Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Ground definition in CST

Status
Not open for further replies.

snkhan

Full Member level 6
Joined
Oct 19, 2005
Messages
324
Helped
38
Reputation
74
Reaction score
20
Trophy points
1,298
Location
Gods place
Activity points
3,213
Hello:
usually the gound on lower side of the substrate is of thickness .03-.05mm. But if in the tutorial of CSt "rectangular patcha antena", ground is about 3mm.
It seem that thickness of ground plane has no effect on the result or i am missing somthing.

Another quesiton:
What should be the length of coaxial feed in CST
 

KMPA

Member level 5
Joined
Dec 4, 2003
Messages
89
Helped
16
Reputation
32
Reaction score
13
Trophy points
1,288
Activity points
773
Hi,
The 3 mm thickness for ground plate assumed suporrting (Aluminum) plate for it, and I believe that it is not important, if ground is large.

Regards
KMPA
 

snkhan

Full Member level 6
Joined
Oct 19, 2005
Messages
324
Helped
38
Reputation
74
Reaction score
20
Trophy points
1,298
Location
Gods place
Activity points
3,213
Dear KMPA:
The material used for ground is PEC. The manual of CST says that it need atleast three time steps before it excite the patch.
 

snkhan

Full Member level 6
Joined
Oct 19, 2005
Messages
324
Helped
38
Reputation
74
Reaction score
20
Trophy points
1,298
Location
Gods place
Activity points
3,213
Hi KMPA:
Yes you r quite right, "Thickness of Ground plane do not effect the results much", Althoug it increases the simulation time.
 

Pushhead

Full Member level 4
Joined
Jan 19, 2005
Messages
199
Helped
20
Reputation
40
Reaction score
10
Trophy points
1,298
Activity points
1,870
Theoretically, you are wrong.
The thickness should be « λ, otherwise surface currents on the thick face will radiate and deform the radiation pattern.

I guess in this case the thickness is « λ, and that is why you see no difference in the results.

P.
 

loucy

Advanced Member level 1
Joined
Aug 26, 2001
Messages
414
Helped
24
Reputation
48
Reaction score
11
Trophy points
1,298
Activity points
4,657
for perfect electric conductor, the current would flow/concentrate on the surface.
 

snkhan

Full Member level 6
Joined
Oct 19, 2005
Messages
324
Helped
38
Reputation
74
Reaction score
20
Trophy points
1,298
Location
Gods place
Activity points
3,213
Hi Lousy:
Can u explain it bit more

for perfect electric conductor, the current would flow/concentrate on the surface.



Thanks
 

ryfnjust

Member level 1
Joined
Apr 11, 2006
Messages
40
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,288
Activity points
1,550
It should be at least three time steps and <<lamda.
 

doug freeman

Member level 2
Joined
Mar 27, 2006
Messages
42
Helped
6
Reputation
12
Reaction score
0
Trophy points
1,286
Location
Bristol, UK
Activity points
1,707
the reason for the thickness is to make the solve time quicker for the tutorial.

As mentioned before, CST needs at least 3 homogenous cells in the direction of the propogation of a port, therefore for a coax feed it needs to be long. If you constructed a full connector with a thin wall etc then you would have small cells --> small time step. This is why a 3mm groundplane is used in this example.

Hope this helps.
 

3dandyw

Member level 1
Joined
Jan 18, 2007
Messages
35
Helped
1
Reputation
2
Reaction score
0
Trophy points
1,286
Activity points
1,477
Hi

here is latest on ground plane with MICROSTRIPES, 3D EM Solution version 7.5

In version 7.5, ground planes can also be used for models without meshing all of the space between the system and ground plane. A specific algorithm accounts for the effects of the ground plane outside of the simulation domain, substantially reducing solution time.

hope this helps
AW
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top