Technical Tips for Designing Performance-Driven Rogers PCBs

Rogers is a brand of laminate materials used in making circuit boards. These are made by Rogers Corporation. The company provides advanced PCB materials to many manufacturers, and they are hugely popular among players because of their robust features. Their Fire Retardant 4 (FR4) material for PCB substrates offers benefits such as a wide range of dielectric constant and decreased signal losses. They offer better thermal resistance in harsh application environments. Rogers PCBs are widely used in devices and systems for mission-critical applications such as defense and aerospace. Owing to their increasing using, today, it is easy for you to find Rogers PCB manufacturers who specialize in making circuit boards with Rogers materials. Unlike other standard materials there are certain things to be kept in mind when choosing Rogers material for your printed circuit board. This post focuses on the factors you should consider when buying Rogers materials and beneficial features of Rogers 4350 in PCBs.

More About Rogers 4350 and Its Usage in Making Complex and Robust PCBs

Rogers PCB 4350 materials are primarily hydrocarbons or woven glass reinforced ceramics, which are processed complying to the FR4 standards. Rogers 4350 helps raise the dielectric strength and does not require special tooling or through-hole technology for mounting components like PTFE materials. They are cost effective in the long run and are UL 94 V-0 rated for high power RF designs and active devices. They offer an excellent dimensional stability. Here are some of the core featured of Rogers 4350

  • They have a Dk of 3.48 +/- 0.05.
  • They have a low Z-axis coefficient of thermal expansion at 32 ppm/ degree Celsius.
  • They offer a low dissipation factor of 0.0037 at 10GHz.

Factors to Consider When Choosing a Rogers Material

Although experienced Rogers PCB manufacturers will guide you on the best Rogers substrates, still knowing your application requirement is extremely important. Aside from this, here are some more factors based on which you choose the right Rogers material:

  • Coefficient of thermal expansion: Going by the principle of things expanding when heated, PCB materials also expand when exposed to a certain temperature. Typically, they expand when the temperature exceeds the set glass transition temperature. The rate at which they expand beyond this temperature is called the coefficient of thermal expansion and is measured in parts per million (ppm).
  • Dielectric constant: A stable dielectric constant is crucial, especially in applications with high operating frequencies. Dielectric constant is basically the amount of charge stored in a PCB material, the high value of which results in higher capacitance and increased voltage through the PCB. Rogers 4350B has a dielectric constant of 3.66 and is hence ideal for microwave point-to-point links.
  • Moisture absorption: Ideally, the material should not absorb any moisture even when dipped in water; however, this is highly unrealistic. But it is important the moisture absorption rate is minimal. Most materials used for PCBs have a moisture absorption rate of anything between 0.01% and 0.2%. Materials with low absorption rates will have better thermal and electrical properties.
  • Decomposition temperature: The maximum and minimum temperature a PCB can withstand should be decided based on the application and designed accordingly using the right materials. There should be a reversal mechanism in place if by any chance the temperature exceeds its upper limit. Otherwise, the PCB would decompose and lose some percentage of its mass. The ideal upper limit temperature for most applications would be 350 degrees Celsius. The decomposition temperature should be set at anything beyond this.