focal length – How can I calculate a camera sensors width and height?

I try to compute the focal length for different field of views of a camera.

Therefore I need the sensor size horizontally and vertically, but in the datasheet I only have the information: 1/3" 2.4 MP Image Sensor.
The image size is 1920x1080 it that’s needed.

How do I get the size of the size of the sensor?