This is a picture of 3 unfinished circles that connect to a square with one of the corners being cut off. There is a smaller, full square in the middle of the other square.
This RFID Sensor icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 5,700 icons, all in the same style and quality.