## CHARACTERISTIC IMPEDANCE OF TRANSMISSION LINES TUTORIALS AND LINKS

Characteristic Impedance is one of the most important, and a recurring concept in the design of Transmission Lines. This article will give light to the value and importance of characteristic impedance to the transmission line design process.

What Is Characteristic Impedance?
The characteristic impedance (Z0) of a transmission line is the resistance it would exhibit if it were infinite in length. This is entirely different from leakage resistance of the dielectric separating the two conductors, and the metallic resistance of the wires themselves. Characteristic impedance is purely a function of the capacitance and inductance distributed along the line's length, and would exist even exist even if the dielectric were perfect (infinite parallel resistance) and the wires superconducting (zero series resistance). Read more...

Characteristic Impedance Explained
To begin with, we need to remember that radio signals do not travel instantly from one end of a wire or transmission line to the other. Secondly, these same signals travel even slower down various conductive mediums (wire, coax, etc.), compared with that of free space. For our example, we will use a nice long coax that we are told represents a 50 ohm "Characteristic Impedance". Read more...

Definition and Symbols of Transmission Lines Characteristic Impedance
Every transmission line possesses a certain CHARACTERISTIC IMPEDANCE, usually designatedas Z0. Z0 is the ratio of E to I at every point along the line. If a load equal to the characteristic impedanceis placed at the output end of any length of line, the same impedance will appear at the input terminals ofthe line. Read more...

Characteristic Impedance Calculation
The best way to think about characteristic impedance it envision an infinitely long transmission line, which means that there will be no reflections from the load. Placing an alternating current voltage Vin(t) will result in a current Iin(t). Read more...

Transmission Lines and Measurement of their Characteristics
The theory of transmission lines is introduced in most amateur radio handbooks and it is not proposed to iterate on all that theory here. For our purposes, it is sufficient to introduce some of the most important constants and characteristics such as the electrical line constants, characteristic impedance, attenuation per unit length and velocity factor with an aim to discuss how these constants and characteristics can be measured. Read more...