Delta pattern in microstrip antenna

Hello RF people,

I am looking for a microstrip antenna that can make a conical multibeam (delta-pattern) .. peak gain = 12 dBi.

Any idea? Array? stacked patch? Ring parch?

Please, support me.. it's quite important for my teacher...

Best regards,

Lupin

How large a size are you looking for?

Well, as size constraints I have a circle whose diameter is 55 cm...

Thanks in advance,

Lupin