ebg structure in simulation

[mehdi22]

hi edaboard's members

EBG structures, surely you know them

how to design this structure in hfss ? (i am begginer in hfss)

when i want to stop band frequency [f1-f2] , how to choice ebg structure ? how get the diemensions of the structure ?

in ads mom , there is possible to design ebg structure?

thank u very much for this forum

i wait ur help , thank u

 

[mehdi22]

1- I found formulas for mushroom like ebg , if it is considered as a filter LC

band width of ebg bw = 1/n (sqrt (L/c) n:impedance free space
and L has its forumule also C (capacity)

can be based on its formulas very simple for design ebg mushroom?

2-for array patch application , ebg is used to delete surface wave , but in certain publication , he said "...band gap is higher than the resonant frequency fr. Therefore, the mutual coupling is not reduced..."

to impose the bandgap of ebg , normally we should be based on the frequency of surface waves , and not on the resonance frequency of the patch antenna ,...???

 

[mehdi22]

forumlas are :





but
if i want to stop frequency range [f1-f2].
i can calculate L (inductor)
i have BW (band gap frrequency that i want to stop ), the capacity C(capacitor) is pulled

finally , i cant calculate gap (g) and width(W) because there are the 2 unidentified variable

please how do i for calculate a desirable design mushroom like?
thank u

 

[polarizadmax]

hope this paper (radiation characteristic of microstrip patch over an ebg) will help you to understand a lot..

https://docs.google.com/viewer?a=v&...kdfaHo&sig=AHIEtbRnl57YY2WI64Mq1cdCyWl80d4kag
paper

 

[mehdi22]

thak you...
in formula of capacitance (C)

what is \[{ \cosh }^{ -1}\]

is there

argcosh : reciprocal function

or

only

\[{ \cosh }^{ -1}\]=\[\frac{ 1}{\cosh }\] (inverse !)

thank u for ur pdf polariza

 

[polarizadmax]

yes its inverse to cosh
why dont u use a scientific calculator it already have this inbuilt function
its bit easier to u to calculate

 

[mehdi22]

yes thank u polar , i use matlab for calculate...
but tell me
how you knew that it was (1/cosh) and not (argcosh)?
thnak u very much

 

[polarizadmax]

hey are u working over sm project relates to EBG STRUCTURE
which s/w are u using to design periodic geometry?
(If possible share sm details)

 

[mehdi22]

ok than u polar

I give you a simple matlab program

you give (gap) it calculates (width) EBG

but i obtain undesirable results!

trying to see may be something you can do

 

[mehdi22]

I followed these logical steps :

1-modelisation of EBG (mushroom )with LC filter give frequency
\[{f }_{ r}\]=\[\frac{1}{2.\pi }\].\[\frac{ 1}{\sqrt{L.C } }\]

\[{f }_{ r}\] of mushroom like will be the same that operate patch antenna!.

2-we can calculate L(inductor) , and so we can have C(capacitor) with the formulas of resonance frequency

3-if we have C(capacitor) ,and we can have width from formulas of capacity (if we give the gap g)!

4-height (h) is the same with this of patch antenna if ebg is in the same layer with patch antenna.

you can program this !

so,what you have behind you ?

 

[polarizadmax]

using these formulae how u can depict band gap frequencies.........
If i m not wrong it requires to plot Dispersion diagram for that....
I m not getting clear idea what r u trying to calculate and why for?
8-O

 

[mehdi22]

these formulas are for an initial design ...
if not, tell me how to have an initial design of the EBG structrues.?

About a diagramme of dispersion , i dont know how to have this diagram with (this modelisation)
but there is a direct method
extracting a s-parameter between 2 ports placed across the ebg structure.

if you know(or you can ) how to obtain the dispersion , please tell me

 

[polarizadmax]

i m not that much good at it.............But u can use existing discussion over this topic in the forum.............................
i m still trying to understand dispersion plots ...................hope
u will get it far

 

[mehdi22]

please , tell me
,how do you do, to calculate the dimensions of the EBG structure (for example , width ).
to start the design of the structure , on which you are relying on what?

you make me afraid with your doubts!!!

 

[khaled.ayman]

Can anyone help with this post?

https://www.edaboard.com/threads/259642/#post1113760