port characteristic impedance =? port input impedance

[SIQ]

Hi,

I am not clear if port characteristic impedance is just port input impedance? If I use the lumped port, does Z parameter Z11 represent the input impedance? what is difference if I use Zpi, Zpv, Zvi to calculate the z parameter, will they be have the same value?
thx!

 

[loucy]

port characteristic impedance != port input impedance

strictly speaking there is no "port characteristic impedance". It should be called "mode characteristic impedance". A port can support more than 1 propagating modes. But normally there is only one mode, most likely a quasi-tem mode. but this impedance is the "characteristic" of a mode in a transmission line.

port input impedance is the impedance looking into the whole circuit through the port. so it is a character of the circuit. and if you have many other ports, it depends on the loads connected to those ports too.

 

[SIQ]

Hi,

Thanks to correct my concept! While could you answer me for other questions:

in HFSS, If I use the lumped port, does Z parameter Z11 represent the input impedance? what is difference if I use Zpi, Zpv, Zvi to calculate the z parameter, do they have the same value?
thx!

 

[caoshuxun]

Hi,

Thanks to correct my concept! While could you answer me for other questions:

in HFSS, If I use the lumped port, does Z parameter Z11 represent the input impedance? what is difference if I use Zpi, Zpv, Zvi to calculate the z parameter, do they have the same value?
thx!

Z11 should be the input impedance. But however, if u use a lumped port instead of waveport, u may hardly get the characteristic impedance