Comunicações Rádio

Communication Systems
Electromagnetism

Teaching methods: Presential

Theoretical classes are essentially expository, in which the teacher presents the fundamental concepts associated with current radio communication systems and wireless networks.

In laboratory classes, direct contact with existing technologies is privileged. Students have to carry out, in groups, several laboratory works regarding the analysis, design and/or implementation of antennas and transmission lines used on radio systems and the development of a web application using one radio communication  technology. The resolution of application exercises will also be conducted during the lab classes.

Objectives: To acquire scientific knowledge about radio communications systems. Assumes particular relevance the understanding and analysis of guided transmission media and antennas; digital modulation techniques; most common systems using Wireless Personal Area Networks (WPAN) and Low Power Wide Area Networks (LPWAN) technologies.

Generic skills: Ability to analyze and synthesize; ability to develop autonomous and team work; ability to apply technical knowledge to the design and implementation of different aspects related to radio communications systems; ability to speak and write in Portuguese.

Specific skills: Know and understand the characteristics of transmission lines; to know and understand the radiation diagrams and the fundamental parameters of the antennas; know and understand the different types of antennas and modulation techniques used in today’s radio communications systems. Among them, special attention is given to WPAN and LPWAN systems, namely those used in energy and automation monitoring and control applications: smart metering and smart grids; Internet of Things (IoT) and Industry 4.0; between others.

Introduction

• Motivation; historical perspective and social impact of radio communications;
• Radio spectrum: Frequency assignment table;
• Current radio communications systems;

Transmission lines

• Two-wire transmission line; coaxial cable; microstrip line, etc.
• Telegrapher equation; characteristic impedance and propagation constant;
• Terminated transmission line: reflection coefficient; VSWR; RL and input impedance.

Fundamental concepts and parameters of antennas

• Antennas in radio communications systems;
• Radiation mechanism topics;
• Antennas fundamentals
• Poynting vector, power density and radiation intensity;
• Electromagnetic waves propagation impedance of free space.
• Fundamental parameters:
• Radiation pattern in polar and Cartesian coordinates (main lobe, side lobe; HPBW; FNBW; etc.);
• Directivity; gain; effective area; efficiency; bandwidth; polarization; input Impedance; etc.

Wire, aperture and printed antennas

• Linear antenas: dipoles and monopoles;
• Microstrip antennas: analysis and synthesis;
• Aperture antennas and reflectors;
• N elements linear array.

Digital communications (Band-pass digital modulations)

• Elementar digital modulations techniques: ASK, PSK, FSK and QAM.
• Linear digital modulations with coherent detection:
• binary modulation (ASK e PSK); and non binary (MPSK) .
• Nonlinear digital modulations with coherent detection:
• binary modulation (FSK e MSK); and non binary (MFSK).
• QAM modulation;
• error probabilities and spectral efficiency evaluation.

Wireless Personal Area Networks (WPAN) and Low Power Wide Area Networks (LPWAN) systems

• IEEE 802.15.x standards;
• Bluetooth / IEEE 802.15.1;
• ZigBee versus IEEE 802.15.4;
• LoRa and LoRaWAN;
• Topics about Sigfox and other LPWAN systems.

Radio technologies applications for energy and automation systems

• Smart metering and smart grids applications;
• Applications for Internet of Things (IoT) and Industry 4.0;
• Topics on wireless interface for smart sensors (IEEE 1451.5);
• Topics on Industrial 5G applications;
• Other applications: fleet management and warehouse management; RFID technologies; security and access control, etc.

NAO

Recommended Bibliography

• Balanis, C. A. (2016). Antenna theory: analysis and design. John wiley & sons. [1-8-72 (ISEC) – 14986]
• Hayt Jr, W. H., Buck (2001). Engineering Electromagnetics| (SIE). McGraw-Hill Education. [1-3-161 (ISEC) – 17524]
• Carlson, A. B., Crilly, P. B., & Rutledge, J. C. (2002). Communication systems: An introduction to signals and noise in electrical communication (4^th ed.). McGraw-Hill. [1-8-56 (ISEC) – 14812]

Complementary Bibliography

• Chaudhari, B. S., &; Zennaro, M. (2020). LPWAN Technologies for IoT and M2M applications. Academic Press. 
• Kraus, J. D. (2003). Antennas for all applications. McGraw-Hill companies Inc. New York  [1-8-71 (ISEC) – 14980]
• Sadiku, M. N. (2014). Elements of electromagnetics. Oxford university press.
• Huang, Y., & Boyle, K. (2008). Antennas: from theory to practice. John Wiley & Sons
• Haykin, S. (2016). Introduction to analog and digital communications (2^nd ed.). New York: John Wiley & Sons. [1-8-43 (ISEC) – 05482]
• Gutierrez, J. A. (2010). Low-rate wireless personal area networks: Enabling Wireless Sensors with Ieee 802.15.4. IEEE Press.
• Several articles on the topics covered: IEEE Communications Surveys & Tutorials and IEEE Transactions on Wireless Communications