Antennas & Wireless Communications
About this course
The explosive growth and continuous development of the wireless and personal telecommunication systems creates a growing demand for telecommunication engineers with (a) very good background on the theory of antennas and electromagnetic wave propagation, and (b) special knowledge and experience in modern wireless systems.
This course prepares students for a career in the rapidly evolving telecommunications industry, because the antenna is the interface between any telecommunication system and the transmission means in wireless communications.
Expected learning outcomes
This course aims to get students acquainted with the principles of antenna theory and electromagnetic wave propagation, in order to use them during analysis and design of wireless telecommunication links.
Upon successful completion of the course, students will have acquired knowledge, skills, appropriate tools for dealing with practical applications related to antennas and propagation models, as well as experience in designing and optimizing real antennas. More specifically students will be able to:
+ understand electromagnetic theory and its applications to antennas and transmission of electromagnetic signals carrying information,
+ understand the theory of antennas and electromagnetic wave propagation in a uniform way, in order to use them in the analysis and design of wireless telecommunications,
+ describe the basic mechanisms of radio wave propagation and understand the interaction of electromagnetic waves with the environment,
+ be aware of the wave propagation phenomena caused in the real environment and the measurement methods used in practice,
+ calculate and measure the basic antenna parameters and characteristics (eg radiated power, radiation intensity, directivity, gain, radiation resistance),
+ compare antenna characteristics (advantages/disadvantages), deciding which is the most suitable antenna for each practical application,
+ perform antenna and electromagnetic radiation measurements,
+ familiarize with various practical antenna devices,
+ calculate the radiation diagram of an antenna, when its current distribution is known,
+ evaluate propagation models and select the appropriate model for calculating losses in a telecommunications link,
+ prepare radio coverage studies,
+ be informed about the latest developments in the field of wireless and personal communication systems,
+ analyze and design wireless telecommunication systems according to the respective needs,
+ be ready to supervise and maintain wireless telecommunications systems.
The course is at the core of the Electronic Engineer curriculum.
Note: The project-based version of the course will help the Erasmus students to get many of the above mentioned learning outcomes.
Indicative Syllabus
The project-based version of the course will cover many of the following subjects:
Review on telecommunications and electromagnetic theory. Electric, magnetic, electromagnetic field. Electrical signals. Telecommunication systems. Wireless telecommunications. Frequency spectrum (HF, VHF, UHF, microwaves). Maxwell Equations. Wave equations. Boundary conditions. Scalar and vector potentials. Fields of sinusoidal time change. Electromagnetic radiation and power. Poynting vector. Planar electromagnetic waves [polarization, wave propagation in conductive and non-conductive media, phase and group velocities, reciprocity]. Reflection and refraction of planar waves [Snell’s law, Fresnel equations, reflection and transmission coefficients, normal and oblique incidence on perfect dielectric and lossy media, standing waves, incidence on dielectric plates, scattering].
Transmission lines [complex and characteristic line resistance, wave reflection, transmitted power, adjustment, standing wave, Smith diagram]. Microwave waveguides [parallel plated, rectangular, circular, coaxial, microstrip, dielectric]. Optical waveguides. TE, TM and TEM propagation modes. Power and losses. Rectangular and cylindrical cavities. Electromagnetic waves in free space. Introduction to antenna theory. Antenna and transmission line matching.
Radiation mechanisms. Antenna characteristics, radiation diagrams, gain, bandwidth, quality factor. Theory of simple linear antennas. Analysis of antennas with assumed current distributions. Hertz dipole. Applications of electrically small antennas.
Linear dipole antennas. Field and radiation pattern, directivity, gain, radiation resistance, active antenna height. Dipole λ/2.
Traveling wave antennas.
Loop antennas.
Antennas above perfect ground. Mirroring and image theory.
General analysis of the radiation field of any antenna. Applications.
Antenna arrays. Rhombic antenna. Principles of antenna design. Applications.
Linear arrays. Uniform linear arrays with small and large number of elements. Polynomial theory of linear arrays. Applications.
Superdirective antennas. Phase detection. Methods of radiation pattern synthesis. Dolph-Chebyshev linear arrays. Composition of linear arrays with Fourier sums.
Applications and examples of antenna analysis and synthesis. Antenna applications and measurements.
Aperture antennas. Radiation from flat surfaces. Radiation from rectangular surfaces. Horn antennas. Parabolic reflector antennas. Horn-reflector antennas. Lens antennas. Passive reflectors.
Input antenna resistance. Equivalent sources. Magnetic charges and currents. Voltage and current sources. Reciprocity theorem. Self-impedance of conductive antennas. Voltage induced on open-ended antenna by an incident field. Induced electromotive force method. Transmission and reception equivalent circuits. Dipole near field. Bandwidth. Receiving antennas. Antenna polarization. Noise in telecommunication systems and antenna noise temperature.
Dipole self-impedance. Antenna as terminal impedance. Asymmetric excitation of dipoles. Matching conditions and maximum transmitted power. Matching using stubs. Folded dipole. Mutual complex resistance between dipoles. Antenna array excitation impedance. Impedance of dipoles above perfect ground. Antenna feeding with appropriate currents. Yagi-Uda antennas. The antenna as a receiver. Equality of mutual complex resistances. Equality of transmission and reception radiation patterns. Equality of transmission and reception self-impedances. Equality of transmission and reception antenna active heights. Active antenna surface. Received to transmitted power ratio.
Transmission of waves in free space. Friis equation. Losses and maximum transmission distance. Radar equation. Propagation of electromagnetic waves in the earth environment. Ground reflection of obliquely incident plane waves with vertical or parallel polarization. Brewster angles. Ground wave. Space wave. Surface wave. Antennas elevated above ground level. Approximate relationship for propagation at very high frequencies. Near ground surface wave tilt and polarization.
Spherical earth. Effects of the earth’s curvature. Line-of-sight condition. Barrier effects in wave propagation. Diffraction links. Tropospheric refractive index. Tropospheric propagation, refraction, waveguiding, scattering. Radio horizon. Multiple routes. Intervals. Differential reception systems. Atmosphere attenuation. Critical frequency and ionosphere changes. Ionospheric propagation, refraction, reflection, scattering. Applications.
Calculation of radio links. Over sharp obstacle links. Line-of-sight links. Above perfect ground links. Technical characteristics and practical applications of wireless links.
Teaching / Learning Methodology
Project-based (exclusively)
Recommended Reading
TBA
Prerequisites
Basic knowledge of engineering electromagnetics (electromagnetic fields and waves, Maxwell equations, boundary conditions, boundary value problems, etc.)
Start Date
2023
End Date
2024
Apply
2023
Local Course Code
TBA
Cycle
TBA
Year of study
TBA
Language
English
Study Load
4 ECTS
Mode of delivery
Final project evaluation. Blended learning using synchronous and asynchronous methods.
Instructors
Dr. Ioannis Vardiambasis
Course coordinator
Dr. Ioannis Vardiambasis
ivardia@hmu.gr