Problem with using lumped port in HFSS simulation

[ldynasa]

Hi, I'm trying to feed a 360 deg open ended microstrip simply to play around with HFSS.

I got line length calculated in ADS's line calculator, got substrate set, then simulated the same setting in HFSS.

But the S11 shows a angle of -30 deg. So I guess there might be something wrong with the basic settings, possibly incorrect usage of lumped port?

I've uploaded my project file in the attachment



Pretty new to HFSS, thanx 4 ur help.
Regards

 

[bya036]

Hi,

Use two ports, each at each end of the line, and measure the S21 phase instead.

 

[flanello]

The S11 parameter describes the reflection coefficient, e.g. the signal that is reflected to the port. But you would probably have the characteristic of the transmission, thus you have to use two ports and the S21 or S12 parameter (they are the same in this case). They describe the transmission between the two ports.

 

[ldynasa]

Thanx 4 ur reply!

Is it abt the radiation issues related?

I've compared between a 2.5D EM simulator and a 3D EM simulator.
The difference lies there abt 30 deg for an open ended lamda/2 MSL