Bandwidth limitation of electrical PCB interconnect
Calculated loss per meter for 50 W microstrip PCB including skin-effect and dielectric losses for trace widths 8, 5 and 3 mils in 1 oz copper.
- FR-4 (er = 4.5, tan d = 0.02)
- RT-Duroid (er = 2.35, tan d = 0.005)
-10 dB per 20 cm at 10 GHz for w = 3 mil and d = 0.02
Measured S11 for a standard 50 W high-speed electrical test-fixture (Tektronix #671-3273-00).
- Poor (SMA) launch onto a 3”-long, 60 mil wide microstrip trace results in severe reflections at 10 GHz.