L = 1e9; % inductance
Z0 = 50; % reference impedance
C = 0.0253e-12; % capacity
clear
f = logspace(8. 10. 100); % log. vector of frequencies
omega = 2*Pi*f; % angular frequency
% reflection coefficient calculation:
Gamma = (1 - omega.^2*L*C)/ ..
(1 + omega*C.*(2*1j*Z0 - omega*L));
semilogx(f, imag(Gamma)) % plotting the graph
grid off % turning the grid on
xlabel(f (Hz)) % x-axis label
ylabel('\Gamma (-)') % y-axis label