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Precision Power Measurement Solutions from Bird

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Page 1: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Precision Power Measurement Solutions

from Bird

Precision Power Measurement Solutions

from Bird

Page 2: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Agenda• National Standards Traceability- Challenges &

Bird’s Solution• RF Metrology Paths at Bird Electronic Corporation

– High power RF Calorimetry– Low power microwave attenuation– Low power microwave power– MCS (master calibration system)– Test Setups & system considerations

• 4020 Series Power Sensors and the 4421 Power Meter

• Typical Field Power Measurement Systems

Page 3: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

National Standards Traceability- Challenges & Bird’s Solution

Page 4: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Generic Traceability Path

National Reference Standard

Measurement Reference Standard

Working Standard

NIST

Bird Metrology

Bird Manufacturing Facility

Power Sensors

Page 5: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Power Measurement Requirements of the Semiconductor Industry

Power

Frequency

Various frequency & power combos

13.56 Mhz

40 kW

Page 6: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Accuracy Capability of the Scientific Community

Power

Frequency

Bird’s performance range& capability

NIST, NPL etc.

Page 7: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Accuracy Capability of the Scientific Community

Power

Frequency

Bird’s performance range& capability

NIST, NPL etc.

Calorimetry Path

Precision Attn & Power Path

Page 8: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Bird’s Multi-Path Solution

Primary Lab

MCS TransferStandard

WorkingStandard

PrimaryStandard

NIST AttenationStandard

NIST FixedAttenuator

Set

WorkingStandard

NISTStandard

Working Standard

Measurement Ref.Standard

Test Setups

NIST AC & DCStandard

4027, 4028 4024, 4025 Model 43

Precision 60 HzPower Analyzer

High PowerCalorimeter

Low Power Precision Attenuator

RF & Microwave Path

Low PowerRF & Microwave Power Path

High PowerRF Calorimetric Path

Couplers + Power Meter

VNA ThermistorMount

ThermistorCN Mount

Micro-Calorimeter

< 10 mw

Coupler VerificationCal FactorVerification

< 10 mw

AC Voltage &Current Stds.

MCS TransferStandard

Test Setups

4027, 4028 4024, 4025 Model 43

Page 9: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Calibration Subtleties of the Bird System

• +/- 1% calibration requirements dictate daily calibration• +/- 3% is calibrated every 6 months• +/- 5% is calibrated annually• Cross correlations are on-going and constant• Multiple paths are used to cross correlate high power &

high frequency standards • It is capital intensive, time consuming, and demands

high skill levels, but worth every effort in order to guarantee the high accuracy demands of the semiconductor industry

Page 10: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

RF Metrology Paths at Bird Electronic Corporation

• High power RF Calorimetry

• Low power microwave attenuation

• Low power microwave power

• MCS (master calibration system)

• Test Setups & system considerations

Page 11: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Primary Lab

Working Standard

Measurement Ref.Standard

NIST AC & DCStandard

Precision 60 HzPower Analyzer

High PowerCalorimeter

AC voltage &Current Stds.

High Power RF Calorimetric Path

• Calorimetry is the critical link between high power AC standards & high power RF standards

Page 12: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

8860

6091

Power (kW) = .263 x flow rate (GPM) x T (0C)

Calorimetric Power Meters

Page 13: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Bird Metrology

Manufacturing Facility

Calorimeter Block Diagram

Page 14: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Characteristics of Calorimetric Power Meters

• Highly Accurate, Especially When Using 60Hz Substitution Technique

• Measures True Heating Power, Regardless of Harmonic Content or Modulation Characteristics of Signals

• Requires Careful Setup and Maintenance, Due to Coolant Characteristics

• Long Settling Time

Page 15: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Specific Heat of Water

Page 16: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Precision AC Power

Meter RF

Calorimeter

RF

Source

60 HzAC Source

• Measure 60 Hz power into calorimeter w/AC Power meter• Adjust calorimeter display to match AC power meter• Accuracy of AC standard has now been transferred to calorimeter• When RF is supplied to load, read calibrated watts from calorimeter display

AC Substitution Method

Page 17: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

AC Substitution Technique

• Use Low Distortion 60Hz Source• Calibrate Calorimeter Using Precision 60Hz Power

Meter (Accuracy = <0.1%)• Apply Unknown RF Source to Calorimeter• Adjust Coolant Flow Rate to Maintain ΔT Across

Load of > 2º C

• Allow 1 hour For Stabilization

Page 18: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Transfer of Accuracy from AC to RF

frequency

VSWR

RFAC (60 Hz)

• Calorimetric load has virtually identical response at both AC & RF

Page 19: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

% Error

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

Days

Error

Calorimetric Stability

Page 20: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

MCS TransferStandard

NIST AttenuationStandard

NIST FixedAttenuator

Set

WorkingStandard

VNA

Coupler verification

< 10 mw

MCS TransferStandard

Low Power Precision AttenuatorRF & Microwave Path

• Provides the important link between low power, high frequency attenuation values & high frequency coupling values

Page 21: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Working Standard

PrecisionCoupler

• Transfers the accuracy of the VNA to the precision coupler when the coupling value is determined

VNA

Page 22: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Attenuation Standards

VNA

Attenuation Kit

• Attenuation kit traceable to NIST

Page 23: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

WorkingStandard

PrimaryStandard

NISTStandard

ThermistorMount

ThermistorCN Mount

Micro-Calorimeter

< 10 mw

Cal Factorverification

Low PowerRF & Microwave Power Path

Provides the link between highfrequency low power standards

and high frequency power meters

MCS TransferStandard

MCS TransferStandard

Page 24: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Working Standard

Thermal PowerMeter

CN ThermisterMount

• Cal factor of power meter is verified with reference to Thermister mount

Page 25: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

MCS Transfer Standard

MCS TransferStandard

MCS TransferStandard

Provides the combinational accuracyof calibrated high frequency power& coupling standards into a single calibrated device that can be used as a measurement standard in a high frequency, high power test setup

Page 26: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Directional Coupler - Thermal Power Meter MCS Standard

Page 27: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Characteristics of Directional Coupler-Thermal Power Meter Standards

• Wide Dynamic Range• Useful Frequency Range Determined by Directional Coupler• Complicated Error Budget

– Internal Reference Uncertainty– Mismatch Uncertainty– Calibration Factor Uncertainty

• Fundamental Accuracy Limited by Knowledge of Directional Coupler Attenuation, as well as Power Meter Error Sources.

• Mismatch Uncertainty is a Major Contributor to Total Uncertainty

Page 28: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Precision Power Measurement Test Setups

Test Setups

4027, 4028 Model 43

Test Setups

4027, 4028 4024, 4025 Model 43

Page 29: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

These two measurements mustagree within +/- .2%

4027A +/-1% Calibration System

Page 30: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Test Results

-1.00

-0.80

-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

5 10 15 20 25 30 35 40 45 50 55 60

Elapsed Time (minutes)

Dif

fere

nc

e f

rom

Ca

lori

me

ter

(%)

SN 11569

MCS-59 w ith 11569

SN 11596

MCS-59 w ith 11596

SN 11597

MCS-59 w ith 11597

SN 11598

MCS-59 w ith 11598

Test Results 4027A

Page 31: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

5 kW RF Generator at 13.56 MHz

Bird 4020AMPower Sensor

Bird 4421 Power Meter

RF Matching Network

Plasma Etching

Chamber

Mismatches are present at each interconnection of system components

Bird Oil load

p1p1

p1

p2

p2 p2

p2

A Typical Field Calibration Setup

Page 32: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

p1 p2

p2SS

p1p2Sp2p1p2S

p2 +/- p1p2p2 = p2’

Total reflected signal

Mismatch Uncertainty

Page 33: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

p2 +/- p1p2p2 = p2’1 + p2’

1 – p2’

1 + ( p2 +/- p1p2p2 ) 1 - ( p2 +/- p1p2p2 )

VSWR (apparent) = =1 + p2 +/- p1p2p2

1 - p2 -/+ p1p2p2

Recognize that this expression can be approximated as the product of

VSWR (apparent) =

1 + p2

1 – p2

x1 +/- p1p2p2

1 -/+ p1p2p2 =

1 +/- p1p2p2 + p2 +/- p1 p32

1 -/+ p1p2p2 + p2 +/- p1 p32

Then:

VSWR (true) x 1 +/- p1p2p2

1 -/+ p1p2p2

~ VSWR (apparent)

Very small contribution

Mismatch Uncertainty

Page 34: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

VSWR (true) x 1 +/- p1p2p2

1 -/+ p1p2p2

~ VSWR (apparent)

• The true VSWR is multiplied by an uncertainty factor which can only be controlledby carefully choosing the reflection coefficients (p1 and p2) at the source and test points

1 - p1p2p2

1 + p1p2p2

1 + p1p2p2

1 - p1p2p2

1 + p2

1 – p2

Lower limit of multiplier factor =

Upper limit of multiplier factor =

Lower uncertainty limit of measured VSWR =

= F-

F-

= F+

1 + p2

1 – p2

Upper uncertainty limit of measured VSWR = F+

Mismatch Uncertainty

Page 35: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Where:

Pg = Reflection Coefficient of Source

Pl = Reflection Coefficient of Load

Pg and Pl are FREQUENCY DEPENDENT QUANTITIES!

Mu (%) = 100 [(1 Pg Pl)2 – 1]±

Mismatch Uncertainty

Page 36: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

VSWR Mismatch Uncertainty

-3

-2

-1

0

1

2

3

1 2 3 4 5

Load VSWR

VS

WR

Un

ce

rta

inty

1.1 source VSWR

1.1 source VSWR

1.5 source VSWR

1.5 source VSWR

2.0 Source VSWR

2.0 Source VSWR

2.5 Source VSWR

2.5 Source VSWR

3.0 Source VSWR

3.0 Source VSWR

3.5 Source VSWR

3.5 Source VSWR

Page 37: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

p1 p2

p2SS

p1p2Sp2p1p2S

S(1 +/- p1p2)

Total transmitted signal

+/- dB (ripple) = 20 log | 1- p1p2 |

Transmission Uncertainty

Page 38: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

• If data is taken at discrete points, then each individualreading carries an uncertainty of +/- x dB

High point

Low point

Ripple averagedout

flatness Measurementuncertainty

Transmission Uncertainty

Page 39: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Transmission Uncertainty

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

1 2 3 4 5

Load VSWR

Un

cert

ain

ty +

/- d

B 1.1 Source VSWR

1.5 Source VSWR

2.0 Source VSWR

2.5 Source VSWR

3.0 Source VSWR

3.5 Source VSWR

3.5 Source VSWR

1.1 Source VSWR

Page 40: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Transmission Uncertainty

0

0.05

0.1

0.15

0.2

0.25

15 20 25 30 35 40

Load Return Loss (dB)

Un

cert

ain

ty +

/- d

B 1.1 Source VSWR

1.15 Source VSWR

1.2 Source VSWR

1.25 Source VSWR

1.3 Source VSWR

1.35 Source VSWR

Page 41: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Prototype RF Delivery System Gain/Mismatch Analysis

No. Device Return Loss Watt Budget

(dB) (dB) (db)Input Output Mag. Ripple Watts In Watts out dbm out stage loss Cumulative loss

1 Generator 25.00 1,700.0 62.30 0.0

2 cable 25.00 30.00 -0.010 0.03 1700.0 1,696.1 62.29 3.9 3.93 Power Sensor 30.00 30.00 -0.025 0.02 1696.1 1,686.4 62.27 9.7 13.64 cable 30.00 30.00 -0.010 0.02 1686.4 1,682.5 62.26 3.9 17.55 Matching Network 30.00 30.00 -0.050 0.02 1682.5 1,663.2 62.21 19.3 36.86 cable 30.00 37.00 -0.010 0.01 1663.2 1,659.4 62.20 3.8 40.67 termination 37.00 8 62.159 62.24

10 Low Uncertainty Hi Uncertainty Delta Watts

Total -0.11 +/- 0.05 1659.4 1,642.1 1,676.8 40.6 34.7

Gain/Loss

PowerSensor

RFGenerator

Cable

Termination

MatchingNetwork

Cable Cable

Example of Typical RF System Error Budget

Page 42: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Prototype RF Delivery System Gain/Mismatch Analysis

No. Device Return Loss Watt Budget

(dB) (dB) (db)Input Output Mag. Ripple Watts In Watts out dbm out stage loss Cumulative loss

1 Generator 25.00 1,700.0 62.30 0.0

2 cable 25.00 26.44 -0.010 0.05 1700.0 1,696.1 62.29 3.9 3.9adapter 26.44 26.44 -0.005 0.04 1696.1 1,694.1 62.29 2.0 5.9adapter 26.44 26.44 -0.005 0.04 1694.1 1,692.2 62.28 1.9 7.8

3 Power Sensor 30.00 30.00 -0.025 0.02 1692.2 1,682.5 62.26 9.7 17.5adapter 26.44 26.44 -0.005 0.04 1682.5 1,680.5 62.25 1.9 19.5adapter 26.44 26.44 -0.005 0.04 1680.5 1,678.6 62.25 1.9 21.4

4 cable 26.44 26.44 -0.010 0.04 1678.6 1,674.7 62.24 3.9 25.3adapter 26.44 26.44 -0.005 0.04 1674.7 1,672.8 62.23 1.9 27.2

5 Matching Network 30.00 30.00 -0.050 0.02 1672.8 1,653.7 62.18 19.1 46.3adapter 26.44 26.44 -0.005 0.04 1653.7 1,651.8 62.18 1.9 48.2adapter 26.44 26.44 -0.005 0.04 1651.8 1,649.9 62.17 1.9 50.1

6 cable 26.44 26.44 -0.010 0.04 1649.9 1,646.1 62.16 3.8 53.9adapter 26.44 26.44 -0.005 0.04 1646.1 1,644.2 62.16 1.9 55.8adapter 26.44 26.44 -0.005 0.04 1644.2 1,642.3 62.15 1.9 57.7

7 termination 37.00 61.90 62.41 Low Uncertainty Hi Uncertainty Delta watts

Total -0.15 +/- 0.26 1646.1 1,547.7 1,742.6 57.7 194.9

Gain/Loss

PowerSensor

RFGenerator

Cable

Termination

MatchingNetwork

Cable Cable

Page 43: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

These two measurements mustagree within +/- .2%

4027A +/-1% Calibration System

Page 44: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Effects of Harmonics on Power Measurement

• 4027 Power Sensor Detector Scheme is Very Sensitive to Harmonics in the Signal.

• 4027 is Calibrated with Signals Having Harmonics of Less than –60dBc.

• Signals with Harmonic Content Greater Than –60dBc will Cause Offsets in Power Readings

• Effects of Harmonics are Determined not Only by Diode Response, but Also by Directional Coupler Response Characteristics, as well as Phase Relationships of Harmonic.

Page 45: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Effects of Harmonics on Power Measurement

Worst Case Errors

Harmonic Level

% Error with One Harmonic

% Error with Two

Harmonics

% Error with Three Harmonics

-55 0.36% 0.70% 1.00%-50 0.63% 1.10% 1.80%-45 1.10% 2.10% 2.90%-40 1.90% 3.90% 5.80%

Page 46: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Effects of Modulation on Power Measurement

• Detector Scheme Used in 4027 is Sensitive to Amplitude Modulation of the Signal.

• Magnitude of Change in Power reading is Related to Power Level and Instrument Range.

• Approximate Error:– At 10% of Full Scale: 5% AM Results in 2% Error– At 90% of Full Scale: 5% AM Results in 8% Error

Page 47: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Additional Tips for MakingAccurate Power Measurements

• Know the effects of the mismatches present in the system architecture on the power measurement uncertainty

• Avoid the use of multiple adapters or non-compensated (high VSWR) adapters between cables and components

• Perform a system error budget to quantify the effects of mismatches and component tolerances in the system

• Avoid the use of long interconnecting cables, as the ripple period will be more frequent as the length is increased for a given frequency

• Use coupler based measurement techniques when the load is unstable or poor in performance compared to the system line impedance

• Averaging techniques over wider frequency bands can be effective in minimizing the effect of mismatch uncertainties

Page 48: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

4020 Series Power Sensors and the 4421 Power Meter

Page 49: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

4421/4020 Series Power Meters

• Highly Accurate, Highly Repeatable Power Meter System

• Long Product History, Introduced in 1988• Has Become the Power Meter of Choice in

Semiconductor Processing Applications• Extremely Wide Dynamic Range

Page 50: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

• Designed for Service in Semiconductor Processing Applications

• 1% Accuracy at Calibration Points

• Several Models to Address Specific Semiconductor Power Levels and Frequencies

Model Power Range Frequency VSWR Range Directivity Insertion Loss

4027A12M 300 mW to 1 kW 10-15 MHz 1.0 to 2.0 28 dB <0.05 dB

4027A250K 3 W to 10 kW 250-400 kHz 1.0 to 2.0 28 dB <0.05 dB

4027A400K 3 W to 10 kW 400-550 kHz 1.0 to 2.0 28 dB <0.05 dB

4027A800K 3 W to 10 kW 800-950 kHz 1.0 to 2.0 28 dB <0.05 dB

4027A2M 3 W to 10 kW 1.5-2.5 MHz 1.0 to 2.0 28 dB <0.05 dB

4027A4M 3 W to 10 kW 3-5 MHz 1.0 to 2.0 28 dB <0.05 dB

4027A10M 3 W to 10 kW 10-15 MHz 1.0 to 2.0 28 dB <0.05 dB

4027A25M 3 W to 10 kW 25-30 MHz 1.0 to 2.0 28 dB <0.05 dB

4027A35M 3W to 10 kW 35-45 MHz 1.0 to 2.0 28 dB <0.05 dB

4027A60M 3W to 6kW 45-65 MHz 1.0 to 2.0 28dB <0.05 dB

±

4027A PrecisionPower Sensor

Page 51: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

• First generation diode detectors operate over transition region of diode response curve limiting use in modulated communications systems.

• The entire dynamic range of the 4027 series sensor is contained within the square law operating range of the detector

• Sensor will behave similar to a thermal device, responding to the heating power of the signal being measured

=VOUT

VIN

5.77

2

4027 true average responding detector scheme

Page 52: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

4027A Power Sensor

Page 53: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

LP Filter

LP Filter

4027F Power Sensor

Page 54: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Error Source 4027A Limit R2

1 Calibration Standards Uncertainty ± 0.4% 0.162 Frequency Response Error 0.0% 03 Dynamic Linearity ± 0.5% 0.254 Temperature Effects ± 0.5% 0.255 Noise ± 0.5% 0.25

Worst Case Error ± 1.9%RSS (Probable) Error ± 0.91%

Notes:

Based upon a temperature range of +35 degrees celcius.

Error Budget

4027A Power Sensor

Page 55: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

-0.50

-0.40

-0.30

-0.20

-0.10

0.00

0.10

0.20

0.30

0.50 1.00 1.50 2.00 2.50 3.00

S/N#11758

S/N#11759

S/N#11822

S/N#11823

S/N#11817

S/N#11818

S/N#11820

S/N#11821

S/N#11824

S/N#11825

S/N#11826

4027A10M Serial #

Power Levels (kW)

% Error

4027A Typical Linearity, 13.56 MHz

Page 56: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Power Levels in (kW)

11596 11597 11598

.5kw 0.00 0.00 0.601kw 0.00 0.00 0.20

1.5kw 0.00 0.00 0.102.0kw 0.00 0.00 -0.072.5kw 0.00 0.00 -0.503.0kw 0.00 0.00 0.00

4027A10M Serial #

4027A Typical Linearity, 12 MHz

Page 57: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Time (Min) 15 Min Warmup MCS-59 (w)

4027A10M (w) MCS-59 (w)

4027A10M (w) MCS-59 (w)

4027A10M (w)

0 99.8 99.8 1009 1009 3.01 3.015 99.6 99.6 1008 1008 3.01 3.0110 99.5 99.5 1009 1009 3.00 3.0015 99.6 99.6 1010 1010 2.99 2.9920 99.7 99.7 1012 1012 2.98 2.9825 100 100 1013 1013 2.98 2.9830 100 100 1011 1011 2.99 2.9935 100 100 1009 1009 2.99 2.9940 99.6 99.6 1011 1011 2.98 2.9845 99.3 99.3 1013 1013 2.99 2.9950 99.6 99.6 1015 1015 2.99 2.9955 99.4 99.4 1013 1013 2.97 2.9760 99.3 99.3 1009 1009 2.97 2.97

3000w1000w100w

4027A10M S/N#11820

Short Term Drift at Elevated Power Level

Page 58: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

4028A 1-5/8” or 3-1/8”

Transmission Line

Higher Power 4028 Capability

• Similar Accuracy To Other 4027 Models

• Uses Larger Transmission Line (1-5/8” or 3-1/8”) Flanged or Unflanged

• Power Measurement Capability Up To 40Kw

Page 59: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Typical Field Power Measurement Systems

Page 60: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

SourceAmplifier

DirectionalCoupler High Power

Termination

Forwardwatts

Reversewatts

Wattmeter

p2p1p1p1 p2

p2

A Typical Power Measurement SetupUtilizing a Directional Coupler

Page 61: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Coupler Based MeasurementsAdvantages:• Typically not limited by power- very little power dissipated• Typically have good thru line reflection coefficients• Forward Power readings are basically isolated from load

stability issues• Allows in-line monitoring of signal with actual system load

Disadvantages:• Must know the coupling value very accurately• Directivity limits reflected power reading• Frequency bandwidth limited

Page 62: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Source

Amplifier

Attenuator

Forwardwatts

Wattmeter

• Knowledge of the attenuation factor and stability is crucialto making a precise power measurement

A Typical Power Measurement Setup utilizing an Attenuator and Thermal Power Meter

A Typical Power Measurement Setup utilizing an Attenuator and Thermal Power Meter

ThermalSensor

Page 63: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Forward attenuation +/- attn. Output Low High +/- % fwdPower tolerance power reading reading power change

1000 30 0.01 1 0.998 1.002 0.23

1000 30 0.1 1 0.977 1.023 2.28

1000 30 0.25 1 0.944 1.059 5.59

1000 30 0.5 1 0.891 1.122 10.87

• Assuming nominal attenuation value can lead to significant errors

• Errors can be minimized by calibrating the attenuator at the specificfrequency or band of frequencies

Attenuators and Their EffectOn Accuracy

Attenuators and Their EffectOn Accuracy

Page 64: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Attenuator Based Measurements

Advantages:• Wideband frequency response, DC coupled• Convenient to use, eliminates a termination

Disadvantages:• Limited in power dissipation• Attenuation accuracy is often not precise, not

as stable• Reflection coefficients are generally higher

Page 65: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Attenuator Based Measurements

• Uncertainties Associated With This System– Input Mismatch Uncertainty (Typically Small Due to Low

Input VSWR)– Output Mismatch Uncertainty– Uncertainties Associated With Thermal Power Meter – Attenuation Factor Uncertainty– Stability of Attenuation Factor Over Temperature– Additional Thermal Errors Due To Excessive Load

Temperatures Affecting Thermal Power Sensor

When an attenuator is used, obtain the calibrated attenuation factor from the manufacturer (or make the measurement yourself) for best possible precision measurements.

Page 66: Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Summary

• National Standards Traceability- Challenges & Bird’s Solution– Bird’s multi-path solution and test capabilities make it unique

in the industry• RF Metrology Paths at Bird Electronic Corporation

– High accuracy transfer of standards at every step of the way– Know the concepts behind the error sources in a test setup

• 4020 Series Power Sensors and the 4421 Power Meter– +/- 1% power sensor ideal for semiconductor industry

• Typical Field Power Measurement Systems– Know your system and the errors associated with it