Project: RF Transmitter in a metal box

EElder99

I have a question on my Junior Design project:

My project will be going into a metal enclosure, but contains an RF transmitter with PCB antenna to allow it to be controlled from a USB port on a laptop. Our current plan is to make a 1"x1" glass opening to allow the signal to get out (2.4GHz, so the window is slightly larger than 1/4 wave).

However, I thinking about seeing if I could use one of the fan vents to get the signal out instead. What I was wondering was:

1) Would it be possible to get an RF signal out of a long, thin aperture?
2) Would the length of the opening need to be aligned with the direction of polarity of the antenna (vertical)? Or would I be able to make the opening horizontal, as the majority of the power is in the horizontal region (omnidirectional antenna)?

Thanks for the help.

Also, if you don't know the answers but know of books or other references where I may be able to find the answers, that would be great as well.