Except for an antenna and an integrated circuit, a RFID passive tag doesn't have extra components.

In order to read or store data on the tag, a reader (interrogator) sends a radio wave to the antenna. 
Then the antenna converts it into energy and activates the circuit. This process is known as backscatter. 
It can write new information to the passive tag in some applications. The read distance of passive tag can reach 8-10m.

However, active tags usually add components in the design, like an integrated battery. 
With an internal battery, active RFID tags can get longer read distance. 
It may include extra sensors to catch specific information of a product.
The read distance of active tag can reach more than 10m or 100m and so on.

Our long range rfid tag OPP130 can get 30m read distance. So long read distance, but don't doubt, it is passive tag. 
It can work on both metal and off-metal surface. Thus it is also anti metal rfid tag.
Sample available for testing.  Welcome for inquiry. 

Michelle Zheng
Tel: 8618750070819
Email: sales11@oppiot.com