Ing Ind - Inf (Mag.)(ord. 270) - MI (474) TELECOMMUNICATION ENGINEERING - INGEGNERIA DELLE TELECOMUNICAZIONI

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ZZZZ

052484 - RF SYSTEMS

Ing Ind - Inf (Mag.)(ord. 270) - MI (476) ELECTRONICS ENGINEERING - INGEGNERIA ELETTRONICA

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A

ZZZZ

052484 - RF SYSTEMS

Obiettivi dell'insegnamento

The aim of the teaching is to present the student with the methodologies for modeling, analysis and design of the radio front-end of a communication system, with reference to its main macro elements (subsystems). In addition, the teaching provides the students with the tools for understanding the technologies related to devices and circuits operating at microwave frequencies. Each topic related to modelling methodologies is treated theoretically and from the application point of view.

To stimulate the students involvement, the teaching includes 1 credits of innovative didactic (Blended learning & flipped classroom)

Risultati di apprendimento attesi

1) Knowledge and Understanding

Students will learn how to: - Define mathematical models for the analysis the RF front-end of a microwave transceiver - Define mathematical models for the analysis the sub-systems composing the RF front-end - Analyze complex technologies related to circuit and devices used in the sub-systems - Identify system components and their relations

2) Applying knowledge and Understanding

Students will be able to: - Dimension the RF radio front-end given the quality requirements of the received/transmitted signal - Evaluate the performance of the RF front-end for different type of signals - Apply the mathematical models learned

3) Making judgements

Students will be able to: - Understand the fundamental tradeoff that govern the design of a modern RF radio front-end - Identify how the fundamental system limitations impact the design of the RF system - Recognize the design space and its degrees of freedom enabled by new technologies at microwave frequencies

Argomenti trattati

Specific topics (1st part):

Introduction to microwave communication systems. Fundamentals of frequency conversion: the super heterodyne radio receiver. Block diagram of the RF front-end in receivers and transmitters. Basic blocks: Antenna, Amplifier (low noise and power), Mixer, Local Oscillator. Recalls on signals in communication systems: carrier and complex (baseband) modulation.

Introduction to antennas: guided and radiated electromagnetic waves. System aspects of antennas. Fundamental parameters: directivity, radiation pattern, gain, effective area, efficiency, radiation impedance.

The radio link: Friis equation (link budget)

Noise in RF front-end. Definition of the noise temperature. Noise in frequency conversion (SSB and DSB). Evaluation of the equivalent noise temperature of the receiver. Comparison with the direct conversion receiver. Noise generated at antenna output.

Linear and non-linear distortion: definitions and characterization. Transfer function: no- distortion condition for amplitude and group delay. Weak non-linearity in 2-port networks: 1dB compression point and 3th order intercept point.

Specific topics (2nd part):

Matrix characterization of n-port networks. Classical Z and Y matrices and limits of their use in high frequency circuits. Definition of power waves. Scattering matrix: definitions and properties.

Introduction to microwave circuits. Main differences with lumped-element circuits. Conventional voltage and currents. Interconnections and their effects. Discontinuities: meaning and representation. Analysis with CAD techniques.

Impedance matching: basic concepts (matching and maximum power transfer). Matching with lumped elements (L network). Single stub and double stub tuners.

Coupled transmission lines: analysis with the conventional lumped model; even and odd mode parameters. Directional couplers and combiners.

Introduction to the design of narrow band microwave amplifiers. Maximization of transducer gain and stability issues. Evaluation of optimum loads with the Smith Chart. CAD techniques for non-linear analysis of amplifiers: the Harmonic Balance method.

Microwave Oscillators: topological configuration and evaluation of optimum load with the Smith Chart. The dielectric oscillators: scheme and dimensioning criteria.

Overview of semiconductor active devices at microwave frequencies. Basics on fabrication technologies of RF and microwave circuits

Blended Learning & Flipped Classroom

Techniques for improving linearity in RF Transmitter (Pre-distortion, Envelope Tracking, Feed-Forward)

Computation techniques: system simulation with commercial software

Figure of merits of the complete RF front-end.

Prerequisiti

Students are required to know the principles of electrical networks. They are also expected to have a basic knowledge of guided propagation of signals (transmission lines).

Modalità di valutazione

The assessment is based either on a written exam at the end of the course or through two "in itinere" tests (one mid-term test on the first part of the program and one test at the end of the course on the second part of the program). For the students passing both "in itinere" tests (minimum grade 15/30), the final grade is the average of the points achieved in each test. Those who do not pass one of the "in itinere" tests are allowed to answer the problems of the regular exam (written test) concerning only the part of the program not passed. Those who do not pass both "in itinere" test must take the entire regular exam.

The first exam after the end of the course will be reserved for the second "in itinere" test.

The written tests (both regular exam and "in itinere" tests) are based on numerical exercises and problems similar to those discussed during the course. The purpose of the exam is to assess the student's ability to solve problems and design RF systems and microwave circuits. During the tests the students are allowed to use books, notes and computer (with no internet connection).

In addition to the points gained with the tests, the final score can be increased with additional points (up to 3) awarded during innovative didactic activities.