What refers to the ability of the antenna to focus scattered EMF waves into a narrower, useful plane, thereby increasing signal strength, and is expressed in decibels (dB).

• A. Directivity
• B. Efficiency
• C. Gain
• D. Bandwidth

Answer: (C)

Concentrating energy in a particular direction and turning that into more signal power in that direction is described by gain. Gain measures how much power the antenna delivers in the desired direction relative to a reference, and it is expressed in decibels (dB), commonly as dBi or dBd. This combines the focusing ability (directivity) with how efficiently the antenna radiates that energy; directivity alone explains focusing, but gain reflects the actual usable strength after accounting for losses. Bandwidth is about the range of frequencies the antenna works over, and efficiency alone doesn’t account for directional focus. So the statement points to gain.