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Home Transmission Lines Characteristic Impedance of Radio-Frequency Transmission Lines
 
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Characteristic Impedance of Radio-Frequency Transmission Lines

The characteristic impedance of any line at any frequency is given by equation 50. At radio frequencies ωL and ωC become so much greater than R and G that they may be neglected, and accordingly

where L is the series inductance of the line in henrys, C is the shunt capacitance; Z0 will be the characteristic impedance in ohms and will be pure resistance. The values of L and C may be for any (but the same) length of line. If equations 73 and 74 are substituted in equation 79, the characteristic impedance of a radio-frequency line becomes

where Z0 is ohms resistance.

A helpful set of radio-frequency transmission-line nomographs, prepared by P. H. Smith, has been published in the February, 1949, issue of Electronics, Vol. 22, No. 2.


Home Transmission Lines Characteristic Impedance of Radio-Frequency Transmission Lines

Last Update: 2011-05-18