KOCH CURVE Vs AWR (Simulation)

[Sara88]

Hi everybody,

I'm trying to simulate 850-900MHz Koch curve dipole antenna by using AWR microwave but i'm quite new with this and not familiar with its settings.

I tried to follow some of the examples and tutorials in the internet and "getting started" from the Help option but i have a lot of questions.

1) How do i know what is the suitable simulator for my design, for example there's AWR AXIEM & AWR EMSight Simulator.

2) Which kind of ports should i use "Edge port" or "internal port"? and i connect one port or two. and where should i place them?
- I simulated with two internal ports attached to the two shapes at the gape- But i can't get the expected results within the range freq -

3) if i'm using EMSigt simulator it shows me a dimension of the enclosure "X=70 mm, Y=20mm" and asking for sidewalls ports to complete the simulation which i don't understand why? while in AXIEM simulator, it sets the suitable dimensions for my antenna. ( 62mm length and 10mm height and with 4.2 Er.) By these dimensions, how can i tune my shape to to match my requirements of 850-900MHz freq and -6 dB of return loss.??? What is the main element that should I focus to help me to get the expected results?

4) I already draw the shape of the koch curve of the third iteration by using path line, how ever i have reviewed some articals that can use circuit schematics to draw the curve by using MLIN & MBEND elements but i'm not familiar with that two, but i tried to build the circuit but the output layout does not match and its quiet messy, but i tried to use "snap together" option but still didn't work or i didn't know how??

5) Should i use Agilent ADS software to simulate or AWR is enough?

6) at first i tried using CST studio simulation for a long a time and wasted my time with it and end up giving up, because drawing fractals specially koch curve is not easy comparing to AWR which is much simpler. My question is, after i draw my third iteration of koch curve dipole antenna, i tried to import my design from the AWR to CST, but is says i can't edit or change and when i tried to simulate its stuck"

7) IS THERE ANYWAY THAT COULD MAKE MY LIFE EASIER????

Thanx.. I NEED YOUR HELP RESPECTED PEOPLE.. My deadline is in 29th of July" so i have should fabricated my design already, but its my first time to do antenna and using these software"

:grin:

 

[Manjunatha_hv]

Hello,

Answers

1. use AWR AXIEM

2. use "Edge Ports"

3. for Resonance frequency change the length & for return loss change the width of the trace along with the koch shape

4. it depend upon the shape you are trying usually using MLINs / MBENDs it should be possible to draw such shapes...

5. If you have access to AWR use AWR XIEM and even in Agilent ADS also same procedure you need to follow

6. hmmnnn ...thats interesting why can't you use the AWR EM & CST MWS- EMSocket co-simulation interface?
if not export it as DXF or GDSII then import in CST MWS

---manju---

 

[Sara88]

For my dipole antenna, i used one EDGE PORT with AWR AXIEM simulator, which is while its simulating shows "port 1 de-embedded" (Great, it worked)..

I have the output simulations with S11, VSWR .. i read my graphs and found that S-Parameters is within the range of 875.13 - 887.16 MHz. And the VSWR, is within the range of 875.1 - 887 MHz. But at the side of each graph, there is some points which i don't understand for S11 (0.9961104 for 875.13 and 0.9961208 for 887.13MHz) & VSWR (54.186 for 875.1 & 54.224 for 887MHz). My question is,

- what are these points? is it input return loss or for something else?

- I read that i can get the radiation patterns graphs from E-field visualization (add annotation, to view the structure mesh and current) by:

+ add new graph > add measurements > Data > (Con_etheta, PPC_ephi and PPC_etheta) to show the output radiation patterns, but when i try that, it shows some errors and ask to disable advanced freq. sweep AFS, or put ports at the sidewalls of the antenna but it slow down my simulation and i can't get any results?

- Is there any mistake i might have done through my simulation or setting options? how by adding annotation could help me with the simulation?

- it shows an error if i used the simulator for the AWR EM & CST MWS- EMSocket co-simulation interface (5:24:19 PM An unexpected error occured in the remote em simulator ( CST MICROWAVE STUDIO ) Error Text = Internal Error : Attempt to access the DC surface resistance of a real conductor)

-I tried to import it to CST Microwave office and i had first to connect the port and define the brick for the substrate but i don't understand two things:
1) Boundaries and (open , electric or magnetic - for yin, zin) what is the suitable option for me?
2) It shows at the message window while its simulating by (transient solver) that (the simulation whould take long time: check the mesh to avoid the mesh small steps) which i don't understand too.?

-besides till now its simulating (Processing excitation, count down: 6325) anyway i will post the results later.

Thank you a lot Mr. Manju for your big help and sharing your knowledge.

Note: I can attach my output graphs or design if that would help.

 

[Manjunatha_hv]

Hello Sara,

Upload your MWO file (*.emp) that may help in suggesting or providing some more inputs to you....


---manju---

 

[Sara88]

Hi, Mr. Manju.. i upload the MWO file (*.emp) at following link,

**broken link removed**

Thank you

 

[Manjunatha_hv]

Hello Sara,

Okay now I understand why you asked so many questions...

for this type of structure (Dipole) you should or must use internal port (with + & - tighten to two conductors ) so that it excites the structure accordingly for that you need to place the conductors very close...

Your substrate stack-up settings are wrong, you need to set the default top Air to 10 times the substrate hight for antennas
Also I have set up the AXIEM simulation to moderate accuracy ....

Most important I hope you are using AWR latest version i.e AWRDE 2010 version 9.05 (AXIEM) ....


See the modified project file now it works better....But still it is not acting as antenna, you should get somewhere below -10db return loss at resonant frequencies...
check yoour structure dimensions, & substrate parameters...

---manju---

 

[Sara88]

Thank you Mr. Manju for your contribution..

I didn't know that i should set my substrate stack-up setting (top Air) 10 times the substrate hight for antennas! Thanks !

I was using AWR v.9.00 from the college computer lab. So i downloaded the V. of 9.05 after i emailed the AWR branch in Singapore and replied me a license valid within a month only.

Anyway, finally i got it!and now i'm trying to change the trace line width with different values.

- For 0.7 mm, resonant frequency is at 860.04 MHz & mag max -0.3 dB, mag min -0.8 dB!

... i'm trying to change the structure dimensions to get -6dB to act as antenna ..

Thanks again

 

[Sara88]

This's one of my best results * I Think!*

 

[Sara88]

Mr. Manju..

I'm kinda stuck . I can't figure how to achieve the expected results of return loss at least -6dB and operating within the range of 850-900MHz.


I'll attach you one the articles that i'm refereing to.. I hope it may help!

Thank you!

 

[nanny88]

Hey Sara88
Could you attach the AWR file in version2008?
I cant open your file.
Thanks.

 

[Sara88]

Thanks dear but i have successfully finished my design and fabricated it. And i used CST MWS to simulate it.

 

[nanny88]

hey ,

Do you mind to send me the CST file as well?
Thanks=)

regards

 

[loucy]

Mr. Manju..

I'm kinda stuck . I can't figure how to achieve the expected results of return loss at least -6dB and operating within the range of 850-900MHz.


Thank you!

The problem is most likely impedance matching. For AWR Axiem the port impedance is always 50ohm. You need to change the source impedance through a circuit simulation.