Radio Communications

Subject description

Characteristics of Coaxial Cables. Propagation of electromagnetic waves in free space and in the presence of natural barriers. Fresnel zone ellipsoid, wedge attenuation barriers. Measurements of fading of the received field and distortion of radio channel, fading statistics treatment, probability of the radio link failure, diversity reception and transmission. Thermal noise, antenna noise temperature, natural sources of noise on Earth and in Space. Shannon and performance of a link. Basic measurements of antenna parameters. Polarization of electromagnetic waves and definition of the polarization of the antenna and taking into account the polarization mismatch in radio link. Radio frequency circuits and devices. Measurements in the radio band and measurements with the radiofrequency spectrum analyzer.

The subject is taught in programs

Objectives and competences

The purpose of this course is to provide principles of radio transmission path and basic principles of radio waves as part of the electromagnetic waves. The course presents physical limitations of wireless communications in terms of radio wave propagation, noise and intermodulation products. Understanding the design of fixed and mobile radio systems based on analogue and digital modulation. Understanding general methods in the radio measurement, measurement of the spectrum and antenna parameters.

Teaching and learning methods

Lectures, where students are introduced by theoretical basics of radio communications, and laboratory courses, where students make practical experiments from the topics of antennas and wave propagation.

Expected study results

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

– describe advantages and limitations of radio waves,

– describe the mechanism of radio wave propagation in the presence of obstacles and atmosphere,

– measure signals and noise in the radio spectrum,

– measure the antenna parameters (directivity, gain, impedance),

– design of radio networks of different ranges,

– calculate the loss of line of sight radio link in the linear and logarithmic scale,

– calculate radio link capacity.

Basic sources and literature

Matjaž Vidmar. Radiokomunikacije. izd. Ljubljana: Fakulteta za elektrotehniko, 2005. ISBN 961-243-026-8.
Tomaž Korošec, Leon Pavlovič, Matjaž Vidmar. Radijske komunikacije: laboratorijske vaje. Ljubljana: Fakulteta za elektrotehniko, Laboratorij za sevanje in optiko, 2014. http://lso.fe.uni-lj.si/studij/rk_vs/gradivo/RK-VS_LaboratorijskeVaje.pdf
J. Budin, Razširjanje radijskih valov, FE, Ljubljana, 1975.
M. Vidmar, Sevanje in Razširjanje, Laboratorijske vaje, FE, Ljubljana 1998.
Ian Robertson, Nutapong Somjit, Mitchai Chongcheawchamnan: Microwave and Millimetre-wave Design for Wireless Communications, 2016.