Henry Dave Demorito
1. Define transmission line.
A system of conductors having a precise geometry and arrangement which is used to transfer energy from one
point to another with minimum loss.
2. Describe a transverse electromagnetic wave.
It is an oscillatory wave motion. It propagates primarily in the nonconductor (dielectric) that separates
the two conductors of the transmission lines
3. Describe balanced and unbalanced transmission line.
Balance transmission line = One conductor carries the signal and the other is the return path. It is also
called differential signal transmission. It has the advantage that most noise interference is included in
equally in both wires, producing longitudinal currents that cancel in the load.
Unbalanced transmission line = One wire is the ground potential, where as the other wire is at signal
potential. It is also called single-ended signal transmission.
4. Define velocity factor for a transmission line.
It is the ratio of the speed at which a wavefront passes through the medium, to the speed of eight in a
vacuum.
5. Define reflection coefficient.
It measures the amplitude of the reflected wave versus the amplitude of the incident wave.
6. List and describe the five types of transmission line losses.
Conduction losses = The inherit and unavoidable power loss because of electrical that flows through a
metallic transmission line and the like has infinite resistance.
Dielectric heating losses = A difference of potential between two conductors of a metallic transmission
line causes dielectric hearing Heat is a form of energy and must be taken from the energy propagating
down the line.
Radiation losses = If the separation between conductors in a metallic transmission line is an
appreciable fraction of a wavelength, the electrostatic and electromagnetic fields that surround the
conductor cause the line to act as if it were an antenna and transfer energy to any nearby conductive
material. The energy radiated is called radiation loss and depends on dielectric material, conductor
spacing, length the transmission line.
Coupling losses = Coupling loss occurs whenever a connection made to or from a transmission line or
when two sections of transmission line are connected together.
Corona = Corona is a luminous discharge that occurs between the two conductors of a transmission
line when the difference of potential between them exceeds the breakdown voltage of the dielectric
insulator.
7. Define input impedance and characteristic impedance for a transmission line.
Input impedance is the ratio of voltage to the current which consists of both the incident and reflected
waves while Characteristic Impedance (Z0) is the impedance with no reflections existing on the
transmission line. Here the load impedance and source impedance are matched to the impedance of
the transmission line. Hence, the transmission line impedance is independent of its length.
8. Describe time-domain reflectomerty.
It is a measurement technique used to determine the characteristics of electrical lives by observing
reflected waveforms.
9. Describe the behavior of an open and shorted transmission line as a circuit element.
It can be seen that an open line is resistive and maximum at the open and at each successive half-
wavelength interval and resistive and minimum one-quarter wavelength from the open and at each
successive half-wavelength interval.
It can be seen that a shorted line is resistive and minimum at the short and at each successive half-
wavelength interval and resistive and maximum one-quarter wavelength from the short and at each
successive half-wavelength interval.
10. Describe how stub matching and quarter wavelength transformer matching is accomplished.
A stub is terminated in a short (or open) circuit and the length is chosen so as to produce the required
impedance while the quarter wavelength transformer is the other way around, it is a pre-determined
length and the termination is designed to produce the required impedance.
