Anechoic Chamber for Near-Field antenna measurements
In Southern Germany, Albatross Projects designed and installed an antenna measurement chamber for a well known research institute for integrated circuits in Erlangen. The institute is developing micro-electronic circuits for information, communication, x-ray and medical technologies as well as researching into microwave circuits, video and audio coding, image detection, high speed camera systems and integrated digital systems.
For all areas of wireless transmission technologies, the characteristics of their appropriate antennas are designed to meet specific criteria. Correspondingly, the chamber has been designed to characterize antennas patterns in the near field and far field capacity.
Dimensions: 15.4m x 6.1m x 5.5m (L x W x H)
usable frequency range 800MHz to 40GHz
quiet zone: sphere with 1.5m diameter
test distance: 4.0m … 7.0m (near field, far field)
free space VSWR: typically –45dB above 1GHz
The chamber features a fully remote controlled near and far field antenna system for the measurement and characterization of antennas up to 40GHz. The RF absorber lining of the chamber, with resistive foam RF absorbers 36 inch for far field range and 26 inch for near field range and partially lined with walkway floor absorbers, offers different measurement distances from two opposite directions in the chamber.
To ensure a high degree of repetitive and reproducible measurements, the geometrical accuracy of the RF absorber lining is crucial. This has been achieved using our modular “plate & rail” absorber installation method. Utilization of metal, not only for the shielding panels, but all structural components, avoids mismatches that would otherwise be due because of different dilatation coefficient.
The two entrance RF doors with 1.2m x 2.05m clearance to the EUT area, are lined with 36 inch absorbers. These are mounted onto an ‘absorber trolley’ which is mechanically linked to the rf door operation; this provides a fully clear void when the door is in the open position and an automatic realignment of the absorbers when in the closed position.