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#1 Posted : Saturday, January 09, 2021 2:10:40 PM(UTC)

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PTFE Laminates Becoming A Secondary Choice

With high-frequency technologies in PCBs gaining speed, manufacturers turned to polytetrafluoroethylene (PTFE) as a suitable laminate. Although costing more than FR4, PTFE is a synthetic thermoplastic fluoropolymer that offers excellent dielectric properties when the application uses microwaves. It also provides better dielectric loss (Df).To get more news about BT PCB, you can visit pcbmake official website.

In the past, the two basic choices for laminates became FR4 and PTFE. While PTFE offered advantages over FR4 for high-frequency applications, a major hurdle that was experienced with this laminate was that it had a high coefficient of thermal expansion (CTE). The laminate would change properties and expand when experiencing changes in temperature.

To overcome this issue, reinforced woven glass became added to PTFE that could combat against the size changes of the laminate. Manufacturers also began experimenting with ceramic fillers and microfiber glass to increase the dielectric constant (Dk) values of PTFE and enhance the thermal coefficient of dielectric constant (TCDk), as well as to make it easier to use the laminate when fabricating PCBs. With the addition of ceramic fillers, PTFE would experience an increase of DK values from 2.1 (without fillers) to a possible 2.94 (with fillers).

Manufacturers will often use a base material of PTFE and enhance the formula to offer different material compositions. Teflon, while sounding like a separate laminate material, is another type of PTFE-based formula. When woven glass is introduced into Teflon, the laminate is easier to work with although only experienced manufacturers should handle this material because of its difficulties during the lamination process.
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