Research findings were reported from an investigation of new gallium nitride (GaN) monolithic millimeter-wave integrated circuit (MMIC) power amplifiers (PAs) targeting the highest output power and the highest efficiency for class-A operation in W-band (75–110 GHz). W-band PAs are a major component of many frequency multiplied submillimeter-wave LO signal sources. For spectrometer arrays, substantial W-band power is required due to the passive lossy frequency multipliers used to generate higher frequency signals in nonlinear Schottky diode-based LO sources. By advancing PA technology, the LO system performance can be increased with possible cost reductions compared to current GaAs PAs.
High-power, high-efficiency GaN PAs are cross-cutting and can enable more efficient local oscillator distribution systems for new astrophysics and planetary receivers and heterodyne array instruments. It can also allow for a new, electronically scannable solid-state array technology for future Earth science radar instruments and communications platforms.
This work was done by King Man Fung, Lorene A. Samoska, Pekka P. Kangaslahti, Bjorn H. Lambrigtsen, Paul F. Goldsmith, Robert H. Lin, Mary M. Soria, and Joelle T. Cooperrider of Caltech and Miroslav Micovic and Ara Kurdoghlian of HRL Laboratories for NASA’s Jet Propulsion Laboratory. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Electronics/Computers category. NPO-47364
This Brief includes a Technical Support Package (TSP).
Power Amplifier Module with 734-mW Continuous Wave Output Power
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Overview
The document outlines advancements in power amplifier technology developed by NASA's Jet Propulsion Laboratory (JPL), specifically focusing on Gallium Nitride (GaN) Monolithic Millimeter-wave Integrated Circuit (MMIC) power amplifiers. These amplifiers are designed for high-frequency applications, particularly in the W-band (75-110 GHz), and aim to enhance the performance of remote sensing instruments used in planetary science and astrophysics.
The primary objective of the research is to improve local oscillator (LO) signal sources, which are crucial for downconverting received radio frequency (RF) signals for analysis. By increasing output power and efficiency while reducing the size of components, the new GaN technology promises to simplify the architecture of spectrometer array systems.
In fiscal year 2009 (FY09), two main tasks were completed to demonstrate the capabilities of GaN power amplifiers. The first task involved characterizing two recently produced GaN PA chips from HRL Laboratories, which included designing and fabricating packaging modules and measuring their performance characteristics. The second task utilized circuit models to explore various PA designs for different applications.
The results from these tasks were significant. A record performance was achieved with a packaged GaN power amplifier module that delivered 734 mW of continuous wave output power, 10.3 dB gain, and 14.1% Power Added Efficiency (PAE) at 89 GHz. This performance indicates substantial improvements over existing GaAs PA technology, such as that used in the Herschel space telescope.
Two specific GaN PA designs were highlighted: one with a broadband capability of 76-99 GHz and an expected output power of 0.5 W for applications in planetary science, and another at 94 GHz with a 1.5 W output power for radar applications. The document emphasizes that GaN PAs can be 240% more efficient and 95% less massive than comparable GaAs PAs, leading to potential cost savings and enhanced reliability.
The implications of this research extend to various NASA programs and mission concepts, including astrophysics and Earth science missions. The advancements in GaN technology could enable new capabilities in radar and communication systems, potentially replacing GaAs PAs in suitable applications and competing with traditional tube technologies.
Overall, the document highlights the significant progress made in power amplifier technology, which is crucial for future space exploration and scientific research.
