Standards Development

Scope

This document specifies the designation and the characterization methods of the decorative metallic coatings of the products for radio wave transmissive application. The designation consists of the transmission loss of the radio wave, the frequency band of the radio wave under consideration, the lightness and hue of the parts, as well as the main material and manufacturing process of metallic coatings. The characterization methods consist of the determination of the transmission loss of radio wave with specific frequency band and the evaluation of lightness and hue which represent the colour and appearance.

Purpose

This document was developed to provide the designation of the characteristics of the decorative metallic coatings for radio wave transmissive application products, in response to worldwide demand for the standardization of such products. This document was also developed to specify the standard method to quantitatively characterize the decorative parts with the metallic coatings that both have the low transmission loss of radio wave and the metallic appearance.

One of the typical applications of the radio wave transmissive application products is the metallized plastic emblem and other decorative exterior parts for automobiles. These parts are placed in front of the millimetre wave radar transmitter-receivers of the collision prevention system. A typical example of these parts has the low transmission loss of the specific radio wave lower than 2,5 dB and the bright metallic appearance with lightness of 70 or higher. Low transmission loss is consistent with metallic appearance by forming a discontinuous structure of metallic coatings. An example of the discontinuous coating is the sputter-deposited film of low melting point metals such as indium having island structure. This document specifies the designation and the characterization methods of the decorative metallic coatings of the products for radio wave transmissive application. The designation consists of the transmission loss of the radio wave, the frequency band of the radio wave under consideration, the lightness and hue of the parts, as well as the main material and manufacturing process of metallic coatings. The characterization methods consist of the determination of the transmission loss of radio wave with specific frequency band and the evaluation of lightness and hue which represent the colour and appearance.