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GibMeclay

May 14th, 2025

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close all ;
clear; clc;
%% Parametry systemu
frequencies = [865e6, 915e6]; % [Hz], podstawowe cz?stotliwo?ci
frequency_range = 800e6:5e6:1000e6; % [Hz], zakres modelowania
rPwrMax = 8.8; % Maksymalny promie? [m] Zmierzone w modelu idealnym
r_values = [0.9, 0.7, 0.5] * rPwrMax; % Promienie analizy
mode_tag_methods = {'real', 'ideal'}; % Dwie metody modelowania anteny taga
%% Parametry anteny czytnika
G0R_dBi = 7; % Maksymalny zysk [dBi]
HPBWR = 58; % Half-Power Beamwidth [deg]
%% Parametry ogólne
C_chip = 0.63e-12; % [F] pojemno?? chipa RFID
Rc = 14.5; % [Ohm] rezystancja chipa
Za = 293; % [Ohm] impedancja anteny (przyj?ta sta?a)
RC = 0.5; % strata polaryzacyjna [dB]
Ptx_dBm = 30; % Moc nadajnika [dBm]
Pr_min_dBm = -21; % Czu?o?? taga [dBm]
%% Wczytanie danych z 4nec2 (charakterystyka promieniowania taga)
rawData = readtable('book3.csv', 'Delimiter', ';');
theta = rawData{:,1};
phi = rawData{:,2};
gain = rawData{:,3};
gain(gain < -100) = NaN;
valid = ~isnan(gain);
theta = theta(valid);
phi = phi(valid);
gain = gain(valid);
[uniquePairs, ia, ~] = unique([theta, phi], 'rows');
theta = uniquePairs(:,1);
phi = uniquePairs(:,2);
gain = gain(ia);
F_tag = scatteredInterpolant(theta, phi, gain, 'linear', 'nearest');
%% Funkcja anteny czytnika (modelowana)
readerPattern = @(theta, G0, HPBW) G0 - 3*(abs(theta)/HPBW).^(-log(0.5)/log(cosd(HPBWR/2)));
idealTagPattern = @(theta) 0; % Model izotropowy (sta?y zysk 0 dBi)
%% Analiza i wykresy: PT(f) dla ró?nych r i metod
for m = 1:length(mode_tag_methods)
method = mode_tag_methods{m};
figure('Name', sprintf('Metoda: %s', method)); hold on;
legends = {};
for r = r_values
PT = zeros(size(frequency_range));
for i = 1:length(frequency_range)
f = frequency_range(i);
lambda = 3e8 / f;
gain_reader = readerPattern(30, G0R_dBi, HPBWR);
if strcmp(method, 'real')
gain_tag = F_tag(90, -30);
else
gain_tag = idealTagPattern(0);
end
L = (4 * pi * r / lambda)^2;
L_dB = 10 * log10(L);
%% Obliczenie dopasowania impedancyjnego
Xc = 2 * pi * f * C_chip;
Zc = Rc + 1i * Xc;
Z_tag = Zc;
Z_chip = Zc;
ReZ_tag = real(Z_tag);
ReZ_chip = real(Z_chip);
ImZ_sum = imag(Z_tag + Z_chip);
ReZ_sum = real(Z_tag + Z_chip);
matching_loss = (4 * ReZ_tag * ReZ_chip) / (ReZ_sum^2 + ImZ_sum^2);
% Moc dostarczona z uwzgl?dnieniem odbicia
Pr_lin = 10^((Ptx_dBm + gain_reader + gain_tag - L_dB - RC)/10);
Pd_lin = Pr_lin * matching_loss;
PT(i) = 2*log10(Pd_lin);
end
plot(frequency_range/1e6, PT);
legends{end+1} = sprintf('r = %.1f m', r);
end
xlabel('Cz?stotliwo?? [MHz]');
ylabel('Moc dostarczona do taga [dBm]');
title(sprintf('Charakterystyka PT(f) – metoda: %s', method));
legend(legends, 'Location', 'best');
grid on;
end
%% Mapa 2D mocy odbieranej Pr(x, y) dla f = 865 MHz
f_map = 865e6;
lambda = 3e8 / f_map;
range = -10:0.2:15;
[X, Y] = meshgrid(range, range);
for m = 1:length(mode_tag_methods)
method = mode_tag_methods{m};
Pr_map = zeros(size(X));
for i = 1:size(X, 1)
for j = 1:size(X, 2)
x = X(i, j);
y = Y(i, j);
r = sqrt(x^2 + y^2);
theta = atan2d(y, sqrt(x^2));
theta = mod(theta + 360, 360);
gain_reader = readerPattern(theta, G0R_dBi, HPBWR);
if strcmp(method, 'real')
gain_tag = F_tag(theta, -30);
else
gain_tag = idealTagPattern(theta);
end
L = (4 * pi * r / lambda)^2;
L_dB = 10 * log10(L);
%% Impedancyjne dopasowanie
Xc = 2 * pi * f_map * C_chip;
Zc = Rc + 1i * Xc;
Gamma = (Zc - Za) / (Zc + Za);
matching_loss = 1 - abs(Gamma)^2;
% Moc z uwzgl?dnieniem odbicia
Pr_lin = 10^((Ptx_dBm + gain_reader + gain_tag - L_dB - RC)/10);
Pd_lin = Pr_lin * matching_loss;
Pr_map(i, j) = 10 * log10(Pd_lin);
end
end
figure;
imagesc(range, range, Pr_map .* (Y >= 0));
colormap('jet'); % lub 'parula', 'hot', 'turbo'
caxis([-40 0]); % ustalony zakres dBm
hold on;
[C, h] = contour(X, Y, Pr_map, [-21 -21], 'LineColor', 'k', 'LineWidth', 1.5);
clabel(C, h, '-18 dBm');
set(gca, 'YDir', 'normal');
colorbar;
title(sprintf('Mapa Pr(x,y) dla f = %.0f MHz, metoda: %s', f_map/1e6, method));
xlabel('x [m]'); ylabel('y [m]');
end
%% Ocena poprawnej pracy dla f = 865, 915 MHz
theta_tag = 90;
phi_tag = -30;
fprintf('\n--- Ocena poprawnej pracy (f = 865, 915 MHz) ---\n');
for f = frequencies
lambda = 3e8 / f;
fprintf('\nCzestotliwosc: %.0f MHz\n', f/1e6);
for r = r_values
gain_reader = readerPattern(theta_tag, G0R_dBi, HPBWR);
gain_tag = F_tag(theta_tag, phi_tag);
L = (4 * pi * r / lambda)^2;
L_dB = 10 * log10(L);
%% Dopasowanie impedancji
Xc = 2 * pi * f * C_chip;
Zc = Rc + 1i * Xc;
Gamma = (Zc - Za) / (Zc + Za);
matching_loss = 1 - abs(Gamma)^2;
Pr_lin = 10^((Ptx_dBm + gain_reader + gain_tag - L_dB - RC)/10);
Pd_lin = Pr_lin * matching_loss;
Pr_dBm = 10 * log10(Pd_lin);
status = 'NIE';
if Pr_dBm >= Pr_min_dBm
status = 'TAK';
end
fprintf('r = %.2f m, Pr = %.2f dBm, Poprawna praca: ''%s''\n', r, Pr_dBm, status);
end
end

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