The Sender property sets filtering on the name of a message's sender. Read/write.
objMessageFilter.Sender
String
The Sender property specifies that the message filter should pass only messages sent by a messaging user having a name corresponding to the Sender property. The filter passes the message if the Name property of the AddressEntry object returned by the message's Sender property contains the filter's Sender property as a substring.
The Sender property corresponds to the MAPI property PR_SENDER_NAME.