SQL Server Backup and Query Execution
Yes backing up a database will affect performance if you run queries against the server / database. 

Your server no matter how amazing it is has a limited amount of resources; backing up the database will add load to the disks and cpu; the amount depending on the size and the options that were chosen for the backup (e.g. compression or verification will add more load.)

What you can do is use a backup strategy that does a full backup at a low utilisation time and smaller incremental transaction log backups during the day to minimise the backup time window if you are backing up in operational hours. Or you could investigate alternatives like database mirroring which may help you remove the need to backup the active database; at the cost in terms of extra server resource and a small increase in load on the server for all transactions.