A microwave device includes a semiconductor package comprising a microwave semiconductor chip and a waveguide part associated with the semiconductor package. The waveguide part is configured to transfer a microwave waveguide signal. It includes one or more pieces. The microwave device further includes a transformer element configured to transform a microwave signal from the microwave semiconductor chip into the microwave waveguide signal or to transform the microwave waveguide signal into a microwave signal for the microwave semiconductor chip.