A portable sweeping radar for millimeter-wave reflectivity measurements

Portable frequency agile millimeter wave test radar design and performance together with first measuring results are described. Covering the entire Ka-band and utilizing microcontroller steering, this radar allows pulse widths from 50 ns to infinity, pulse repetition waveforms of arbitrary pattern and time scale to 200 kHz and output frequency control bandwidth up to 10 MHz. The core radio part relies on double mixing with an auxiliary oscillator and frequency multipliers together with extensive filtering. Logarithmically detected video has a dynamic range of 55 dB or more and due to microcontroller-based automatic correction, a measured average level uncertainty of 1 dB. The radar´s total weight is just 6 kg without 12V/3A battery. Effective radar reflectivity results of trees and soil show frequency-related mean value variations of 5-15 dB and man-made corrugated objects up to 10 dB for 32-36 GHz and grazing angles of 90 degrees and one degree.