GaN Technology for GPS L-band Space Power Amplification

ABSTRACT: Research Proposed: Research is proposed to investigate the feasibility of an innovative push-pull configured GaN power amplifier design for space GPS navigation using a novel harmonic transformer to achieve a radiation tolerant, increased bandwidth, 400W output power and 60% power-added efficiency (PAE). Problem Statement: Power amplifiers are notoriously inefficient when running linear enough to support communications such as GPS. A power amplifier will become more efficient as the amplifier approaches saturation; however, this makes the amplifier less linear and distortion causes errors. Backing off an amplifier increases linearity but decreases efficiency and requires more size, weight and power. Recent research shows that Class E or F designs can achieve much higher efficiencies, although these methods tend to be more narrowband and non-linear at higher efficiencies. Using a true Class B Push-Pull design with an improved harmonic transformer, much lower distortion and harmonic levels can be achieved while maintaining high power and efficiency. Plan/Process Outline: The Push-Pull amplifier will be designed in detail, then modeled and optimized to obtain an accurate view of system performance. This model will be simulated and validated against the requirements to determine feasibility. 400W output power and 60% PAE will be required for feasibility. BENEFIT: If this innovation is successful, today"s high energy consumption power amplifiers can be replaced with this new design which will provide dramatically higher efficiency at lower size, weight and power while still meeting performance requirements. This will be a revolutionary change that will result in power amplifier manufacturers adopting the approach, leading to systematic changes in how amplification is approached in both communications and electronic warfare.