CEN/CLC/TR 17603-20-01:2021

Space engineering - Multipactor handbook

This Handbook describes the guidelines and recommendations for the design and test of RF components and equipment to achieve acceptable performance with respect to multipactor-free operation in service in space. This document is the mirror document of the EN 16603-20-01 (based on ECSS-ST-20-01) normative document. Thus it includes the same contents as the normative text and has the same structure.
This Handbook is intended to result in the effective design and verification of the multipactor performance of the equipment and consequently in a high confidence in achieving successful product operation.
This Handbook covers multipactor events occurring in all classes of RF satellite components and equipment at all frequency bands of interest. Operation in single carrier CW and pulse modulated mode are included, as w ell as multicarrier operations. A detailed chapter on secondary emission yield is also included.
This Handbook does not include breakdow n processes caused by collisional processes, such as plasma formation.

Raumfahrttechnik - Multipactorhandbuch

Ingénierie spatiale - Manuel sur l’effet Multipactor

Vesoljska tehnika - Priročnik o pojavu multipaktor

General Information

• Status: Published
• Publication Date: 28-Sep-2021
• ICS: 49.140 - Space systems and operations
• Technical Committee: CEN/CLC/TC 5 - Space
• Drafting Committee: CEN/CLC/TC 5/WG 6 - Upstream standards
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 29-Sep-2021
• Due Date: 26-Aug-2022
• Completion Date: 29-Sep-2021
• Mandate: M/496 - Mandate addressed to CEN, CENELEC and ETSI to develop standardisation regarding space industry (Phase 3 of the process)
• Ref Project: SIST-TP CEN/CLC/TR 17603-20-01:2021 - Space engineering - Multipactor handbook

Overview

CEN/CLC/TR 17603-20-01:2021 - Space engineering: Multipactor handbook - is a technical report that gives guidelines and recommendations for the design and testing of RF components and equipment to achieve multipactor‑free operation in space. It is the mirror of EN 16603-20-01 (based on ECSS‑ST‑20‑01) and contains the same normative structure and content. The Handbook covers multipactor events across all RF satellite component classes and frequency bands and includes single‑carrier CW, pulsed, and multicarrier operation. It explicitly excludes breakdown processes caused by collisional plasma formation.

Key topics and technical requirements

• Verification and test planning: requirements for a multipactor verification plan, classification of components, verification routes by analysis and test, and power requirement handling for realistic downstream mismatch.
• Design analysis: field analysis, multipactor design analysis levels (L1/L2), frequency selection, and methods for predicting vulnerable gaps and field distributions.
• Test conditions: mandatory considerations for cleanliness, pressure, temperature, signal characteristics (bandwidth, single/multi‑frequency, pulsed waveforms) and electron seeding strategies.
• Detection methods: global and local multipactor detection techniques, detector sensitivity, rise time and verification parameters.
• Test procedures and test bed: configuration, validation with reference tests, test sequences and power profiles, acceptance criteria and reporting requirements.
• Secondary Electron Yield (SEY): extensive chapter on SEY definition, measurement conditions, environmental control, worst‑case SEY justification and measurement procedures - critical for assessing multipactor susceptibility.
• Documentation and bibliography: references, terms and definitions, and supporting figures and case studies.

Practical applications and users

This Handbook is intended for:

• RF component and subsystem designers (filters, waveguides, isolators, high‑power loads, power amplifiers, payload front‑ends) who need to mitigate multipactor risk during design.
• Test laboratories and systems engineers responsible for qualification and acceptance testing of satellite RF hardware.
• Procurement, quality assurance, and project managers who require objective acceptance criteria and verification evidence for multipactor‑free operation. Use cases:
• Designing gap geometries and materials with low SEY to prevent discharge.
• Preparing test plans and building validated test beds for CW, pulsed and multicarrier verification.
• Assessing component acceptance and diagnosing anomalous RF events in development and pre‑launch test campaigns.

Related standards

• EN 16603-20-01 (mirror/normative link)
• ECSS‑ST‑20‑01 (basis for the normative content)

Keywords: multipactor, space engineering, RF components, satellite, multipactor‑free, SEY, verification, testing, CW, pulsed, multicarrier, EN 16603-20-01, ECSS.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2021
Vesoljska tehnika - Priročnik o pojavu multipaktor
Space engineering - Multipactor handbook
Raumfahrttechnik - Multipactorhandbuch
Ingénierie spatiale - Manuel sur l’effet Multipactor
Ta slovenski standard je istoveten z: CEN/CLC/TR 17603-20-01:2021
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/CLC/TR 17603-20-
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
September 2021
ICS 49.140
English version
Space engineering - Multipactor handbook
Ingénierie spatiale - Manuel sur l'effet Multipactor Raumfahrttechnik - Multipactorhandbuch

This Technical Report was approved by CEN on 13 September 2021. It has been drawn up by the Technical Committee
CEN/CLC/JTC 5.
CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2021 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. CEN/CLC/TR 17603-20-01:2021 E
reserved worldwide for CEN national Members and for
CENELEC Members.
Table of contents
European Foreword . 9
Introduction . 10
Scope . 11
References . 12
Terms, definitions and abbreviated terms . 14
3.1 Terms from other documents .14
3.2 Abbreviated terms. 15
Verification . 16
4.1 Verification process .16
4.2 Multipactor verification plan .16
4.2.1 Generation and updating .16
4.2.2 Description .16
4.3 Power requirements .16
4.3.1 General power requirements .16
4.4 Classification of equipment or component type . 17
4.4.1 General classification of equipment or component type . 17
4.5 Verification routes .20
4.6 Single carrier . 20
4.6.1 General . 20
4.6.2 Verification by analysis .20
4.6.3 Verification by test .20
4.7 Multicarrier .22
4.7.1 General . 22
4.7.2 Verification by analysis .22
4.7.3 Verification by test .22
4.8 Bibliography for clause 4.23
Design analysis . 24
5.1 Overview .24
5.2 Field analysis . 24
5.3 Multipactor design analysis .24
5.3.1 Frequency selection .24
5.3.2 Design analysis levels .24
5.3.3 Available data for Multipactor analysis . 58
5.4 Bibliography for clause 5.62
Multipactor - Test conditions . 64
6.1 Cleanliness .64
6.2 Pressure .65
6.3 Temperature .66
6.4 Signal characteristics .67
6.4.1 Applicable bandwidth .67
6.4.2 Single-frequency test case .67
6.4.3 Multi-frequency test case . 68
6.4.4 Pulsed testing .73
6.5 Electron seeding . 74
6.5.1 General . 74
6.5.2 Multipactor test in CW operation . 74
6.5.3 Multipactor test in pulsed operation . 74
6.5.4 Multipactor test in multi-carrier operation . 74
6.5.5 Seeding sources .74
6.5.6 Seeding verification .82
6.6 Bibliography for clause 6.82
Multipactor - Methods of detection . 83
7.1 General .83
7.2 Detection methods .83
7.2.1 Introduction .83
7.2.2 Global detection methods. 84
7.2.3 Local detection methods .86
7.3 Detection method parameters .87
7.3.1 Verification .87
7.3.2 Sensitivity .87
7.3.3 Rise time .87
Multipactor - test procedure . 88
8.1 General .88
8.2 Test bed configuration .89
8.3 Test bed validation.89
8.3.1 Reference multipactor test .89
8.4 Test sequence .93
8.4.1 Power profile .93
8.5 Acceptance criteria .93
8.5.1 Definitions .93
8.5.2 Multipactor Free Equipment or component . 93
8.5.3 Steps in case of Discharges or Events during test. 93
8.5.4 Investigation of Test Anomalies. 93
8.6 Test procedure .93
8.6.1 Test procedure for high power loads . 93
8.7 Test reporting .97
8.8 Bibliography for clause 8.99
Secondary electron emission yield requirements . 100
9.1 General .100
9.1.1 SEY definition and properties . 100
9.1.2 SEY and Multipactor . 101
9.1.3 Factors affecting SEY . 102
9.1.4 SEY testing . 103
9.2 SEY measurements justification . 106
9.3 Worst case SEY measurement . 106
9.4 SEY measurements conditions . 106
9.4.1 Environmental conditions . 106
9.4.2 SEY test bed conditions . 115
9.4.3 SEY sample characteristics . 118
9.5 SEY measurements procedure . 119
9.5.1 SEY Measurements procedure documents . 119
9.5.2 SEY measurement calibration . 119
9.6 ECSS SEY data selection . 120
9.7 Bibliography for clause 9. 139

Figures
Figure 4-1: Component assembly with consideration of reflection coefficient . 16
Figure 4-2: Isolator block diagram .17
Figure 4-3: Tested component – Coaxial filter .18
Figure 4-4: Multipactor simulations and multipactor measurements with and without
thermal baking for a RF component with different dielectric materials . 19
Figure 4-5: Schematic diagram of discharge at a triple point in the inverted voltage
gradient configuration with potential contours indicated by colour scale. . 20
Figure 4-6: Component assembly with consideration of the reflection coefficient of the
downstream component assembly for test margin . 21
Figure 4-7: Power correction with respect to mismatch of the payload downstream
component assembly .21
Figure 5-1: 2D schematic of a typical iris-like structure . 25
Figure 5-2: 2D Typical Sombrin chart with fringing field effect for different d/l ratios. . 27
Figure 5-3: 2D Typical multipactor chart computed with non-stationary theory with
fringing field effect for different d/l ratios. . 28
Figure 5-4: 2D Experimental results corresponding to EVEREST project [5-12] . 29
Figure 5-5: 2D Experimental results corresponding to ESA-TESAT activity [5-10] . 29
Figure 5-6: 2D Experimental results corresponding to ESA-AURORASAT activity [5-
11] .30
Figure 5-7: 2D Numerical results corresponding to ESA-AURORASAT activity [5-11] . 30
Figure 5-8: 2D Analytical results corresponding to ESA-AURORASAT activity [5-11] . 31
Figure 5-9: Fringing field analysis method 1 for L1 analysis type. . 32
Figure 5-10: Fringing field analysis method 2 for L1 analysis type. . 33
Figure 5-11: Single-carrier L1 analysis flow diagram. . 34
Figure 5-12: Schematic network used for multipactor analysis. . 36
Figure 5-13: Example of multicarrier signal and corresponding pulse approximation. . 37
Figure 5-14: Electron absorption rate for zero applied voltage. . 38
Figure 5-15: L1 analysis for multicarrier, Pulsed model flow chart . 39
Figure 5-16: 3D view of Ku-band transformer of ESA TRP activity [5-19] . 40
Figure 5-17: Pulse amplitude and carrier amplitude vs t . 41
on
Figure 5-18: Example with 3 different “on intervals” corresponding to 10%, 30% and
70% of the envelope period together with the theoretical limit (boundary) . 42
Figure 5-19: 3D of Ku band bandpass filter of ESA TRP activity [5-19] . 43
Figure 5-20: Hybrid L1/L2 multi-carrier analysis steps. . 45
Figure 5-21: Electron growth over 10 envelope periods for 10 different “on intervals” for
one amplitude factor .47
Figure 5-22: Convergence of the amplitude factor, showing also how Γ converges
towards one electron .47
Figure 5-23: Hatch and William chart with the multicarrier in-phase amplitude indicated
by a green circle. The red dashed line is the fd-product of the average
multicarrier frequency and the critical gap size . 48
Figure 5-24: KS3 sample geometry. .49
Figure 5-25: KS3 sample simulated RF performance . 50
Figure 5-26: 3D view of L-band sample .51
Figure 5-27: Predicted S-parameter Performance of Preliminary L-band RF Device
Design .52
Figure 5-28: Predicted Voltage Distribution in Preliminary L-band RF Device Design . 53
Figure 5-29: Predicted S-parameter Performance of Finalised L-band RF Device (1525
MHz) .53
Figure 5-30: Predicted Voltage Distribution in Finalised L-band RF Device
(1525 MHz) .54
Figure 5-31: Predicted S-parameter Performance of Finalised L-band RF Device
(1405 MHz) .54
Figure 5-32: Predicted Voltage Distribution in Finalised L-band RF Device
(1405 MHz) .55
Figure 5-33: Variation of peak voltage on each resonator with frequency – 30 MHz
design bandwidth .56
Figure 5-34: Variation of peak voltage on each resonator with frequency – 10 MHz
design bandwidth .56
Figure 5-35: Variation of peak voltage on central resonator with bandwidth change (Fc
= 1525 MHz) .57
Figure 5-36: RF performances with machining tolerances (Resonant reference sample
S-3 and S-4) .58
Figure 5-37: Electric field (12,75 GHz – samples S-3 and S-4) . 59
Figure 5-38: Voltage inside critical gap (samples S-3 and S-4) . 59
Figure 5-39: Nominal model .60
Figure 5-40: Re-tuned model .61
Figure 5-41: Return Loss nominal (red) and tuned (pink) . 61
Figure 6-1: Work in a clean room environment. .64
Figure 6-2: Screenshot of clean room monitoring. The pressure reading corresponds to
the overpressure delta in the clean room. . 64
Figure 6-3: A pressure gauge. .65
Figure 6-4: Picture of a typical pressure profile for a P1 component or equipment. . 65
Figure 6-5: Picture of a typical pressure profile for a P2/P3 component or equipment
with pressure spikes related to outgassing. . 66
Figure 6-6: RF cable with thermocouples. . 66
Figure 6-7: RF cable with thermocouples. . 67
Figure 6-8: A multicarrier test facility .68
Figure 6-9: Schematic of a three-carrier multipactor test bed. 68
Figure 6-10: Error probability distributions for different f·d . 69
Figure 6-11: Error dependency on the similarity degree . 70
Figure 6-12: Margin definition with respect pulsed model and CW operation . 71
Figure 6-13: Typical pulse parameters during multipactor test . 73
Figure 6-14: Decay of Strontium-90. .75
Figure 6-15: Picture of an encapsulated radioactive source. . 75
Figure 6-16: Sketch of the photoelectric effect. .77
Figure 6-17: Picture of the UV lamp as part of a test bed. . 77
Figure 6-18: Spectrum of the typical lamps used for electron seeding. . 78
Figure 6-19: Diagram of an electron gun. .79
Figure 6-20: Sketch of the functioning of an electron gun. . 79
Figure 6-21: Picture of an electron gun installed into a test bed. . 80
Figure 7-1: Schematic of global detection systems implemented in a typical test bed. 84
Figure 7-2: Electron probe circuit diagram. .86
Figure 8-1: Multipactor test procedure overview. .89
Figure 8-2: Example of an L- and S-band reference sample. . 90
Figure 8-3: Measured S-parameter performance of broadband multipactor sample. . 91
Figure 8-4: Ku-band Broadband Multipactor Sample. . 91
Figure 8-5: Multipactor threshold variation vs. gap height. . 92
Figure 8-6: Ku-band reference sample dimensions. . 92
Figure 8-7: Heat pipe. .94
Figure 9-1: Typical dependence of SEY coefficients on primary electron energy. . 101
Figure 9-2: Energy distribution curve of emitted electron from gold target surface
submitted to 112 eV electron irradiation [9-1] . 101
Figure 9-3: Experimental arrangement for SEY test with emission collector . 103
Figure 9-4: SEY experimental setup (without collector around the sample) . 105
Figure 9-5: Typical composition of exposed to air metal surface . 107
Figure 9-6: Measured SEY of metals exposed to air without a specific surface cleaning
procedure .108
Figure 9-7: Schematic view of material exposed to atmosphere: the case of silver . 109
Figure 9-8: Effect of cleaning of the surface by heating on the SEY of Nb. . 110
Figure 9-9: Effect of the water absorption on the SEY. . 110
Figure 9-10: Effect of baking on the SEY of dielectrics. . 111
Figure 9-11: Evolution of the SEY of the technical silver versus pressure. 112
Figure 9-12: Effect of the temperature on the SEY of silver. Figure extracted from [9-
18]. .113
Figure 9-13: Effect of the temperature on the SEY of MgO and BN-SiO2 ceramics. . 114
Figure 9-14: Effect of the temperature on the SEY of coverglass and CVD diamond . 115
Figure 9-15: Effect of the incidence angle variations on the SEY of silver . 116
Figure 9-16: Effect of electron irradiation on SEY (CERN) . 116
Figure 9-17: Influence of the primary electron energy on the charging process. TEEY =
= E1 and E =E2 . 117
SEY, EC1 C2
Figure 9-18: Influence of the primary electron energy on the charging process,
EEY = SEY, E = E1 and E =E2 . 118
C1 C2
Figure 9-19: SEY as a function of the primary electron energy for aluminium . 120
Figure 9-20: SEY as a function of the primary electron energy for copper . 121
Figure 9-21: SEY as a function of the primary electron energy for gold . 121
Figure 9-22: SEY as a function of the primary electron energy for silver coatings. 122
Figure 9-23: Comparison of the SEY curves for Cu, Al, Ag and Au . 122

Tables
Table 4-1:Multipactor simulations and multipactor measurements with and without
thermal baking for a RF component with different dielectric materials . 18
Table 5-1: Characteristics Ku-band transformer of ESA TRP activity [5-19] . 40
Table 5-2: Characteristics Ku-band transformer of ESA TRP activity [5-19] . 43
Table 5-3: Multicarrier signal characteristics .43
Table 5-4: Predicted and testes multipactor breakdown levels . 44
Table 5-5: SEY characteristics of KS3 sample .50
Table 5-6: Multipactor thresholds for KS3 sample . 51
Table 5-7: SEY data for L-band sample .57
Table 5-8: Multipactor thresholds for L-band sample . 57
Table 5-9: Multipactor threshold vs. manufacturing errors (samples S-3 and S-4) . 60
Table 6-1: Error statistics in dB for silver and aluminium, and different values of
carriers, frequency band and fxd product . 69
Table 6-2: Rate and energy of injected electrons going through a particular aluminium
wall [6-4]. .76
Table 8-1: Example of Multipactor Test Specification Sheet . 88
Table 8-2: Maximum RF power applied to the load range (margin in bold). . 95
Table 8-3: Multipactor test report summary . 97
Table 8-4: Test setup validation without sample .98
Table 8-5: Test setup validation with reference sample . 98
Table 8-6: Test of DUT at reduced power level at ambient pressure just before closing
the vacuum chamber (RECOMMENDED . 99
Table 9-1: Average values of the main SEY parameters for all “as built” (mentioned,
“Before RF testing” in the below table) and all the “as tested” SEY samples
(mentioned, “After RF testing” in the below table) for a given SEY
measurement facility . 109
Table 9-2: Requirement in the experimental conditions for SEY measurement . 119
Table 9-3: SEY parameters of the SEY curves of Al, Cu, Au and Ag samples . 120
Table 9-4: SEY curve data for aluminium . 123
Table 9-5: SEY curve data for copper. . 127
Table 9-6: SEY curve data for gold . 131
Table 9-7: SEY curve data for silver . 135

European Foreword
This document (CEN/CLC/TR 17603-20-01:2021) has been prepared by Technical Committee
CEN/CLC/JTC 5 “Space”, the secretariat of which is held by DIN.
It is highlighted that this technical report does not contain any requirement but only collection of data
or descriptions and guidelines about how to organize and perform the work in support of EN 16603-20-
01:2020.
This Technical report (CEN/CLC/TR 17603-20-01:2021) originates from ECSS-E-HB-20-01A.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such
patent rights.
This document has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association.
This document has been developed to cover specifically space systems and has therefore precedence
over any TR covering the same scope but with a wider domain of applicability (e.g.: aerospace).
Introduction
Multipactor is a well-understood RF breakdown mechanism in high vacuum conditions. It has been
investigated both theoretically and experimentally over many years, as listed in references from [2-1] to
[2-7]. Essential ingredient for multipactor is initial free electrons, also called primary electrons. Free
electrons can be accelerated under the action of the high power electromagnetic signals inside the RF
component. These accelerated electrons impact the RF internal surface with such a kinetic energy to
knock out secondary electrons. This resonant process repeats until an avalanche-like growth of electrons
is reached, and a multipactor discharge occurs. A multipactor discharge produces signal noise, power
reflection and ultimately a local ionization that leads to a complete short circuit. In the worst case, this
can develop to a complete system failure.
A typical multipactor event can be described as follows:
1. Free electrons exist within the RF field region of a component whose dimensions are small
compared with the electron mean free path as a result of low pressure within the
component.
2. The electric field within the component accelerates the free electrons towards a surface.
3. The electrons impact on the surface with appropriate energies to liberate more secondary
electrons than the incident ones.
4. Under the specific condition of synchronism of the RF electric field and the electron impact
time, resonance conditions are met and steps b. and c. repeat until multipactor discharge
occurrence.
Beside the multipactor discharge, other electrical breakdown of different nature in RF components such
as multipactor leading to corona due to local outgassing and discharge occurrence in intermediate
pressure range can also arise [2-8], [2-9] and [2-10].
NOTE The Multipactor Handbook follows the same structure as the Standard.
Where the WG has decided that the content of a clause of the Standard
needs no supporting material this clause is left empty. The text
"No supporting material needed. " is added there.
Scope
This Handbook describes the guidelines and recommendations for the design and test of RF
components and equipment to achieve acceptable performance with respect to multipactor-free
operation in service in space. This document is the mirror document of the ECSS-ST-20-01 normative
document. Thus it includes the same contents as the normative text and has the same structure.
This Handbook is intended to result in the effective design and verification of the multipactor
performance of the equipment and consequently in a high confidence in achieving successful product
operation.
This Handbook covers multipactor events occurring in all classes of RF satellite components and
equipment at all frequency bands of interest. Operation in single carrier CW and pulse modulated mode
are included, as well as multi-carrier operations. A detailed chapter on secondary emission yield is also
included.
This Handbook does not include breakdown processes caused by collisional processes, such as plasma
formation.
References
EN Reference Reference in text Title
EN 16601-00-01 ECSS-S-ST-00-01 ECSS system – Glossary of terms
EN 16603-10-02 ECSS-E-ST-10-02 Space engineering – Verification
EN 16603-10-03 ECSS-E-ST-10-03 Space engineering - Testing
EN 16603-20-01 ECSS-E-ST-20-01 Space engineering – Multipactor design and test
EN 16601-10 ECSS-M-ST-10 Space project management – Project planning and
implementation
EN 16601-40 ECSS-M-ST-40 Space project management – Configuration and
information management
EN 16602-20-08 ECSS-Q-ST-20-08 Space product assurance – Storage, handling and
transportation of spacecraft hardware
EN 16602-70-01 ECSS-Q-ST-70-01 Space product assurance – Cleanliness and
contamination control
EN 16602-70-02 ECSS-Q-ST-70-02 Space product assurance – Thermal vacuum outgassing
test for the screening of space materials
ESCC-20600 Preservation, packaging and despatch of ESCC
component
ISO 14644–1:2015 Clean rooms and associated controlled environments –
Part 1: Classification of air cleanliness by particle
concentration
[2-1] A. Woode & J. Petit, Diagnostic Investigations into the Multipactor Effect, Susceptibility Zone
Measurements and Parameters Affecting A Discharge, ESTEC Working Paper 1556, November
[2-2] Abstract Book, Workshop on Multipactor and Passive Intermodulation Products Problems in
Spacecraft Antennas, ESTEC, December 1990
[2-3] Final Presentations & Working Meeting: Multipactor & PIM in Space RF Hardware, ESTEC,
January 1993
[2-4] A. J. Marrison, R. May, J.D. Sanders, A. D. Dyne, A. D. Rawlins, J. Petit, A study of Multipactor
in Multicarrier RF Components, Report no AEA/ TYKB/31761/01/RP/05 Issue 1, January 1997
[2-5] A. J. Hatch and H.B. Williams, J. Appl. Phys. 25, 417 (1954)
[2-6] A. J. Hatch and H.B. Williams, Phys. Rev. 112, 681 (1958)
[2-7] R. Woo, Multipacting Discharges between Coaxial Electrodes, J. Appl. Phys. 39, 1528-1533
(1968)
[2-8] R. Woo, Final Report on RF Voltage Breakdown in Coaxial Transmission Lines, JPL Technical
Report 32-1500, October 1970
[2-9] F. Höhn, W. Jacob, R. Beckmann, R. Wilhelm, The Transition of a Multipactor to a low-pressure
gas discharge, Phys. Plasma, 4, 940-944 (1997)
[2-10] J. M. Meek and J. D. Craggs, Electrical Breakdown of Gases, Wiley (1978)

Terms, definitions and abbreviated terms
3.1 Terms from other documents
a. For the purpose of this standard, the terms and definitions from ECSS-S-ST-00-01 apply, in
particular the following terms:
1. acceptance
2. bakeout
3. component
4. development
5. equipment
6. integration
7. uncertainty
8. validation
9. verification
b. For the purpose of this standard, the terms and definitions from ECSS-E-ST-10-02 apply, in
particular the following terms:
1. acceptance stage
2. analysis
3. inspection
4. model philosophy
5. qualification stage
6. review of design
7. test
8. verification level
c. For the purpose of this standard, the terms and definitions from ECSS-E-ST-10-03 apply, in
particular the following terms:
1. acceptance margin
2. qualification margin
d. For the purpose of this standard, the terms and definitions from ECSS-Q-ST-70-02 apply, in
particular the following terms:
1. outgassing
3.2 Abbreviated terms
For the purpose of this document, the abbreviated terms from ECSS-S-ST-00-01 and the following apply:

Abbreviation Meaning
device under test
DUT
energy distribution curve
EDC
electromagnetic
EM
electron stimulated discharge
ESD
finite element method
FEM
high power amplifier
HPA
low noise amplifier
LNA
output multiplexer
OMUX
regulated electron gun
REG
radiofrequency
RF
secondary emission yield
SEY
thermal vacuum chamber
TVAC
ultraviolet
UV
Verification
4.1 Verification process
No supporting material needed.
4.2 Multipactor verification plan
No supporting material needed.
4.2.1 Generation and updating
No supporting material needed.
4.2.2 Description
No supporting material needed.
4.3 Power requirements
4.3.1 General power requirements
4.3.1.1 Nominal power
No supporting material needed.
4.3.1.2 Increased power ∆P due to payload mismatch
The increased power ∆P, as a positive value expressed in dB, within the component i due to payload
mismatch can be derived as follows:
∆P=20log10(1+|Γi-1|)
where Γi-1 is the reflection coefficient of the downstream component assembly (also called “component
i-1” in the Figure 4-1).
Figure 4-1: Component assembly with consideration of reflection coefficient
Since ∆P is frequency dependent, the worst case ∆P over the operational frequency bandwidth is taken
into account.
4.3.1.3 Failure
Failure case for circulators
Circulators are used for protecting high power amplifiers in case of a failure or for improving the RF
performance of a network. Therefore, the isolated port has to be matched towards an adequate load.
The key feature, the non-reciprocity, of the circulator enables the isolation of the corresponding paths
of the system and leads to the mentioned properties.
The next picture shows a typical block diagram of such a circulator with a connected or integrated load.
The combination of a circulator with a load is a so-called isolator.

Figure 4-2: Isolator block diagram
To use an isolator for a high power application (peak and average) two failure cases are considered. The
first case is the mismatch of the system, which causes additional superposition of the E-Field with
respect to the phase. The second case is the total reflection of the signal, e.g. miscommand of a switch,
which leads to a standing wave in the circulator. Standing wave condition with respect to worst-case
phase produces 2 times the E-field amplitude of the input signal. To prevent an over specification of the
isolator the proper application are considered case by case. Therefore, the complete isolator is analysed
for multipactor to locate the area where multipactor occurred. This is important for definition of the
surface property for the multipactor analysis itself. It is good practise for the margin definition to
distinguish between nominal case and the failure case. The margin for the failure case is orientated on
the actual application to avoid the situation for over specification, that no isolator design can physically
meet.
The impact of the failure case is assessed at system level, taking into account the downstream
component assembly.
4.4 Classification of equipment or component type
4.4.1 General classification of equipment or component type
Effect of dielectric charging for P2 components
For RF components with dielectrics, the charging effect adds DC electrostatic fields that can affect the
multipactor discharge significantly, depending on the geometry of the device and the applied RF fields.
Moreover, the charging properties of dielectrics are extremely sensitive to the dielectric history
(handling, triboelectrification, temperature baking…). Thus, baking can have different effects on the
charging behaviour and therefore on the multipactor effect. The initial charge of the dielectric, as well
as the induced charge during the multipactor avalanche, are highly unpredictable, which implies a high
uncertainty of the multipactor threshold on both analysis and test. The analytical multipactor analysis
for the moment do not take into account the charging effect. On the other hand, numerical analysis can
model it accurately, although the initial charge of the dielectrics is an input parameter that is usually
unknown and is non uniform over the dielectric surface. In most cases, the charging effect implies an
increase of the multipactor breakdown [4-1] [4-2] and therefore, analysis with zero charge is usually
considered as the worst-case. However, this depends on many parameters and is studied case by case.
In addition, the SEY characteristics of the dielectrics can be affected by charging leading to dispersion
in the result. This can generate inaccuracy in the analysis (see clause 9). For high power measurements,
the dielectric charge is an unknown parameter and can produce significant differences with respect
analysis and also between different test campaigns. The Table 4-1 and Figure 4-4 below given by ESA
illustrate the discrepancy between multipactor simulations and multipactor measurements for a RF
component with different dielectric materials.

Figure 4-3: Tested component – Coaxial filter
Table 4-1:Multipactor simulations and multipactor measurements with and
without thermal baking for a RF component with different dielectric materials

SEY data used for computing the predicted threshold of Table 4-1 was obtained by different test
campaigns.
The worst predicted values of Table 4-1correspond to the Multipactor analysis considering the less
conservative SEY figures for each sample.
The best predicted values of Table 4-1 correspond to the Multipactor analysis considering the more
conservative SEY figures for each sample.

Figure 4-4: Multipactor simulations and multipactor measurements with and
without thermal baking for a RF component with different dielectric materials
The discrepancy noticed on the multipactor threshold in the above table can also be explained by other
phenomena than multipactor such as corona triggered by local outgassing, or triple point effects.
In [4-3], the modelling accuracy for dielectrics with different conductivities was investigated. For
dielectrics with relatively high conductivity, a good agreement between the measured and predicted
multipactor threshold with ‘metal-like’ approach was found. A ‘metal-like’ approach do not take into
account the charging properties. For dielectrics with lower conductivity, a large discrepancy between
test and prediction was observed.
In order to differentiate between dielectrics showing a high conductivity or not, a charging test can be
performed as in [4-4].
Other types of discharge related to P2 and P3 components
In presence of dielectrics inside space RF components (for type 2 and possibly type 3 components),
electron stimulated discharge (ESD) phenomena can occur.
These ESD phenomena named “triple point effect” can also occur with RF fields inside RF components
with 3 media such as metal, dielectric and vacuum intersecting and with a sharp edge in the metal in
an area called “triple point” (see Figure 4-5). When a critical RF field is reached at the level of the metal
sharp edge, field emission of electrons can occur. The electron is driven towards the relat
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