Drain-voltage dependency of memory effects in W-CDMA base station digital predistortion linearizers with compound semiconductor power amplifiers

With regard to wideband predistortion type power amplifiers, such as shared antplifiers 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 ACLR performance to mitigate semiconductor device has sufficient ACLR performance to miti gate these memory effects. We tested two kinds of compound semiconductor devices, namely, a GaAs FET and a GoN HEMT The GaAs FET, with an operating voltage (V,,,) of 12 1 a saturation output of 240 W, and a push-pull configuration, was used as a low-voltage device. The GaN HEMT with V-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. (c) 2005 Wiley Periodicals, Inc.