Reverberation chambers: the modern EMC test environment

Paul Boughton

Teseq, a developer and provider of instrumentation and systems for EMC emission and immunity testing, has introduced two new Reverberation Chambers, models RVC XS and 2XS, further expanding its chamber portfolio.

Reverberation chambers (RVCs) are modern EMC test environments that provide an alternative to semi- or full anechoic rooms (SAR/FAR), open area test sites (OATS) or Gigahertz Transverse Electromagnetic (GTEM) cells.

Consisting of a shielded room and a 'stirrer', which changes the resonant electromagnetic field distribution inside the chamber, producing a statistically uniform field.

Standards which include high field strength testing requirements often list Reverberation Chambers as an alternative to absorber-lined chambers because high field strengths can be generated much more efficiently in an RVC, requiring lower power RF amplifiers and thereby reducing the system’s cost. RVCs are specifically mentioned in several automotive standards, as well as in military standard MIL 461F and aircraft standard RTCA DO-160G.

In addition to immunity testing, RVCs can also be used for emission testing of material, cable and enclosure shielding. Detailed information on the use of RVCs for EMC testing can be found in the basic standard IEC 61000-4-21.

Reverberation chambers are also used in non-EMC applications, for the measurement of Total Radiated Power (TRP) and Total Isotropic Sensitivity (TIS) of antennas and mobile devices.

The two new RVC models are designed specifically to accommodate small Equipment Under Test (EUTs), eliminating the need for a larger, more expensive, traditional chamber. Both models are fully assembled and tested in at the factory. No on-site assembly is required as the chambers are delivered ready to use.

The operating frequency range of a RVC is limited by its dimensions and the stirrer design. 2XS, the smaller of the two chambers, has an internal size of (1.5 x 0.8 x 1.0) m3, providing a test volume of (0.5 x 0.3 x 0.5) m3 at a start frequency of about 800 MHz. The larger model XS has an internal size of (2.7 x 1.5 x 1.3) m3, resulting in a test volume of (1.2 x 1.0 x 0.8) m3 and a start frequency of about 500 MHz.

Optimal mechanical stability of the two RVCs is achieved using a rigid construction and an outside reinforced frame. Furthermore, the inside of the chamber has a completely flat surface (no connective elements are used for pan type or sandwich construction), which is made of aluminium for optimal power and field performance.

Field strengths of more than 100 V/m are easy to achieve with 1 Watt applied to the antenna and with an empty chamber.

Both chambers are fully equipped with a stirrer-designed and optimized for the intended frequency range in accordance with the requirements of the basic standards. The stirrer commands are provided in the user manual and enable easy implementation of the stirrer controller within any measurement software. Drivers and RVC application packages for Teseq’s Compliance 5 EMC software are available.

With its broad range of instruments, software and services, Teseq can provide complete turnkey Reverberation Chamber solutions.

For further more information, visit www.teseq.com