Antenna Test Facilities and Electro-Magnetic Compatibility Laboratories
What are their roles?
The Antenna Test Facilities focus on assessing the performance of antennas, an essential element of space systems.
They comprise the newly upgraded Hybrid European RF and Antenna Test Zone (HERTZ), the Compact Antenna Test Range (CATR) and a microwave and (sub)millimetre-wavematerial characterisation laboratory located in a cleanroom environment. An offsite facility, the DTU-ESA Spherical Near Field Antenna Test Facility, operated by the Technical University of Denmark, provides additional services.
Between them, these facilities support testing across the entire spectrum of antenna development, from characterising the properties of candidate materials for antennas, including measurement of their RF absorption, reflectivity and dielectric properties, to assessing the performance of antenna subsystems up to the qualification validation of full-scale complex radiating systems such as a fully-integrated satellite incorporating multiple antennas aboard.
The Electro-Magnetic Compatibility (EMC) Laboratories are comprised of the EMC lab and the Magnetic Coil Facility (MCF). The EMC lab serves to determine the electromagnetic compatibility (EMC) properties of electronic equipment and subsystems by measuring conducted and radiated emissions and testing conducted and radiated susceptibility. Its instrumentation is also used to support troubleshooting activities. The Magnetic Coil Facility is used in the frame of magnetic cleanliness programmes to measure and characterise the magnetostatic properties of parts and small equipment.
What services do they offer?
The 100 000 cleanroom HERTZ facility combines the Compensated Compact Range (CCR) and a Near Field Range (NFR) in the same anechoic room, both dedicated to radiating payload measurements. The purpose is to verify the in-orbit performance of complex radiating systems by testing the different units forming part of the system as a whole. HERTZ is capable of offering direct far field measurements, through a plane wave zone of 5 x 5x 7 m, covering a frequency range of 3.4 – 20 GHz. The Near Field facility complements the latter through state-of-the-art capability in Planar, Cylindrical and Spherical Near field measurements between 400 MHz and 50 GHz. This hybrid test aptitude is offered to antennas, payloads and full spacecraft up to 5000 Kg and 6-meter maximum dimension (depending on test requirements).
The (sub)millimetre-wave Quasi Optical Test Facility characterises the RF characteristics of space materials across a frequency range of 50-750 GHz, allowing sample as small as 50 mm. The Microwave Material Characterisation Free Space Test Facility, installed in the CATR, allows characterizing materials in transmission and reflection configurations (both monostatic and bistatic) between 8-110 GHz and accommodates sample sizes of 300x300 mm or 400x400 mm.
The CATR is dedicated to testing small to medium sized antennas, up to 1 m diameter and 100 kg mass, in an ambient but anechoic and EM-isolated chamber across a standard frequency range of 4-110 GHz with custom-made instrumentation able to cover 110-250 GHz. Radar measurements such as absolute reflectivity of absorber materials or Radar Cross Section (RCS) characterization are also possible.
The offsite DTU-ESA Spherical Near Field Antenna Test Facility offers expertise in high precision measurements and calibration services for antenna systems, catering to a frequency range of 0.4 – 40 GHz, a load capacity of 250 kg and a maximum gain calibration accuracy down to 0.03 dB.
The EMC Laboratory offers support to projects by assessing EMC requirements, providing expert advice, performing EMC pre-compliance measurements and tests on breadboards or development models, performing troubleshooting activities, defining and carrying out customised tests for specific project needs that cannot be covered by standard EMC Labs. The Magnetic Coil Facility enables magneto-static measurements for the magnetic characterisation of components and small equipment and to derive equivalent magnetic dipole models. The MCF also supports magnetic 'perm/de-perm' for missions that require a tight control of magnetic cleanliness.
How are they equipped?
The 25 x 16 x 11 m HERTZ is located in a 100 000 class cleanroom, combining the CCR and NFR. The CCR is a compensated compact range designed for low cross-polar performance. The walls are covered in pyramidal absorbers, with a pair of carbon fibre based reflectors producing a plane wave zone of 5 x 5 x 7 m across a frequency range of 3.4 – 20 GHz.
The NFR consists of an inverted-T planar scanner used in combination with the heavy-duty 5000 kg load capacity positioning system to support all three main Near Field acquisition schemes: Planar, Cylindrical and Spherical. The acquired near-fields are then post processed and all required far field parameters calculated. For planar scanning, the test item does not need to move and can even be positioned on its own support, allowing for example, testing antenna and payload performance without removing the spacecraft from its multi purpose trolley.
The CATR incorporates two parabolic cylindrical aluminium reflectors to collimate RF signals in order to mimic the far distance of space, inside a shielded anechoic chamber with an overall size of 12.5 x 8.5 x 4.3 m. It operates in ambient conditions, making it a convenient and flexible site for testing antenna subsystems, as well as the development of new measurement techniques.
The Microwave Material Characterisation Free Space Test Facility – which can be mounted on the CATR positioner – comprises two corrugated feeds and grids with collimating elliptical mirror focused at the sample position. In addition, to the normal incidence capability, this facility makes use of an highly flexible positioning system that allows rotation of the sample and the transmit and/or receive units, enabling bi-static and off axis characterization.
The (sub)millimetre-wave Quasi Optical Test Facility is based on a quasi-optical setup in a class 100 000 cleanroom, with RF measurements performed with a network analyser, frequency extender units and analysis software developed and validated in house. Co-polar and cross-polar components of the transmission and reflection coefficients of the measured samples can be determined by using high-performing corrugated horns, grids and refocusing mirrors.
The EMC laboratory consists of a shielded anechoic test chamber (LxWxH 8.55m x 7.5m x 4.75m) with shielded control room providing controlled environmental conditions. The anechoic test chamber is equipped with pyramid foam absorbers and the floor is covered with ferrites. In the control room as well as in the test chamber test tables with a copper ground reference plane are available. The EMC facility can be used for measurements and tests in a frequency range from DC to 26 GHz and is equipped with state of the art test and measurement instrumentation.
The Lab’s Magnetic Coil Facility for magneto-static testing consists of two pairs of squared Helmholtz coils for compensation of the local magnetic field (70 cm x 70 cm x 70 cm), one pair of perm/deperm coils (3 Hz / ~3.5 mT), four 3-axis magnetometers and a turntable with motor drive. Numerical software is used for magnetic modelling.
Who are their customers?
The Antenna Test Facilities provide support to both ESA projects and external customers – including small-medium-sized companies lacking access to comparable private-sector facilities – needing to assess new antenna designs and techniques and qualifying designs for flight. This has included some of ESA’s largest flight hardware.
Projects that received recent support include vegetation monitoring mission Proba-V - checking the performance of the communication antenna and GPS sensor on vegetation-monitoring mission – tests on the Copernicus Sentinel-3 ground transponder – an instrument that will enable the calibration of the on board radar altimeter– as well as the Galileo IOV and FOC programmes. The DTU-ESA Spherical Near Field Antenna Test Facility has played a major role in the development of ESA’s SMOS and Biomass missions.
The EMC laboratory is specialised to provide support to ESA projects for highly demanding, non-standard EMC requirements and their verification, is used for troubleshooting activities and and serves to perform EMC pre-compliance tests during development. Examples for projects using the EMC laboratory are: Solar Orbiter, BepiColombo, Euclid, Vega as well as several ISS payloads and experiments. The Magnetic Coil Facility has served missions including Swarm and BepiColombo, which are equipped with sensitive magnetometers, and LISA Pathfinder, Solar Orbiter and JUICE, which will carry payloads sensitive to magnetic fields, gradients and their fluctuations.
How do I find out more?
Head of the Antenna and Sub-mm wave Section, Peter de Maagt firstname.lastname@example.org,
Head of the RF Payloads and Technology Division, Piero Angeletti email@example.com
Head of the Electromagnetic Compatability Section, Johannes Wolf firstname.lastname@example.org for the Electro-Magnetic Compatibility (EMC) Laboratories and Magnetic Coil Facility.