1. Software-defined radio (SDR) is a rapidly evolving technology that takes advantage of the high programmability and low cost of digital radio systems. SDR offers the benefits of ubiquitous connectivity, reconfigurablilty, and interoperability in radios, but poses challenges in designing highly efficient, programmable hardware modules. The Radio Frequency (RF) front-end transmit path, which performs analog up-conversion, filtering and RF power amplification, is the major bottleneck in extending the programmability of SDR to the RF section. This is primarily because existing digital to analog converters (DAC) and state-of-the-art power amplifiers cannot efficiently support the modulation bandwidths and dynamic range required to implement SDR systems in low-power wireless handsets. Since the RF power amplifier (PA) consumes over 85% of the power in the SDR transmitter and is the main cause for signal distortion, it is a critical hardware component in the SDR transmitter design.   Further, programmable filters are required to handle new frequency standards with a matching network to connect the PA to the antenna.  The proposed research is aimed at the development of fundamental system-design concepts targeting the digitally programmable RF transmitter for SDR wireless handhelds. A programmable RF front end transmitter based on a FPGA-controlled parallel architecture which addresses the issue of wide-bandwidth, linearity, power efficiency and frequency agile filtering will be demonstrated in collaboration with our Connection-One partners.  The envisioned transmitter will permit handling of several modulation bandwidths while improving efficiency and meeting spectral regrowth requirements of OFDM and WCDMA, UWB, WLAN and WiMAX  over 2-6 GHz.