Choosing a circuit material for a high-frequency printed-circuit board (PCB) is generally a tradeoff, often between price and performance. But PCB materials are also selected by two key factors: how well they meet the needs of an end-use application and what kind of effort is required to fabricate a desired circuit with a particular material.
These two factors may not mesh: one material may be well suited for a particular application but may pose challenges in terms of circuit fabrication, and vice versa. There is no foolproof, step-by-step procedure for selecting a PCB material.
However, by relying on some tangible guidelines designed to evaluate a material in terms of its suitability for circuit fabrication and for meeting the requirements of an application, the process of selecting a PCB for a particular application can be simplified. The approach will be demonstrated with some of the more popular high-frequency PCB materials, and where each stands in terms of fabrication qualities and suitability for end-applications.
Note that high-performance FR-4 is often used in combination with other high-frequency materials for certain applications and requirements. However, in terms of electrical performance, FR-4 is not considered a true high-frequency circuit material.
This article, which originally appeared at EE Times Europe , examines the characteristics and tradeoffs when choosing your material, beginning with the well-known FR-4 base.Click to read “Selecting PCB materials for high-frequency applications“, which looks at choosing among seven materials, based on circuit-fabrication issues and end-use applications.