Google needs to make Android more appealing to developers and stickier for consumers, analysts said. As part of that challenge, it will have to demonstrate that the OS can be successful on tablets, which it has not been to date.

Industry watchers expect Google to announce a tablet with its own brand this week. A Google tablet has long been , but the timing remained uncertain.

"Let's put it this way, I'm 100 percent sure they will launch a tablet before midyear, and as far as I know, I/O is their big splash," said , an analyst at IDC

According to Mainelli, the tablet will be made by Asustek Computer. It will have a 7-inch screen and sell for US$199, he said.

He added one caveat on the timing: Microsoft waited until a few weeks after its recent TechEd to unveil its tablet, he noted.