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Post subject: Ansoft Design Users Unite: Q on Modeling a Magnetic Dipole
Posted: Fri Aug 05, 2005 10:41 pm
Joined: Fri Aug 05, 2005 8:25 pm
I have just begun interfacing with Ansoft's Designer (SV). I am trying to model a
magnetic dipole in free space, operating at 10GHz and extract the radiation resistance.
is well known theory:
where: a=the radius of the loop
omega = 2*pi*f
c=the speed of light
Here is what I have thus far:
Two layers of air dielectric both of thickness = lambda/2 =15mm
A lossless conductor for my
signal layer. The signal layer is sandwiched between the two dielectrics.
extent" (Layout>>Settings) such that each edge (Left, right, top, bottom) are 2*lambda from the
center where the dipole is located. I have done this too provide adequate space for the far-field
approximation to be accurate, but I would like to know if this is necessary. Any thoughts?
I have constructed a square loop (at this level of approximation (a<<lambda) it
shouldn’t matter if the geometry is square or circular) by making a square cell 60x60 microns^2. I
copied and pasted this cell four times then assembled to form a square horseshoe. I closed the
loop with two rectangles 60x90microns^2. This leaves a void of 60x60 microns^2 in the middle.
I would like to have one port located between the two rectangles (centrally located rather
than on a corner) to provide a voltage potential and setup circulating currents. Is there a better
design choice? Any suggestions?
Results (so far):
I tried the single edge port (which
then defaulted to a gap source) and Ansoft gave me the following error:
“Edge port is not
represented in the mesh: port 1”
Then I tried separating the loop just slightly and
defined two ports one on each edge (now facing each other) so the geometry looks like square “C”.
No errors. However, the currents are virtually non-existent.
I would appreciate any
Meshing: Fixed (with or with out edge mesh) vs. Adaptive