cst simulation

hello everyone....
can someone tell me why i can't simulate the design for meander line
the error state that the waveguide port too short and waveguide must homogenous
at least 3mesh planes along propagation
i already change the mesh but still have problem
so actually how we can define the port for each type antenna in my case
the meander line use dual sleeve at the ground plane
anyone know how to solve it?

hi
i think if you increase the thickness of the ground plane of your antenna , it will solve your problem
regards

tq for reply
actually the ground plane is a copper material with thickness 0.5mm
the thickness must increase must follow the available thickness copper in the market
so do u know the maximum thickness copper available in the market?[/img]

here i attach my design look likes

well thickness of the ground plane has no significant effect on the operation of your circuit.
but as it is recommended for successful simulation in cst to have at least 3 homogenous mesh lines in the longitudinal direction of the port so you should increase the thickness.
regarding the thickness of copper available in the market.
i think it varies from 8μm to 70μm
regard

hi shahid...
i will try to find the maximum thickness copper that can provide in malaysia
then i will try simulate again my design
and before that i try to increase the thickness for ground plane but it is not affect
still the same so i will try tomorrow within range that u give
regard

The thickness will surely affect the results if its low frequency device.

hi all...
thanks for the information and its really done
and before that see that the boundary must be open add space in all direction and that's why i can't simulate also
in addition , the line per wavelength should be at least 10-15, otherwise the energy decays rapidly.
but i have a new problem because the design must put SMA connector as a feed point
so do you have any suggestion how to put the feed point?

open add space are required if u want radiation pattern at some frequency but it takes much time. If the meander line is on the top then its better to use waveguide port

Hi all.....
after a few simulation the result the i get is to worse.
the gain i get to small.
how to increase the gain beside that i already do the parameter sweep
and the result still no change
hope you all can help me....
regards
kyg

Normally, i use coaxial cable to feed. At the end of the coaxial cable is feeded by waveguide port. It may give the results more accurately.
For the substrate material, i generally use 0.035mm for copper.
I'm think it depends your antenna design. I suspect that the meander line will affect the gain.
Hope this help.
BR,

hi,
I think that increasing the thickness of the ground plane will not solve the problem of the inhomogenous mesh at waveguide port. The problem is that the geometry must stay constant in the first 3 mesh cells of the port in the direction perpendicular to the port face. If the first meander section, perpendicular to the port, is within the 3 mesh lines then this problem will arise.
You can actually solve this by either brute force : increase the lines/wavelength to say 15 or 20, or increase the length of the feed microstrip by a certain length and then deembeding this in the port definition dialog i.e. you deembed "out" the extra phase introduced. Normally, selecting the right project template can avoid this problem but perhaps not always. Basically you need 3 mesh cells in the feed microstrip in the z-direction.
Adaptive meshing should help to improve the result.
hope this is useful to you.....
aw

hi all,
for this week i see a new progress with my design
to all know my design freq range about 400MHz to 470MHz
the S11 now i get range 0.5 to -4 dB
the meander line i redesign using line curve and design one by one line
b4 this i put the coordinate and load to generate the meander line
maybe i can try to decrease number of turn to archive under -10dB for S11 or anyone can give any suggestion to me.....
thanks a lot to give me information and hope u all can give more idea...
regards,
kyg

hi all,
now i get the freq 472.59MHz for my antenna but the problem i get now the bandwidth i get too small only 5.56MHz and S11 is -32.78dB with number of turns N=2. i should get about 20MHz because UHF band that i use for hand held radio application........
so anyone know how to get the wider bandwidth.....?
i already do alot parameter sweep but i can't find the way to get more wider bw.
hope u all can give idea to me....
tq
regards,
kyg