To design an antenna and analyze its radiation pattern using MATLAB, follow these steps with the provided code

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To design an antenna and analyze its radiation pattern using MATLAB, follow these steps with the provided code example:

Step 1: Design the Antenna

Design a half-wave dipole antenna resonant at 2.4 GHz using MATLAB’s Antenna Toolbox.

matlab
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% Define frequency
freq = 2.4e9; % 2.4 GHz

% Create a half-wave dipole antenna
d = design(dipole, freq); % Resonant at 2.4 GHz
d.Width = cylinder2strip(0.001); % Set width as a thin cylinder

% Visualize the antenna structure
figure;
show(d);
title('Dipole Antenna Design');

Step 2: Impedance and VSWR Analysis

Calculate input impedance, reflection coefficient, and VSWR.

matlab
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% Calculate input impedance
Z = impedance(d, freq);

% Assuming a 50 Ohm system
Z0 = 50;
Gamma = (Z - Z0) / (Z + Z0);
VSWR = (1 + abs(Gamma)) / (1 - abs(Gamma));

fprintf('Input Impedance: %.2f + j%.2f Ω\n', real(Z), imag(Z));
fprintf('Reflection Coefficient: |Γ| = %.2f, VSWR = %.2f\n', abs(Gamma), VSWR);

Step 3: Radiation Pattern Analysis

Plot 3D radiation pattern and 2D E-plane/H-plane cuts.

matlab
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% 3D Radiation Pattern
figure;
pattern(d, freq);
title('3D Radiation Pattern at 2.4 GHz');

% E-plane (Elevation) and H-plane (Azimuth) Cuts
figure;
patternElevation(d, freq, 0, 'Azimuth', 0, 'Elevation', 0:360); % E-plane (phi=0)
title('E-Plane (Elevation) Pattern');

figure;
patternAzimuth(d, freq, 0, 'Elevation', 90, 'Azimuth', 0:360); % H-plane (theta=90°)
title('H-Plane (Azimuth) Pattern');

Step 4: Gain, Directivity, and Beamwidth

Compute peak directivity and beamwidth.

matlab
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% Peak Directivity (at theta=90°, phi=0°)
D = pattern(d, freq, 90, 0); % Directivity in linear scale
Gain_dBi = 10*log10(D); % Convert to dBi
fprintf('Peak Gain: %.2f dBi\n', Gain_dBi);

% Half-Power Beamwidth (HPBW)
HPBW = beamwidth(d, freq, 0, 'Cut', 'Azimuth');
fprintf('E-Plane Beamwidth: %.2f°\n', HPBW);

Explanation of Results

  • Antenna Design: The dipole is automatically tuned to resonance at 2.4 GHz.
  • Impedance: A half-wave dipole typically has ~73 Ω impedance. Mismatch with 50 Ω causes reflection.
  • Radiation Patterns:
    • 3D: Toroidal shape with maximum radiation perpendicular to the dipole axis.
    • E-plane: Figure-8 pattern (directional in elevation).
    • H-plane: Omnidirectional (circular in azimuth).
  • Beamwidth: Half-wave dipole E-plane beamwidth is ~78°.

Notes

  • Ensure the Antenna Toolbox is installed.
  • Adjust freq to analyze other frequencies.
  • Use patternCustom for custom radiation data.
  • Add matching networks to improve VSWR if needed.

This code provides a comprehensive analysis of a dipole antenna’s performance in MATLAB.

Published by howdy