Tekbox

TekBox TBTC1 OPEN TEM CELL small

Description

TEM (Transverse Electromagnetic Mode) anechoic chamber developed by Tekbox. Suitable for frequencies up to 2GHz and beyond.

A 50-ohm termination (25W) and a DC component cancellation module are included to protect the spectrum analyzer input.

Specifications:

TEM cell dimensions
Length: 390 mm
Width: 200mm
Height: 108mm
Septum height: 50mm
TEM cell connectors: N-female
Nominal cell impedance: 50 Ohm
Wave impedance: 377 Ohm
Maximum RF input power: 25W
Input return loss: S11 up to 1.2 GHz < -20dB, up to 2.1 GHz < -17dB, up to 3GHz < -14dB
Transmission loss: up to 1.4 GHz < 1 dB, up to 2.1 GHz < 3dB, up to 3 GHz < 6dB


DC-Block 50V-6GHz-N

Connectors: N-Male/Female
Nominal impedance: 50 Ohm
Max. continuous RF power: 2W
Max. continuous RF voltage: 50V RMS
Frequency: 500kHz to 6 GHz
VSWR: ≤ 1.2


RF-Termination 50Ω-3GHz-25W-N

Connector: N-Male
Nominal impedance: 50 Ohm
Max. continuous RF power: 25W
Frequency: DC to 3 GHz
VSWR: ≤ 1.2
Third order intermodulation: ≤ 120 dBc

What is the usable volume of Tekbox TEM Cells?
The TBTC1 TEM cell has a septum height of 5cm and a septum width of 13cm. The flat section of the bottom plane has an area of 20cm x 20cm.
The TBTC1 was designed to be a small device, which easily fits on a lab desk and which typically would be used to investigate spurious signals emitted by small to medium size PCB assemblies.
If the purpose is rather checking frequencies than levels of spurious signals, basically any DUT that would physically fit can be inserted into the TEM cell. For safety reason, an insulation distance of 0.5 cm to 1cm to the bottom and 1cm to the septum is recommended. Thus the usable height of a DUT would be limited to 3-4 cm. A consequence of a large DUT would be a degradation of the impedance matching of the TEM cell. Tests with large DUTs in the TBTC1 have shown the S11 to vary between the value at empty state and -10dB. Consequently, a physically large DUT adds to the uncertainty when it comes to estimate equivalent spurious levels that would be measured using antennas in anechoic chamber set up.
The TBTC2 TEM cell has a septum height of 5cm and a septum width of 23cm. The flat section of the bottom plane has an area of 30cm x 30cm. The TBTC2 was dimensioned according to specifications given in Annex E of the CISPR 25 specification. With respect to the maximum DUT size, similar considerations as mentioned above can be applied. However CISPR 25 specifies an allowed working region which is 18cm x 18cm and located as per the screenshot below. Of course, similar considerations can be applied to the TBTC1.

TekBox Temcell TBTC

Documents:

TBTC manual

Q&A Open TEM Cells

EMC pre compliance testing guide

Application Note: Radiated Noise Measurement example using Tekbox TEM Cells

TBTC 1 insertion loss (S21)

Features

Manuals