Doherty Amplifier Input Phase Network for Wideband Efficiency
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Solution Overview
Problem
Current Doherty amplifiers experience efficiency degradation when amplifying wideband modulated RF signals, such as 5G New Radio signals, due to limitations in maintaining high efficiency across a wide frequency band.
Innovation Solution
Incorporating phase lead and phase lag components between the RF input and either the main or auxiliary amplifiers, with specific phase shifts to ensure that the split RF signals are recombined in phase across a wider frequency band, thereby maintaining maximum output power within ±0.5dB of a target power level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional Doherty amplifier structure is used, then high efficiency at average power is achieved, but efficiency degrades when amplifying wideband modulated RF signals
Solution Approach 1:
The amplifier is segmented into main amplifier and auxiliary amplifier paths, each with independent phase control. The phase lead component is connected to the main amplifier path while the phase lag component is connected to the auxiliary amplifier path, allowing independent phase adjustment to achieve wideband constructive combination
Solution Approach 2:
The phase shift amounts are dynamically adjusted based on frequency. The phase lead component provides a first phase shift amount that varies with frequency, and the phase lag component provides a second phase shift amount that varies with frequency, enabling the amplifier to maintain high efficiency across wide frequency bands
2Adaptability or versatility
If phase lead and phase lag components are added to achieve wideband operation, then operating bandwidth is improved, but device complexity increases
Solution Approach 1:
Different phase control characteristics are applied to different parts of the circuit. The phase lead component is specifically designed with inductive reactance characteristics and is connected in the main amplifier path, while the phase lag component is designed with capacitive reactance characteristics and is connected in the auxiliary amplifier path, optimizing each section for its specific function
Solution Approach 2:
The phase control mechanism uses a composite approach combining phase lead and phase lag components with different reactance characteristics. This composite structure enables wideband phase control by leveraging the complementary properties of inductive and capacitive elements
Data Source
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AI summary
This disclosure relates generally to Doherty amplifiers. In one embodiment, a Doherty amplifier includes an RF input of the Doherty amplifier for receiving a radio frequency (RF) signal, a main amplifier (104) coupled to the RF input, and an auxiliary amplifier (106) coupled to the RF input. A phase lag component (116) connected between the RF input and one of either the main amplifier (104) or the auxiliary amplifier (106) and a phase lead component (114) connected between the RF input and another one of either the main amplifier (104) or the auxiliary amplifier (106). In some embodiments, the phase lead and phase lag components (114, 116) ensure that the split signals output from the main and auxiliary amplifiers (104, 106) are recombined in phase throughout a frequency band.