designing a triangular patch antenna with cst design suite

hi,
I need help on designing triangular patch antenna with cst design suite and I need to see the resonant frequency?
how can I see the resonant frequency and which mode should I use?
thanks

i am working on the same project by using finit difference time domain please if you have any information or matlab code for FDTD
PS:
i have this one wich i got it from IEEE
''chracteristics of equilateral triangular patch antenna using cavity'' model and it shows the resonante frequency
PS:
conatact me on samirazoul@yahoo.fr