Plotting the attenuation constant against frequency

Question

Vinci 2021-3-23

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/780742-plotting-the-attenuation-constant-against-frequency

回答： Abrham De La Torre 2021-9-29

Hello, I'm trying to plot the attenuation coefficient and phase coefficient against a frequency range. The values produced for a single freqency check out correct but my plots don't look similar to the characteristics curves that that I'm expecting from textbooks. Am I messing up the units or dimensions somewhere?

% Clear screen and variables
clc, clear all
% Define distributed parameters
R = 100;
L = 80e-9;
C = 200e-12;
G = 1.6;
% Define frequency range
low_freq = 1; % Enter low frequency here
high_freq = 1e7; % Enter high frequency here
% Calculate frequency axis
freq = low_freq:high_freq;
% Angular frequency
omega = 2*pi.*freq;
% Propagation coefficient
gamma = sqrt((R+(omega.*L*i)).*(G+(omega.*C*i)));
% Attenuation coefficient
alpha = real(gamma);
% Phase coefficient
beta = imag(gamma);
% Plot attenuation coefficient verses frequency
figure('units','pixels','position',[150 200 1000 600])%Set figure properties
plot (freq,alpha)
grid on
title('Attenuation Coefficient verses frequency')% Graph title
xlabel('Frequency (Hz)')% x axis label
ylabel('Attenuation Coefficient')% y axis label
% Plot phase coefficient verses frequency
figure('units','pixels','position',[150 200 1000 600])%Set figure properties
plot (freq,beta)
grid on
title('Phase Coefficient verses frequency')% Graph title
xlabel('Frequency (Hz)')% x axis label
ylabel('Phase Coefficient')% y axis label