Copper Type
Extremely smooth copper cladding with a profile height of less than two microns enables the production of high-performance microwave circuitry. Electrolytic ultra-low profile foil consists of electrolytic copper with a surface topography specifically treated to achieve minimal peak-to-valley height. The use of this foil minimizes the resistive losses associated with the skin effect at very high frequencies.
At frequencies above 10 GHz, most of the current flows in a thin layer at the surface of the conductor.
High-Frequency Loss
Dielectric loss becomes more manageable when the conductor interface is smooth. Because ultra-low profile foil has almost no mechanical teeth, it must be used with specialized high-adhesion resins or chemical coupling agents. This combination prevents the traces from peeling during the assembly process or under thermal stress.
Etching Precision
Fine-line imaging benefits from the lack of deep copper roots in the substrate. For ultra-low profile foil, the absence of these roots means that the etching process can be completed more quickly and with less undercut. This precision is necessary for maintaining the tight impedance tolerances required by 5G and radar applications.
If a standard foil were used instead, the variation in the trace width would be too high for these sensitive circuits. Automated optical inspection confirms that the etched features match the design requirements.
