No  @dika ...you have to have the Gateway server because Veeam uses a ‘Data Mover’ to move the data & can't install it on the DD device 

Please reference the User Guide , as it appears you have already 

could I deploy a gateway server as virtual or it must be a physical ? 

is a gateway server same as tape server ? 

No...it can be virtual. It is just recommended to be "near" your DD device 

No...a GW server is different than a Tape Server. A GW server assists Veeam in performing Backups. Tape Server is used for Backups performed via tapes 

Gateway Server:

Tape Server

Hope that helps.

well, does veeam need 2 data mover at least in backup job to transfer data from source to target(backup repository) ? 

if gateway server and tape server is different, where is veeam data mover on backup tape infrastructure ?

correct me if Im wrong

Yes, as shown in the graph above.

As far as for Tape Servers...the Data Mover is installed on the Tape Server, since it is a Windows device.

...as noted in the ‘Tape deployment’ section of the Guide:

@coolsport00 thanks for the answer, it helps me a lot  

Sure thing. I will say...I’ve been using Veeam about 12yrs or so now. Their product in the early yrs wasn’t too bad, complexity-wise. It still isn’t “horrible”, but with all it has integrated and added feature-wise the past 4-5yrs, the complexity has indeed increased!