34885 - Antenna Systems M

Learning outcomes

DEVELOPMENT OF A THOROUGH SCIENTIFIC-METHODOLOGICAL UNDERSTANDING OF THE WORKING PRINCIPLES AND OF THE ANALYSIS AND DESIGN TECHNIQUES OF THE PRINCIPAL ANTENNA SYSTEMS USED IN MODERN TELECOMMUNICATIONS SYSTEMS.

Course contents

General properties of antennas treated as mathematical sources. Phase center. Antenna thermal noise and equivalent noise temperature. Basic approach to radio system design. Foundations of computational electromagnetics. Method of moments. Scattering problems. Received and re-radiated power by an antenna. Monostatic and bistatic radar cross section and its numerical computation. Radar's equation. Radar cross section of elementary obstacles. Scattered field polarisation. Electromagnetic dipoles. Radiation from a mathematical dipole described by a known current distribution. Half-wave dipole. Efficiency. Image theorem and realisation of a dipole by means of a monopole radiating in the presence of a ground plane. Pocklington's integral equation for the current distribution and its solution by the method of moments. Input impedance and operating bandwith of a dipole antenna. Array antennas. Complex array factor and far field. Broadside and end-fire linear uniform arrays. Binomial arrays. Two-dimensional planar arrays. Phased arrays and electronic scanning. Dipole antenna arrays. Applications: radar antennas, radio base station antennas, plane and corner reflectors. Coupling between array elements and parasitic elements. Computation of the current distributions by the method of moments. Computation of the array impedance matrix. Applications: Yagi-Uda arrays, folded dipoles, log-periodic antennas. Radiation from an aperture under general conditions. Aperture efficiency. Computation of far-field quantities under uniform TEM illumination. Huygens' source and Huygens-Fresnel's principle. Electromagnetic diffraction. Uniformly illuminated circular aperture. Effects of an axially symmetric amplitude taper. Parabolic reflector antennas. Computation of the aperture field distribution and of the aperture efficiency. System power gain, spillover efficiency, and illumination efficiency. Aperture field polarisation and cross-polarisation suppression. Feeder design. Rectangular and circular horn feeders. Dual-mode circular feeders. Offset-reflector systems. Illumination by sub-reflectors and Cassegrain systems. Integrated (microstrip) antennas. Rectangular patch antenna: approximate analysis by an intuitive model. Numerical analysis of arbitrarily shaped antennas by the method of moments. Computation of the input impedance. Applications: microstrip antenna arrays, internal integrated antennas for mobile transceivers, broadband integrated antennas, spiral antennas.

Readings/Bibliography

LECTURE NOTES: V. RIZZOLI AND D. MASOTTI, 'LEZIONI DI SISTEMI D'ANTENNA' (VOL. 1 AND 2), ESCULAPIO-PROGETTO LEONARDO, 2006/2008.

REFERENCE TEXTBOOK: L. STUTZMAN AND G. A. THIELE, 'ANTENNA THEORY AND DESIGN', JOHN WILEY & SONS, 1998.

Teaching methods

THE CLASSROOM LECTURES ARE INITIALLY DEVOTED TO THE DISCUSSION OF THE GENERAL ASPECTS AND OF THE ANALYSIS TECHNIQUES FOR ANTENNA SYSTEMS, INCLUDING THE FOUNDATIONS OF COMPUTATIONAL ELECTROMAGNETICS. SUCH KNOWLEDGE IS SUBSEQUENTLY APPLIED TO THE IN-DEPTH TREATMENT OF SOME OF THE MOST COMMONLY USED ANTENNAS, INCLUDING YAGI-UDA ARRAYS, LOG-PERIODIC ANTENNAS, PARABOLIC REFLECTOR SYSTEMS, AND MICROSTRIP ANTENNAS. THE TRAINING HOURS ARE DEVOTED TO THE USE OF ELECTROMAGNETIC SIMULATION PROGRAMS FOR THE ANALYSIS OF ANTENNA SYSTEMS OF COMPLEX REALISTIC CONFIGURATION, AND TO THE SOLUTION OF SIMPLE RADIO-SYSTEM EVALUATION AND DESIGN PROBLEMS.

Assessment methods

ORAL DISCUSSION AIMED AT ESTABLISHING THE STUDENT'S UNDERSTANDING OF THE ANALYSIS AND DESIGN TECHNIQUES AND OF THE SPECIFIC PROPERTIES OF THE PRINCIPAL ANTENNA SYSTEMS. SOLUTION OF SIMPLE PROBLEMS ON RADIO SYSTEMS.

Teaching tools

A DEDICATED TEXTBOOK IS AVAILABLE WHERE THE TOPICS DEVELOPED IN THE COURSE ARE DEALT WITH IN DETAIL. THE CLASSROOM TEACHING IS SUPPORTED BY THE PROJECTION OF SLIDES CONTAINING MOST OF THE MATHEMATICAL DETAILS, IN ORDER TO PARTLY WAIVE THE NEED FOR THE STUDENTS TO TAKE NOTES DURING THE LECTURES, ESPECIALLY FOR MATHEMATICS. COPIES OF ALL SUCH SLIDES ARE AVAILABLE THROUGH THE INTERNET (IN THE COURSE HOME PAGE, FOLLOW THE LINK "MATERIAL").

Office hours

See the website of Vittorio Rizzoli