Distributed Wideband Power Amplifier for High-Efficiency RF Output
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Solution Overview
Problem
Existing RF power amplifiers face challenges in achieving high efficiency and wide bandwidth due to their narrowband nature, which is exacerbated by the use of resonators and parasitic components, and the high transistor cost associated with vertically sliced signal amplification methods.
Innovation Solution
A power amplifier arrangement comprising multiple amplifier sections with uniform impedance transmission lines that horizontally slice the input signal into flat-topped portions, allowing for high waveform efficiency and large bandwidth operation without the need for resonators or filters, and minimizing transistor cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If resonators are used to shape waveforms for high efficiency, then waveform efficiency is improved, but bandwidth is reduced
Solution Approach 1:
The amplifier is divided into multiple amplifier sections (first, second, third sections) that are distributed along the transmission lines. Each section processes a different amplitude range of the input signal, allowing the system to achieve high efficiency across multiple operating points without requiring narrowband resonators. This segmentation enables wideband operation while maintaining efficiency.
Solution Approach 2:
The patent transitions from traditional narrowband resonant amplification to a distributed amplifier architecture where gain is achieved through the cumulative effect of multiple amplifier sections along transmission lines. This dimensional change from point-based resonant circuits to distributed continuous structures enables wideband high-efficiency operation.
2Use of energy by moving object
If vertically sliced signal amplification is used to achieve high efficiency, then waveform efficiency is improved, but transistor cost increases
Solution Approach 1:
Different amplifier sections are positioned at different locations along the transmission lines, with each section optimized for specific local conditions (amplitude ranges). The first amplifier section handles low-amplitude signals, while subsequent sections handle progressively higher amplitudes. This local optimization allows efficient use of transistors across different operating points without requiring excessive transistor power.
3Use of energy by moving object
If Doherty amplifier configuration is used for backed off operation, then efficiency at low amplitudes is improved, but bandwidth is reduced
Solution Approach 1:
The amplifier sections are dynamically activated based on the instantaneous amplitude of the input signal. At low amplitudes, only the first amplifier section is active, providing high efficiency. As the signal amplitude increases, additional sections are progressively activated. This dynamic operation allows the amplifier to maintain high efficiency across a wide bandwidth without requiring narrowband impedance-inverting circuits.
Data Source
AI summary
A power amplifier arrangement (200) for amplifying an input signal to produce an output signal comprises a plurality N of amplifier sections (212, 213), a first input transmission line (221) comprising multiple segments and a first output transmission line (231) comprising multiple segments. Each amplifier section comprises one or more first transistors (T1) distributed along the first input transmission line (221) and the first output transmission line (231). Each amplifier section is configured to amplify a portion of the input signal to produce a portion of the output signal. A portion of the input signal is one of N portions of the input signal partitioned on any one or a combination of an amplitude basis and a time basis. The output signal is produced at an end of the first output transmission line (231) by building up N potions of the output signal from each amplifier section.