Balanced Power Amplifier With Adjustable Load Lines for Backoff Efficiency
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Solution Overview
Problem
Conventional balanced power amplifiers have fixed load lines, leading to low efficiency at backoff power and inability to optimize performance across different power ranges, which affects the operating time of electronic devices.
Innovation Solution
An adjustable balanced power amplifier with a reflection coefficient phase variable device at the isolation port, allowing for dynamic adjustment of load lines by changing the output power ratio, coupling coefficient, or reflection coefficient phase, using components like switched capacitors and inductors or variable phase transmission lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a fixed load line is used in a balanced power amplifier, then the output power is increased by 3 dBc compared to single-channel amplifiers, but the efficiency at backoff power becomes very low
Solution Approach 1:
The patent applies dynamics by making the load line adjustable rather than fixed. The isolation port is connected to a variable device that can change the reflection coefficient phase dynamically, allowing the load line to be adapted according to different power ranges. This resolves the contradiction by enabling high efficiency at backoff power while maintaining the 3 dBc output power advantage of balanced amplifiers.
Solution Approach 2:
The patent changes the parameter of the load line from fixed to variable by introducing a variable device at the isolation port that can adjust the reflection coefficient phase. This parameter change allows the system to optimize efficiency across different power ranges while maintaining the power combining benefit, directly addressing the efficiency problem at backoff power.
2Device complexity
If a fixed load line is used in a balanced power amplifier, then the amplifier structure remains simple, but the ability to optimize efficiency across different power ranges is lost
Solution Approach 1:
The patent introduces dynamic adjustability to the amplifier structure by connecting a variable device to the isolation port. This allows the load line to be changed according to different power ranges, providing the adaptability needed to optimize efficiency while adding minimal complexity to the overall amplifier structure.
Solution Approach 2:
The variable device at the isolation port serves multiple functions: it maintains the balanced amplifier's inherent power combining capability while simultaneously enabling load line adjustment for efficiency optimization across different power ranges. This multi-functionality addresses the adaptability issue without proportionally increasing device complexity.
3Loss of energy
If different load lines are switched in different power ranges, then efficiency in different power ranges can be optimized, but the device complexity increases
Solution Approach 1:
The patent implements a dynamic load line adjustment mechanism through a variable device connected to the isolation port. This single variable component enables load line switching across different power ranges without requiring multiple separate amplifier paths, thus optimizing efficiency while controlling the increase in device complexity.
Solution Approach 2:
The variable device at the isolation port acts as an intermediary that enables load line adjustment without directly modifying the main amplifier paths. This intermediary approach allows efficiency optimization across different power ranges while adding minimal complexity, as the variable device mediates the load line change without requiring complex reconfiguration of the power combining structure.
Data Source
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AI summary
Disclosed in the present invention are an adjustable balanced power amplifier, a radiofrequency front-end module, and a communication terminal. The adjustable balanced power amplifier at least comprises an input power divider, a primary power amplifier, a secondary power amplifier, and an output power combiner. The input power divider divides an input radiofrequency signal into two parts which are respectively amplified by the primary power amplifier and the secondary power amplifier and then are output to the output power combiner. The output power combiner combines the two parts of the signal and outputs same to the outside, an isolation end of the output power combiner being a device having a variable reflection coefficient phase. The adjustable balanced power amplifier can obtain the power boost characteristic the same as that of a conventional balanced power amplifier. In addition, changing the reflection coefficient phase of the isolation end may obtain the optimal efficiency in different power ranges.