預警系統
One of the first projects was to build equipment to transition from the British long-wave radar to the new microwave centimeter-band radar made possible by the cavity magnetron. In working on the Microwave Early Warning system (MEW), Alvarez invented a linear dipole array antenna that not only suppressed the unwanted side lobes of the radiation field, but also could be electronically scanned without the need for mechanical scanning. This was the first microwave phased-array antenna, and Alvarez used it not only in MEW but in two additional radar systems. The antenna enabled the Eagle precision bombing radar to support precision bombing in bad weather or through clouds. It was completed rather late in the war; although a number of B-29s were equipped with Eagle and it worked well, it came too late to make much difference.