Antennas and wave propagation

Course description

Half-wave dipole, implementation of a directional antenna, Fraunhofer far field criteria, basic measurements of antenna parameters. Huygens source, antenna apertures, design of horn antennas, square phase error, phase-error correction with a collimating lens, lenses from artificial dielectrics, slow-wave structures. Parabolic mirror, computation of its focal point, selection of the section, mirror illumination, illumination efficiency, multiple-reflector antennas: Gregorian and Cassegrain. Antenna arrays and their design, array feeding networks, electrical array steering. Polarization of electromagnetic waves, definition of the antenna polarization, accounting for polarization mismatch in a radio link. Thermal noise, antenna noise temperature, natural noise sources on Earth and in the universe. Fresnel zones, propagation of radio waves in the presence of natural obstacles, mirrors and diffractors, radar cross-section, radar range equation. Propagation of electromagnetic waves in the Earth's atmosphere, absorption, refraction and reflection in the troposphere. Signal fading and channel distortion, fading statistics, link-failure probability, transmit and receive diversity.

Course is carried out on study programme

Elektrotehnika 2. stopnja

Objectives and competences

Learning fundamental antenna characteristics. Learning directional antenna design. Learning radiation from distributed sources and thermal noise. Learning electromagnetic-wave propagation through the atmosphere and in the presence of obstacles. Learning reception fading and related countermeasures.

Learning and teaching methods

Lectures for theoretical background and laboratory experiments to practically confirm the theory working in a team environment.

Intended learning outcomes

After successful completion of the course, students should be able to:

– analyze the requirements and possibilities of a free-space radio link

– design simple antennas

– select an appropriate frequency band and corresponding antennas for a certain radio link

– build simple antenna arrays

– compute simple obstacle losses in a radio link

– consider tropospheric and ionospheric effects in a radio link

– calculate the probabily of signal loss in a radio link

– compute the capacity of a MIMO radio link

Reference nosilca

  1. BOGATAJ, Luka, VIDMAR, Matjaž, BATAGELJ, Boštjan. Opto-electronic oscillator with quality multiplier. IEEE transactions on microwave theory and techniques, ISSN 0018-9480. [Print ed.], Feb. 2016, vol. 64, no. 2, str. 663-668.
  2. TRATNIK, Jurij, LEMUT, Primož, VIDMAR, Matjaž. Time-transfer and synchronization equipment for high-performance particle accelerators = Prenos takta in sinhronizacijska oprema za visoko-zmogljive pospeševalnike osnovnih delcev. Informacije MIDEM, ISSN 0352-9045, jun. 2012, letn. 42, št. 2, str. 115-12
  3.  STEED, Robert J., PAVLOVIČ, Leon, NAGLIČ, Luka, VIDMAR, Matjaž, et al. Hybrid integrated optical phase-lock loops for photonic terahertz sources. IEEE journal of selected topics in quantum electronics, ISSN 1077-260X. [Print ed.], Jan./Feb. 2011, vol. 17, no. 1, str. 210-217.
  4. TRATNIK, Jurij, VIDMAR, Matjaž. 2.8 GHz – 5.7 GHz very fast UWB CCO using discrete-packaged SiGe RF transistors = 2,8 GHz – 5,7 GHz zelo hiter ultra širokopasoven tokovno krmiljen oscilator z diskretnimi SiGe RF tranzistorji. Informacije MIDEM, ISSN 0352-9045, mar. 2011, letn. 41, št. 1, str. 70-72.
  5. RASPOR, Adam, VIDMAR, Matjaž. Two double-ring cavity antennas in 19-22 dBi directivity range. Electronics letters, ISSN 0013-5194. [Print ed.], Dec. 2009, vol. 45, no. 25, str. 1288-1289.

Study materials

  1. J. D. Kraus, Antennas, McGraw-Hill, New York, 1950.
  2. J. Budin, Razširjanje radijskih valov, FE, Ljubljana, 1975.
  3. M. Vidmar, Sevanje in Razširjanje, Laboratorijske vaje, FE, Ljubljana 1998.

Bodi na tekočem

Univerza v Ljubljani, Fakulteta za elektrotehniko, Tržaška cesta 25, 1000 Ljubljana

E: T:  01 4768 411