help "The background does not fully touch the following boundaries: 'PerfE_inf_GND' ?

i am very novice in hfss and this is my final year project so guys , please help me to sort this error

when ignore the error and get rectangular plot it shows 0 db ,

here i use circular patch with circular slot ,coaxial feed, and partial ground plane ..

to further improve bandwidth i want to create a airgap between substrate (rodger 5880) and ground , but i cant sort this error,

i also include pic

waiting for your kind reply.

i extend my airbox -z axis to cover extended gnd plane but i am having same prolem after simulation i get plot like this..

You've given insufficient information in order for us to help you. Please explain your problem in detail and/or attach your hfss file.

here is my hfss file.

I was having a similar problem when building a microstripline coil with a gap in the middle. I had to remove the gap.

The file you attached runs fine for me.

However, I'm not sure why you have it set up as a driven terminal simulation. I switched the simulation driven modal and the simulation data was better -- your antenna just seems to be very poorly matched to the port impedance (50 Ohms).