Help In Designing Slot Antenna Array

Help!
I need to design 5Ghz horizontally polarised omnidirectional antenna
Freq: 4.9-5.9GHz
Gain: > 7dbi
Return loss: >10db
Impedance: 50 ohm
Conducter: SMA
Substrate: dielectric constant: 2.65, thickness 0.8mm, loss: 0.002

I am using CST but I dont know where to start. I dunno what is maxwell equation and how to select the waveguide size.

Hello Clar

I am not very familiar with CST, but look at the link below to see the standard waveguide dimensions.once you have the dimensions down, you have to cut slots size of a dipole on the waveguide,to get you going check the second link below.

Rectangular Waveguide Dimensions - Microwave Encyclopedia - Microwaves101.com

Slot Antenna

Hope that helps

Regards
Rotmanlens

The problem is that I am not even sure how to obtain the dimensions.

well the dimensions of the waveguide are standard, the slots are supposed to be close to half a wavelength.

if you go through the links you will for sure understand and do things,everything is put down to make it easy for a beginner in those links refer to them and let me know

Regards
Rotmanlens.