Hello, You can design power divider using CST design suit with CST Microwave studio.

For bandwidth enhancement, refer this https://www.youtube.com/watch?v=d2gdC-D96cc

You can use CST/HFSS for designing power divider for phased array antenna. Before designing read the basics of power divider. Check this out might be helpful.

http://tempest.das.ucdavis.edu/mmwave/paa.html

CST is suitable, yes. You can design the network using CST's schematic editor, and then extract the 3D model.

Thanks Pranita , Hafiz and Alex for your support. I have gone through the video. Can you suggest me any material/ Book on equivalent circuits of an antenna and mathematical analysis. Hafiz I have gone through the web page you have suggested. Please tell me in phased array radar antenna, would I work on enhancement of bandwidth or work on other parameters like SLL, beamwidth, directivtiy and gain. Please guide me. I am getting confuse here. Is BW plays important role in radar antenna or other parameter are dominating on BW?

The basic parameter is S11 you can use HFSS 3D with optimization componenet

Kanchan go through the chapter 9 of this book. I hope you will get clear idea about the performance parameters of radar antennas. It includes all the mathematical formulas for radar antenna. Also check this site it might be helpful

http://www.radartutorial.eu/06.antennas/Phased%20Array%20Antenna.en.html

Thank you Ali sir and Hafiz sir