FR1 dielectric constant?

[pion]

Can someone help me out with the dielectric constant of the Voltera FR1 boards? I’m having a really hard time finding a reliable number after about an hour of googling, and I’m not quite at the point where I want to try measuring it myself. Voltera folks, can you provide a number or point me to your manufacturer’s data sheets? Thanks much!

[jazozaya]

Hi @pion,

I’m afraid we don’t the value on hand. However, I have reached out to the manufacturer to see if they have it.

FR1 is not too common so I wouldn’t be surprised if they don’t know it either.

Regards,

[jazozaya]

Hi @pion,

Heard back from the manufacturer, they said it is between 4.0 - 5.0

Hope this helps!

[pion]

Thanks Jesus. 4.0–5.0 is the range I was finding during my Googling for generic FR1. I was hoping that the manufacturer could give me a specific value, as I’m trying to create impedance matched microstrips. Would you be able to tell me if the manufacturer is also providing a generic range, or is their substrate really that highly variable in its permittivity?

[jazozaya]

Hi @pion,

Unfortunately they just provided a range.

I’ve attached the datasheet we received, this isn’t our supplier, it’s our supplier’s supplier. (I believe this company just supplies raw laminates of FR1 to the factory that cuts our substrates.)

KB-3151C .pdf (216.7 KB)

[pion]

Ok that’s understandable. Thanks for attaching the datasheet! I’ll split the difference and use 4.5 as the dielectric constant and hope there’s enough link budget to account for the impedance mismatch.