關于CST超寬頻仿真的警告

么有人知道么

最近在做一個超寬頻的天線設計，設計帶寬是3-40 GHz，我仿真頻率設置的是2-40 GHz。仿真的時候報錯：some higer order propagation modes at port 1 are not considered in time domain caculation. This possibly leads to an inaccurate energy balance. consider to increase the number of modes or decrease the upper frequency limit. 請問大家這是怎么回事啊?我把port的mode order 由1改為3后還是報相同的警告。謝謝大家！