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# stripline_Z0.lsf
#
# This script calculates the expected characteristic
# impedance of a stripline from Pozar 3.179
# This equation assumes 0 strip thickness
#
# Copyright 2016 Lumerical Solutions Inc
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# input variables
eps_r = 2.08327^2; # relative permittivity of insulator
W = 0.42e-3; # Width of strip
b = 1e-3-0.035e-3; # distance between ground conductors

# calculate effective width, We, of center conductor (equation 3.179b)
if((W/b) >= 0){
    We = W;
} else {
    We = b*(W/b-(0.35-W/b)^2);
}

# Calculate characteristic impedance (equation 3.179a)
Z0 = 30*pi/sqrt(eps_r)*b/(We+0.441*b);

?Z0; # print out characteristic impdance to script prompt