Doherty Amplifier Phase Segmentation
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Solution Overview
Problem
Existing Doherty amplifiers have limited bandwidth and are sensitive to noise, leading to performance degradation and oscillation risks, especially at high reference levels, which affects their efficiency and electromagnetic compatibility (EMC).
Innovation Solution
A Doherty amplifier arrangement with a signal splitter that phases input signals 90°, 180°, and 270° apart, combined using a lumped LCLC power combiner, allowing for differential amplifiers and a differential antenna, reducing noise sensitivity and enabling load modulation over a wide frequency band with improved adjacent channel power ratio (ACPR) and low EMC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional Doherty amplifier architecture is used, then amplification efficiency is improved, but bandwidth is limited and noise sensitivity increases
Solution Approach 1:
The amplifier is divided into four parallel amplifier stages instead of the traditional two stages, with each stage receiving signal components with different phase shifts (0°, 90°, 180°, 270°). This segmentation allows broader bandwidth operation and reduced noise sensitivity while maintaining efficiency through the combination of all four stages at the output.
2Power
If reference level is increased to improve performance, then amplification capability is enhanced, but oscillation risk and noise sensitivity increase
Solution Approach 1:
The four amplifier stages are configured with asymmetric phase relationships (0°, 90°, 180°, 270°) rather than symmetric configurations. This asymmetric phase distribution, combined with the lumped LCLC power combiner, allows the system to handle high reference levels effectively while reducing noise sensitivity and preventing oscillation through the distributed phase architecture.
3Adaptability or versatility
If bandwidth is increased to cover wide frequency range, then frequency coverage is improved, but gain-versus-power characteristic smoothness may degrade
Solution Approach 1:
The invention extends the traditional two-stage amplifier architecture into a four-dimensional phase space by introducing four amplifier stages with phase shifts of 0°, 90°, 180°, and 270°. This dimensional expansion in the phase domain enables wide frequency bandwidth while maintaining smooth gain-versus-power characteristics through the coordinated operation of all four stages across the frequency range.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a Doherty amplifier with increased bandwidth, reduced noise sensitivity, and improved performance across a wide frequency range, enhancing efficiency and EMC while maintaining smooth gain-versus-power characteristics.
Implementation Method 1
a signal splitter for phasing an input signal into a first signal component, a second signal component that is substantially 90° apart in phase in relation to the first signal component, a third signal component that is substantially 180° apart in phase in relation to the first signal component and a fourth signal component
Implementation Method 2
wherein the signal combiner comprises a first inductor with a first inductor terminal and a second inductor terminal, a first capacitor with a first capacitor terminal and a second capacitor terminal
Implementation Method 3
a first capacitor with a first capacitor terminal and a second capacitor terminal, a second inductor with a third inductor terminal and a fourth inductor terminal, a second capacitor with a third capacitor terminal and a fourth capacitor terminal
Data Source
AI summary
A Doherty amplifier (1) is described which comprises an input terminal (102) for receiving an input signal (101) and an output terminal (103) for providing an amplified signal (104) of the input signal (101). The Doherty amplifier (1) comprises a carrier amplifier stage (300) with a first signal input (311) and a second signal input (312) and a peak amplifier stage (400) with a third signal input (411) and a fourth signal input (421). A signal splitter (200) splits and delays the input signal (101) so that the signal at the first signal input (311) and the signal at the second signal input (321) are 180° apart in phase and that the signal at the third signal input (421) and the fourth signal input (431) are also 180° apart in phase.