
181Group III-Nitride Microwave Monolithically Integrated Circuits
For even higher frequencies and then based on dual-gate devices, Figure 5.27
gives the image of a dual-stage dual-gate PA for W-band operation [168].
The typical cell size of the dual-gate power cell is again 4 × 45 μm in this case for
operation at 88–94 GHz. The dual-gate devices provide an even lower outputimped-
ance due to the transformation of the high-intrinsic impedance throughthe parasitics
[156]. As explained by van Heijningen et al. [168], the optimum load determined by
simulation is (−0.66 + j 0.57) around 90 GHz for a dual-gate device. The achiev-
able matching to t ...