The invention relates to a portable compact antenna formed from a first dipole type radiating element operating in a first frequency band and comprising a first and at least one second conductive arm, differentially supplied, the first arm, referred to as cold arm, forming at least one cover for an electronic card and the second arm, referred to as hot arm, being linked to the cold arm at the level of the supply. According to the invention, the hot arm comprises at least one slot resonating in a second frequency band such as the GSM band.