4. The "Doubles" Trick (Multiplying by 2) Concept: Multiplying a number by 2 is the same as adding the number to itself. How it Works: To find 6×2, just think 6+6=12. For 9×2, think 9+9=18.

In this letter, a near-field focused array antenna is applied to two-dimensional microwave imaging, which steers its focus on the designed focal plane by changing the operating frequency and by phase ...