HFSS: Exact size of the lumped port

hfss sheet lumped port

hi,

Is the size of the lumped port matters on S-parameters/Response in HFSS?


if it is so Can any body pl. tell me know how to calculate the exact size of the lumped port?


i have gone through below topics, they tell how to set the lumped port and contains different port tutorials






Thank you in advance...

As far as I know the lumped port attempts to simulate an excitation probe on your circuit.
I have used a lumped port on cpw structure to simulate my sample.

I have used for the port a width equal to the width of the cpw signal trace.
I left the same gaps of the cpw line and I connected the opposite side to some extended grounds.

I also simulate the same structure with a waveport instead of a lumped port.

After fabricating my sample and tested on a probe station, I realized that the results coming from the simulation with a lumped port was more close to the real measurements than the simulations with waveport.

Moreover, changing the lumped port size in the simulation was actually giving a slightly different results.

By the way, The result that was close to the real measurements was the one I just suggested above.

So, just add to the input of the cpw signal trace a square whose side is equal to the cpw trace width and thatn after close behind this square the two grounds.

Don't forget the integration line which goes from the ground to the trace.

A bit of a brain dump but hope it helps.

hi,
Thank you sir,

first of all, I am new to HFSS as well as microwave engg....

i am using lumped port for Stripline cavity coupler ( Air as the dielectric media)

This coupler has got stripline Conductor of about 3mm thickness and width depending on Impedence..... starting with 50ohm line of 3.62mm width.

i have created a rectangle sheet of width equal to this stripline conductor (3.62mm) and length of 3mm. Then assigned the Lumped port to this rectangle sheet.
Head of the arrow is towards 3mm thickness stripline conductor and Tail of the port is attached to Ground. (Ground--Stripline conductor is covered with a Vaccum Box, All the sides of this box are assigned with PERFECT-E Boundary)

Is this method correct?
am i explaining the problem correctly?

Stripline cavity coupler - a pair of stripline conductors(having T thickness) of width "W"kept side by side with a separation "S" between them. This pair is covered with Ground Plates. Separation between the ground plates is B (usually it is 6mm or 7mm)


thank you in advance.....

@oby: I am currently designing some CPW line and I have noticed just like you that height Lumped Port matters in S parameters results. Thus, did you conclude anything about the optimal height/width of your Lumped Port during your study?


Cheers.

Post your project and I can take a look at it

Ok, here is the project I am currently working on: this is a submount with a 15 Ohms CPW line on it and the Lumped port I have to deal with is at the end of the CPW.