% Microstrip computation

% You can use this program by setting Er and d according to your PCB
% material, and then tweaking W to get the desired Zo. You can then see 
% what the corresponding Ee is, and use that to compute signal
% propagation velocity or line length, if needed.

Er=4.8; % Er of PCB material
d=.062; % PCB thickness (inches)

W=.148; % Trace width

Ee=0.5*(Er+1)+0.5*(Er-1)/sqrt(1+12*d/W);

% NOTE: for W/d >= 1 only

Zo=120*pi/(sqrt(Ee)*(W/d+1.393+0.667*log(W/d+1.444)))