on/off someone's radar idiom
（某人）知道／不知道;（某人）想到／没想到
If someone or something is on your radar, you are/are not aware of them or have/have not thought about them.
She has been on my radar since her first novel came out, but I haven't read any of her books. 她第一部小说出版时我就注意到她了，但是我从来没看过她的作品。
Five years ago, having a child wasn't even on my radar. 五年前我根本没想到要孩子。
We recycle our waste, but what happens to it afterwards is completely off our radar. 我们回收垃圾，但是这之后发生了什么我们就一点都不知道了。