Substrate

using CircuitSim

fr4 = Substrate("FR4", er=4.5, h=1.6e-3, t=35e-6, tand=0.02)
ro4003c = Substrate("RO4003C", er=3.55, h=0.508e-3, t=17e-6, tand=0.0027)

Substrate("RO4003C", 3.55, 0.000508, 1.7e-5, 0.0027, 2.2e-8, 0.0)