difference between Open and open addspace boundary

[ravi8331]

Hii
Anyopne tell me what is the basic difference between Open and Open add space boundary conditions in CST Microwave Studio???

When i use open boundary condition then i m getting different result in comaprison to Open add space boundary condition.

i don't understand why such things happen n what is the basic problem within that??

plz reply..............

 

[ravi8331]

plz respond.............. i m waiting for ur reply..............................

 

[abdoeng]

I think that open space means if you for example try to simulate infinite ground so you use open space at ground edges
but if you use add space ,that will be good as perfect matched layers when you simulate finite structure with calculating the radiation pattern
more space more accurate farfield
i hope you understand

 

[eri]

Open boundaries:
operates like free space – waves can pass this
boundary with minimal reflections. Perfectly matched layer (PML)

Open add space boundaries:
same as Open, but adds some extra space
for farfield calculation (automatically adapted to center frequency of
desired bandwidth). This option is recommended for antenna problems.