TEM cell for simple and cost-effective measurement of interference radiation and interference immunity. Why a TEM cell? A TEM cell (Transverse ElectroMagnetic Cell) is used to record test objects for measuring and testing the interference radiation or interference immunity of electronic devices. The interference radiation is usually measured in reflection-free rooms and the interference signals are picked up using antennas. Due to bandwidth limitations, different antennas are required to cover the entire frequency range. Furthermore, you need a lot of space and the costs of the equipment for a standard-compliant structure are enormous.
What is required is an affordable laboratory setup to measure the interference radiation in your own laboratory before acceptance in the EMC test house. The handy TEM cells from Tekbox cover the entire frequency range up to 2 GHz and are also suitable for frequencies beyond that. In conjunction with a spectrum analyzer, products can be tested before and after EMC-relevant modifications. The test setup with a TEM cell provides valuable information as to whether the design has major defects with regard to radiated interference signals. The engineer can clearly see whether his changes have worsened or improved the EMC behavior. Advantages of the Tekbox TEM cell: The TBTC3 is a so-called open TEM cell as it has no side walls to allow the placement of the DUT (Device -Under test) to facilitate. Although interference radiation from outside can penetrate the cell, it can be easily identified by measuring the output signal of the cell with the DUT switched off and can therefore be taken into account in the measurement result. A TEM cell consists of a septum, the conductive plane in the middle and outer walls connected to ground. The geometry is dimensioned such that an impedance of 50 O results. The DUT is placed between the lower wall (floor) and septum. Technical data: TEM cell TBTC3 Dimensions (L x W x H): 1038 x 501 x 305 mm Rectangular area under the septum: 360 x 480 mm Septum height: 150 mm Maximum volume of the test specimen (L x W x H): 300 x 300 x 100 mm TEM cell connections: N sockets Nominal cell impedance: 50 O Characteristic impedance: 377 O Maximum RF input power: 25 W Return loss* S: up to 700 MHz Frequency [MHz] 0.3 0.7 1 10 100 1000 3000 Insertion loss [dB] 7.5 3 1.5 0.02 0.02 0.06 0.2 HF terminating resistor 50O-3GHz-25W-NConnection: N connector Nominal impedance: 50 O Max. HF continuous power : 25 W Frequency: DC to 3 GHz Standing wave ratio: =1.2 3rd order intermodulation product: =120 dBc Incl.: DC blocker (N plug/socket), HF terminating resistor (N plug), coaxial cable N -Male to N-male (1 m). * Each TEM cell comes with a measurement report (plot) for return loss S and insertion loss S.
Tekbox's TBTC3 offers better frequency response than standard TEM cells of the same size. TEM cells suffer from undesirable vibration modes at higher frequencies, which limit the usable bandwidth. An outstanding design feature of the Tekbox TEM cells is the implementation of a resistor perpendicular to the direction of wave propagation. Higher order modes and resonances are effectively suppressed. The TEM cell is supplied together with a 50O/25W RF terminator and a DC blocker to protect the input of the spectrum analyzer or RF receiver.