I was wondering if I can get help on setting up transmitting antenna and receiving antenna spacing with far field without using extremely memory heavy simulations. I found some examples using integral equations(IE) to reduce the solution in free space but I'm not sure how to set it up properly for our application, especially for boundaries of two antennas and the air between them.
As for what I tried, two separate air boxes with FE-BI boundaries are used. But how to deal with the air between them, and does the air need extra boundary settings? Besides, I also tried using only one large radiation box for two antennas, however,the radiation pattern shows rough and periodic surface, which looks like the effect caused by reflection from the receiving antenna.For these two situations, the couplings are different by around 7dB.
I always get the radiation pattern of Tx array as shown in the picture, in one air box and two FE-BI boxes too. I wonder if this rough surface pattern is normal, or caused by reflection from Rx antenna.
Thank you in advance.