What happens when displaying through Miracast using low resolution device and high resolution external display? I am considering purchase of an Android tablet with 1024 x 600 screen resolution and Android 4.4 KitKat. I believe it will support Miracast to cast its display to a Miracast receiver.

The Miracast receiver will be attached to a 1920 × 1080 native resolution TV.

Will Android take full advantage of the full 1920 × 1080 resolution of the Miracast destination device? 

What are my options and what would happen on the tablet's screen? What happens on the TV's screen?

OR: Do I need a tablet / phone with  1920 × 1080 resolution in order to Miracast at full 1920 × 1080 resolution on the external display?
Will Android take full advantage of the full 1920 × 1080 resolution of
  the Miracast destination device?


No. You will end up with a stretched yet aspect-intact mirror of what is on your android.


  What are my options and what would happen on the tablet's screen? What
  happens on the TV's screen?


Tablet screen remains the same. TV will appear as indicated above. You don't really have options aside from tilting the device to switch between portrait/landscape.


  OR: Do I need a tablet / phone with 1920 × 1080 resolution in order to
  Miracast at full 1920 × 1080 resolution on the external display?


Nope. If the device supports miracast, it will display on whatever screen the miracast dongle is set up with.