ETSDataFormat3D

A MATLAB function for parsing and loading 3D antenna pattern data from ETS-Lindgren CSV exports into structured arrays.

Overview

ETSDataFormat3D reads a 3D antenna measurement CSV file (as exported by ETS-Lindgren systems) and returns antenna pattern data organized by polarization (phi, theta, and/or total power), along with the corresponding angle and frequency vectors. To speed up repeated loads, the function automatically saves a .mat cache file on first use and loads from it on subsequent calls.

Usage

% Four-output form — returns whichever single polarization is available
[D, phi, theta, freqs] = ETSDataFormat3D(filename)

% Six-output form — returns both polarizations AND vector sum (total gain)
[D_total, D_phi, D_theta, phi, theta, freqs] = ETSDataFormat3D(filename)

Caching Behavior

The function uses 'readcell()' to fetch the data from the csv file. For large datasets this operation can be very slow and use a lot of RAM.

On the first call, the function parses the CSV and saves a .mat file in the same directory with the same base filename. On subsequent calls, if the .mat file is detected it is loaded directly, significantly reducing load time for large datasets. To force a re-parse, simply delete the .mat file.

Output Arguments

Variable	Size	Description
D / D_total	numPhi × numTheta × numFreqs	Total power directivity array
D_phi	numPhi × numTheta × numFreqs	Phi-polarization directivity array
D_theta	numPhi × numTheta × numFreqs	Theta-polarization directivity array
phi	numPhi × 1	Phi angles (degrees)
theta	1 × numTheta	Theta angles (degrees)
freqs	1 × numFreqs	Frequencies (Hz)

Data Format

All data matrices (D_total, D_phi, D_theta) are formatted as a numPhi × numTheta × numFreqs array. Therefore, to get a pattern at a particular frequency, all that is required is D_atFreqToPlot = D_total(:, :, freqs == freq_toPlot).

Input Arguments

Argument	Description
filename	Full or relative path to the ETS-Lindgren .csv measurement file

Examples

% Load total power only
[D, phi, theta, freqs] = ETSDataFormat3D('myAntenna_3D.csv');

% Plot pattern at first frequency
figure;
imagesc(theta, phi, D(:,:,1));
xlabel('Theta (deg)'); ylabel('Phi (deg)');
title('Total Power Pattern');
colorbar;

% Load all polarizations
[D_total, D_phi, D_theta, phi, theta, freqs] = ETSDataFormat3D('myAntenna_3D.csv');

Notes

• Frequencies in the raw CSV are assumed to be in MHz and are automatically converted to Hz on output.
• The six-output form requires that all three polarizations (total, phi, theta) are present in the CSV. An error is thrown if any are missing.
• The four-output form returns whichever single polarization is available (D_total takes priority, followed by D_vert, then D_horiz).

Requirements

• MATLAB R2019b or later (uses readcell)
• No additional toolboxes required