Hello Bapi,
No it's not possible to download only the client from the SAP portal. But if you already download the installation files you're be able to extract them and create a separated zip of the client. This zip you could use for install the client (and after installation, upgrade to the correct patchlevel).
Or as Prasanna says: locate your B1_shr and download your client installation.
HTH.
Regards Teun