Aspect Ratio and resolution question ( black bars)

Hi Guys! I have a question on the aspect ratio and resolution of my game, i developed the game in portrait mode in 720x1080, this probably work for many mobile phones, but for the tablets is not good, there is a way to force the aspect ratio inside the tablets and put two black bar or something like that ?

If you setup your UI to scale with the screen size and use 100% width in combination with the camera rendering the UI also rendering black as the background color, it should just work.