Dimensions of airbox in HFSS

hello,

i wanted to know the dimensions of air box i should use in my antenna. it has a cylindrical substrate Neltec NY9217 having radius 150mm height 3.175mm and using coax feed. for a frequency range 12 to 13 GHz.

Thank you.

Hi Priyanka Garg,

One typically wants a minimum of a quarter wavelength of free space (at the lowest frequency) between the edge of the simulated object and the radiation boundary.

thanks for giving so early reply....

ya...but is it different in case of coax feed? i have seen the patch antenna example in hfss help and i found it to be different. Moreover, my antenna is 300x300 mm^2 in dimension and according to the quarter wavelength factor the radiation boundary is coming out to be just 6.25mm above the simulated object. so is it alright?

I would think that should be fine. If you're not comfortable with it, there's no problem with extending it past a quarter wavelength.

could u tell me the meaning of focusing plane? it is given that height of focusing plane is 150mm. Does it means i have to keep air box 150mm above the substrate?

In a general context, I have no idea what a "focus plane" is.

Good Luck!

height can be varied depending on which application you are working. May be it helps if you could mention your application. Regards,

its an antenna for bessel beam generation

usually big airbox is used if you want to monitor spatial diversity of waves in E-Field. I am not sure about bessel beam if these require a height of 150mm. like 4-6 times lambda.Regards,