Wideband Doherty-Distributed Amplifier Phase Combining
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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 topology 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 Doherty unit cells, each operating at a different frequency band. These unit cells are connected in parallel to handle different frequency ranges simultaneously, allowing the system to achieve both high efficiency in each band and wide overall bandwidth coverage.
Solution Approach 2:
Each Doherty unit cell is designed to be multi-functional, capable of operating efficiently across multiple frequency bands through broadband impedance matching networks. This allows a single unit cell to serve multiple frequency ranges, reducing the need for separate amplifiers for each band while maintaining high efficiency.
2Adaptability or versatility
If distributed amplifier topology 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 patent merges the distributed amplifier topology with Doherty amplifier principles by combining multiple amplifying elements in a distributed arrangement while incorporating Doherty-style combining networks. This integration allows the system to achieve wideband operation through distributed elements while maintaining high efficiency through proper power combining and impedance matching.
Solution Approach 2:
Broadband impedance matching networks are introduced as intermediary components between the distributed amplifying elements and the output combining network. These matching networks serve as mediators that transform the output impedances of individual elements to ensure optimal power transfer and minimize reflections across wide bandwidth, thereby improving efficiency without compromising bandwidth.
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.