The antenna is used to transmit airplane identification information. LOT sent parts and personnel to Iceland to fix the problem, a Boeing spokesman said in an emailed statement. The airplane maker was ready to help if needed, he said.
Representatives of LOT could not be reached.
The landing came a day after Norwegian Air Shuttle ASA Dreamliner was grounded for and unspecified technical problem.
Boeing's 787 Dreamliner plane has been plagued by a series of technical glitches since it was introduced in September 2011. The worldwide fleet of about 50 planes was grounded for almost four months this year after lithium batteries smoldered on two planes in January.