Wiktionary
a. (context idiomatic English) likely to happen, or be important in the near future or tending to attract attention.
Usage examples of "on the radar".
Your work here on the radar bridge did as much toward saving Tom's life as anything.
At 3:18, a blip appeared to the east on the radar screen, followed a moment later by two more.
Gosigo turned on the radar screen to look through the steam which their own jets had called up.
They had appeared on the radar screen at a nearby auxiliary SAM station only for an instant.
Jones noticed a small, barely visible object bringing up the rear of the air train, an object that Crunch would never see on the radar screen.
From far above on the radar mast, the ship's foghorn gave a deafening blast.
And they put a missile in the air and waited for the first stage to drop off before they turned on the radar.
When the objective is sighted, turn on the radar jammer of the SAM-6s and pray it works.