ASSIGNMENT IN TRANSMISSION LINE

Submitted by:Jonabelle MendozaECE5

Submitted to:Engr. Pablo Asi

June 2015

1. What is transmission line?Transmission lines are used to transmit electrical energy and signals from one point to another, specifically from a source to a load. This may include the connection between a transmitter and an antenna, connections between computers in a network, or between a hydroelectric generating plant and a substation several hundred miles away. Other familiar examples include the interconnects between components of a stereo system, and the connection between a cable service provider and your television set. Examples that are less familiar include the connection between devices on a circuit board that are designed to operate at high frequencies.Transmission lines are used to carry electromagnetic energy from one point to another. It means it transfer from one point to another. Generally it consists of two conductors. It is used to connect a source to a load. The source may be a transmitter or an electric generator and the load may be an antenna. Transmission lines are used for operational frequencies equal to or less than about 3GHz. Above 3GHz they will be replaced by waveguides.

2. What are the different types of transmission lines? Balanced Transmission Lines. With two-wire balanced lines, both conductors carry current; however, one conductor carries the signal, and the other conductor is the return path. The signal propagating down the wire is measured as the potential difference between the two wires.

Unbalanced Transmission Line. With an unbalanced transmission line, one wire is at ground potential, whereas the other wire is at signal potential. With unbalanced signal transmission, the ground wire may also be the reference for other signal-carrying wires.

Two wire transmission line:- This transmission line consists of a pair of parallel conducting wires separated by a uniform distance .These are used in power systems or telephones lines.

Coaxial transmission line:- This consists of an inner and a coaxial outer conducting sheath separated by a dielectric medium . They are used as TV cables, telephones cables and power cables.

Parallel plate transmission line or planar line:- It has two parallel conducting plates separated by a dielectric slab of uniform thickness

Optical fibres transmission line:- It consists of core and cladding . Information passes through the core in the form of totally internal reflected TEM waves.

3. Explain how energy is being propagated to a transmission line.Propagation of electrical power along a transmission line occurs in the form of transverse electromagnetic wave (TEM). A wave is an oscillatory motion. The vibration of a particle excites similar vibrations in nearby particles, a TEM wave propagates primarily in the nonconductor (dielectric) that separates the two conductors of the transmission line. Therefore, a wave travels or propagates itself through medium. Electromagneric waves are produced by the acceleration of an electric charge. In conductor, current and voltage are always accompanied by an electric (E) field and a magnetic (H) field in adjoining region of spaceSOURCE: http://www.ie.itcr.ac.cr/acotoc/Maestria_en_Computacion/Sistemas_de_Comunicacion_II/Material/Biblio2/chapt13.pdf http://www.winnerscience.com/transmission-lines/transmission-line-and-its-types/ Electronic Communication Systems by Wayne Tomasi