Hi, there..
I am trying to simulate dual band antenna from a paper, I get around 90% similar S11, little shift on resonances and also different S11 levels, antenna is working in 2.44 GHz and 5.6 GHz bands, for both bands I get good match radiation pattern and radiation efficiency... the problem is related to the current distribution.. at 2.44 Ghz I get perfect current distribution on the corresponding arm.. and also some current on the laminate surface.. but when I look at 5.6 band, current distribution is totally different on the resonant arm (compare to the paper)regarding the maximum value of the surface current and also there s more current density on the laminate surface and one more thing the S11 bottom at this band is more smother compare to what in the paper is sharp resonance .. can any one explain to me what is different in my situation..!!! I am using HFSS, exciting the model with lumped port .. refer to the attached photos foe currents, S11 and also the simulation setting in HFSS...I am using bigger enough radiation boundaries.... is it the lumped port causing this..!!!!!
The currents look very similar to me at both frequencies. Try changing the scale for the contour plots. Theirs might be saturated in the red which will put red on both sides of a line where yours has red only on one side.
The current on the ground will be very similar to the current on the track - they have to be opposite and equal. The current density may not be the same, as the currents in the ground will be a bit more spread out, but it may be that you are not plotting the results that you mean to.
Maryam Jaldi thanks for your suggestion, yes the port size is different, but the paper didn't say the port size, so I tried to choose the best width, and the distance from the structure is fixed in both cases ...
Most of the paper doesn't mention to the port size the best way is to use textbook or help of the software
It is always difficult to estimate the current density directly on the antenna. Therefore the kind of current density we find in the simulated software is based on the Equivalence Principle (An approximation technique). The calculated current density from the Equivalence principle for displacement vector solves Helmholtz's equation based on the boundary condition. When there is a difference in any parameter, the software may show a different result. Please compare your simulated result with the fabricated prototype result.
try to match the feed length impedance or change the length of feed.
- Badges
- Science topic