Help needed in MWO AWR

[asad123]

Hi Manju,
I have just started working with MWO and have to design a microstrip patch antenna. I want to know that how can I move my schematic design to EM structure? I wanted to start my work from the EM STRUCTURE but the shape of the micro strip was very difficult to be drawn directly with EM structure as it has some curves so now I have designed it in schematic and want to move it in EM structure can any one help?

 

[Manjunatha_hv]

Hello asad123,


Yes it is possible in AWR MWO, you need just Simulation control block called EXTRACT & Substrate Stackup Block STACKUP
on the schematic ...Setup all the options, select the schemtic elements & add EM Extraction then it will automatically generate the EM Structure from Schematic...

See the attached picture...

If you have problems then upload your file, I set the options for you...

---manju---

 

[asad123]

Thanks for the reply manju, by some hit and trial method i also found that i can just copy the layout of the schematic in EM structure, another problem i am facing right now is that when I set the drawing layers in layout I could not access them on Enclosure properties> EM Layer mapping.
I am attaching my file and also the paper from which I found this design can u please check why its not working(I havent set the ground plane in this design because I couldn't acess the ground plane layer which I defined in drawing layer, but I then included my em structure where the ground plane was accessible but the results were not still desirable)

 

[Manjunatha_hv]

Hello asad,

Attached is the modified file for EM layer 2 with copper metal of 35um(1oz)...
Even I modified the feed excitation settings to CPW and changed the bottom boundary condition to freespace or open instead of PEC....
Now it works fine...bit results are shifted may be due to some dimenion or parameter change...check all once again...

---manju---

 

[asad123]

thanks for the quick reply, can u also tell me that how can i ACCESS the the layers from Enclosure properties> EM Layer mapping because I couldn't see them there although I have drawn them in layout drawing layer options, and also tell me that how to add schematic elements to extraction

---------- Post added at 16:08 ---------- Previous post was at 15:53 ----------

Thanks a lot Manju, I have checked it the results are better i will check the dimensions to get rid of the little shift, please tell me the following things i will be really thankful:
1) how u give the port num -1 to ground and what was the reason for that
2) why did u use copper metal of 35um(1oz)
3) how did u modified the feed excitation setting to cpw
4) Is there a possibility that we can change the polarization of this antenna from linear to polar

 

[Manjunatha_hv]

Here are the answers
1. just select the conductor & add the edge port & rename it to -1 then it becomes differntial port
2. usually all substrates comes with copper clad of 1/4Oz to 2 Oz and generally for low frequencies thick conductors ar used hence i picked 1Oz u can try with1/2 Oz
3. because the article says use the CPW feed & not the microstrip line feed
4. You mean circular polarization! then add one more feed to the structure or modify the structure...

----manju---

 

[asad123]

thanks for the reply manju, i have some more:

1, how to add elements to the extraction.
2, I am having a same problem with different antennas when I designed them on MWO i.e. slight shift from the article results any suggestions about that. It has happened to 3 antennas now
3, How can I calculate the gain of the Antenna, when ever I tried it gives me this error saying " The antenna measurements can not be displayed when using the Advanced Frequency Sweep (AFS) Option" and " Measurement - EM Structure 1B(|PPC_RHCP(0,0,0,2)|)[1] : Unable to calculate swept theta radiation pattern"


As you are an expert in Antenna field I just wanted a recommendation from you

I have just started my master thesis and I have to design an antenna for a transponder which will be used on the windscreen of the car. Transponder is used for automatic road tolling. The problem in designing this antenna is that the size should be minimal (the existing antenna is 17mm x17mm which is needed to be replaced as it is a little big and it is a slot antenna which is a bit expensive to manufacture), and the antenna should be a printed antenna and should have a gain more than 5 dB and should only radiate in +-35 degree of elevation and azimuth. I have studied a lot of IEEE papers but couldn't find any antenna fulfilling the requirements, in fact most of the small printed antennas which I have studied so far radiate in both directions which isn't needed as the requirement want the antenna to radiate in only one direction(not in the back direction). Can I get some help that which design I should choose, what methods I can choose to increase the gain, my supervisor said that look for the antennas which don't have ground plane. What do you think?

 

[Manjunatha_hv]

1. Go through the Extract_Example.emp example Design Notes
2. some articles have missing info or data you need to assume & vary those parameter still it matchs with the article data
say conductor thickness, loss tangent, etc...
3. Rightclick on EM structure select options & then go to AXIEM & uncheck AFS option
& then simulate

You need to search for research papers from IEEE,MTT etc and is the only source for this solution...
This is the only start point I know & it works for any new design...


---manju---

 

[asad123]

thanks for the reply manju but I still couldn't fix the AFS error although I disabled the AFS option in AXIEM, I have attached a design kindly check it, will be really thankful again

 

[Manjunatha_hv]

Hello asad,

Attached is the modified AXIEM file with Antenna Plots & current density annimation annotation....

if you want to specific clarification then you can write to me at manjunatha_hv@ieee.org


---manju---

 

[asad123]

I have sent you the email kindly check it and please do let me know that what changes u made to get rid of the errors?

 

[asad123]

Hi Manju,
I need a little help from u again:
In designing patch antennas which have just one substrate and a ground plane below the substrate which of the following option is correct for them to define layers.

1. In layers we just need to add substrate and use perfect conductor as bottom and approx open for the top, and just draw a patch above the substrate and add some air over the patch
2. In layers add first layer from the bottom as air and over that layer draw the ground plane with any perfect conductor, then add a substrate layer and then over the substrate layer draw the patch, add some air over the patch
waiting for your reply

 

[Manjunatha_hv]

Hello Asad,

Yes, absolutely correct, your stack up is right for Explicit Ground metal Antenna in AWR AXIEM....
But make sure the ir layer height is at least 10 times the substrate height....

---manju---

 

[eoncu]

Hello all,
i am trying to desing a simple two-way wilkinson power divider by using AWR.I calculated the widths and lengths of the microstrip lines.And i draw them on the EM simulation layout.But i couldnt place the isolation resistor (2Zo) between two arms of the circuit.How can i describe resistance between two points on the design in EM Simulation layout in AWR.In CST user can specify RLC values between any points on the structure.But in AWR i couldnt find a way to describe.

 

[loucy]

Hello all,
How can i describe resistance between two points on the design in EM Simulation layout in AWR.

Draw a rectangle connecting to two points and assign "impedance" material with the correct "ResSq" value.