Ka-Band Efficient, Linear Power Amplifiers for SATCOM Ground Terminals

ABSTRACT:The Ka-band SATCOM systems offer potential for transportable and mobile communications through the effective use of the wide bandwidths available while requiring that adequate linearity performance be maintained. In environments where size and power conservation is of high importance, power consumption and heat dissipation in the power amplifier (PA) must be minimized. However, it is widely accepted that linearity and efficiency are competing constraints. To address these challenges, MaXentric Technologies proposes a cost-effective envelope tracking Ka-band power amplifier, GETSAT (GreenAmp Envelope Tracking for SATCOM), for high efficiency satellite transmitters, capable of greater than 70W of output power over 29-31 GHz with greater than 35% efficiency. The technology supports QPSK and QAM signals, as well as others. To achieve high linearity while simultaneously maintaining high efficiency, GreenAmp envelope tracking with MaXPAL (MaXentrics PA Linearizer) will be used. Cost, size, weight, and power are of prime importance for these mobile SATCOM ground terminals. Our strategy throughout the program will improve our project prototypes on other performance parameters such as output power, operating voltage, output power, power-added-efficiency (PAE) and the response speed of the control circuitry with wideband operation. The success of our approach will depend on successful developments in wideband modulators and process integration with GaN MMICs.BENEFIT:MaXentrics proposed techniques for developing high efficiency Ka-band power amplifier with high linearity directly addresses design constraints with GreenAmps envelope tracking technology in conjunction MaXPALs real-time digital pre-distortion, a key-enabler technology. The U.S. government is interested in commercial satellite services for a variety of applications, including emergency response, remote locations, video broadcast, distance learning, and continuity of operations. The Ka-band satellite systems offer potential for transportable and mobile communications due to the wide bandwidths available and the high gain achievable with small antennas. GETSAT (GreenAmp Envelope Tracking for SATCOM) has the potential for improving the communication link performance, power, and spectrum efficiency of Wideband Global SATCOM (WGS), Warfighter Information Network-Tactical (WIN-T), and Defense Communications and Army Transmission (DCAT). Additionally, this technology can be leveraged by portable manpacks and radios carried by the warfighters so as to prolong battery usage and eliminate existing cooling systems by achieving high efficiency and linearity simultaneously. Commercial applications that benefit for these capabilities provided by GETSAT include cellular phone usage, direct-to-home television service, Internet (satellite systems can deliver pictures and video 200 times faster than a typical modem and telephone line), video conferencing, private data networks, telemedicine, content distribution, interactive games, and more.