Wideband Doherty Amplifier Carrier-Specific Phase and Magnitude Tuning
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Solution Overview
Problem
Wideband Doherty power amplifiers face significant performance degradation due to constant magnitude and phase differences between the main and peak branches across varying frequency bands, especially when transmitting multicarrier signals over large bandwidths, as existing solutions fail to optimize these differences for each frequency band.
Innovation Solution
The method involves separately configuring the magnitude and phase differences between the main and peak branches of the Doherty amplifier for each carrier frequency, using filtering and adjustment processes to produce optimized signals for each frequency band, and then combining these signals to produce a composite output, which is upconverted and amplified to achieve improved performance across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If constant magnitude and phase differences are applied across the whole frequency band, then the device complexity is reduced, but the PA performance degrades significantly in wideband applications
Solution Approach 1:
The frequency band is segmented into multiple bands, with each band having its own optimized magnitude and phase difference settings. This allows the system to apply frequency-selective adjustments rather than constant values across the entire band, resolving the contradiction by dividing the adjustment parameters according to frequency ranges.
Solution Approach 2:
The magnitude and phase difference parameters are made dynamic and adjustable based on the operating frequency band. The system can switch between different parameter sets depending on which frequency band is currently in use, enabling optimal performance across wideband applications while maintaining manageable complexity through controlled adaptability.
2Reliability
If frequency-selective magnitude and phase adjustments are applied for each carrier frequency, then the PA performance is improved, but the device complexity increases
Solution Approach 1:
The system changes the magnitude and phase difference parameters based on the detected frequency band or carrier frequency. By implementing frequency-selective parameter adjustment, the system optimizes PA performance for each frequency band while managing complexity through systematic parameter variation rather than complete redesign for each frequency.
Data Source
AI summary
A method and transmitter for a Doherty power amplifier are provided. According to one aspect, a radio transmitter includes, for each carrier frequency, a filter, a main path and a peak path. The filter suppresses signals outside the selected frequency band to produce a filter output. The main path is configured to make a first adjustment of a magnitude and phase of the filter output to produce a main path signal. The peak path is configured to make a second adjustment of the magnitude and phase of the filter output to produce a peak path signal, a difference between the first adjustment and the second adjustment being dependent on the carrier frequency. Main path signals for each carrier frequency produce a composite main path signal. Peak path signals for each carrier frequency produce a composite peak path signal.