I understand you want to get back panels...
What distro are you using??? What desktop environment are you using???
Unless you provide that info, you may not be able to get an accurate answer.
By mistake I delete Panels!
What do you mean by delete? Did you remove the panels from your computer or you lost the panels simply because you did something wrong.
BTW, it is always a good option to include your distro in your profile. Also refer the
guide to ask questions the smart way