DRAIN-VOLTAGE DEPENDENCY OF MEMORY EFFECTS IN W-CDMA BASE STATION DIGITAL PREDISTORTION LINEARIZERS WITH COMPOUND SEMICONDUCTOR POWER AMPLIFIERS

摘要

With regard to wideband predistortion type power amplifiers, such as shared amplifiers used in W-CDMA base stations, the memory effects associated with RF power amplifiers degrade power efficiency. Aiming to solve this problem, we find that a high-voltage compound semiconductor device has sufficient ACLR performance to mitigate these memory effects. We tested two kinds of compound-semiconductor devices, namely, a GaAs FET and a GaN HEMT. The GaAs FET, with an operating voltage (V{sub}(op)) of 12 V, a saturation output of 240 W, and a push-pull configuration, was used as a low-voltage device. The GaN HEMT, with V{sub}(op) of 50 V, a saturation output of 200 W, and a push-pull configuration as well, was used as a high-voltage device. The test results for these devices in a predistortion linearizer configuration show that the high-voltage device (the GaN HEMT) achieved excellent characteristics in terms of distortion suppression and drain efficiency in four-carrier W-CDMA applications.