Direct Transmission Method For EBG Structures

[Mustafa_Engineer]

direct transmission method

My Friends,

I uploaded here a very good paper about the direct transmission method used to indentify the surface waves bandgap. The details of the wave guide is given in this paper.

One more think I have changed the hight of the wave guide to be 2*substrate thickness and it gave good results.

Regards

Mustafa

 

[sassyboy]

ebg direct transmission method

Be aware that this paper only focus on the TE waves. This approach has been known and used since 1999 only to quickly estimate where the suppression bandgap is. However, if you are going use the surface as a high-impedance surface, the TM waves bandgap is an essential information.

So, please be aware!

 

[Mustafa_Engineer]

Hi sassyboy ,


Ok ...I will keep this in mind ...

by the way ...as you know the using of Dispersion diagram method to specify the surface waves assumes that the EBG sheet in infinitely in length ...this is good ...but in our real applications we using only few raws of EBG ...and the direct method its better !!

Am I right ?


Regards

Mustafa

 

[sassyboy]

Yes, it gives you a rough idea in the shortest space of time. It is certainly correct if only TE waves are going to propagate along the surface. In truth, there is TM waves to consider. So when you come to write a paper, you should explain why you have neglect TM mode.

In addition, I want you know that (if you haven't already knew) if the mushroom-like structure contains no via, there is only TM waves bandgap where e-field is parallel to the surface.

 

[shahid78]

hi sassyboy

i agree with you that this direct transmission method gives you the bandgap for the TE waves.

but i dont know the concept behind TE and TM waves. i mean in which case we will have TE waves and in which case we have will have TM waves and lastly under which condition we will have both TM and TE waves?

also which simulation model we can use to find the bandgap for TM waves as well other then dispersion diagram?

your comments on these questions would be greatly appreciated

kind regards

 

[cuongtran]

hi sassyboy, do u have any ideas about the fig8 of measuring results in the article above, ?
thankss.

 

[shahid78]

Hi

well i have observed that when i change the height of the waveguide for the same strucuture i get different results for trasmission bandgap position.

so my question is how much height we should take for accurate results?

also i dont understand how E field is parallel to the surface for TM wave case?

this TM and TE wave terminology is confusing?

any one have knowledge about this please elaborate for other people

regards

 

[pinguincomel]

I use method of suspended microstrip line.. and it depend to the application you will work to..

 

[cuongtran]

Yes, in TM case not the E parallel to the surface but the H vector.

 

[shahid78]

hi all

when i am just wondering when we have PEC symmtery planes at the top and bottom and PMC symmtery planes at sides of the structure . isnt it TEM mode ? rather than TM mode

anyone wants to comment on that

thanks

 

[pwst]

thank you for your paper.