A structure may pertain-to (microwave background anisotropies).
A structure of (microwave background anisotropies) may be determined by some effects.
The (antenna temperature) can be due to a (microwave background).
A cosmic (microwave background) can be over billions of years.
Cooling of a cosmic (microwave background) can be explainable.
Levels can be constituted-of-or-filled-with (microwave power).
Systems can be constituted-of-or-filled-with (microwave heating).
Experimental design can be constituted-of-or-filled-with (microwave devices).