function [ecer,ecer_2_dB,re_in_pow] = Sim__e_a__e_r(C,atten)
% C = 0.0211;
% atten = 40;
c = 299792458;
L = 0.48;
text = 2*L/c;
tl = 7.0422e-11;
alph = -1.92;
R2 = 0.32;
Rext = 1;
ea = 1/10^(atten/20);

kappa = C/((text/tl)*sqrt(1+alph^2));
ecer = kappa/(ea*(1-R2)*sqrt(Rext/R2));
ecer_2_dB = 20*log10(1/ecer);

pow = 22.4e-6;
re_in_pow = (pow/10^((80+ecer_2_dB*2)/20))*1e12/sqrt(0.025);