Near-field bases

The near field base is based on an extremely rapid acquisition of the tangential electric field using an arch on which the probes are arranged. It allows rapid testing of many antenna concepts developed at IETR in the 800 MHz to 6 GHz band for the 6 GHz base and from 650 MHz to 18 GHz for the 18 GHz base. It provides, in addition to the conventional characteristics of an antenna, compact information in the form of the spherical harmonic expansion of the radiation thus measured which can possibly be re-used in this form in an electromagnetic calculation code.
This technical platform thus allows the measurement of radiation diagrams, the measurement of radiation efficiency, access to the coefficients of the projection of the field in spherical harmonics.
The near-field base is above all a means of rapid antenna characterization, it provides the elements of characterization allowing the validation of new concepts giving rise to publications.

Technical characteristics of the 6 GHz near-field base :

 

  • multi-probe measurement system : MVG Stargate SG32 ;
  • anechoic chamber : 3.5 m X 3.5 m X 2.7 m (height) ;
  • internal diameter : 1 m 50 ;
  • maximum size EUT : 84 cm ;
  • frequency band : 0,8 GHz - 6 GHz ;
  • number of probes : 31 + 1 reference probe ;
  • measurement dynamic : 70 dB ;
  • measurements in real time.

 

Technical characteristics of the 18 GHz near-field base :

  • multi-probe measurement system : MVG Starlab 18 GHz ;
  • externals dimensions : 1.82 m x 1.08 m x 2.00 m (height) ;
  • 2 size absorbers panels 2 m x 2 m ;
  • internal diameter : 0,90 m ;
  • maximum size EUT : 45 cm ;
  • frequency band : 0,650 GHz - 18 GHz ;
  • vector network analyzer associated 4 ports 67 GHz ;
  • number of probes :

        650 MHz – 6 GHz : 15 + 1 reference channel ;

        6 GHz – 18 GHz : 14 + 1 reference channel.

  • measurement dynamic :

        650 MHz – 6 GHz : 70 dB ;

        6 GHz – 18 GHz : 60 dB.

  • arch rotation ;
  • measurements in real time.

 

Scientific results

 

  • development of specific approaches in terms of antenna integration on systems (vehicle issues) ;
  • establishment of equivalent radiation models from near-field measurement, analysis and validation of these models ;
  • refinement of model extraction methods for their adaptation to different types of radiating elements and the extension of these models in very close near-field areas.