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Excitation with CPW fed in slot antenna with square patch.. and slotting is square

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khubu

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Please help me to find a excitation to Cpw-fed.
I tried but their is an problem like..
"[info] Fast sweep setup, process hf3d: '1' conductors touch lumped port '1', typically a lumped port contains 2 conductors. Please verify conducting boundaries and objects are correctly assigned and touch the port. If a Radiation boundary touches the port and it is desired for use during the port solution, select 'Use Radiation Boundary on Ports' under the Advanced tab in the Solution Setup. (3:20:29 AM Aug 10, 2013)
[info] Normal completion of simulation on server: Local Machine. (3:20:30 AM Aug 10, 2013)"


And i want to complete it ASAP..! please provide a solution. I have design a Slot square patch antenna with CPW-fed with a lumped port.
 
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Darktrax

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The very first thing one needs to know is what simulation tool you were using.

From the error message, it seems you might have set up a discrete port instead of a waveguide port to excite the coplanar waveguide, and then not managed to connect one end to the groundplane. The constraint of having to use a discrete (lumped?) port seems unreasonable, and limits the accuracy of the solution. Use the best type of port for the structure instead. I cannot think of a good reason why not.

Also, the boundaries of the structure are very important. I suggest you start with an example of a similar board, and look at how the conditions are set up, and particularly, how the CPW is fed. It will be similar to feeding microstrip, with some special conditions to accomodate the grounded parts on the topside.

This is, of course, all only my speculative guess. Any help folk can offer will be probably severely limited until you say what type of software delivered the error message.
 
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khubu

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Thanks.. yeah you are right. I am using HFSS12 v.1
I used lumped port just because it was used in some research paper.. so i used it.. I am new to Coplanar waveguides and it's feeding technique.. and actually I don't know how to excite a CPW.

I look forward in conditions to accommodate the ground plane on topside and the waveguide port to excite the coplanar waveguide(CPW) instead of lumped port.
Thank you very much.
 

Darktrax

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Choose the right simulation environment at the beginning. Do explore HFSS examples. There is bound to be some CPW you can exploit. Look for the setup, or simply "Save As" a new file, and trash most of the example, keeping only the ports.

You can then change the substrate and CPW dimension parameters to suit yourself. Maybe just construct a simple test line with a little stub set between two ports, just to quickly check you get the S-Parameters OK.

I know it seems a little counter-intuitive, but CPW is Co-Planar-Waveguide. It can be fed from a waveguide port. So is microstrip. Even coax, so wrapped around itself it can only have a radial electric field, and supports TEM exclusively, can be fed with a waveguide port stuck on the end of it. Discrete ports, I think, force a voltage function between points on the track underside and to nearby on the groundplane, and you have to specifically define those points. Discrete ports are very useful, but you have to know what you are doing, and I do not think they are likely best when driving CPW.
 
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