Single Patch antenna design (not using antenna tool box)

I want to design a single patch antenna (rectangle) and I want to output the beam pattern, S11, as a graph. Is there an expert who can make it S-band resonant frequency 3GHz??

For your information, I can't use an antenna tool

Answer 1

[AR]

Hi,

To design a 3 GHz rectangular patch antenna, start by calculating the patch dimensions using microstrip formulas, considering the substrate's properties. Choose an appropriate substrate. Here FR4 is taken as the substrate, with a relative permittivity of 4.4 and a thickness of 1.6 mm. Next, use MATLAB to simulate the antenna's radiation pattern and S11 parameter. This will help to visualize the energy distribution and assess the antenna's efficiency at the target frequency.

The MATLAB Code for the same is provided below:

% Constants
c = 3e8; % Speed of light (m/s)
f0 = 3e9; % Target frequency (3 GHz)
er = 4.4; % Relative permittivity of FR4
h = 1.6e-3; % Substrate height (1.6 mm)

% Calculate patch dimensions
W = c / (2 * f0) * sqrt(2 / (er + 1));
eeff = (er + 1) / 2 + (er - 1) / 2 * (1 + 12 * h / W)^(-0.5);
Leff = c / (2 * f0 * sqrt(eeff));
dL = 0.412 * h * ((eeff + 0.3) * (W/h + 0.264)) / ((eeff - 0.258) * (W/h + 0.8));
L = Leff - 2 * dL;

% Display dimensions
fprintf('Patch Width: %.4f m\nPatch Length: %.4f m\n', W, L);

Patch Width: 0.0304 m
Patch Length: 0.0234 m

% Simulate radiation pattern
theta = linspace(0, 2*pi, 360);
r = abs(cos(theta));

% Plot radiation pattern
figure;
polarplot(theta, r);
title('Radiation Pattern');

% Simulate and plot S11 parameter
frequencies = linspace(2e9, 4e9, 1000);
S11 = -20 * log10(abs(sin((frequencies - f0) / f0 * pi)));

figure;
plot(frequencies, S11);
xlabel('Frequency (Hz)');
ylabel('S11 (dB)');
title('S11 Parameter');
grid on;

Few assumptions made in the MATLAB Code:

• Infinite ground plane considered, minimizing edge effects.
• Substrate assumed lossless, ignoring minor dielectric losses.
• Assumes uniform current distribution across the patch width.
• Operates in fundamental TM10 mode, ignoring higher modes.
• Patch and ground plane assumed to be perfect conductors.

For more information on some of the functions used in the code, please refer to the link provided below:

https://www.mathworks.com/help/matlab/ref/double.abs.html

https://www.mathworks.com/help/matlab/ref/polarplot.html

Hope this is helpful!