ROG Blog - PCB materials related topics
ROG Blog - PCB materials related topics RSS FeedRSS

ROG

The Rog Blog is contributed by John Coonrod and various other experts from Rogers Corporation, providing technical advice and information about high-speed digital PCB materials.

The Role of PCB Materials in Printed-Circuit Impedance

Printed circuits for high-speed and high-frequency applications rely on fine-featured transmission lines for signal transmission. Ideally, the loss through these transmission lines is minimal, and this requires an electrical impedance that is consistent and without interruptions, and with a value most appropriate for the types of signals to be transferred through the circuit. However, a number of factors can affect the impedance of a PCB, including the physical and electrical characteristics of the circuit and circuit material, but by reviewing and better understanding these variables, their effects can be minimized.


Read More

Working Through Woven Glass Weaves

Woven glass is incorporated into printed-circuit-board (PCB) materials to provide structural strength. It aids the mechanical stability of a laminate, but what does it do to its electrical behavior? One of the classic concerns regarding woven glass reinforced laminate PCBs is that the “glass weave effect” can have negative impact on the electrical performance of high-speed or high-frequency circuits fabricated on these laminates. In this blog, we examine some of the factors affecting the glass weave effect phenomenon.
Read More

Changing Temperature Can Change Performance

Circuit materials are evaluated by a number of different parameters, including dielectric constant (Dk) and dissipation factor (Df). Those two parameters also have temperature-based variants that provide insight into the expected behavior of a circuit material with changes in temperature, notably the thermal coefficient of dielectric constant (TCDk) and the thermal coefficient of dissipation factor (TCDf). 


Read More

People Help Turn Those Laminates into Perfect PCBs

Specifying the optimum circuit laminate for an electronic design project is often a case of reviewing the numbers. Once all these numbers have been analyzed and reviewed, the field of PCB material choices narrows until, finally, the optimum circuit material for a project can be selected. But what happens next?


Read More

Differences Between Thermoplastic And Thermoset Materials

Two types of composite materials—thermoplastic and thermoset materials—are commonly used for the dielectric layers in PCBs or as adhesives in manufacturing circuit laminates and they each have their own traits and characteristics. But how do they differ? What are the strengths and weaknesses of each type of material and why choose one over the other for an application?


Read More

How Is PCB Laminate Dk Determined Anyway?

The dimensions of high-frequency circuit structures, including different types of transmission lines and the spacing between lines for proper isolation and/or coupling, are determined by the circuit material’s dielectric characteristics, and one of the main parameters for understanding those characteristics is Dk. Many designers grow to trust that the Dk value assigned to a given circuit material is truly accurate and consistent from board to board and base their designs on that trust. But how does the material supplier determine a circuit material’s Dk value anyway?


Read More

Those Holes Are Part of the Circuit

For many circuit designers, plated through holes (PTHs) form pathways, from one circuit plane to another. The key to making PTHs work for the benefit of a circuit design is to understand their effects on electrical performance, especially at higher frequencies. They should be considered as circuit elements, and they can have a great deal to do with a number of analog circuit transmission-line performance parameters, including insertion loss and return loss, and they can also affect high-speed digital circuit performance by degrading signal integrity (SI) and bit-error-rate (BER) performance.


Read More

Finish Makes a Difference In Broadband PCB Loss

The choice of plated finish can make a real difference in a PCB’s conductive loss, especially for broadband, high-frequency circuits. To better understand the loss performance of different plated finishes, various transmission lines were fabricated on different circuit laminates and different plated finishes applied.  


Read More