RPG-FMCW-94-DP-G1/S W-Band Radar

Sponsor: Office of Naval Research DURIP (Grant Number: N00014-19-1-2588)

This is a DURIP funded Frequency Modulated Continuous Wave (FMCW) W-band radar for research involving atmospheric water droplets (hydrometeors; e.g., fog, clouds and rain). Hydrometeors cover a range of sizes, and radars operating at different frequency bands are used for their observations. For instance, Ka (~35 GHz) and W (~94 GHz) band radars operating at millimeter-wavelength are employed to observe cloud microphysical processes, measure the velocity structure, estimate rain rates, obtain distribution of small cloud particles from non-precipitating or weakly precipitating clouds, and retrieve information on in-cloud turbulence. Where higher sensitivity is needed and the size and weight of the instrument are not a factor, Ka band radars that require larger antennas are used. Where instrument compactness and weight are a limiting factor, such as deployment on a research vessel with the radar resting on a motion compensated platform, W-band is the radar of choice for hydrometeor research. Recent advent of a new generation of user-friendly commercial FMCW W-band radars has enabled researchers and observatories to engage in hygrometric research without facing onerous infrastructure and maintenance challenges. The FMCW W-band cloud Doppler radar (model RPG-FMCW-94-DP-G1/S) manufactured by Radiometer Physics GmbH (RPG), is of this type. It is a dual polarization, single frequency turnkey system provided with an elevation/azimuth scanner designed for cloud and fog research. These radars measure small water droplets of millimeter and submillimeter scales (≥10 μm) enabling retrieval of useful quantities such as reflectivity, mean radial velocity, spectrum width, skewness and kurtosis for characterization of atmospheric water droplets. Its compactness, low power (several Watts), agility, and high space-time resolution (~ 1m spatial and integration times of seconds) allow characterization of small cloud drops and ice particles, fog, liquid and solid precipitation, and even non-meteorological scatterers such as insects and pollen. The versatility of the instrument can be significantly enhanced by operating it alongside other available instruments to the PI such as Doppler lidars and microwave radiometers. It is the pioneering commercial W-band radar of its kind, extensively field tested. It will greatly add to the atmospheric instrumentation capabilities of University of Notre Dame, thus enhancing ability to characterize fog and clouds.

Specifications for RPG-FMCW-94-DP-G1/S

  • FMCW Cloud Radar, dual polarization
  • Solid-state / low power source
  • RF at 94 GHz (W-band)
  • Very High Sensitivity (down to -60 dBz)
  • High Dynamic Range (-60 to +20 dBz)
  • Complete Rain Mitigation System
  • Full Networking Capability (TCP/IP)
  • Positioner system for moving the radar in azimuth and elevation
  • Built-in weather station to monitor weather conditions at ground level
  • Passive channel for absolute calibration
  • Includes embedded 89 GHz passive channel for measurements of integrated liquid water path (LWP)
  • Easy adaption of operating modes, allowing the researchers to focus on certain parameters by re-coding the chirps
  • Compact and easily transportable