Sensores de nivel tipo radar

© KROHNE 07/2003
GR

7.02337.22.00

Fundamentals of

Radar Technology
for Level Gauging
4th edition (revised and expanded) by Dr.-Ing. Detlef Brumbi KROHNE Messtechnik GmbH & Co. KG

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Foreword to the 4th edition

The first edition of "Fundamentals of Radar Technology for Level Gauging" in 1995 originated from the wish to write a concise account of the technical basis of the thenstill relatively young field of industrial radar technology. Although countless books and articles had already been published on radio frequency technology and radar methods, there was still a general lack of information on the special issues relating to level measurement. Owing to popular demand, this booklet now appears in its 4th edition. Following the additions made to the 3rd edition, thecontents of this new edition have again been updated, adapted to the latest state of the art and greatly expanded. Thus many aspects have been annotated by additional information, formulae of calculation and diagrams, and more space given to the subjects of TDR and signal evaluation. This booklet is not a brochure for a particular industrial product but a well-grounded article on technicalfundamentals to explain the processes taking place in radar and TDR level gauges. For some it may serve as a kind of textbook to provide a deeper understanding of level measurement technology, for others it may serve as a reference work to provide more details on specific matters. Not included are subjects of a general nature, such as bus systems and power supply concepts (e.g. 2-wire technology), since theyare generally applicable to process measurement technology and are dealt with extensively in many works.

Duisburg, January 2003 Detlef Brumbi

Radar handbook

Content 1 Introduction 1.1 RADAR systems 1.2 Radar milestones 2 General 2.1 Frequency, wavelength and propagation rate 2.2 Electromagnetic frequency spectrum 2.3 Postal regulations 2.4 Hazards from microwaves 2.5 Fields ofapplication 3 Radar level measurement systems 3.1 Overview of level measurement methods 3.2 Radar level measurement - General 3.3 Comparison of radar methods 3.4 Interferometer radar 3.5 Pulse radar 3.5.1 Bandwidth of an HF pulse 3.6 FMCW radar 3.6.1 Principle 3.6.2 Type model 3.6.3 Frequency control by PLL 3.7 Power balance (“radar equation”) 4 Components for radar systems 4.1 Active devices 4.1.1 GaAstransistors 4.1.2 Active diodes 4.1.3 Silicon devices 4.1.4 Velocity-modulated tubes 4.2 Oscillators to generate microwave frequency oscillations 4.2.1 Fixed-frequency transmitters 4.2.2 DRO 4.2.3 VCO 4.3 Circuit stages for processing radar signals 4.3.1 Mixers 4.3.2 Receiver noise 4.4 Line transmission 4.4.1 Coaxial cable 4.4.2 Twin line 4.4.3 Planar lines 4.4.4 Wire in free space 4.4.5 Waveguide4.4.6 Coupling into waveguides 4.4.7 Directional coupler 4.4.8 Reflections at junctions 4.4.9 Plug connectors 5 Antennas 5.1 Types of antenna 5.2 Antenna gain 5.3 Radiation angle 5.4 Polarization 5.5 Directional diagrams
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Radar handbook

Content 6Wave propagation 6.1 Propagation rate 6.1.1 Influence of the carrier medium (atmosphere) 6.1.2 Propagation rate on lines 6.1.3 Propagation rate in stillwells/waveguides 6.2 Transmission through dielectric windows 6.3 Free-space attenuation 6.4 Atmospheric signal attenuation 6.5 Modified radar equation 6.6 Equivalent isotropic radiation power (EIRP) 6.7 Propagation along electric lines (TDR method)7 Reflection 7.1 Reflection factor 7.2 Reflection at interfaces 7.3 Dielectric permittivity 7.3.1 Chemico-physical assessment 7.3.2 Frequency dependence 7.3.3 Temperature and viscosity dependence 7.3.4 Liquid mixes 7.3.5 Bulk (particulate) materials 7.4 Scattering from particulate materials 7.5 Reflected radar cross-section from limited targets 7.6 Angle of reflection 8 Evaluation methods 8.1...