I have been asked to confirm that the propagation characteristics of a transmission line, with the given parameters
R= 2.2 Ohm, L = 105nH, C = 69pF, G = 14 nS.
Along with these two equations,
I have been able to confirm all except the phase coefficient (Beta) against frequency. The given characteristic plot being:
However when running my MATLAB Code:
% Constants R = [2.2]; % ohm m^-1 L = *1e-9; % H m^-1 C = *1e-12; % F m^-1 G = *1e-9; % S m^-1 % Frequency range f = logspace(0,30); % Hz w=(2*pi*f); %Freq in rad/sec y=sqrt(R+(1i.*w.*L)).*(G+(1i.*w.*C)); alpha = real(y); beta = imag(y); % Characteristic impedance Zo = sqrt((R + 1i*2*pi*f.*L)./(G + 1i*2*pi*f.*C)); % Plot results loglog(f, 2*pi*f*sqrt(L*C)); xlabel('Frequency (Hz)'); ylabel('Phase Coefficient'); title('Phase Coefficient vs Freq'); hold on loglog(f, beta); grid on;
I get this plot;
I am confused as to why at higher frequencies the two lines don't merge like in the characteristic plot