Designing a D-band differential power combiner
Traditional approaches of power combining such as Wilkinson or transformer-based have been widely used in lower frequency ranges as their theory is very well-known and their design procedure is straightforward. In frequencies beyond 100 GHz, however, transmission-line based power combiners could be preferred as their size shrinks appreciably and they prove comparatively low insertion loss.
To this end, a D-band differential power combiner with 1:1 impedance ratio was designed based on transmission lines in GLOBALFOUNDRIES 22nm FDSOI technology. Transmission lines provide 50 Ω impedance both at the input and the output of the combiner.