Fig. 1. Scanning electron microscope picture of the T-gate

Fig. 2. Transfer characteristics of the 2×25 μm InP HEMT device

Fig. 3. Current gain H₂₁ and U gain of 2×25 μm InP HEMT device（Bias：V_g=-0.4 V，V_d=2 V）

Fig. 4. Single stage common source amplifier

Fig. 5. The Wilkinson power divider layout

Fig. 6. Simulation curve of the power divider

Fig. 7. Schematic diagram of the PA

Fig. 8. Single-channel amplifier gain simulation curve

Fig. 9. Output power versus input power

Fig. 10. Photograph of the PA TMIC

Fig. 11. Measurement and simulation results for S-parameters of the 220 GHz PA MMIC

Fig. 12. Power measurement diagram

Fig. 13. Measurement and simulation results for the saturated output power of the 220 GHz PA MMIC