A 68-PERCENT PAE, GAAS POWER MESFET OPERATING AT 2.3 V DRAIN BIAS FORLOW DISTORTION POWER APPLICATIONS

A high-efficient GaAs power metal semiconductor field effect transisto r operating at a drain voltage of 2.3 V has been developed for low dis tortion power applications, The device has been fabricated on an epita xial layer with a high-low doped structure grown by molecular beam epi taxy, The MESFET with a gate length of 0.8 mu m and a total gate width of 21.16 mm showed a maximum drain current of 5.9 A at V-g8 = 0.5 V, a knee voltage of 1.0 V and a gate-to-drain breakdown voltage of 28 V. The MESFET tested at a 2.3 V drain bias and a 900 MHz operation frequ ency displayed the best power-added efficiency of 68% with an output p ower of 31.3 dBm. The associate power gain at 20 dBm input pow er and the linear gain were 11.3 dB and 16.0 dB, respectively, The power char acteristics of the device operating under a bias of 2V exhibit power-a dded efficiency of 67% and output power of 30.1 dBm at an input power of 20 dBm. Two tone test measured at 900.00 MHz and 900.03 MHz shows t hat 3rd-order inter-modulation and power-added efficiency at an output power of 27 dBm were -30.6 dBc and 36%, respectively, which are good for CDMA digital applications, A third-order intercept point and a lin earity figure-of-merit were measured to be 49.5 dBm and 53.8, respecti vely.