what is full wave analysis?

full wave analysis

I find that it is used by many RF circuits design, but i don't know its real meaning.
I also want to know how to complete it?
can you help me?

full-wave analysis

Hi,

A simple explanation that facilitates the understanding is: full wave analysis is to solve the complete set of Maxwells equations without any simplifying assumptions. Usually the fields described by the equations are time-variant/frequency-dependent. Compared to full wave analysis are some methods such as Quasi-static analysis, where the Maxwell's equations are simplified first(the fields are assumed time-invariant/frequency-independent).

Full-wave analysis is often used to analyze electrically-large structures(physical size is much much larger compared to wavelength), in other words, doing high frequency analysis. Some famous full-wave solvers are: Ansoft HFSS, CST Microwave Studio

Quasi-static analysis is suitable for electrically small structures(usually phsical size is assumed to be less than 1/10 wavelength or 1/6 wavelength or... depends on applications as can be seen from a lot of text books). One of the most famous solver is: Ansoft SpiceLink which is also known as Q2D/Q3D

Hope this helps.

Best regards,

full wave analysis meaning

Jackwang said:

I find that it is used by many RF circuits design, but i don't know its real meaning.
I also want to know how to complete it?
can you help me?

Click to expand...

Simple explanation:

Full wave: considering all field components: Ex,Ey,Ez,Hx,Hy,Hz

Quasi static (as example of non full wave one): only one component is considered to be dominant. Imagine you have microstrip line in XY plane --> then Ez component is dominant in substrate region. You omit Ex and Ey and speed up the calculation

Greetz

eirp

what is full wave

HI,
your explaination is very much useful to me.
but, i have a new question, if i want to design a filter with hairpin structure,
I want to know how to simulate coupling coefficient between the two hairpin,
whether to use full wave EM simulation or Quasi-static analysis. Hope to get your help!

best regards.

rolf jansen full-wave

Regarding your coupling problem:

If the dimensions of the pins and distance between them are much smaller than one wavelength, quasi-static can do the job.

See Ya.

full-wave simulation versus quasistatic solver

I think Prof. Dr. Rolf Jansen introduced the term full wave back in the 1970's. I prefer to use the term "complete EM analysis", because it is confusing to try to think of what a "partial wave" analysis might be. But "full wave" does sound really cool.

Full-wave is best defined by contrast to static and quasi-static methods.

Static means simplifying Maxwell's equations such that there is no coupling at all between E and B fields:

ε div(E)= ρ
curl(B)=µ J

With quasi-static, one form of coupling between B and E is considered: the E field generates conventional current in conductive materials (Ohms Law) and then this conventional current adds to the external J stimulus and generates B in the normal (Biot-Savart) way.

curl(B)=µ(Jexternal+σE)

In both static and quasi-static, the time derivative terms in Maxwell's equations are set to zero. In other words, the displacement current term that Maxwell added to Ampere's Law is set back to zero and Faraday's Law becomes:

curl(E) = -dB/dt = 0

In contrast, full wave solvers consider all the time derivative coupling terms in Maxwell's equations to be finite.

At high frequencies where Faraday's Law and the displacement current are significant, one must invest in the computational expense of a full-wave solver to get accurate results.

Best regards,

-- Colin Warwick
**broken link removed**

Re: full-wave analysis

smithchart said:

Full-wave analysis is often used to analyze electrically-large structures(physical size is much much larger compared to wavelength), in other words, doing high frequency analysis. Some famous full-wave solvers are: Ansoft HFSS, CST Microwave Studio

Click to expand...

You're right in the sense that full-wave methods are used to analyze structure whose size in comparable with the wavelength. However, if the size is much much larger than the wavelength (above 50x50 wavelengths), then the computational cost of full-wave methods is too high and non-full-wave methods are used like Geometrical Optics (GO), General Theory of Diffraction (GTD).

Therefore, I would rather say:

Size below 0.01λ: Quasi-static or static methods.
Size between 0.01λ and 50λ: Full-wave methods.
Size above 50λ: Approximate optics-like methods (GO, GTD, UTD...)

Hi all
The topic and replies was excellent.thank you

Colin Warwick said:

In both static and quasi-static, the time derivative terms in Maxwell's equations are set to zero.

Click to expand...

Oops! I meant to say "in static the time derivative terms in Maxwell's equations are set to zero. In quasi-static, the wave propagation terms are instantatious (a good approximation if the bounding box is smaller than the wavelength of the highest frequency of interest). In full-wave, the wave propagation is at the speed of light in the media." Apologies for the error.