Difference between Fast sweep and interpolating sweep in HFSS

Hello
i want to know the difference between the fast sweep and the interpolating sweep in HFSS.
when i simulated my design with interpolating sweep it gave me vswr from 2 GHZ to 12 GHz but when i simulated the same design it gave me vswr from 2GHz to 8 GHz, why is it so?
And do we need to do simulation with Fast sweep for getting the Gain v/s frequency graph?
Regards
vishal

Discrete Sweep

The discrete sweep is the most accurate since it resolves the problem at each frequency point in your frequency bandwidth. However, it is the slowest and the adaptive frequency should be set at the higher limit of your bandwidth or at the frequency where the wavelength is smallest.

Fast Sweep

The fast sweep requires less simulation time than the discrete sweep but at the expense of a limited frequency bandwidth range and reduced accuracy. The adaptive frequency should be set within the center of your frequency bandwidth and should coincide within the pass-band of your structure. if your adaptive frequency is 10 GHz, your frequency sweep can go from 1 GHz to 20 GHz.

Interpolating Sweep

The interpolating sweep is the fastest, but the least accurate sweep. In addition, the field data cannot be saved for the frequency range and therefore has limited post processing attributes.

So the problem with your VSWR curve is that your frequency of operation, when you use the center frequency of your curve as the frequency of operation for Fast sweep then you will see a wider frequency response.

yes you would have to do Fastsweep for the gain vs frequency plot

Regards
Elchiquito

and how to select the right value of theta and phi to get the graph between gain v/s frequency?

Sorry bit of a confusion, When we talk about gain vs frequency we are talking about the position of main beam, where the gain value is max.

So the plot is independent of the theta and phi value, in a sense, if you know what i mean.

Regards
Elchiquito

can we get the graph of particular frequencies.?
suppose i m getting 3 frequencies 3, 4, 5 so can i get the gain on these frequencies?
as like as IE3D we can easily get the gain on any frequency we want?

when you do a sweep of frequency vs gain, whatever frequency points you have included in the sweep will be the X-axis of your plot.

When you create a far field plot you go to the sweeps tab then to the frequency and there you can select the frequency for the plot

If you want to check your sweeps you can use a discrete sweep with very few points eg. at 2GHz, 8GHz and 12 GHz and plot the results into the other sweeps. If the point doesn't match your fast or interpolating sweep range is probably to big.
If you wanta wide sweep range with good results, you could combine the results of different solution frequencies with small fast sweeps:
solution at 2 GHz and sweep from 0 to 4 GHz
solution at 8 GHz and sweep from 4 to 2 GHz and so on

if i want to convert the gain 24dB so what will be the value in dBi

Brother

dB here is dBi unless mentioned otherwise.

Regards
Elchiquito

ohk
if i m getting 24.51dB at 3.10 Ghz so what will be the value in dBi.

24.51dB = 24.51dBi