In one example an apparatus is provided. The apparatus includes a low frequency radiator, a high frequency radiator, a high frequency waveguide that carries high frequency bands to the high frequency radiator, a low frequency coaxial waveguide coupled to the high frequency waveguide in a coaxial structure, wherein the low frequency coaxial waveguide carries low frequency bands to the low frequency radiator and a low frequency combiner in communication with the low frequency coaxial waveguide, wherein the low frequency combiner comprises a circular low frequency waveguide and air dielectric transmission lines formed by air channels formed above and below a plurality of printed circuits in a metal housing.