Fraunhofer Institute for High Frequency Physics and Radar Techniques FHR
Antenna Characterization and RCS Measurements from 800 MHz to 400 GHz
Accurate measurements of antennas and scattering objects require environmental interference to be minimized as much as possible. Anechoic chambers provide controlled and reproducible measurement conditions by using microwave absorbers on the walls, ceiling and floor to reduce unwanted reflections of electromagnetic waves.
Fraunhofer FHR operates five anechoic chambers for the characterization of antennas and scattering objects. The facilities support antenna and radar cross section (RCS) measurements over a frequency range from 800 MHz to 400 GHz. This infrastructure provides a versatile platform for antenna development and characterization, RF measurements and the investigation of electromagnetic scattering properties.
Far-Field Measurements and Planar and Spherical Near-Field Measurements
Different measurement methods and chamber geometries are available depending on the specific measurement task. Antennas can be characterized using far-field measurements as well as planar and spherical near-field measurements. The available far-field measurement setups provide measurement distances of up to 7.2 meters. Depending on the measurement system, near-field characterization can be performed over planar scan areas of up to 1.5 × 1.5 meters and spherical measurement surfaces with diameters of up to 4.3 meters. The largest spherical near-field system provides a theta scan range of up to ±120°.
The individual chambers are designed for different frequency ranges and measurement tasks. The far-field measurement systems cover frequency ranges including 800 MHz to 40 GHz, 3 to 40 GHz, and 5 to 110 GHz. An additional chamber supports measurements from 8.2 to 40 GHz and from 60 to 90 GHz and is equipped with systems for planar and spherical near-field measurements. This allows measurement configurations to be tailored to the respective frequency range and to the dimensions and characteristics of the object under test.
RCS Measurements and Applications
In addition to determining typical antenna parameters, the anechoic chambers can be used to investigate the electromagnetic scattering properties of objects and determine their radar signatures. Applications include RCS measurements, the development and evaluation of radar signature reduction measures, the investigation of metamaterials and metamaterial surfaces, and the characterization of reflectarrays.
An electronically controlled heavy-duty turntable provides additional measurement capabilities for larger or heavier antennas and scattering objects.
The combination of different measurement chambers, far-field and near-field techniques, and flexible positioning capabilities enables a wide range of application-specific measurements across a broad frequency range.