iPad keeps losing connection to wifi

If the iPad disconnects when idle (sleep/locked) you may need to verify the your WiFi Settings for each of your configured WiFi Networks - ensuring that they are set to Auto Join:

Settings > WiFi > [WiFi Network / SSID] - tap the “i” icon - set Auto-Join to ON

Unless Auto-Join is enabled, your iPad will not automatically reconnect to the WiFi network when resuming from sleep - or when coming into range of your WiFi network.

Auto-Join is enabled/disabled for each configured WiFi network.