Use of transmission line at high frequency

[circuitking]

Why should transmission lines be used at high frequencies, instead of inductors?

 

[barry]

What? They are two totally different things. That's like asking 'why should we put air in our tires instead of eggs?'

 

[t4_v]

I think he meant something like microwave transmission line vs conductor.

 

[ZoOneR]

Hi,
All circuit elements that are much smaller in length than the wavelength of a signal are called lumped elements, because its voltages and currents don't vary in magnitude and phase over its length. The inductor, capacitor and resitor are all lumped elements.

If the wavelenght of the signal is much smaller than the physical lenght, we have a transmission line (because current and voltage vary across the length).

For example: One can model a 10 cm pice of steel as a resistor, if he uses it at low frequencies, let's say 10 Hz, but must model the pice of steel as a transmission line if the operating frequency is 3Ghz.