Feeding antenna in CST

Hi, I have an antenna model (planar type - the antenna is placed on a dielectric substrate) in CST and I want to analyze its operation in free space without the effect of ground so my model doesn't contain ground. My problem is that if I use coaxial cable to excite this antenna, is it OK without ground. I've constructed the coaxial cable in CST with the inner feed, dielectric, outer conductor (the outer conductor doesn't connect to ground).
Please help me. Thanks in advance.

申明：网友回复良莠不齐，仅供参考。如需专业解答，请学习易迪拓培训专家讲授的CST视频培训教程。