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Thank you for your answers! At least now I get correctly the cutoff frequencies for a rectangular waveguide (using Driven Modal, not Eigenmode). If it wont work correctly for more complex geometries, we'll wait till we get 18.1.
Thanks!
D.
Thank you for your answer!
But how should I set the 'solution type" in this case? Because Modal/Terminal solution types do not allow to specify number of modes to compute and anyway I should add the excitation source... I use the rectangular waveguide just for testing purposes (if HFSS would...
Hello,
can the HFSS eigenmode solver be used for structures which are not completely surrounded by metallic walls? (for instance a parallel plate waveguide, without side walls). If so, what type of boundary should I choose? I tried for rectangular waveguide and the resonance found are those of a...
I know the transmitting power (is 0 dBm), and I have s21 (in dB) - this is my antenna gain. If I integrate it (I did the average over all phi*theta angles) I obtain an avarage gain. This would mean that the efficiency if equal to the average gain of the antenna which I don't know if it is correct...
I have the following problem: the radiation pattern of an antenna is measured in an anechoic chamber at a certain frequency and the gain is read by a VNA (path loss, cable loss ant receiving antenna gain are removed in the post-processing software). If I have the gain at different (theta,phi)...
It is known that the energy of a photon is proportional to the frequency. I don't understand what's the relation , if any, between this energy and the energy (power actually) one uses to feed an antenna. If the antenna is made to resonate at higher frequencies less power should be applied then...
Hello again!
I have computed the S-parameters of a TEM cell and determined the absorbed power as P_abs=P_incident(1-|s11|^2-|s21|^2)
The absorbed power determined as such is actually the active power (not the reactive, nor the apparent), isn't it?
Then I loaded the cell with some lossy probes...
Ok, I understand now what you're saying. I don't know how to set the accuracy for VNA, I have to look for it.
As regards the power I think about introducing something in that dish, a liquid or smtg with known parameters which would absorb some greater power than the dish itself.
I see. So I cannot trust the power I get from computed S-parameters... As regards the VNA, the calibration was performed for 12dBm input power, 1.5 kHz IF BW and 20000 samples between .1 and 1.2 GHZ. It seemed resonable to me.
Re: s21>0 for passive device!!
so, the stimulated input power (in CST Studio) is 1W. At a certain frequency (200 MHz), |s11|=0.03091351 and |s21|=0.9978061 (of course, these are not in dB)
It results that P_absorbed[W]= P_input[W] x (1-(|S11|^2 + |S21|^2)) which is P_absorbed= 1W x...
Re: s21>0 for passive device!!
Yes, it is a complex number, but what I use is the magnitude (dimensionless). It is the linear magnitude actually, not the one expressed in dB. The problem was that I have a passive device and s21 was greater than 0 dB! This is fixed now. What I don't...
Re: s21>0 for passive device!!
the power loss in the dish obtained from measured S-paremeters is 25.9mW while for computed S, I get a power of 11.27mW. What's more confusing is that CST says is that the absorbed power is 0.26mW! This is what I get out from SAR info and what I get from "Loss...
Re: s21>0 dB for passive device!!
Thank you very much for your answer! I increased the required accuracy (at the price of increasing the simulation time; it takes though a bit too long, almost 2 hours...) Anyway, I still don't get what I was supposed to for the absorbed power. I used a VNA to...
For an empty TEM cell I get s21<0 (in CST Studio) but, when loading it (I put a glass inside) s21 is sometimes slightly greater than zero!! Why is it so as long as there no active device there? I thought that it might be some oscillations due to improper spatial resolution (meshing?) and...
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