Using HFSS for*simulating of FSS dual bandstop filter (0.9 and 1.8 GHz), a Floquet-Port needs to be assigned at an appropriate height over the surface. How much is that height supposed to be? and how can I be so sure of the results if any small change in this height dramatically changes the results??
what should be the Deembed distance?
and what is the value of Solution Frequency in the Driven *Solution Setup?
More than one-quarter wavelength at your lowest frequency is a good rule of thumb. All you need is appropriate distance for near-fields on your surface to decay towards the port.
I have to frequencies : 0.9 GHz and 1.8 Ghz "dual band stop passive FSS filter , the sweep is from 0.5 to 2.2 GHz I put Solution Frequency to 1.8GHz is this is best and close to real measurements.
Mode distance between the floquet port and the surface will allow evanescent modes to decay to a smaller level, increasing the accuracy of the result (which is based only on the fields corresponding to propagating modes).
I have to frequencies : 0.9 GHz and 1.8 Ghz "dual band stop passive FSS filter , the sweep is from 0.5 to 2.2 GHz I put Solution Frequency to 1.8GHz is this is best and close to real measurements.
Usually the highest frequency (2.2 GHz), although it depends on your structure. You want the frequency to be high for accuracy, but not so high that it converges on an undesired mode.