An antenna structure for transmitting and/or receiving radio waves has a symmetrically arranged radiator element with a first connecting terminal and a second connecting terminal, said radiator element being tuned to a useful frequency. Moreover, it has at least one conductor structure connected in parallel with the radiator element. The conductor structure comprises an open-circuited first line element, which is coupled to the first connecting terminal, and an open-circuited second line element, which is coupled to the second connecting terminal. In this case, a length of the first line element and of the second line element essentially corresponds to the integral multiple of a quarter wavelength corresponding to a blocking frequency. The first line element and the second line element run parallel to one another.