Set 1 TBTC1,1 TBMDA1
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 is a so called “open TEM cell”, 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.
The TBTC1 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 TBTC1 implements resistance perpendicular to the desired propagation direction of the wave. Consequently higher order wave modes and resonances are suppressed.
The device is supplied together with a 50Ω/25W RF termination and a DC block to protect the spectrum analyzer or RF receiver input.
The TBMDA1 modulated wideband driver amplifier is designed in order to create an inexpensive signal source for immunity testing of electronic building blocks and products. It is designed to be driven by the tracking generator output of spectrum analyzers. With its gain of 22 dB and 1dB compression point of +22dBm, it can boost the output power of a tracking generator up to 150mW. The TBMDA1 is ideal to drive Tekbox near field probes in order to find the sensitive spot of an electronic circuit or to create electric fields up to 50V/m when driving the Tekbox TEM Cell TBTC1, 25V/m when driving the TBTC2 or 18V/m when driving the TBTC3. Test signals for immunity testing can be CW, AM or PM. Consequently, the TBMDA1 provides built in modulation capability to generate 1kHz AM or PM signals. In PM mode, the TBMDA1 can also generate a 217Hz Signal with 12.5% duty cycle in order to simulate mobile phone TDMA noise.