FR-4 names a broad material class rather than one RF property set. Specify a grade and construction, then assess dielectric loss, thermal requirements and compatibility with other layers.
Named grades and families
Define the requirement before choosing the grade
Write down the function of this material in your board. Is it the dielectric around a critical RF line, a bonding layer, a flexible interconnect, or a specialty functional layer? Follow that with the frequency range, finished thickness, temperature conditions and mechanical constraints. This prevents a familiar product name from becoming an unsupported design assumption.
What to request from the fabricator
- The exact manufacturer and grade, with a current data sheet and lifecycle status.
- Available thickness, copper foil and construction combinations.
- Compatibility with the proposed lamination cycle and adjoining materials.
- Property values with frequency and test conditions, rather than an isolated Dk or Df number.
- A written substitution policy and the inspection evidence available for the finished board.
Qualify the construction
For an RF route, re-evaluate impedance and electrical length using the proposed finished stackup. For a flexible region, include the mechanical bend and coverlay construction. For a functional layer, agree on the specific electrical or thermal acceptance criterion. Keep the prototype configuration traceable so later changes can be compared meaningfully.
Listed names provide directory coverage, not a promise of availability or an assertion that each entry suits every RF application.
Source and revision check
Reference product listing · Manufacturer information. Check the current grade-specific data sheet before release.
Review your next RF PCB
Share the operating band, board outline, proposed materials and the question you want to resolve. Drawings are optional.
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