TESTOTA: Testsystem für OTA-Messungen (Over The Air Performance)

The introduction of new and the further development of existing wireless technologies (e.g. multi-antenna systems MIMO, multiple input multiple output) require suitable measurement methods to be implemented as needed. The current standard for the measurement of such WLAN terminals requires the performance of three-dimensional measurements to determine the transmit and receive characteristics (over the air performance, OTA). Both the transmitted power and the reception sensitivity are recorded in three dimensions and important parameters are derived from them (total radiated power, TRP; total isotropic sensitivity, TIS). 

The Institute Industrial IT (inIT) at the Ostwestfalen-Lippe University of Applied Sciences has a suitable measurement room for OTA measurements in the form of the existing antenna and EMC measurement room. Until now, only two-dimensional antenna measurements and EMC measurements were performed.

As part of this project, a new hardware platform was procured and suitable measurement software was developed to enable three-dimensional measurements to be carried out (Fig. 1). Thus, the institute inIT is now able to offer the following automated measurements:

• Three-dimensional EMC measurements regarding emission and immunity.
• Determination of three-dimensional antenna directional patterns,measurement of the radiated power (Fig. 2) of radio transmitters (total radiated power, TRP).
• Measurement of the sensitivity of radio receivers (total isotropic sensitivity, TIS).

The established OTA measuring station is an important prerequisite to secure and further expand the competence of the institute inIT in the field of industrial wireless technologies. Ongoing research projects are already using the expanded measurement capabilities.