Measured electric field distribution of two GTEM cells in different vertical planes with a 3-axis field probe

There is only a minor amount of freely available measurement data for the distribution of the electric field strength in a GTEM cell. For this reason, the electric field strength of two GTEM cells was measured with a 3-axis field probe at three different planes, which are hereby made available.

The datasets were created in different positions:

• GTEM 5305: 480 mm septum height (40 W input power, 25 measuring points)
• GTEM 1250: 500 mm septum height (50 W input power, 25 measuring points)
• GTEM 1250: 1000 mm septum height (50 W input power, 196 measuring points)

All measurements were carried out identically on each plane. The key data are briefly listed below:

• Inclination of the septum: 15 degrees
• Excitation with CW
• constant input power of the GTEM cells in the entire frequency range: 40 W / 50 W.
• Frequency range: 10 kHz to 6 GHz
• Frequency points: 700
• Measuring points: 25/196
• Measurements of the magnitude of all three electrical field components

The input power at the port of the GTEM cells was kept constant over the entire frequency range (max. 0.16 dB deviation from the target value). The Lumiloop LSProbe probe was used to measure the electric field strength in all three directions simultaneously. After all results had been recorded at one measuring point, the field probe was repositioned. To increase the positional accuracy, the probe was positioned using an expanded polystyrene plane. Between 10 kHz and 30 MHz, two adjacent frequencies were a maximum of 5 percent apart, between 30 MHz and 6 GHz the frequency spacing was reduced to just 1 percent.

The position of the measuring points and the direction of the electrical field components correspond to that of the coordinate system according to IEC 61000-4-20.

Datasets:

• noise level of the probe
• position of the measuring points in m
• electric field strength (absolute) in V / m
• electric field strength (x component) in V / m
• electric field strength (y component) in V / m
• electric field strength (z component) in V / m
• frequency in Hz
• forward power in W.
• reverse power in W.
• VSWR