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

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.

% 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.

% 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.

% 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.

% 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.