[SI-LIST] Re: 2D, 2.5D,3D

From: "Zhou, Xingling (Mick)" <xlzhou@xxxxxxxxx>
To: "'brian.young@xxxxxx'" <brian.young@xxxxxx>
Date: Tue, 3 Dec 2002 09:56:11 -0500
Hi, 

We are confusing ourselves because of the story. Here there are dimensions
about three quantities: Geometry, field and current (circuit concept).   In
some cases, we mixed them to have a name 2.5D.  Obviously, 2.5D becomes an
alias of planar structures in our society. If it is just a name, it's fine.
The problem is that we are trying to find reasons for this confusing word
although we do employ some special characteristics when we solve those
structures.. 

In classical electromagnetic theory, except for static cases, the field
distribution is always 3D even for 2D structures such as waveguides. The
phase term tells us the fact.  The current could even be 1D for ideal
transmission lines. The frequency domain telegrapher equations indicate the
conclusion. Only z is included.  However, in the time domain, it becomes 2D
if we use an abstract concept by counting the variables. Time is another
dimension. In relativity, we discuss 4D form of Maxwell' equations etc. We
can imagine some other special cases. Anyway, we can not have 2.5D in the
sense of classical dimension (either space or variable). The only
possibility is in the fractional theory. However, it is too far in our case.
I remember we do introduce fractional dimensions in the so-called
"fractional electromagnetics/electrodynamics". I believe we have experts of
the topic on this forum. 

Shortly 2.5D is another name of planar structures to me.

Regards,

Mick

 

-----Original Message-----
From: Brian Young [mailto:brian.young@xxxxxx]
Sent: Monday, December 02, 2002 4:01 PM
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: 2D, 2.5D,3D



My $0.02 worth on the definition of 2.5D:

A 2.5D electromagnetic simulator is a general-purpose full-wave
3D electromagnetic simulator that is optimized and restricted to
layered planar structures.  If your problem looks like a PCB, then
you can use a 2.5D simulator and get the full result.  If your problem
does not look like a PCB and is not a transmission line or
waveguide, then you have to use an unrestricted 3D EM simulator.

The 2.5D simulators use the method of moments with Greens
functions explicitly coded for layered planar dielectrics.  Since
Greens functions are solutions to Maxwell's equations, the problem
is partially solved before you even start.  That is how the 2.5D
solvers can solve such huge problems.

Regards,
Brian

--
****************************************************
* Brian Young                    Texas Instruments *
* 512-347-1819 (work)         Austin Design Center *
* 512-468-5410 (cell)           brian.young@xxxxxx *
****************************************************



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[SI-LIST] Re: 2D, 2.5D,3D

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