i need suggestions to design antenna for specified parameters

[redcrystalline]

hi
i have to design an antenna with theses parameters
1- gain around or more than 2 db
2-beam width about 100 degree
3-frequency around 450MHz
4- omni directional pattern
first ideaS are PIFA or IFA BUT THEY HAVE LOW GAIN AND PATTERN PROBLEMS
could any one suggest me another antenna?
thanks for your attention
regards
red

 

[Positron89]

Hi,
I got almost the same results when I was designing a helical antenna but the resonant frequency was much higher.

 

[redcrystalline]

hi. resonant frequency only change size of antenna , im thinking that the only way is using array antenna, but it's complex!