High-Efficiency Amplifiers with Discretely Variable Output Power

Award Information
Agency:
Department of Defense
Branch
Air Force
Amount:
$737,988.00
Award Year:
2004
Program:
SBIR
Phase:
Phase II
Contract:
F19628-03-C-0028
Award Id:
57679
Agency Tracking Number:
021SN-0655
Solicitation Year:
n/a
Solicitation Topic Code:
n/a
Solicitation Number:
n/a
Small Business Information
GREEN MOUNTAIN RADIO RESEARCH CO. (Currently Green Mountain Radio Research Company)
50 Vermont Avenue, Colchester, VT, 05446
Hubzone Owned:
N
Minority Owned:
N
Woman Owned:
N
Duns:
057688624
Principal Investigator:
Frederick Raab
(802) 655-9670
f.raab@ieee.org
Business Contact:
Frederick Raab
(802) 655-9670
f.raab@ieee.org
Research Institution:
n/a
Abstract
Space-based radar (SBR) requires multiple RF power amplifiers (PAs) to drive phased-arrays antennas. Control of the beam direction requires an amplitude range of 22 dB, and coupling between elements results in load impedances with significant mismatch. Both factors make conventional linear RF PAs very inefficient. The proposed approach employs a high-efficiency RF PA, class-S modulator, and electronically tuned matching network. The class-EF RF PA provides the best combination of efficiency and power output. Wide-bandgap transistors (e.g., SiC or GaN) provide significant output power with reasonable load impedances. The class-S modulator controls signal amplitude, allowing the RF PA to remain saturated for maximum efficiency. A digital signal processor removes amplitude variations due to heating of the transistors. The electronically tuned matching network adapts to impedance changes associated with changes in beam direction. The average efficiency is nearly triple that of a conventional PA. The corresponding reduction in dc-input power in turn produces significant savings in the cost of the satellite power system. The proposed Phase-II program is an experimental evaluation of technologies, culminating in a prototype system.

* information listed above is at the time of submission.

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