Overview
ISO 5154:2022 - Decorative metallic coatings for radio wave transmissive application products - specifies a standardized designation and characterization method for decorative metallic coatings that must transmit radio waves (e.g., for automotive radar) while retaining a metallic appearance. The standard defines how to describe coating performance (transmission loss, frequency band, lightness, hue, main material, manufacturing process) and how to measure those properties reproducibly.
Key topics and requirements
- Designation format: A compact code beginning with the elementary symbol StM, followed by frequency-band letter, transmission loss (T), lightness (L), hue, main element symbol and manufacturing method (e.g., StM D T0,4 / L90 BG/ Cr/ Sp).
- Transmission loss: Defined per frequency band and reported to one decimal place (designations include T0,1, Tx (0,2–2,4), T2,5). Measurement accounts for reflection and absorption.
- Frequency bands: The standard covers microwave to millimetre‑wave bands (example: W band 75–110 GHz is explicitly referenced).
- Colour and appearance: Uses CIE Lab* (CIELAB 1976) parameters - lightness (L*), chroma (C*), hue angle. Colour names map to hue-angle sectors (Munsell/ASTM/JIS conventions) and coatings with C* ≤ 0.8 are classed as achromatic.
- Manufacturing methods: Designation symbols include Ve (vacuum evaporation), Sp (sputtering), Ep (electroplating/electroless), OP (other processes).
- Measurement methods:
- Radio-wave transmission loss: in accordance with IEC 62431 (examples include free‑space millimetre‑wave measurement using a VNA and TRL calibration).
- Colour: per ISO/CIE 11664‑4 (CIELAB) and hue/chroma conversion rules.
- Sampling: per ISO 4519.
- Terminology: Definitions for VNA, TRL calibration, skin depth, SCI/SCE measurement modes are included.
Applications and users
- Automotive OEMs and Tier‑1 suppliers specifying metallized emblems, trims, and exterior parts that sit in front of radar sensors (collision avoidance, adaptive cruise).
- Coating manufacturers designing discontinuous metallic films (e.g., sputtered indium islands, chromium) that balance low radar attenuation with metallic appearance.
- Materials engineers and test labs performing radio‑frequency and colour characterization to verify compliance.
- Radar system and vehicle integration teams ensuring sensor performance is not degraded by decorative elements.
Practical benefits include reproducible acceptance criteria for radar transparency and appearance, streamlined supplier communication, and easier conformity assessment during design and production.
Related standards
Key normative references cited by ISO 5154:2022:
- ISO/CIE 11664‑4 (CIELAB colourimetry)
- IEC 62431 (millimetre‑wave reflectivity/measurement methods)
- ISO 4519 (sampling procedures)
- ISO 2080, ISO 16348, ASTM D1535, JIS Z 8721 (colour/appearance and coating vocabularies)
Keywords: ISO 5154:2022, decorative metallic coatings, radio wave transmissive, transmission loss, CIELAB, automotive radar, sputtering, vacuum evaporation, electroplating.