Samsung Electronics Co., the world\'s top smartphone maker, is under a preliminary investigation by a European Union (EU) antitrust watchdog over possible abuse of its wireless patents, a court filing showed on Friday. \"Samsung\'s litigation campaign and other conduct related to its Declared-Essential Patents is so egregious that the European Commission recently has opened an investigation to determine whether Samsung\'s behavior violates EU competition laws,\" said Apple Inc. in a recent filing with a U.S. district court in California.