A new concept in near field antenna testing has been developed by Astrium GmbH which meets multiple market needs and could revolutionise the way antennas are verified. The Portable Antenna Measurement System concept provides an ingenious solution to the current difficulties faced when testing and verifying large antennas.
As devices continue to grow in size and expand their frequency ranges, this places ever growing demands on traditional antenna testing sites. It is difficult and expensive to build dedicated test sites or move large antenna farms and reflector mesh antennas to those sites. The test sites themselves are also now required to accommodate increasingly large scale pieces of test equipment.
In response to this, an Astrium project, supported by the ARTES 3-4
programme, has assessed the needs of the changing antenna measurement facilities market and has come up with an entirely new approach. If you cannot bring the antenna to the test site, or your test site is not big enough, then take the testing equipment to the antenna. The result of the project is the Portable Antenna Measurement System, affectionately known as PAMS, which has been developed in the form of a gondola which is suspended from the existing crane systems within a satellite or antenna assembly hall.
PAMS performs Near Field (NF) probing and applies a complex algorithm, the so called Fast Irregular Antenna Field Transformation Algorithm (FIAFTA), based on plane wave expansion highly accelerated by Multilevel Fast Multipole Method (MLFMM) principles. Unlike conventional test systems, PAMS does not try to perform NF-probing along accurate geometrical scan contours and equidistant measurement grids, instead it works as a free-form near-field scanner allowing NF-probing in front of and around the device under test (DUT). The exact location and orientation of the NF-probe at any measuring point is provided by commercially available laser trackers.
The crane and gondola based design transforms existing crane facilities into a ground-breaking antenna measurement system with a range of features designed to meet the current and future needs of the aerospace industry and the stringent requirements of the satcom sector. These include system transportability, nearly unlimited measurement volumes, multi-contour and free-form scan contours, DUT motion-free operation and the capability to perform accurate antenna measurements in anechoic environments and diagnostic antenna measurements in echoic environments.
The flexible system could potentially be used for the verification of radiated antenna performances during the antenna and satellite manufacturing and testing processes. Due to its transportability and ability to carry out diagnostic pattern measurements in echoic environments, the system has the potential to be used in satellite assembly, integration and test (AIT) halls or even at launch sites after satellite transportation. The system is also suitable for customers who have occasional antenna measurement needs, antenna measurement facilities which are too small for the testing of very large DUTs, or for additional testing during peaks in capacity demand.
The use of existing crane facilities reduces costs and the need for precision heavy machinery. The gondola design offers the flexibility to be equipped with single NF-probes for low frequencies or with probe arrays for high frequencies to reduce measurement times. The system has been designed to take approximately 8 hours to set-up and align and around 2 hours to dismantle.
The current PAMS prototype is to be put to use in a demonstration facility at the Astrium Antenna Test Centre in Munich, where it will provide data for a process of on-going product improvement. Performance verifications are planned to be carried out in L-Band and in K-Band at 33 GHz from summer 2014.
Massimiliano Simeoni, Payload Engineer at ESA explained “The PAMS concept is a landmark in NF-antenna measurement techniques. With this new system the market has a solution to many of the major logistical difficulties for antenna testing and verification. Not only does it demonstrate the European satcom industry’s ingenuity in delivering commercially attractive solutions for the sector but it also has the potential to help European satcom products reach the market quicker while lowering the costs associated with testing and verification.”
The sensor unit ready for deployment