EN 2591-221:2007

Aerospace series - Elements of electrical and optical connection - Test methods - Part 221: Voltage Standing Wave Ratio (VSWR)

This standard specifies a measurement method of VSWR, in the required frequency bandwidth of coax contacts or connectors with characteristic impedance.
It shall be used together with EN 2591-100.
The measurement is carried out according to vectorial method using “S” parameters (see definition in Annex A).

Luft- und Raumfahrt - Elektrische und optische Verbindungselemente - Prüfverfahren - Teil 221: Stehwellenverhältnis

Diese Norm legt ein Messverfahren für das Stehwellenverhältnis in der geforderten Frequenzbandbreite von koaxialen Kontakten oder Steckverbindern mit charakteristischer Impedanz fest.
Sie ist in Verbindung mit EN 2591-100 anzuwenden.
Die Messung wird nach dem vektoriellen Verfahren unter Verwendung von „S“-Parametern (siehe Definition in Anhang A) durchgeführt.

Série aérospatiale - Organes de connexion électrique et optique - Méthodes d'essais - Partie 221 : Ratio d’Ondes Stationnaires

Aeronavtika - Elementi električnih in optičnih povezav - Preskusne metode - 221. del: Koeficient stojnega vala (VSWR)

General Information

• Status: Published
• Publication Date: 11-Dec-2007
• Withdrawal Date: 29-Jun-2008
• ICS: 49.060 - Aerospace electric equipment and systems
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 2 - Electrical
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 30-Jun-2017
• Completion Date: 11-Feb-2026
• Ref Project: SIST EN 2591-221:2008 - Aerospace series - Elements of electrical and optical connection - Test methods - Part 221: Voltage Standing Wave Ratio (VSWR)

Relations

• Refers: EN 2591-100:2024 - Aerospace series - Elements of electrical and optical connection - Test methods - Part 100: General
• Effective Date: 28-Jan-2026
• Referred By: EN 4644-001:2017 - Aerospace series - Connector, electrical and optical, rectangular, modular, rectangular inserts, operating temperature 175 °C (or 125 °C) continuous - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: EN 3645-001:2019 - Aerospace series - Connectors, electrical, circular, scoop-proof, triple start threaded coupling, operating temperature 175 °C or 200 °C continuous - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: EN 3155-017:2006 - Aerospace series - Electrical contacts used in elements of connection - Part 017: Contacts, electrical, relay base, female, type A, crimp, class P - Product standard
• Effective Date: 28-Jan-2026
• Referred By: EN 3155-012:2006 - Aerospace series - Electrical contacts used in elements of connection - Part 012: Contacts, electrical, triaxial, size 8, male, type D, solder, class R - Product standard
• Effective Date: 28-Jan-2026
• Referred By: EN 3155-083:2019 - Aerospace series - Electrical contacts used in elements of connection - Part 083: Contact, electrical, female, type A, crimp, class S, size 8 - Product standard
• Effective Date: 28-Jan-2026
• Referred By: EN 3155-009:2025 - Aerospace series - Electrical contacts used in elements of connection - Part 009: Contacts, electrical, female 009, type A, crimp, class S - Product standard
• Effective Date: 28-Jan-2026
• Referred By: EN 3646-001:2007 - Aerospace series - Connectors, electrical, circular, bayonet coupling, op-erating temperature 175 °C or 200 °C continuous - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: EN 3155-066:2006 - Aerospace series - Electrical contacts used in elements of connection - Part 066: Contacts, electrical, female, type A, crimp, class S, size 8 - Product standard
• Effective Date: 28-Jan-2026
• Referred By: EN 3660-004:2023 - Aerospace series - Cable outlet accessories for circular and rectangular electrical and optical connectors - Part 004: Cable outlet, style A, straight, unsealed with clamp strain relief - Product standard
• Effective Date: 28-Jan-2026
• Referred By: EN 3155-066:2013 - Aerospace series - Electrical contacts used in elements of connection - Part 066: Contacts, electrical, female, type A, crimp, class S, size 8 - Product standard
• Effective Date: 28-Jan-2026
• Referred By: EN 3155-035:2012 - Aerospace series - Electrical contacts used in elements of connection - Part 035: Contacts, electrical, triaxial, size 08, female, type D, crimp, class R - Product standard
• Effective Date: 28-Jan-2026
• Referred By: EN 3155-079:2019 - Aerospace series - Electrical contacts used in elements of connection - Part 079: Contacts size 22 for EN 2997, electrical, female, type A, crimp, class S - Product standard
• Effective Date: 28-Jan-2026
• Referred By: EN 3155-001:2016 - Aerospace series - Electrical contacts used in elements of connection - Part 001: Technical Specification
• Effective Date: 28-Jan-2026
• Referred By: EN 4531-101:2016 - Aerospace series - Connectors, optical, circular, single and multipin, coupled by triple start threaded ring - Flush contacts - Part 101: Optical contact for EN 4641 multimode cable -55 °C to 125 °C - Product standard
• Effective Date: 28-Jan-2026

Overview

EN 2591-221:2007 is a European standard developed by CEN, part of the broader EN 2591 series for aerospace applications. This specific document defines standardized test methods for measuring the Voltage Standing Wave Ratio (VSWR) of electrical and optical connection elements, particularly coaxial contacts and connectors. The VSWR measurement process is essential for ensuring signal integrity and performance in high-frequency aerospace systems. Testing is based on the vectorial method using S-parameters, as detailed in Annex A. EN 2591-221:2007 is intended to be used in conjunction with EN 2591-100, which provides general test method guidelines.

Key Topics

• VSWR Measurement: Establishes procedures for reliably evaluating VSWR across specified frequency bandwidths for coaxial contacts/connectors.
• S-parameters (Scattering Parameters): Utilizes the vector network analyzer and S-parameter methodology to assess reflection and transmission characteristics.
• Test Setups: Specifies two methods for specimen preparation and measurement:
  • Method A: Measures an individual coaxial device at each cable end.
  • Method B: Evaluates a device positioned mid-cable between standard connectors.
• Test Equipment:
  • Vector network analyzer
  • Calibration kits
  • Precision adapters
  • Transformation kits (for impedance conversion, e.g., 50 Ω to 75 Ω)
• Calibration and Procedure: Details the process for calibrating equipment, selecting measurement frequency range and sampling points, performing measurements, and isolating device under test.
• Documentation Requirements: Lists items such as part numbers, frequency range, connector types, measurement impedance, and test instructions that must be specified for each test.

Applications

EN 2591-221:2007 is crucial in aerospace engineering and related industries where high-frequency cables and connectors play a vital role in electrical and optical systems. Its test methodology ensures:

• Signal Integrity: By evaluating VSWR, designers and quality engineers can minimize signal loss and reflections in RF and microwave circuits.
• Product Qualification: Enables consistent verification of connector and cable designs for use in aircraft, satellites, and other aerospace platforms.
• Compliance and Interoperability: Ensures that connection components meet interoperability and reliability requirements set by the aerospace industry.
• Quality Assurance: Supports manufacturers in certifying their products against standardized international criteria to meet safety and performance benchmarks.
• Procurement and Maintenance: Assists aerospace subcontractors, integrators, and maintenance providers in selecting and verifying compliant components.

Related Standards

EN 2591-221:2007 should be considered as part of a broader family of aerospace connection test standards, including:

• EN 2591-100: Aerospace series - Elements of electrical and optical connection - Test methods - Part 100: General
  Foundation document outlining general principles and requirements for all EN 2591 test methods.
• EN 2591 Series: Covers a comprehensive range of tests for electrical and optical connectors, including mechanical, climatic, and electromagnetic compatibility assessments.
• IEC and ISO Standards: Additional international standards may apply for components intended for broader use beyond aerospace applications.

By following EN 2591-221:2007, organizations benefit from improved reliability, safety, and performance of vital electrical and optical interconnections in aerospace systems. The use of standardized test methods also facilitates international trade and component sourcing by harmonizing requirements across markets.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aerospace series - Elements of electrical and optical connection - Test methods - Part 221: Voltage Standing Wave Ratio (VSWR)Série aérospatiale - Organes de connexion électrique et optique - Méthodes d'essais - Partie 221 : Ratio d’Ondes StationnairesLuft- und Raumfahrt - Elektrische und optische Verbindungselemente - Prüfverfahren - Teil 221: StehwellenverhältnisTa slovenski standard je istoveten z:EN 2591-221:2007SIST EN 2591-221:2008en49.060ICS:SLOVENSKI
STANDARDSIST EN 2591-221:200801-marec-2008

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 2591-221December 2007ICS 49.060 English VersionAerospace series - Elements of electrical and optical connection- Test methods - Part 221: Voltage Standing Wave Ratio(VSWR)Série aérospatiale - Organes de connexion électrique etoptique - Méthodes d'essais - Partie 221 : Ratio d'OndesStationnairesLuft- und Raumfahrt - Elektrische und optischeVerbindungselemente - Prüfverfahren - Teil 221:StehwellenverhältnisThis European Standard was approved by CEN on 27 April 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 2591-221:2007: E

Definition of S parameters.8

Key 1 Male coaxial device 2 Female coaxial device 3 Coaxial cable; Lg. = (600 ± 2,5) mm Figure 1

Key 1 Coaxial (Std) male connector 2 Device under test 3 Coaxial (Std) female connector 4 Coaxial cable; Lg. = 2 × (300 ± 2,5) mm Figure 2 4 Apparatus The apparatus shall comprise measuring equipment which includes (see Figure 3):  vector network analyser  calibration kit  standard precision adapters  a 75 Ω kit of transformation, to perform measurement from 50 Ω netwo
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