The present invention relates to a portable communication device arrangement comprising a main unit and an auxiliary unit. The main unit includes an electrical interface to an auxiliary unit, a ground plane dimensioned for antenna operation at a multiple of a quarter of a wavelength of a desired frequency, and a radio communication unit connected to the ground plane and to the electrical interface. The auxiliary unit comprises at least one electrical conductor to be connected to the electrical interface and including a first radio frequency trap, where the distance between the first radio frequency trap and an end of the conductor that is to be connected to the electrical interface corresponds to an odd multiple of a quarter of a wavelength of the desired frequency. The invention provides a good antenna through reuse of elements already provided in relation to a portable communication device.