Microstrip large to have 50 ohm

[ssayan79]

Hi to all
my professor told us that if we have a microstrip and we set the line large to obtain the characteristic impedance of 50 ohm, we have that the trasmission of the signal is indipendent from how much is long the line. Is this true? And if it is true, why?

Thank you!!

 

[ahmed osama]

Hi to all
my professor told us that if we have a microstrip and we set the line large to obtain the characteristic impedance of 50 ohm, we have that the trasmission of the signal is indipendent from how much is long the line. Is this true? And if it is true, why?

Thank you!!

kindly can you explain more and in ENGLISH :?: :!:

thx

 

[spikeyang]

He asks if the impedance of microstip line dont change with the length.
Of course it's not.

Dont mess it with serial resistors. It's different. The impedance means the ratio between Voltage and current on the line.

 

[ldanielrosa]

What he means is that if the transmission line has a characteristic impedance that matches the source, then the length of the line doesn't matter- the load will always see the same impedance source. There will still be attenuation that is proportional to length. It requires that a load be connected at the end of the line.

 

[vacikel]

characteristic impedance of a transmission line is the ratio of voltage wave to current wave propagating in the same direction. And if there is no reflection at the end of the transmission line ( a matched load or a infinite TL) your signal will always see the characteristic impedance of the TL. and when you consider the microstirps magnitudes of current waves and voltage waves effected by the substrate that you use to build TL and the wideness of the TL. So as the magnitudes of current and voltage waves change Z0 of TL also change. But the length of the TL is only effect the attenuation of your signal.