6.4.2 Technology C: Pseudomorphic HEMT on GaAs

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 $_{-3dB}$ , and P $_{-1dB}$ of a high-power amplifier at f= 35 GHz.
$\includegraphics[width=10 cm]{D:/Userquay/Promotion/HtmlDiss/fig90.eps}$

**Figure 6.23:** Load-pull measurement for a 8 $\times$ 60 $\mu$ m device of Technology C at $V_{DS}$ = 3.0 V.
$\includegraphics[width=10 cm]{D:/Userquay/Promotion/HtmlDiss/fig83h.eps}$

Quay
2001-12-21