Design, simulation, and fabrication of broadband coaxial matched loads for the frequency range from 0 to 110 GHz

Combining a theory for reflection-free termination of coaxial lines together with a novel manufacturing method results in 1-mm coaxial matched loads with an excellent absorption behavior over the frequency range from 0 to 110 GHz. Three different electromagnetic (EM) simulation approaches verify the capability of these matched loads to achieve reflection coefficients smaller than -43 dB over the entire frequency range. Matched loads with a maximum reflection coefficient of only -32 dB have been produced. An excellent performance was achieved by exponentially tapering the outer conductor over the region of a coaxial ceramic substrate coated by a thin-film resistance and by compensation for EM wave propagation inside the resistive coating.