Articles by Microwave Journal

Check out the new products in our Jan issue ranging from ICs to components to test/measurement equipment.  The Microwave Journal Buyer's Guide also offers a variety of vendors listed by product category.

Choosing a substrate material for use as the printed-circuit board (PCB) in a new design can be a stressful experience, unless it is a matter of sticking with that “tried-and-true” material that has worked so well in the past. But with ever-evolving and improving dielectric and laminate materials, and increasing demands to achieve high performance levels at reduced costs, most design engineers are wise to consider the cost-versus-performance benefits of different types of commercial PCB materials. Previous blogs have detailed how selecting a PCB material can be influenced by different performance requirements. This blog will explore the role that a computer-aided-design software tool plays in choosing the most suitable PCB material.

Selecting a high-frequency PCB laminate from the many commercially available choices may sometimes seem like an impossible task. But it can be simplified by sorting materials by their key parameters, such as dielectric constant, dissipation factor, thermal conductivity, and CTE, and using those parameters to help match a material to an application. Of course, this also assumes confidence in the values of those key parameters as published by different materials suppliers, and such confidence comes from an understanding of the measurement methods used to determine the values of those key parameters.

Selecting a PCB laminate for a high-frequency application is like picking a foundation for a new building: the strength of the whole project relies on the right choice. The previous blog introduced a strategy to help simplify the PCB laminate selection process, by relating the requirements of an application to laminate specifications. Each RF/microwave application is unique, with its own requirements. But at least one laminate will usually offer the right set of specifications to best meet those requirements.

Previous blogs examined some of the key material parameters pertaining to high-frequency laminates, such as dielectric constant, thermal conductivity, coefficient of thermal expansion (CTE), and even flexibility when used in conformal circuits. But how does an engineer combine all this information about a material’s electrical and mechanical properties when trying to choose the perfect substrate for a particular application? It can be a complex process, but it may be possible to simplify that process.