A Polystrata® 820 mW G-Band Solid State Power Amplifier

Abstract - Using the PolyStrata® 3D additive fabrication process, a novel 16-Way solid state power amplifier at G-band frequency range is demonstrated. InP DHBT PA MMICs, with an excess of 80 mW output power and >15 dB small signal gain, are used in this SSPA. To connect the MMICs to the 16-way splitter-combiner network, a micro-machined WR4 E-probe to CPW transition was developed. These transitions use micro-length-wire-bonds exhibiting capability at sub-mmw frequencies. The broadband transitions showcase <0.5 dB insertion loss and exhibit tight tolerances due to the batch additive manufacturing process. The SSPA was assembled using 16 mounted MMICs with transitions and demonstrated >11 dB small signal gain from 200-230 GHz. Large signal characterization showcased high saturated output power of 580 mW at 200 GHz, 820 mW at 216 GHz, 680 mW at 225 GHz and 380 mW at 230 GHz in an ultra-compact volume of 45 cm3 demonstrating a functional power density of >18 mW/cm3. Nuvotronics measured 823 mW at 216 GHz representing a 15.9% increase to the state of the art for a power module above 210 GHz, while reducing by half the number of MMICs required as compared to other approaches.