# Losses in PCB

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#### engr_david_ee

Joined Mar 10, 2023
166
I was reading this article about Losses in PCB Transmission Lines.

https://www.protoexpress.com/blog/losses-in-pcb-transmission-lines/#

I have attached two tables.

From the table describing conductor losses we understand that the conductor losses in (5 mil, 1 oz) are less then the conductor losses in (4 mil, 0.5 oz). In other words, narrow the conductor, more conductor losses, right ?

From the table describing dielectric losses, we understand that smaller the dielectric constant (Er) and smaller the dissipation factor (Df), smaller is the dielectric losses, right ?

We see that 370 HR has higher dielectric constant (Er) and higher dissipation factor (Df) that results in to higher dielectric losses at 10 GHz and 20 GHz.

Similarly, I-Meta MT40 has smaller dielectric constant (Er) and smaller dissipation factor (Df) that results in to lower dielectric losses at 10 GHz and 20 GHz.

The total loss is the sum of both losses, the conductor loss and the dielectric loss. Can we calculate the total loss in PCB transmission line at 10 GHz for I-Meta MT40 for the following two traces ?

5 mil, 1 oz trace:
0.341 dB/inch + 0.13 dB/inch = 0.471 dB/inch

4 mil, 0.5 oz trace:
0.424 dB/inch + 0.13 dB/inch = 0.554 dB/inch

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