ELECTRONICS FOR WIRELESS SYSTEMS
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- Versione italiana
- Academic year
- 2022/2023
- Teacher
- GIORGIO VANNINI
- Credits
- 6
- Curriculum
- Components & circuits design
- Didactic period
- Secondo Semestre
- SSD
- ING-INF/01
Training objectives
- After introducing the fundamental radio transmitter and receiver architectures, the main problems related to their circuit components (gain amplifiers, low-noise amplifiers, power amplifiers, voltage controlled oscillators, mixers, phase lock loops, analog digital converters, etc.) are examined. Technologies and related electron devices are dealt with too.
Although the main context is wireless communication, the topics dealt with are fundamental in applications where signal acquisition and their analog/digital processing are performed (e.g., electronic instrumentation).
By using a top-down approach (which analyses transceiver architectures and their issues, non linearity and noise in electron device and circuits, electronic circuits for radio receivers and transmitters) the main acquired competences in the electronic field, will be:
- fundamentals on high-frequency electron devices and technologies, high-frequency electronic circuits/systems for wireless communications and signal acquisition/processing;
- analysis and design techniques for high-frequency analog circuits.
The main acquired skills (i.e., the capability of applying what has been learnt) will be:
- analysis and performance evaluation of electron devices and circuits for telecommunications;
- analysis and design criteria for high-frequency analog electronic circuits/systems for telecommunications;
and more specifically:
- fundamental elements for the design of low-noise, gain and transmission amplifiers;
- fundamental elements for the design of mixer and oscillators;
- choice criteria for frequency synthesizers. Prerequisites
- Telecommunications (frequency conversion, analog and digital modulations, noise, etc.); electron devices and fundamental analog electronic circuits (small- and large-signal amplifiers, oscillators); fundamentals of free-space and guided propagation; basic electronic instrumentation.
Course programme
- 60 hours of teaching are given, divided in lectures and exercises/examples.
Lectures:
CAD tools and device models for electronic circuits/systems analysis/design: equivalent circuit and black-box (scattering parameters and behavioral) models.
Nonlinearity and noise - fundamental concepts and parameters: effects of non-linearity in transistors, circuits and electronic systems. Linear distortion and ISI. Noise. Main parameters of a radio receiver (definition and measurement examples).
Transceiver architectures: modulators and de-modulators (analog and digital). Constant envelope modulations and spectral regrowth. Elements on channel access techniques. Channel and band selection. Heterodyne receiver: main issues and implementations. Homodyne receiver (zero IF): advantages and problems. Fast ADC and RF/IF-sampling receivers. Image rejection receivers. Direct conversion and double conversion transmitters.
Technologies: Compound semiconductors and high-frequency transistors (MESFET, HEMT, HBT). Monolithic and hybrid integrated circuits. Smith chart and its adoption for AC parameter representation.
High-frequency small-signal amplifiers and LNA: comparison with low-frequency amplifiers. RF amplifier topology. Unconditional stability and stability circles. K factor. Transducer gain maximization. Smith chart and matching network design. Noise in transistors: Johnson, Shot, Flicker, Burst noise. Noise models for diodes, BJTs and FETs. Two-port noise description. Noise analysis with uncorrelated and correlated sources. Noise figure and noise parameters and experimental characterization. Low-noise amplifier design.
Mixers: main parameters, isolation, spurious and noise; balanced and doubly-balanced mixers. Active mixers (Gilbert cell and trans-conductance) and passive (switching) mixers. Cold-FET mixers (hints). "Hybrids" and implementation and application examples.
Voltage Controlled Oscillators and PLL: feedback oscillators (oscillation amplitude and frequency). Three-point oscillators. Frequency stabilization (quartz and resonators). Cross-coupled oscillators. VCO and varactors. Phase noise in receivers and transmitters. Oscillator phase-noise generation mechanisms (Leeson formula). Oscillator architectures. Phase-Locked Loops (PLL): type 1 and 2 PLL with passive and active filters. PFD and charge pump. Phase noise. Integer-N and fractional-N synthesizers. Direct and indirect frequency synthesis.
Power amplifiers: conduction-angle controlled amplifiers (class A, B and C). High-efficiency amplifiers: class F, E (D, hints). Linearization techniques for power amplifiers: back-off, pre-distortion, feed-forward, feed-back, EER and LINC, Envelope Tracking. Doherty amplifier: structure and load modulation. Output power and efficiency. Implementation. Didactic methods
- The course is organized as follows:
frontal lectures and exercises on all the topics of the course. Learning assessment procedures
- The final examination is in oral form. Questions on the course topics are aimed at evaluating the comprehension of the topics and the gained skills.
Exams are given weekly. The examination list closes two days before the scheduled date.
Passing the exam is proof of having acquired the ability to apply knowledge related to transceiver architectures, and to the analysis and synthesis of the associated electronic circuits. Reference texts
- Didactic material provided by the teacher.
Specific topics can be further developed in the following texts:
B. Razavi, RF Microelectronics, Prentice Hall, seconda edizione, 2012.
M. Steer, Microwave and RF Design: A Systems Approach, SciTech Publishing, 2010.
L.E. Larson, RF and microwave circuit design for wireless communications, Artech House, 1997.
Ludwig, Bretchko, RF Circuit Design: Theory and Applications, Prentice Hall, 2000.
Rohde, Newkirk, RF/Microwave Circuit Design for Wireless Applications, John Wiley, 2000.
S.C. Cripps, RF power amplifiers for wireless communications, Artech Hause, 2006.
G. Ghione, Dispositivi per la microelettronica, McGraw-Hill, 1998.
