You have to export the design from HFSS in step file format (remove radiation box, excitation and boundaries) . Just export the design structure.

Open CST and import the step file. You will get your structure back on CST. Now you have assign boundaries, excitation and material. Simulate and varify your results.

(This is possible only if you are familiar with using CST)

Dear Srinivasarao

For designing your structure in CST Microwave Studio, you can go through the various videos available in CST website and you tube. The design of rectangular patch antenna is link given below:

https://www.youtube.com/watch?v=pSzFhKVmYAw

Other way to export the design from HFSS and import it into the CST microwave studio. Assign the excitation, boundary conditions etc. in CST as per requirement. Simulate the design in the frequency range and verify your results.

Hello,

There are two main options to explore the results, first import antenna design from HFSS to CST and run the solver. Or, form new design of antenna having same parameters and then run it. Second one is the best to understand the CST and its numerical techniques. For verification, you will have compare the results of both. So, by doing or adopting anyone of them given above, can be easy to verify.

Thanks,

And what happens when the results are different? The most likely is that they are both inaccurate compared to the real antenna.

Import your design in CST and simulate it, then check the S- parameters, gain, radiation pattern of your antenna and from that you can compare them with HFSS results.

Many video tutorials are available on youtube regarding CST in case you are not familiar with CST.

Dear Srinivasarao,

The process of exporting the design from HFSS and then importing it in CST is explained in a tutorial video available on the link: https://www.youtube.com/watch?v=9BGVd2uiu-0&