Transponder to be mounted in or on the surface of objects

A transponder (1) to be mounted on or in a surface, and especially at a motor vehicle pneumatic tire, has an antenna which uses air or has a dipole antenna (2,3) with connections (4,5) to the transponder chip (6) in a housing (7). A transponder (1) to be mounted on or in a surface, and especially at a motor vehicle pneumatic tire, has an antenna which uses air or has a dipole antenna (2,3) with connections (4,5) to the transponder chip (6) in a housing (7). The air antenna has a length (Lluft) which equals 0.5 x c divide f, where c is the speed of light and f the transmission frequency of 868-928 MHz. The dipole antenna length (Lkp) is between 0.45 x Lluft and 0.90 x Lluft and preferably between 0.61 x Lluft and 0.71 x Lluft.