Radar Technology for Level Gauging - Krohne

Content page
6 Wave propagation 28
6.1 Propagation rate 28
6.1.1 Influence of the carrier medium (atmosphere) 28
6.1.2 Propagation rate on lines 30
6.1.3 Propagation rate in stillwells/waveguides 31
6.2 Transmission through dielectric windows 31
6.3 Free-space attenuation 32
6.4 Atmospheric signal attenuation 32
6.5 Modified radar equation 34
6.6 Equivalent isotropic radiation power (EIRP) 36
6.7 Propagation along electric lines (TDR method) 37
7 Reflection 38
7.1 Reflection factor 38
7.2 Reflection at interfaces 39
7.3 Dielectric permittivity 40
7.3.1 Chemico-physical assessment 40
7.3.2 Frequency dependence 42
7.3.3 Temperature and viscosity dependence 42
7.3.4 Liquid mixes 42
7.3.5 Bulk (particulate) materials 43
7.4 Scattering from particulate materials 43
7.5 Reflected radar cross-section from limited targets 44
7.6 Angle of reflection 44
8 Evaluation methods 45
8.1 Object discrimination 45
8.2 Unambiguity 45
8.3 Measurement uncertainty 46
8.4 Interference 46
8.5 Sample calculation for received powers 48
8.5.1 Useful signal 48
8.5.2 Signal-to-noise ratio 48
8.5.3 Signal-to-interference ratio of an interference reflector 48
8.6 Signal evaluation in the pulse-radar system 49
8.7 Signal evaluation in FMCW radar 50
8.7.1 Counting method 50
8.7.2 Fourier transform 50
8.7.3 Phasegradient method 51
8.7.4 Tracking 52
8.8 Special methods 54
8.8.1 Empty-tank spectrum 54
8.8.2 Tank bottom tracing 55
8.8.3 Interface detection 56
Annex 58
A Table of dielectric permittivity 58
B System-theoretical comparison between interferometer and FMCW methods 60
C Bibliography 63
Radar handbook 3