The Copper Mistake That Kills 40 GHz mmWave PCB Designs скачать в хорошем качестве

The Copper Mistake That Kills 40 GHz mmWave PCB Designs

Description Your insertion loss is way higher than simulation—and it might not be the dielectric. At 40 GHz, most of the loss often comes from **copper**: thickness and, even more, **surface roughness**. A lot of designers assume thicker copper means lower loss; at millimeter-wave that intuition is wrong. In this ~4 minute guide we cover: *Skin depth at 40 GHz* — why 0.5 oz is already ~50× the skin depth and why 1 oz / 2 oz barely helps RF loss *Why thicker copper hurts* — worse etch, trapezoidal cross-section, and impedance tolerance at 40 GHz *Foil type matters more* — electrodeposited (ED) vs rolled, drum vs treated side, and why HVLP/VLSP or rolled is essential *Roughness vs loss* — how roughness can add 20–50% conductor loss and how to get Rq, SAI, or Huray parameters from your supplier *4-step workflow* — thickness (0.5 oz), foil type (smooth), EM roughness model, and what to ask your fab *Takeaway:* At 40 GHz, *thin and smooth* beats thick and rough. Use 0.5 oz (or 0.25 oz if available), specify smooth foil (rolled or ED HVLP/VLSP), and model roughness—then your link budget will match the board. *PCB Stackup Generator* — get copper and stackup recommendations for your frequency @ https://pcbgenerator.com/app/pcb-stackup