David W. Cripe

Development of High-Efficiency X-Band Outphasing Transmitter

We describe an advanced X-band outphasing power amplifier as a promising solution to provide high power output and wide modulation bandwidth for next-generation RF digital communication. Our proposed PA system consists of a high efficiency X-band GaN HEMT based Class-E outphasing PA MMIC.

High power, high efficiency, wide bandwidth amplification using Optically Sourced Isolated Switch Elements

A novel RF/Microwave amplifier is described which simultaneously provides high power and efficiency over four decades of bandwidth and with a size and weight smaller than any existing technology. The amplifier uses a voltage-mode Class-D configuration with high and low side stacked switches. Timing for the switches is provided by a 10 Gb/s optical link operating at a wavelength of 1310 nm. DC power for the switch drivers is provided by a second optical link at 808 nm. By using only optical link connections to the switch elements complete electrical isolation to each element is realized. Simulation results show output powers greater that 150 W with drain efficiencies of at least 55% at bandwidths up to 2 GHz. A circuit has been fabricated that validates the basic amplifier concept and demonstrates initial capabilities.