Millimeter-Wave Scattering System for Materials Testing

The big picture
The CTL Antenna Metrology Project’s mmWave scattering system characterizes materials using free-field wireless testing. The scanning system has been used to test effective dielectric constant, reflectivity, and microwave surface roughness effects from 100-500 GHz. Initially funded as a DHS science and technology imaging initiative, we have performed baseline material testing for the DHS Explosives Laboratory, the Federal Aviation Administration’s Transportation Security Laboratory, and are now working to test the dielectric constants of energetic materials and variability with packing ratios and grain size. 

Specs
   • ~20 dBi horns are placed at the focal point of the TPX lenses
   • Creates a collimated output
      ◦ 50% waist > 75cm
      ◦ ~1.3° HPBW
   • 25mm aperture creates a well-defined measurement solid angle for bidirectional reflectance distribution function (BRDF)
      ◦ 18 l @ 200 GHz
      ◦ 27 l @ 325 GHz
      ◦ 41 l @ 500 GHz