If the "WiFi Standby Policy" on your phone doesn't work and the WiFi stays always active during standby mode (as on my SGS3) then this little App helps by forcing the WiFi off when the device enters the standby mode - and on again when the display is switched on again.
Be warned: with active "WiFiStandbyKick" any downloads odr internet sessions will be cut when the phone goes to standby!
(sorry, the app is "as-it-is" without support nor guarantee)
