-12 0.162 0.525 0.162 1.000 2.3294E-05 27.344998 1.2948E-05 22.2439541 100.7 22.17 -84.83 3.2885E-12 0.162 0.525 0.162 1.000 2.7895E-05 28.9104613 1.5483E-05 23.7970227

100.75 21.25 -85.75 2.6607E-12 0.161 0.524 0.161 1.000 2.5136E-05 28.0059721 1.3932E-05 22.8800919 100.8 22.44 -84.56 3.4995E-12 0.161 0.524 0.161 1.000 2.8879E-05 29.2115308 1.5983E-05 24.0731618

100.85 17.53 -89.47 1.1298E-12 0.160 0.524 0.160 1.000 1.6438E-05 24.3171376 9.0847E-06 19.1662323 100.9 19.66 -87.34 1.845E-12 0.159 0.523 0.159 1.000 2.1045E-05 26.462793 1.1614E-05 21.2993035

100.95 15.62 -91.38 7.2778E-13 0.159 0.523 0.159 1.000 1.3241E-05 22.4384972 7.2966E-06 17.2623753 101 18.07 -88.93 1.2794E-12 0.158 0.523 0.158 1.000 1.7588E-05 24.9042505 9.6777E-06 19.7154478


Laptop Data in RC with CCFLAPTOP EMISSIONS IN REVERB CHAMBER

0

10

20

30

40

50

60

70

100 1000 10000

Frequency (MHz)

dB

uV

/m


RC Laptop Data CCF vs CLFMAX Power vs AVG Power

Equations 8.2-2 vs 8.2-3

0

10

20

30

40

50

60

70

100 200 300 400 500 600 700 800 900 1000

Frequency (MHz)

dB

uV

/m

avg power max power


Ambient in RC with CCFReverb Chamber Ambient After Update

0

5

10

15

20

25

30

35

40

45

50

10 100 1000 10000

Frequency MHz

dB

uV

/m


Laptop RC Data

• Ambient is a concern– RS testing may be leaking RF– 50MHz emissions for info only

• CCF vs CLF about 5 to 10dB different

• Used both to compare the data


Laptop Measurements in ACBack Horizontal

15

20

25

30

35

40

45

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACBack Vertical

15

20

25

30

35

40

45

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACBottom Horizontal

15

20

25

30

35

40

45

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACBottom Vertical

15

20

25

30

35

40

45

50

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACFront Horizontal

15

20

25

30

35

40

45

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACFront Vertical

15

20

25

30

35

40

45

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACLeft Side Horizontal

15

20

25

30

35

40

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACLeft Side Verical

15

20

25

30

35

40

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACRight Side Horizontal

15

20

25

30

35

40

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACRight Side Vertical

15

20

25

30

35

40

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACTop Side Horizontal

15

20

25

30

35

40

45

100 1000

Frequency (MHz)

dB

uV

/m


Laptop Measurements in ACTop Side Vertical

15

20

25

30

35

40

45

100 1000

Frequency (MHz)

dB

uV

/m


AC vs RC CCF Laptop Data


RC CCF vs AC Data

0

10

20

30

40

50

60

70

100 1000

Frequency (MHz)

dB

uV

/m

RC DATA WITH CCF BK H dBµV/m BK V dBµV/m

Bo H dBµV/m Bo V dBµV/m F H dBµV/m

F V dBµV/m LS H dBµV/m LS V dBµV/m

RS H dBµV/m RS V dBµV/m To H dBµV/m

To V dBµV/m


RC CCF vs AC Data DeltaRC with CCF and Antenna Efficiency vs RSS of Anechoic

-30

-20

-10

0

10

20

30

100 1000

Frequency (MHz)

dB

RC with CCF and Antenna Efficiency vs Average of Anechoic

-30

-20

-10

0

10

20

30

100 1000

Frequency (MHz)

dB


RC CCF vs AC Data DeltaRC with CCF and Antenna Efficiency vs Max of Anechoic

-30

-20

-10

0

10

20

30

100 1000

Frequency (MHz)

dB

RC with CCF and Antenna Efficiency vs RMS of Anechoic

-30

-20

-10

0

10

20

30

100 1000

Frequency (MHz)

dB


RC CCF vs AC Data

15

25

35

45

55

65

75

100 110 120 130 140 150 160 170 180 190 200

Frequency (MHz)

dB

uV

/m

RC DATA WITH CCF RSS OF H/V AND ALL POSITIONS dBuV/m

AVG OF DATA dBuV/m MAXIMUM ALL H/V IN ALL POSITIONS


RC CCF vs AC Data

15

25

35

45

55

65

75

200 250 300 350 400

Frequency (MHz)

dB

uV

/m




RC CCF vs AC Data

15

25

35

45

55

65

75

400 450 500

Frequency (MHz)

dB

uV

/m




RC CCF vs AC Data

15

25

35

45

55

65

75

500 550 600 650 700 750 800 850 900 950 1000

Frequency (MHz)

dB

uV

/m




AC vs RC CCF Laptop Data


RC CLF vs AC Data

15

25

35

45

55

65

75

100 1000

Frequency (MHz)

dB

uV

/m

RC DATA WITH CLF&IL RSS OF H/V AND ALL POSITIONS dBuV/m



RC CLF vs AC Data

15

25

35

45

55

65

75

100 150 200

Frequency (MHz)

dB

uV

/m




RC CLF vs AC Data

15

25

35

45

55

65

75

200 220 240 260 280 300 320 340 360 380 400

Frequency (MHz)

dB

uV

/m




RC CLF vs AC Data

15

25

35

45

55

65

75

400 420 440 460 480 500

Frequency (MHz)

dB

uV

/m




RC CLF vs AC Data

15

25

35

45

55

65

75

500 600 700 800 900 1000

Frequency (MHz)

dB

uV

/m




Conclusions• Laptop data not as good a correlation as the dipole data

– The maximum AC data was the best correlation to the RC CCF or CLF data for the Laptop

– The RSS or MAX was the best for the dipole

• Several spikes that were within 10-20dB of each other for the Laptop data– The dwell time of 50ms may not have been long enough to

capture the full amplitude.– May be due to dwell time of RC data – Tuner speed may need to be increased/decreased– Use of MAX vs AVG equations for E-field


Conclusions• Assumption that the Laptop rotation (in six

different orientations) could be correlated to the reverb chamber data may be incorrect. – A Laptop orientation (other than the 90 degree

changes) may have a higher amplitude emissions.

• The frequency accuracy may also have been different between the two test methods. – Frequencies may have been off– The tuner may modulate the emissions and change the

frequency slightly.


Conclusions

• The method for performing the test and the equation used to calculate the E-fields does appear to have an overall correlation and usefulness. – Generally, the RC had a higher amplitude when using

average power equation and mode-stirring– Data trend was similar– Dipole measurements within 2dB

• Future testing is definite– Spherical dipole radiator– Different dwell/sweep times


Questions??

7/19/2002 kenneth john webb page 1 comparing emission measurements in a reverberation chamber and a...

Documents

kenneth john webb page

rc slide

ac slide

calibration slide

ccf slide

dipole antenna ac data

horn antenna slide

dipole testing slide