#### avins_1234

##### Member level 3

**2.5D**and

**3D**planar simulators? Are these two same or different?

**Practical MMIC Design by Marsh**gives the definition like this

2.5D planar electromagnetic simulators such as Momentum are primarily the same as 2D simulators except the extra half-dimension means that the solver can calculate currents in the vertical (z) direction (usually for through-substrate vias) as well as the x and y directions.

3D planar electromagnetic simulators are similar, but they are also able to calculate the effects of conductor thickness and resistivity. Examples of these include Sonnet Lite and EM3DS.

One more definition is given in this way

Refer Link -

***broken link removed***

One more definition is

2.5D implies that RF currents are allowed in two directions only (X and Y), and fields are calculated in all three dimensions (X Y and Z). No vertical currents are allowed. Examples would include micro strip or strip line filters which do not contain vias to ground. Note: This term has also been used to refer to 3D planar solvers such as Sonnet (Sonnet Software product) and Momentum (Agilent product) even though they all allow vertical currents.

3D Planar implies that currents and fields are allowed in all 3 directions, but circuits are restricted to stratified dielectric media. Examples would include most MMIC, RFIC, and PCB circuits. Examples include Sonnet (Sonnet Software product) and Momentum (Agilent product).

Because, I am also able to see 3D view in either of them (currently using EMSight and Axiem Simulators). What is the difference?

2) One more question on specifically on EMSight (2.5D) and Axiem (3D Planar)

I know that EMSight is closed and Axiem is open. What does this mean? Is it got to do something with the boundary conditions, Also which is more accurate? Also, FYI - Axiem is non-gridded (use mesh) and EMSight is gridded. Big deal, both of them simulate well and 3d em layout view is available in both of them. kindly clarify.

Regards,

Avs