Microstrip line design in hfss with fr4

HELLO

can any one tell where is mistake:

i want to design a microstrip line in hfss with fr4 substrate.

i used line calc of ADS for calculation of dimensions i.e. length and width?
i applied lumped port of hfss with integration line and 50 ohm impedance.

but still s21 is horrible??

it would be so kind of u if any one send me the hfss document that explains the step by step design




thanks
plz help

Hi,

Always use wave ports for microstrip line. And the integration line for microstrip line must be in between the substrate with Zpv as the characteristic impedance.



I hope this is the S-parameter you need, right? If you can send me your e-mail address, I will send you the .hfss file.

You say your S21 is horrible. In which manner? Is the Insertion Loss way too high? If so, reduce the loss tangent of the substrate. Else, your design might not be proper.

It is very difficult to tell you all the steps in one go. It takes some time and practice to expertise HFSS. You can get HFSS manuals which details on microstrip line implementation.

https://www.google.co.in/url?sa=t&r...OFL7zQ7S8FLCIrszf_X3KNg&bvm=bv.69837884,d.c2E

Hope this helps.

Respected sir,

thanks for your rply

I followed the same steps given in manual..

but i could not get a proper s21.

is it required to take so much modes as given in manual?????

i need to plot figure 4 of attached paper.

actually in this manual there is no procedure to plot s21.



i want my s21 to have return loss negative only arround designed frequencies but it is coming negative over a wider frequency range.


is there any tool in hfss itself to calculate line width and length i m still using ads linecalc.

can fr4 be used in 10-15 ghz range???

plz plz plz help....................

You said,

Naveen Jaglan said:

1. I followed the same steps given in manual..

but i could not get a proper s21.

is it required to take so much modes as given in manual?????

2. I need to plot figure 4 of attached paper.

actually in this manual there is no procedure to plot s21.

I want my S21 to have return loss negative only around

designed frequencies but it is coming negative over a wider

frequency range.


3. Is there any tool in HFSS itself to calculate line width and

length i m still using ads line calc.

4. can fr4 be used in 10-15 GHz range???

plz plz plz help....................

Click to expand...

1. No, 1 mode is sufficient. Many modes increase the accuracy, but it simultaneously increases the simulation time too.

2. Hmmm... first of all ensure your design is proper. I mean the dimensions, excitations, boundary conditions, substrate properties( permittivity of substrate, its height, loss tangent, metal thickness(this should not be too high; 0.036mm or 0.07mm is alright)), wave port dimensions (the excitation, integration line, normalization to specific port impedance) et al..

Next, check the analysis setup. The solution frequency must be the highest of the chosen sweep frequency. The maximum number of passes = 20 and maximum delta-S = 2% or 0.02.

Ensure the step-size in the sweep is 0.01GHz, maximum solutions = 100 and error tolerance = 0.5%.

3. Inside Ansoft Designer you can get a line calculator tool. Also, AWR contains transmission line calculator which can calculate the width and length.

4. See this thread;
https://www.edaboard.com/threads/41342/