Transmission Lines and AntennasAnno accademico 2021/2022 - 1° anno - Curriculum Communication Networks and Services e Curriculum Communication Tecnologies and Systems
SSD: ING-INF/02 - Campi elettromagnetici
Organizzazione didattica: 225 ore d'impegno totale, 144 di studio individuale, 56 di lezione frontale, 25 di laboratorio
Knowledge and understanding: The lectures aim to give the conceptual tools and the techniques for the description of the classical electromagnetic phenomena with particular reference to the irradiation and propagation of electromagnetic signals. The aim is the acquisition of basic methodologies concerning radiation and propagation of electromagnetic fields for the study and analysis of transmission lines and antennas.
Applying knowledge and understanding: Analyze guiding structures and antennas for transmission of signals.
Making judgements: Ability to identify and compare the most appropriate methods for studying real problems.
Communication skills: Ability to present orally and through written tests using technical language and proper methodology.
Learning skills: Ability to study new problems in a self-direct and autonomous way.
Modalità di svolgimento dell'insegnamento
The course includes both lectures and experimental laboratories to elaborate on the contents of the lessons.
If the teaching is given in mixed or remote mode, some variations may be introduced in compliance with the program and the purposes stated in the syllabus.
Basic knowledge of differential and integral calculus. Phasors and vectors. Differential operators. Concept of charge, current, electric and magnetic field. Techniques to study lumped circuits.
Although lecture attendance is not mandatory, it is strongly recommended. Highly recommended, for laboratory.
Contenuti del corso
General principles (2 CFU – 14 h):
Introduction to electromagnetics, relevance and applications. Maxwell equations in time domain. Lorentz force. Fields conditions on discontinuity. Maxwell equations in sinusoidal regime. Polarization of the electromagnetic fields. Constitutive relations. Electromagnetic properties of media. Cold and collisionless plasma. Poynting vector and uniqueness conditions. Sommerfeld's radiation conditions.
Transmission lines (2.5 CFU – 17.5 h):
Guiding structures with cylindrical symmetry and metallic contour. TEM modes. Voltage and current on a transmission line. Telegraphers' equations in time and frequency domain. Phase velocity. Solution of Telegraphers' equations in progressive and stationary form. Reflection coefficient. Impedance transformer formula. Matched load, reactive load, generic load. Voltage standing wave ratio (VSWR). Matching techniques, quarter-wave transformer, matching with stubs. Resonant conditions on transmission lines. Transmission lines with losses. Narrowband signal propagation and group velocity. Impedance of coaxial cable and bifilar line.
Reflection and transmission of plane waves (1.5 CFU – 10.5 h):
Homogeneous and inhomogeneous plane waves. Normal incidence. Penetration depth. Snell's laws. Fresnel coefficients for parallel (TM) and orthogonal (TE) polarization. Transmission in lossless media. Total transmission and total reflection. Transmission in lossy media. Leontovic condition.
Radiation and antennas (2 CFU – 14 h):
Electromagnetic potentials. Field radiated by an elementary electric dipole. Field radiated by an elementary current loop. Duality. Field radiated by linear antennas. Far field conditions. Input resistance and radiation resistance. Effective length. Transmitting antenna, directivity and gain. Short dipole, half-wave dipole, monopole. Receiving antennas. Polarization and power matching. Effective area. Friis's formula for link budget. Linear and planar antennas arrays. Image sources.
Laboratory (1 CFU – 25 h):
Experimental verification of Snell's laws at optical frequencies. Study and design of waveguides and linear antennas using numerical CAD. Measurement of radiation patterns of linear antennas.
Testi di riferimento
1. S. J. Orfanidis, "Electromagnetic Waves and Antennas".
2. G. Franceschetti, Electromagnetics, Theory, Techniques, and Engineering Paradigms, Springer.
3. C. G. Someda, "Electromagnetic Waves", CRC Press.
4. F. T. Ulaby, U. Ravaioli Fundamentals of Applied Electromagnetics (7th Edition), Pearson Education.
Programmazione del corso
|1||Maxwell's equations||2 and 3|
|2||Simple solutions of Maxwell's equations: plane waves||2|
|3||Transmission Lines||1 and Studium|
|5||Reflection and Transmission of plane waves||1, 2 and 3|
|6||Radiation Theory and Antennas||1 and 2|
|7||Transmitting and Receiving Antennas||1 and 2|
Modalità di verifica dell'apprendimento
Written and Oral Exams.
Esempi di domande e/o esercizi frequenti
Questions and exercises related to the course program.