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Next: 6.4.3 Technology D: Pseudomorphic HEMT Up: 6.4 Large-Signal Measurements Previous: 6.4.1 Technology A and B:

6.4.2 Technology C: Pseudomorphic HEMT on GaAs

Further load-pull measurements were obtained for Technology C, which is a single recess device suitable for applications up to the W-band similar to Technology A. Devices from this technology can be driven to highest output powers, but for the sake of device reliability load pull measurements were performed at $ {\it V}_{\mathrm{DS}}$= 3 V. Fig. 6.23 shows the load-pull measurements for these HEMTs vs. frequency for 30 GHz and 40 GHz. The device is tuned for maximum output power, which explains the relatively low power gain.

Figure 6.22: Temperature dependence of the $ P_sat$, P$ _{-3dB}$, and P$ _{-1dB}$ of a high-power amplifier at f= 35 GHz.

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Figure 6.23: Load-pull measurement for a 8$ \times $60 $ \mu $m device of Technology C at $ V_{DS}$= 3.0 V.

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