First results of innovative mobile near-field antenna measurement system for extreme large DUTs

Antenna measurement facilities face their physical limits with the growing size of today´s large and narrow packed antenna farms of telecom satellites but also of large unfurlable reflector antennas for low frequency telecom applications. The special operational constraints that come along when measuring such large future antennas demand for new measurement approaches, especially if the availability or realization of present measurement systems with large anechoic chambers is not an option.This paper presents a new system called PAMS (Portable Antenna Measurement System). The most characteristic part of PAMS is that the RF instrumentation is installed inside a gondola that is positioned by an overhead crane. The gondola is equipped with one or several probes to scan the near-fields of the antenna under test. With a modified crane control the gondola can be placed anywhere within the working space of the crane, which is considered as being giant in comparison to measurement volumes of existing large antenna test facilities. The whole system supports but is not limited to common classical near-field scanning techniques. Thanks to new near-field to farfield transformations the system can deal with arbitrary free form scanning surfaces and probe orientations allowing measurements that have been constrained by the classical nearfield theory so far. The paper will explain the PAMS concept on system level and will give an overview of its operational features. First promising measurement results of the core technologies are shown. Verification measurements are currently on-going.