PAGE CONTENTS
Objectives
The objective of this activity was to make available measurement techniques in Near Field antenna test facilities to enable the characterisation of Telecom Payload radiated performance.
These methodologies had to be developed and demonstrated by measurements and their performance compared with the traditional Compact Range approach, allowing a technical and programmatic comparison between the two approaches and a consequent validation of the techniques. The development had to be suitable for payload system testing in the range between 0.4 and 50 GHz.
Challenges
Antenna Near-Fields (NFs) behave completely different than Antenna Far-Fields (FFs). Therefore, it was hard to predict which impact on P/L parameter measurements are to be expected and how to overcome those effects. Although efforts on some methods have been done in the past, a consistent set of techniques to measure satellite payload parameters in Near Field Antenna Test Facilities is not well developed and validated.
Plan
The study was organised into 5 tasks as follows:
- Radiated Payload Testing Parameters Requirements
- Theoretical Formulation of Near Field Methodologies
- Detailed Development of Near Field Methodologies
- Validation Campaign
- Development Plan
Payload parameters were measured with a Payload Ku-Band Demonstrator in the following test facilities:
- Near-Field Antenna Measurement Facility at the Institute for High-Frequency Engineering of the Technische Universität München (TUM)
- Compensated Compact Range (CCR 75/60) at the Antenna Test Centre of Airbus DS in Munich
In HERTZ, the Hybrid Antenna Test Range of ESA / ESTEC in Noordwijk where the validation measurements were executed.
Current Status
Proof of concept was reached for the developed methodologies for EIRP, IPFD, G/T, G/F, and Group Delay parameters. It was shown that P/L measurements in the NF are generally possible. Furthermore, the results in CCRs and in NFs are within the range of specified accuracies. However, results are based so far only on one DUT in one frequency band.
P/L measurements in NF require more time due to the additional pattern measurements (if not available) for determination of required NF correction factors.
There is vital interest of industry to reach higher TRLs ensuring sufficient maturity for industrial implementation already in 2016 / 2017.
