Technology: GLOBALFOUNDRIES 22nm FD-SOI 22FDX
Abouzar Hamidipour, Gernot Hueber
Exploring novel power combining structures
With the growing attention to 6G and frequencies beyond 100 GHz, many attempts are being made to explore novel power combining structures. This is to overcome technology limitations in providing conventionally high output power.
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.
Achieving a good agreement between the simulation and measurement
Impedance matching was accomplished using quarter-wavelength transformers. To fulfill low-characteristic impedance requirements, the signal and ground traces of the strip lines were designed on QA and M1 layers, respectively. As a result, a very good agreement was achieved between the simulation and measurement over the whole D-band frequency range.
Microphotograph of the test structure used to verify the D-band differential power combiner
Measured and simulated S-parameters of the D-band differential power combiner.
