Distributed Doherty Amplifier Phasing for Wideband Efficiency
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Solution Overview
Problem
Existing amplifiers face a tradeoff between efficiency and bandwidth, with Doherty amplifiers being inefficient for wideband applications and distributed amplifiers suffering from poor efficiency due to power matching and phasing issues.
Innovation Solution
Combining Doherty and distributed amplifier technologies by incorporating wideband phase shifters, cascaded reactively terminated single-stage distributed amplifiers, and phase delay modules to achieve high efficiency and wideband performance, with Doherty unit cells embedded within distributed amplifiers for optimal impedance matching and power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If Doherty amplifier architecture is used to improve efficiency dynamic range, then amplifier efficiency is improved, but amplifier bandwidth is limited
Solution Approach 1:
The amplifier is divided into multiple distributed stages, each operating as a separate amplification unit. This segmentation allows each stage to contribute to both efficiency and bandwidth, with the overall system achieving wideband operation through the cumulative effect of multiple narrowband stages.
Solution Approach 2:
The patent combines Doherty amplifier stages with distributed amplifier architecture, merging the efficiency benefits of Doherty operation with the bandwidth capabilities of distributed amplification. The main and auxiliary amplifiers are combined in a distributed configuration to achieve both high efficiency and wide bandwidth simultaneously.
2Adaptability or versatility
If distributed amplifier architecture is used to achieve wideband characteristics, then amplifier bandwidth is improved, but amplifier efficiency deteriorates due to power matching and phasing issues
Solution Approach 1:
The amplifier operates in different modes depending on signal level: at low power levels, the main amplifier operates efficiently while the auxiliary amplifier remains off; at high power levels, both amplifiers are active. This dynamic operation allows the system to maintain high efficiency across a wide bandwidth range.
Solution Approach 2:
The patent changes operating parameters (bias conditions, impedance transformations) across different frequency and power levels to maintain both bandwidth and efficiency. By adjusting these parameters dynamically, the amplifier achieves wideband operation without sacrificing efficiency.
3Loss of energy
If main amplifier operates in saturation during high power signal peaks, then efficiency dynamic range is increased, but bandwidth performance is compromised
Solution Approach 1:
The auxiliary amplifier is nested within the distributed amplifier structure, allowing it to be activated only when needed for high power peaks. This nested configuration enables the main amplifier to operate in saturation for efficiency while the auxiliary amplifier provides the additional power capability needed for wideband operation.
Data Source
AI summary
Doherty and distributed amplifier (DA) designs are combined to achieve, wideband amplifiers with high efficiency dynamic range. A modified Doherty amplifier includes a wideband phase shifter providing first and second outputs, a main amplifier coupled to the first output, an auxiliary amplifier coupled to the second output, and a wideband combining network combining the outputs in phase. A multi-stage DA has a main output and a termination port, and a phase delay module and transforming network allowing power at the termination port to be combined in phase with power at the main output. In one combination, one or more stages of the DA may comprise a Doherty amplifier. In another combination, a modified series-type Doherty amplifying system is achieved by cascading main and auxiliary DAs. In any combination, Doherty topology may include a bias control module.