Aims and contents of the course
The course aims to provide students with a deep knowledge of the experimental methods used in radiofrequency, and of the operation principles of the main measurement instruments for high frequency. Starting from the theory of junctions and scattering parameters, the class will analyze the main advantages and limitations of the methodologies on which the measurement tools are based: power meters, network analyzers, spectrum analyzers. The described topics will include heterodyne conversion, frequency synthesis, and time-domain reflectometry.
The course will include seminars from industry, with practical demonstrations of RF instruments.
Reference to representation of distributed parameter circuits, RF junctions and scattering matrix. Matching theorems for three and four ports junctions: the circulator and the directional coupler.
RF power measurements (calorimeters, bolometers, thermocouples and diodes): working principles, errors, mismatch, calibration procedures and analysis of commercial instrumentation functioning.
Measurement of insertion loss and reflection coefficient.
Mixer and detector. The heterodyne conversion.
RF Impedance measurement methods.
Working principle of a network analyzer. Calibration procedures (one and two ports) and accuracy.
The spectrum analyzer: working principle for baseband and higher bands. Different kind of receiver, the evolution from analog to digital. Real time spectrum analyzer.
Frequency references (quartz) and frequency synthesizers (direct, indirect and digital synthesis).
Time domain reflectometry: transient load-dependent and range resolution of discontinuities.