function cg = gatecap(W,L,ctech, region)
% analysis of gate capacitance;
% return is a vector [cgs cgd cgb]
eox = 3.45E-11;
tox = ctech(1);
cox = (eox/tox)*W*L;
cov = ctech(2)*W;

if (region == 0) % cut-off
   cg = [cov cov cox];
elseif (region == 1) % resistive
   cg = [cov + cox/2 cov + cox/2 0];
elseif (region == 2) % saturation
   cg = [cov + (2/3)*cox cov 0];
end;