TekBox TBTC2 Open TEM Cell - Medium
TekBox TBTC2 Open TEM Cell, rectangular area under the septum: 23 x 28 x 10 cm
Radiated emission tests are typically carried out in anechoic chambers, using antennas to pick up the radiated signals. Due to bandwidth limitations, several antennas are required to cover the complete frequency range. Furthermore, it requires much space and the cost of the equipment for a standard conformant setup is immense.
An engineer of a small or medium size enterprise usually has to rely on his experience and on best practice methods in order to design an EMC compliant product. Nevertheless, it is estimated that > 50% of products fail testing first time around. Anytime an engineer sends a new product for compliance testing, it is a shot in the dark. Failing is very expensive. Not only that re-testing costs are high, but also the project schedule and market introduction gets delayed.
What is needed is an affordable laboratory set up to measure radiated emissions in the own lab, prior to compliance testing. A TEM cell is the right piece of equipment for desktop testing of radiated emissions. Tekbox developed open TEM cells to cover the complete frequency range up to 2GHz and with usability even at frequencies beyond.
Combined with a spectrum analyzer, products can be tested before and after EMC related design modifications. A set up with a TEM cell will not deliver exactly the same quantitative results as a measurement in a certified test house, however it will give an excellent indication on whether the design suffers from excessive radiated noise or not. The engineer will clearly see, whether his changes improved or deteriorated the EMC performance or whether it remained unchanged. Using TEM cells eliminates the guesswork.
TBTC2 TEM cell dimensions:
- Length: 636 mm
- Width: 300 mm
- Height: 205 mm
- Septum height: 100 mm
Rectangular area under the septum: 23 cm x 28 cm x 10 cm
TEM cell connectors: N-female
Nominal cell impedance: 50 Ohm
Wave impedance: 377 Ohm
Maximum RF input power: 25W (limited by supplied 50 Termination)
Input return loss: S11 up to 800 MHz < -15dB, up to 1.5 GHz < -10dB, up to 3GHz < -14dB
Transmission loss: up to 800 MHz < 1 dB, up to 1.15 GHz < 3dB
A TEM cell is a stripline device for radiated emissions and immunity testing of electronic devices. It is not a replacement, but due to its size and cost it is a convenient alternative to measurements in an anechoic chamber.
A TEM cell consists of a septum, the conductive strip in the centre section and walls which are connected to ground. The geometry is designed to present a 50Ω stripline. The device under test (DUT) is placed in between the bottom wall and the septum.
The TBTC1/2/3 are so called “open TEM cells”, which got no side walls for convenient placement of the DUT. It may pick up RF background noise, which however can be taken into account by doing a measurement of the cell output signal before powering on the DUT.
Tekbox open TEM cells got a better frequency response compared to standard TEM cells of similar size. TEM cells suffer from higher order wave modes which limit the usable bandwidth. A unique design feature of the Tekbox TEM cells implements resistance perpendicular to the desired propagation direction of the wave. Consequently higher order wave modes and resonances are suppressed.
All TEM cells are supplied together with a 50Ω/25W RF termination, a DC block to protect the spectrum analyzer or RF receiver input and a N-Male to N-Male coaxial cable.
Nominal impedance: 50 Ohm
Max. continuous RF power: 2W
Max. continuous RF voltage: 50V RMS
Frequency: 500kHz to 6 GHz
VSWR: ≤ 1.2
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 20 cm.
The TBTC1 was designed to be a small device, that 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 an 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 30 cm. 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.
Batter Fly s.r.l. is an Italian company established in 2002 with VAT number IT02235301203
Main contacts: telephone +39 051 6468377 email firstname.lastname@example.org
The address of our headquarters is Via Collodi 7a, 40012 Calderara di Reno (BO) Italy
All shipments depart from the address of our office indicated above by express courier unless otherwise specified in the order confirmation
For customers resident in Italy, both private and corporate, we apply the VAT of 22%
If the customer has specific VAT exemptions, he must communicate this before issuing the purchase order
For private customers residing outside Italy but within the European Union we apply the VAT of the country of destination
For corporate customers residing outside of Italy but within the European Union we do not apply VAT. However, VAT may be applied in the event that the customer enters an incorrect or non-certified VAT number by the VIES system
Customers can send purchase orders either through the website or by requesting a personalized quote using the specific form or through our main contacts indicated above
Batter Fly has been present for years within the MePa, the electronic market of the public administration. If one or more products are not present, contact us and we will load what is necessary quickly
Product availability is indicated on the product page of interest in various ways:
- Units in stock: 1 or more | indicates the actual units available
- Units in stock: 0, std delivery. 2 weeks | indicates the standard weeks that the supplier indicates for procurement
- Units available arriving on 10/24/2022: 3 | indicates that there will be available units arriving on that data
Products ordered before 3pm are shipped the same day, orders received after 3pm will be shipped the next working day
Each shipment is associated with a tracking number that will be communicated via email to the customer after taking charge by the shipper
To see the shipping costs go here https://www.batterfly.com/shop/consegna
To see the payment methods go here https://www.batterfly.com/shop/pagamenti
For any other questions please contact us through our main contacts