desgining a 28GHz patch antenna

Hi, I would like to design a 28 GHz patch antenna in HFSS.....i have a doubt regarding radiation box...should i keep the general lambd/4 size radiation box? or else?.....

Why wouldn't you?

HI, sorry for the late reply, I am trying to simulate the antenna given in the following link...when i used the quarter wavelength radiation box ..i could not get the desired retun loss
.....i am also attaching you the HFSS file for reference...



http://ieeexplore.ieee.org/document/7784999/

In general, I would propose using a half wave box (or sphere or cylinder). Lambda/4 is a little problematic in my view (too small). If possible, try (and error) with half wave box. Compare the results. If there is little difference in the S - Parameters (< about 5 %) it shouldn′t matter.

I had the same discussion with my professor, he also proposed half wave when structure is small and lambda/4 when structure is big. I somewhat share that view, but due to another aspect.

Seb