If you want to deactivate your WiFi connection, you have several solutions:
- In (or) Settings> Wireless & networks, simply slide the WiFi switch to the OFF position.
- In (or) Settings > Wireless & networks > More..., you can tick the box Aeroplane Mode. Please note, it will deactivate all comunication protocols including 3G/4G and Bluetooth®
- You can add the Battery widget on your home page from your applications drawer, letting you activate / deactivate WiFi with one press. Please read the following FAQ for more information about widgets.