2kM WIFI ISP 3360 Degree non Line of Sight

I want to create a Warless ISP with 2Km Radius,360 Degree, NON Line of sight

Which antenna & brand is best Omni Directional,Yagi,Grid Antenna Tp Link,D-Link etc?
Which Freq Range is better 2.5 or 5Ghtz?
What is the meaning by Dual Band Antenna?

If you're talking about 360deg signal coverage of your wireless the omni antenna is the answer but omni-antenna has a less power than directional antenna such as yagi and grid antenna because the power output of omni-antenna concentrate in 360degress. For the best brand there are many routers out there like Linksys, mikrotik etc but if you want a cheaper brand and can cover 50km in directional range TP-Link is the answer.
For wireless frequency the standard frequency is 2.4Ghz but most of devices today uses this frequency so it is not a good idea to use this frequency. The answer is 5Ghz or higher and why? Because the standard frequency 2.4Ghz cannot interfere this frequency.
The dual band antenna operates in two frequency. For example the antenna can operate either 2.4Ghz and 5Ghz.