Overview of Antenna and Over The Air (OTA) Measurements in Reverberation Chambers

Antennas have traditionally been measured in anechoic chambers. An anechoic chamber is a suitable and necessary reference environment to measure large antennas that are used in a Line-Of-Sight (LOS) environment, but it is an unsuitable environment to measure devices with small antennas. Devices with small antennas are normally used in a Non-LOS environment, which is typically characterised by a lot of reflections as e.g indoors or in an urban environment, and not at all by an anechoic environment. A rich scattering environment is much easier to simulate in a reverberation chamber. The reverberation chamber is a reference environment with a Rayleigh distribution suitable for tests of small antennas and devices with small antennas such as mobile phones, laptops, PDAs, etc. The reverberation chamber has the advantage that it can be made much smaller and that the measurements can be performed much faster than in an anechoic chamber. The accuracy of a small reverberation chamber is similar or better to large anechoic chambers and the measurement times for antenna efficiency, TRP and TIS are between 3 15 times faster depending on type of test and communication protocol. For multi-antenna tests the measurement time in reverberation chambers is very fast. Antenna diversity gain can for example be measured in just 1 minute.