Novel multimode J-pHEMT front-end architecture with power-control scheme for maximum efficiency

Based upon a unique junction pseudomorphic high electron-mobility transistor (J-pHEMT) device, a novel method of providing high-efficiency power amplifier (PA) power control for variable envelope modulation schemes is demonstrated for enhanced data rates for global system for mobile communications evolution and wide-band code division multiple access. This new technique, based upon the use of a linear PA, was extended to provide a simple, but highly effective method of PA efficiency enhancement based upon dynamic adaptive bias control. Together, the architecture allows for substantially higher efficiency levels compared with conventional linear solutions over the entire range of handset operating conditions, while avoiding the necessity for complex control loops and linearization schemes. Furthermore, it is shown that the characteristics of the J-pHEMT, when used with this architecture, can be exploited to facilitate an efficient and completely novel single-chip PA plus antenna switch to substantially reduce the RF complexity of a cellular handset.